PET imaging of osteosarcoma in dogs using a fluorine-18-labeled monoclonal antibody fab fragment

Energy Technology Data Exchange (ETDEWEB)

Page, R.L.; Garg, P.K.; Gard, S. [North Carolina State Univ., Raleigh, NC (United States)]|[Duke Univ. Medical Center, Durham, NC (United States)]|[North Carolina and Norke Radium Hospital, Oslo (Norway)] [and others

1994-09-01

Four dogs with histologically confirmed osteogenic sarcoma were studied with PET following intravenous injection of the {sup 18}F-labeled Fab fragment of TP-3, a monoclonal antibody specific for human and canine osteosarcomas. The antibody fragment was labeled using the N-succinimidyl (8-(4{prime}-({sup 18}F)fluorobenzyl)amino)suberate acylation agent. Blood clearance of activity was biphasic in all dogs but half-times were variable (T{sub 1/2{beta}} = 2-13 hr). Catabolism of labeled Fab was reflected by the decrease in protein-associated activity in serum from more than 90% at 1 min to 60%-80% at 4 hr. PET images demonstrated increased accumulation of {sup 18}F at the primary tumor site relative to normal contralateral bone in one dog as early as 15 min after injection. Biopsies obtained after euthanasia indicated higher uptake at the edges of the tumor as observed on the PET scans. Tumor uptake was 1-3 x 10{sup -3}% injected dose/g, a level similar to that reported for other Fab fragments in human tumors. In the three dogs with metastatic disease, early PET images reflected activity in the blood pool but later uptake was observed in suspected metastatic sites. These results, although preliminary, suggest that PET imaging of {sup 18}F-labeled antibody fragments is feasible and that dogs with spontaneous tumors could be a valuable model for preclinical research with radioimmunoconjugates. 34 refs., 6 figs., 2 tabs.

PET imaging of osteosarcoma in dogs using a fluorine-18-labeled monoclonal antibody fab fragment

International Nuclear Information System (INIS)

Page, R.L.; Garg, P.K.; Gard, S.

1994-01-01

Four dogs with histologically confirmed osteogenic sarcoma were studied with PET following intravenous injection of the 18 F-labeled Fab fragment of TP-3, a monoclonal antibody specific for human and canine osteosarcomas. The antibody fragment was labeled using the N-succinimidyl (8-(4'-( 18 F)fluorobenzyl)amino)suberate acylation agent. Blood clearance of activity was biphasic in all dogs but half-times were variable (T 1/2β = 2-13 hr). Catabolism of labeled Fab was reflected by the decrease in protein-associated activity in serum from more than 90% at 1 min to 60%-80% at 4 hr. PET images demonstrated increased accumulation of 18 F at the primary tumor site relative to normal contralateral bone in one dog as early as 15 min after injection. Biopsies obtained after euthanasia indicated higher uptake at the edges of the tumor as observed on the PET scans. Tumor uptake was 1-3 x 10 -3 % injected dose/g, a level similar to that reported for other Fab fragments in human tumors. In the three dogs with metastatic disease, early PET images reflected activity in the blood pool but later uptake was observed in suspected metastatic sites. These results, although preliminary, suggest that PET imaging of 18 F-labeled antibody fragments is feasible and that dogs with spontaneous tumors could be a valuable model for preclinical research with radioimmunoconjugates. 34 refs., 6 figs., 2 tabs

Detection of experimental myocarditis by monoclonal antimyosin antibody, Fab fragment

Energy Technology Data Exchange (ETDEWEB)

Rezkalla, S.; Kloner, R.A.; Khaw, B.A.; Haber, E.; Fallon, J.T.; Smith, F.E.; Khatib, R.

1989-02-01

The purpose of this study was to determine whether monoclonal antimyosin Fab (antigen binding fragment) was capable of labeling hearts with experimental coxsackievirus myocarditis, and to determine whether Fab could be used for detecting myocardial damage in either early or chronic phases of the disease. Sixty-five, 3-week-old cesarean-derived 1 (CD 1) mice were divided into two groups: group I (noninfected animals) and group II (infected with coxsackievirus B3). Mice from each group were killed on days 7, 17, 30, or 90 of infection. Forty-eight hours before killing, mice were injected with monoclonal I-125 antimyosin, Fab (25 microCi/injection) and radioactivity was counted in the heart. Selected heart sections were also examined by autoradiography. Heart radioactivity, count/m/mg (m +/- SEM) on days 7, 17, 30, and 90 of infection was 10.8 +/- 1.7, 21.3 +/- 1.1, 11.2 +/- 3.4, and 12.4 +/- 1.5 for group I, versus 36.7 +/- 8.0 (p less than 0.01), 50.0 +/- 4.5 (p less than 0.001), 33.4 +/- 16.1 (p = NS), and 40.6 +/- 8.5 (p less than 0.01) for group II, respectively. Autoradiography revealed focal uptake within areas of necrotic myocardium. We conclude that I125 Fab may be useful in detecting myocardial damage in the experimental model of murine myocarditis up to day 90 of infection.

Detection of experimental myocarditis by monoclonal antimyosin antibody, Fab fragment

International Nuclear Information System (INIS)

Rezkalla, S.; Kloner, R.A.; Khaw, B.A.; Haber, E.; Fallon, J.T.; Smith, F.E.; Khatib, R.

1989-01-01

The purpose of this study was to determine whether monoclonal antimyosin Fab (antigen binding fragment) was capable of labeling hearts with experimental coxsackievirus myocarditis, and to determine whether Fab could be used for detecting myocardial damage in either early or chronic phases of the disease. Sixty-five, 3-week-old cesarean-derived 1 (CD 1) mice were divided into two groups: group I (noninfected animals) and group II (infected with coxsackievirus B3). Mice from each group were killed on days 7, 17, 30, or 90 of infection. Forty-eight hours before killing, mice were injected with monoclonal I-125 antimyosin, Fab (25 microCi/injection) and radioactivity was counted in the heart. Selected heart sections were also examined by autoradiography. Heart radioactivity, count/m/mg (m +/- SEM) on days 7, 17, 30, and 90 of infection was 10.8 +/- 1.7, 21.3 +/- 1.1, 11.2 +/- 3.4, and 12.4 +/- 1.5 for group I, versus 36.7 +/- 8.0 (p less than 0.01), 50.0 +/- 4.5 (p less than 0.001), 33.4 +/- 16.1 (p = NS), and 40.6 +/- 8.5 (p less than 0.01) for group II, respectively. Autoradiography revealed focal uptake within areas of necrotic myocardium. We conclude that I125 Fab may be useful in detecting myocardial damage in the experimental model of murine myocarditis up to day 90 of infection

The binding parameters of radiolabelled monoclonal F (ab')2 and Fab' fragments relative to immunoglobulin G in reactions with surface-bound antigens

International Nuclear Information System (INIS)

Fjeld, J.G.; Nustad, K.; Michaelsen, T.E.

1992-01-01

The binding parameters of iodine-125-labelled intact monoclonal immunoglobulin G (IgG), F(ab') 2 and Fab' fragments were compared. The study was carried out with the two monoclonal antibodies (MoAbs) K13 and K16 specific for human Ig light chains κ and λ, respectively. When testing the 125 I-MoAbs against monodisperse polymer particles coated with the specific antigens, the K a for the F(ab') 2 fragments were similar to that for IgG, while the K a for the Fab' fragments were reduced to 10%-20% of that for IgG. The number N of effective target sites revealed with Fab' was higher than with F(ab') and IgG, presumably because less surface area is occupied by the small Fab' molecules. The immunoreactive fraction F ranged according to IgG>F(ab') 2 >Fab'. The explanation of the moderate difference between the K a of the monoclonal Fab' and the divalent IgG and F(ab') 2 was that the divalent molecules were not divalently attached to the particles. When testing the same antibody preparations against humanlymphoma cells producing Ig with light chains κ or λ, the binding results were less reliable than when particles were utilised, presumably due to antigen shedding. Different MoAbs vary in their loss of immunoreactivity due to enzymatic degradation and the radiolabelling procedure. The preparation of the radiolabelled fragments should therefore be optimized for each MoAb, and evaluation is necessary before injection. Artificial targets with a low leakage of antigen, like the monodisperse polymer particles here applied, are recommended for the in vitro evaluation of the immunoreactivity of labelled MoAb preparations. (orig.)

Effect of acetylation on monoclonal antibody ZCE-025 Fab': Distribution in normal and tumor-bearing mice

International Nuclear Information System (INIS)

Tarburton, J.P.; Halpern, S.E.; Hagan, P.L.; Sudora, E.; Chen, A.; Fridman, D.M.; Pfaff, A.E.

1990-01-01

Studies were performed to determine in vitro and in vivo effects of acetylation on Fab' fragments of ZCE-025, a monoclonal anti-CEA antibody. Isoelectric focusing revealed a drop in isoelectric point of 1.7 pI units following acetylation. Biodistribution studies of acetylated and nonacetylated [111In]Fab' were performed in normal BALB/c mice and in nude mice bearing the T-380 CEA-producing human colon tumor. The acetylated fragments remained in the vascular compartment longer and had significantly diminished renal uptake of 111In compared to controls. While acetylation itself effected a 50% drop in immunoreactivity, tumor uptake of the acetylated and nonacetylated 111In-labeled Fab' fragments was comparable, with the exception of one data point, through 72 h

Construction and expression of a functional monoclonal antibody SZ-51 specific for GMP-140 chimeric fab fragment in Escherichia coli

International Nuclear Information System (INIS)

Gu Jianming; Zhang Xiaomin; Xia Lijun; Wan Haiying; Liu Yue; Li Peixia; Ruan Changgeng

1996-04-01

The variable region cDNAs of a monoclonal antibody SZ-51 specific for α-granule membrane protein (GMP-140) on the surface of activated human platelets were spliced with the constant region cDNA of the heavy chain CH1 and light chain k of human Ig G by means of the gene recombination techniques. The above recombinant gene was amplified by the polymerase chain reaction (PCR). The expression vector of phage plasmid pHEN1 SZ-51 Fab/Hu was constructed. The pHEN1-51 Fab/Hu was introduced into non-suppressor E. coli HB2151. The amount of expression of SZ-51 chimeric Fab/Hu measured by quantitative ELISA was about 500 μg/L. Western blot demonstrated that the SZ-51 chimeric Fab fragment could specifically bind to GMP-140. (2 figs.)

Feasibility study of the Fab fragment of a monoclonal antibody against tissue factor as a diagnostic tool.

Science.gov (United States)

Tsumura, Ryo; Sato, Ryuta; Furuya, Fumiaki; Koga, Yoshikatsu; Yamamoto, Yoshiyuki; Fujiwara, Yuki; Yasunaga, Masahiro; Matsumura, Yasuhiro

2015-12-01

Tissue factor (TF) is expressed strongly in various types of cancer, especially cancers that are often refractory to treatment, such as pancreatic cancer. In this study, we compared the differences in the biophysical and pharmacological properties of whole IgG and the Fab fragment of anti-human TF monoclonal antibody (1849 antibodies), in order to determine their suitability for application in the diagnosis and treatment of cancers. In the biophysical examination, we investigated the characteristics of 1849-whole IgG and 1849-Fab by SPR sensing and confocal fluorescence microscopy analysis using recombinant human TF antigen and TF-overexpressing human pancreatic cancer cell line, BxPC3, respectively. After conjugation with Alexa-Flour-647, in vivo imaging was conducted in mice bearing BxPC3 xenograft tumors. Furthermore, the distribution of the conjugates in tumors and major organs was evaluated by ex vivo study. The in vitro experiments showed that 1849 antibodies had high affinity against TF antigen. In addition, 1849-Fab showed a faster dissociation rate from the antigen than 1849-whole IgG. In mice, 1849-Fab-Alexa-Flour-647 showed rapid renal clearance and faster tumor accumulation, achieving a high contrast signal over nearby normal tissues in the early phase and enhanced tumor penetration after administration. On the other hand, 1849-whole IgG-Alexa-Flour-647 showed slow clearance from the blood and sustained high tumor accumulation. These results suggest that 1849-Fab may be a useful tool for pancreatic cancer diagnosis.

Characterization of Human Colorectal Cancer MDR1/P-gp Fab Antibody

Directory of Open Access Journals (Sweden)

Xuemei Zhang

2013-01-01

Full Text Available In this study, the peptide sized 21 kDa covering P-gp transmembrane region was first prepared for generating a novel mouse monoclonal antibody Fab fragment with biological activity against multiple drug resistance protein P-gp21 by phage display technology. Phage-displayed antibody library prepared from mice spleen tissues was selected against the recombinant protein P-gp21 with five rounds of panning. A number of clones expressing Fab bound to P-gp21, showing neutralized activity in vitro, were isolated and screened by enzyme-linked immunosorbent assay based on its recognition properties to P-gp21 and human colorectal cancer tissue homogenate, resulting in identification of an optimal recombinant Fab clone (Number 29. Further characterization by recloning number 29 into an expression vector showed significant induction of the Fab antibody in the clone number 29 by Isopropyl β-D-1-thiogalactopyranoside (IPTG. After purified by HiTrap Protein L, the specificity of the Fab antibody to P-gp21 was also confirmed. Not only was the targeted region of this monoclonal Fab antibody identified as a 16-peptide epitope (ALKDKKELEGSGKIAT comprising residues 883–898 within the transmembrane (TM domain of human P-gp, but also the binding ability with it was verified. The clinical implication of our results for development of personalized therapy of colorectal cancer will be further studied.

Imaging Potential Evaluation of Fab Derived from the Anti-EGFRvIII Monoclonal Antibody 4G1.

Science.gov (United States)

Jing, Shen; He, Yujia; He, Yanqiong; Wang, Liang; Jia, Jianhua; Shan, Xiaomin; Liu, Shuang; Tang, Min; Peng, Zhiping; Liu, Xujie

2018-05-31

As one of the most crucial epidermal growth factor receptor (EGFR) variants, EGFRvIII can be detected in various tumors but rarely in normal tissues, making it an ideal target for prognosis, diagnosis or immune therapy. The recently developed anti-EGFRvIII monoclonal antibody (mAb), 4G1, has been validated as a promising molecular probe to detect EGFRvIII expression in tumors by single-photon emission computed tomography/computed tomography imaging. To overcome shortcomings associated with the whole antibody, including long-term retention, circulation and enhanced permeability and retention effects, the Fab fragment of 4G1 (Fab-4G1) was generated, labeled with 131 I and evaluated in vitro and in vivo to test its potential application in molecular imaging. Whole mAb 4G1 was first digested by immobilized ficin and then purified through a protein A column to generate the Fab fragment, Fab-4G1. Next, SDS-PAGE, Western blot, indirect fluorescence assay, flow cytometry and enzyme-linked immunosorbent assay were performed to verify molecular weight, specificity and affinity of Fab-4G1. Finally, biodistribution planar gamma imaging was performed by injection of 131 I-labeled Fab-4G1 into xenografted EGFRvIII-overexpressed tumors in nude mice. Parallel studies were also performed with intact 4G1. The molecular weight of Fab was determined to be 35-40 kDa by SDS-PAGE. In vitro tests confirmed both intact 4G1 and Fab-4G1 specifically bound EGFRvIII but not wild-type EGFR, and Fab-4G1 showed decreased affinity. Compared to 131 I-4G1, biodistribution studies showed lower tumor uptake of 131 I-Fab-4G1 at all time points, but much faster elimination in all normal organs. As for planar gamma imaging, 131 I-Fab-4G1 and 31 I-4G1 showed similar imaging effect at 2 h after injection of tracer, while 131 I-Fab-4G1 was eliminated more quickly with time, suggesting radiolabeled Fab-4G1 could be potentially used for imaging of EGFRvIII-positive tumors at early time points. Radiolabeled

Effect of polyethylene glycol conjugation on conformational and colloidal stability of a monoclonal antibody antigen-binding fragment (Fab').

Science.gov (United States)

Roque, Cristopher; Sheung, Anthony; Rahman, Nausheen; Ausar, S Fernando

2015-02-02

We have investigated the effects of site specific "hinge" polyethylene glycol conjugation (PEGylation) on thermal, pH, and colloidal stability of a monoclonal antibody antigen-binding fragment (Fab') using a variety of biophysical techniques. The results obtained by circular dichroism (CD), ultraviolet (UV) absorbance, and fluorescence spectroscopy suggested that the physical stability of the Fab' is maximized at pH 6-7 with no apparent differences due to PEGylation. Temperature-induced aggregation experiments revealed that PEGylation was able to increase the transition temperature, as well as prevent the formation of visible and subvisible aggregates. Statistical comparison of the three-index empirical phase diagram (EPD) revealed significant differences in thermal and pH stability signatures between Fab' and PEG-Fab'. Upon mechanical stress, micro-flow imaging (MFI) and measurement of the optical density at 360 nm showed that the PEG-Fab' had significantly higher resistance to surface-induced aggregation compared to the Fab'. Analysis of the interaction parameter, kD, indicated repulsive intermolecular forces for PEG-Fab' and attractive forces for Fab'. In conclusion, PEGylation appears to protect Fab' against thermal and mechanical stress-induced aggregation, likely due to a steric hindrance mechanism.

Immunoscintigraphy of adenocarcinomas by means of 111In-labelled F(ab')2 fragments of anti-CEA monoclonal antibody F023C5

International Nuclear Information System (INIS)

Riva, P.; Paganelli, G.; Callegaro, L.

1988-01-01

F(ab') 2 fragments of F023C5, an anti-CEA monoclonal antibody, were conjugated to diethylenetriamine pentaacetic acid (DTPA) and converted into a ready to use reagent for instant 111 In-labelling. The resulting 111 In radiopharmaceutical was administered intravenously and tested for its ability to image (at 48-72 h after administration) 31 primary and 85 metastatic carcinoma lesions in 70 adenocarcinoma patients (26 gastrointestinal, 18 breast and 26 lung tumour patients) whose serum CEA was elevated in 43 cases and normal in the other 27. (author)

Targeting human prostate cancer with In-111-labeled D2B IgG, F(ab ')(2) and Fab fragments in nude mice with PSMA-expressing xenografts

NARCIS (Netherlands)

Lutje, Susanne; van Rij, Catharina M.; Franssen, Gerben M.; Fracasso, Giulio; Helfrich, Wijnand; Eek, Annemarie; Oyen, Wim J.; Colombatti, Marco; Boerman, Otto C.

2014-01-01

D2B is a new monoclonal antibody directed against an extracellular domain of prostate-specific membrane antigen (PSMA), which is overexpressed in prostate cancer. The potential of D2B IgG, and F(ab)(2) and Fab fragments of this antibody for targeting prostate cancer was determined in mice bearing

Targeting human prostate cancer with (111) In-labeled D2B IgG, F(ab')2 and Fab fragments in nude mice with PSMA-expressing xenografts

NARCIS (Netherlands)

Lutje, S.; Rij, C.M. van; Franssen, G.M.; Fracasso, G.; Helfrich, W.; Eek, A.; Oyen, W.J.G.; Colombatti, M.; Boerman, O.C.

2015-01-01

D2B is a new monoclonal antibody directed against an extracellular domain of prostate-specific membrane antigen (PSMA), which is overexpressed in prostate cancer. The potential of D2B IgG, and F(ab')2 and Fab fragments of this antibody for targeting prostate cancer was determined in mice bearing

Radioimmunoimaging of experimental gliomas using radiolabelled monoclonal antibodies

International Nuclear Information System (INIS)

Glaessner, H.

1986-01-01

The biodistribution and tumour uptake of radiolabelled (131 I) glioma-seeking monoclonal antibodies (14 AC1) and their F(ab') 2 fragments were investigated in nude mice having received glioma transplants. Radioimmunoimaging by external scintigraphy at 48 and 96 hours pointed to a superior tumour localisation by the fragments that was clearly related to the dose. Wholebody determinations of the biokinetic behaviour led to the following results: Faster clearance anc more ready elimination from the blood pool for the fragments, preferential uptake in the tumour; intact antibodies; binding in the liver, spleen and lungs. The study confirmed the value of fragments of monoclonal antibodies in the diagnosis of tumours and pointed to the possibility of using intact monoclonal antibodies as carriers of radioisotopes and cytotoxic drugs within the scope of therapeutic programmes. (TRV) [de

Recombinant Human Respiratory Syncytial Virus (RSV) Monoclonal Antibody Fab is Effective Therapeutically when Introduced Directly into the Lungs of RSV-Infected Mice

Science.gov (United States)

Crowe, James E., Jr.; Murphy, Brian R.; Chanock, Robert M.; Williamson, R. Anthony; Barbas, Carlos F., III; Burton, Dennis R.

1994-02-01

Previously, recombinant human respiratory syncytial virus (RSV) monoclonal antibody Fabs were generated by antigen selection from random combinatorial libraries displayed at the tip of filamentous phage. Two such Fabs, which exhibited high binding affinity for RSV F glycoprotein (a major protective antigen), were evaluated for therapeutic efficacy in infected mice just before or at the time of peak virus replication in the lungs. Fab 19, which neutralized RSV infectivity with high efficiency in tissue culture, was effective therapeutically when delivered directly into the lungs by intranasal instillation under anesthesia. In contrast, RSV Fab 126, which failed to neutralize virus in cell culture, did not exhibit a therapeutic effect under these conditions. The amount of Fab 19 required to effect a 5000- to 12,000-fold reduction in titer of RSV in the lungs within 24 hr was rather small. In four separate experiments, a single instillation of 12.9-50 μg of RSV Fab 19 was sufficient to achieve such a reduction in pulmonary virus in a 25g mouse. The use of Fabs instead of the whole immunoglobulin molecules from which they are derived reduced the protein content of a therapeutic dose. This is important because the protein load that can be delivered effectively into the lungs is limited. The therapeutic effect of a single treatment with Fab 19 was not sustained, so that a rebound in pulmonary virus titer occurred on the 2nd day after treatment. This rebound in pulmonary RSV titer could be prevented by treating infected mice with a single dose of Fab 19 daily for 3 days. These observations suggest that human monoclonal Fabs grown in Escherichia coli may prove useful in the treatment of serious RSV disease as well as diseases caused by other viruses where replication in vivo is limited primarily to the lumenal lining of the respiratory tract.

Fab is the most efficient format to express functional antibodies by yeast surface display.

Science.gov (United States)

Sivelle, Coline; Sierocki, Raphaël; Ferreira-Pinto, Kelly; Simon, Stéphanie; Maillere, Bernard; Nozach, Hervé

2018-04-30

Multiple formats are available for engineering of monoclonal antibodies (mAbs) by yeast surface display, but they do not all lead to efficient expression of functional molecules. We therefore expressed four anti-tumor necrosis factor and two anti-IpaD mAbs as single-chain variable fragment (scFv), antigen-binding fragment (Fab) or single-chain Fabs and compared their expression levels and antigen-binding efficiency. Although the scFv and scFab formats are widely used in the literature, 2 of 6 antibodies were either not or weakly expressed. In contrast, all 6 antibodies expressed as Fab revealed strong binding and high affinity, comparable to that of the soluble form. We also demonstrated that the variations in expression did not affect Fab functionality and were due to variations in light chain display and not to misfolded dimers. Our results suggest that Fab is the most versatile format for the engineering of mAbs.

Generation and selection of naïve Fab library for parasitic antigen: Anti-BmSXP antibodies for lymphatic filariasis.

Science.gov (United States)

Omar, Noorsharmimi; Hamidon, Nurul Hamizah; Yunus, Muhammad Hafiznur; Noordin, Rahmah; Choong, Yee Siew; Lim, Theam Soon

2018-05-01

Phage display has been applied successfully as a tool for the generation of monoclonal antibodies (mAbs). Naive antibody libraries are unique as they are able to overcome several limitations associated with conventional mAb generation methods like the hybridoma technology. Here, we performed an in vitro selection and generation of Fab antibodies against Brugia malayi SXP protein (BmSXP), a recombinant antigen for the detection of lymphatic filariasis. We developed a naïve multi ethnic Fab antibody library with an estimated diversity of 2.99 × 10 9 . The antibody library was used to screen for mAbs against BmSXP recombinant antigen. Soluble monoclonal Fab antibodies against BmSXP were successfully isolated from the naïve library. The Fab antibodies obtained were expressed and analyzed to show its binding capability. The diversity obtained from a pool of donors from various ethnic groups allowed for a diverse antibody library to be generated. The mAbs obtained were also functional in soluble form, which makes it useful for further downstream applications. We believe that the Fab mAbs are valuable for further studies and could also contribute to improvements in the diagnosis of filariasis. © 2017 International Union of Biochemistry and Molecular Biology, Inc.

Modified cytokeratins expressed on the surface of carcinoma cells undergo endocytosis upon binding of human monoclonal antibody and its recombinant Fab fragment

DEFF Research Database (Denmark)

Ditzel, H J; Garrigues, U; Andersen, C B

1997-01-01

display selection and the human Fab fragment was expressed in bacteria. Analysis by confocal laser scanning microscopy demonstrated that COU-1 bound in a uniform punctate pattern to the surface of viable carcinoma cells stained at 4 degrees C, and binding increased significantly when cells were cultured...... was significantly reduced. Similar results were obtained using intact IgM COU-1 and the recombinant Fab fragment. Immunohistological studies indicated that COU-1, in contrast to murine monoclonal antibodies against normal cytokeratin 8 and 18, could differentiate between malignant and normal colon epithelia...

Radiolocalization of bovine lymphosarcoma cells in athymic mice, using a monoclonal antibody against tumor-associated antigens

International Nuclear Information System (INIS)

Aida, Y.; Ochiai, K.; Ito, K.; Onuma, M.; Fujimori, F.; Fujimoto, Y.; Izawa, H.

1987-01-01

Mouse monoclonal antibody c 143 was purified and F(ab')2 fragments were generated by pepsin digestion and then radiolabeled with 125 I. The 125 I-labeled c 143 F(ab')2 fragments were injected into athymic mice bearing bovine lymphoid tumor cells. The fragments became preferentially localized in tumor tissues, but not in normal tissues, as determined by differential counting of tissue radioactivity. The fragments became localized specifically in those tumors that were reactive with c 143 in vitro, but did not become localized in unrelated tumors. Localization of labeled F(ab')2 fragments of a monoclonal antibody of the same isotype directed against Taka virus (a variant of Newcastle disease virus) was not observed in athymic mice bearing bovine lymphoid tumor cells. Tumors were detectable by radioimmunoscintigraphy, using radiolabeled c 143 F(ab')2 fragments, without background subtraction, and by use of silver-grain scattering in light microscopic autoradiography

Imaging of melanoma with 131I-labeled monoclonal antibodies

International Nuclear Information System (INIS)

Larson, S.M.; Brown, J.P.; Wright, P.W.; Carrasquillo, J.A.; Hellstroem, I.; Hellstroem, K.E.

1983-01-01

Mouse monoclonal antibodies and Fab fragments specific for p97, a melanoma-associated antigen, were used to image metastatic human melanoma. Preclinical studies in athymic mice showed antigen-specific uptake in melanoma xenografts, and toxicity tests in rabbits gave no evidence for tissue damage after injection of up to 100 times the amount of antibody used in humans. Six patients received 1 mg labeled antibody, and one patient received 1 mg of labeled Fab. No. toxic side effects were observed. All of the six patients had positive scans, visualizing 22 of 25 (88%) of lesions larger than 1.5 cm. In tumors from two patients, greater uptake of p97-specific, versus control IgG and Fab, respectively, was documented by biopsy. Antibodies to mouse immunoglobulin appeared in three patients receiving 1 mg or more of radiolabeled mouse antibody

Pharmacokinetics of indium-111-labeled antimyosin monoclonal antibody in murine experimental viral myocarditis

International Nuclear Information System (INIS)

Yamada, T.; Matsumori, A.; Watanabe, Y.; Tamaki, N.; Yonekura, Y.; Endo, K.; Konishi, J.; Kawai, C.

1990-01-01

The pharmacokinetics of indium-111-labeled antimyosin monoclonal antibody Fab were investigated with use of murine experimental viral myocarditis as a model. The biodistribution of indium-111-labeled antimyosin antibody Fab on days 3, 5, 7, 14, 21 and 28 after encephalomyocarditis virus inoculation demonstrated that myocardial uptake increased significantly on days 5, 7 and 14 (maximum on day 7) in infected versus uninfected mice (p less than 0.001). In vivo kinetics in infected mice on day 7 demonstrated that the heart to blood ratio reached a maximum 48 h after the intravenous administration of indium-111-labeled antimyosin Fab, which was considered to be the optimal time for scintigraphy. The scintigraphic images obtained with indium-111-labeled antimyosin Fab demonstrated positive uptake in the cardiac lesion in infected mice. The pathologic study demonstrated that myocardial uptake correlated well with pathologic grades of myocardial necrosis. High performance liquid chromatography revealed the presence of an antigen-antibody complex in the circulation of infected mice after the injection of indium-111-labeled antimyosin Fab. This antigen bound to indium-111-labeled antimyosin Fab in the circulation might be whole myosin and this complex may decrease myocardial uptake and increase liver uptake. It is concluded that indium-111-labeled antimyosin monoclonal antibody Fab accumulates selectively in damaged heart tissue in mice with acute myocarditis and that indium-111-labeled antimyosin Fab scintigraphy may be a useful method for the visualization of acute myocarditis

Kinetics of intralymphatically delivered monoclonal antibodies

International Nuclear Information System (INIS)

Wahl, R.L.; Geatti, O.; Liebert, M.; Beers, B.; Jackson, G.; Laino, L.; Kronberg, S.; Wilson, B.S.; Beierwaltes, W.H.

1985-01-01

Radiolabeled monoclonal antibody (MoAb) administration subcutaneously (sq), so that preferential uptake is to the lymphatics, holds significant promise for the detection of lymph node metastases. Only limited information is available about clearance rates of intralymphatically administered MoAbs. I-131 labeled intact IgG (225.28S), F(ab's)2 (225.28S) or IgM (FT162) were administered sq to anesthetized Balb/C mice. Eight mice were studied with each MoAb, 4 with a foot-pad injection, 4 with an anterior abdominal injection. Gamma camera images were collected into a computer, over the first 6 hrs after injection with the animals anesthetized and immobile. Animals were then allowed to move about freely. Additional images were then acquired out to 48 hrs. Regions of interest wre selected over the injection site and the kinetics of antibody egress determined. Clearance rates from local sq injection sites are influenced by motion and somewhat by location. The class and fragment status of the MoAb appear relatively less important in determining clearance rates from sq injections than they are in determining whole-body clearance after iv injections. Additional studies using Fab fragments and additional monoclonals will be useful in extending these observations

Use of isothiocyanatobenzyl-DTPA derivatized monoclonal antimyosin fab for enhanced in vivo target localization

International Nuclear Information System (INIS)

Khaw, B.A.; Gansow, O.; Brechbiel, M.W.; O'Donnell, S.M.; Nossiff, N.

1990-01-01

Monoclonal antimyosin Fab (AM-Fab) was radiolabeled with 111In via a new bifunctional chelating agent, isothiocyanatobenzyl-DTPA (SCN-DTPA), and used to visualize acute reperfused experimental myocardial infarction. Antibody localization was compared to 201 Tl (0.6 mCi) distribution in nine animals. Each animal was injected intravenously with 0.5 mCi of 111 In-SCN-DTPA AM-Fab preparations (Prep 1 [n = 5] and 2 [n = 4]). The biodistribution was compared to that of 111 In-labeled conventional bicyclic anhydride DTPA-AM-Fab (n = 5). 111 In-SCN-DTPA AM-Fab Prep 1 (lowest specific activity) showed highest specific target localization (31.6 +/- 3.5, MEAN infarct[0-20% Tl-201] to normal ration +/- SE) and lowest hepatic sequestration (0.0108 +/- 0.002% ID/g). Prep 2 showed similar infarct localization (18.4 +/- 1.2) to control 111 In-DTPA AM-Fab (16.9 +/- 1.1), but had higher hepatic activity (0.0326 +/- 0.014 and 0.0267 +/- 0.006 respectively). This difference in in vivo localization occurred despite the lack of changes in in vitro immunoreactivities of the AM-Fab preparations. The enhanced target localization with minimal hepatic activity may permit a more sensitive diagnostic application of 111 In-labeled AM-Fab in future clinical studies

Antibody guided targeting of non-small cell lung cancer using 111In-labeled HMFG1 F(ab')2 fragments

International Nuclear Information System (INIS)

Kalofonos, H.P.; Sivolapenko, G.B.; Courtenay-Luck, N.S.

1988-01-01

Immunoscintigraphy using F(ab')2 fragments of tumor-associated monoclonal antibody HMFG1 was performed in 14 patients with primary and metastatic non-small cell carcinoma of lung cancer. The antibody was conjugated with diethylenetriamine pentaacetic acid and labeled with 111 In. Quality control studies showed efficient incorporation of 111 In onto antibody (5 mCi/mg), no significant loss of immunoreactivity, and in vitro and in vivo stability. The optimal time for imaging was between 48 and 72 h. Following i.v. administration, serum activity fell rapidly (t1/2a = 2.5 +/- 1.3 (SD) h; t1/2b = 42 +/- 4.5 h). The majority of the radioactivity was associated with the plasma and not with the blood cells. All patients had a significant concentration of 111 In in the liver (approximately 20% of the injected dose, 48 h postadministration). No toxicity was encountered. No human antimurine-IgG antibody was detected in any of the patients within 4 months of follow-up, even in patients receiving two administrations of F(ab')2 fragments. Localization of all primary lesions and the majority (80%) of metastatic lesions was achieved. Seven of 14 patients were also studied using a 111 In-labeled nonspecific antibody (Fab')2 fragment (4C4). In three patients the specificity index was higher than the other four (P less than 0.05). We conclude that although successful targeting of 111 In-labeled (Fab')2 fragments of HMFG1 can be achieved in patients with non-small cell carcinoma of lung, observable tumor localization can also be achieved using a nonspecific antibody

Human kinetic distribution of I-123 F(Ab')/sub 2/ and FAb compared to the parent I-123 intact antibody

International Nuclear Information System (INIS)

De Nardo, S.J.; De Nardo, G.L.; O'Grady, L.F.; Peng, J.S.; Macey, D.J.; Mills, S.L.; Caridiff, R.D.; Epstein, A.L.

1985-01-01

Studies of radiolabeled monoclonal antibodies are being performed by many investigators using a variety of molecular forms of the antibody. This study evaluates two I-123-labeled antibodies (Lym-1 IgG2a and B6.01 IgG1) and their I-123-labeled FAb and F(Ab')/sub 2/ for relative whole body distribution and kinetics, selected organ kinetics, and site of degradation. Evidence of immunocomplex formation, circulating antigen, and HAMA, were monitored by HPLC-TSK analysis and appropriate radioassays of the plasma. Each antibody and each I-123-labeled fragment has been evaluated in 5 patients. One patient had serial comparisons of the radiolabeled parent molecule, F(Ab')/sub 2/ (100μg and 5 mg) and FAb (100μg) of Lym-1. Blood clearance, urine excretion rate, and plasma and urine HPLC fractionation of the radioactive species were determined. Whole body clearance by total body scans and organ clearance were obtained by geometric mean of anterior and posterior areas of interest. The FAb and F(Ab')/sub 2/ fragments had similar blood pool recovery 5 minutes after the 5-minute injection. These were the same as blood levels when 5mg of intact I-123-labeled antibody was given. The second phase of the blood curves for F(Ab')/sub 2/ had a T1/2 of 35-40 hours and for FAb was 15-20 hours. Urine excretion varied, but agreed with total body loss from body scan information. The patient with serial studies had a 24-hour residual dose of 82% for FAb, 62% for 10μg for F(Ab')/sub 2/ and 61% for 5mg of F(Ab')/sub 2/. Renal uptake for all patients was higher and more persistent with both fragments than intact antibody, but hepatic uptake was less

Contribution of Antibody Hydrodynamic Size to Vitreal Clearance Revealed through Rabbit Studies Using a Species-Matched Fab.

Science.gov (United States)

Shatz, Whitney; Hass, Philip E; Mathieu, Mary; Kim, Hok Seon; Leach, Kim; Zhou, Michelle; Crawford, Yongping; Shen, Amy; Wang, Kathryn; Chang, Debby P; Maia, Mauricio; Crowell, Susan R; Dickmann, Leslie; Scheer, Justin M; Kelley, Robert F

2016-09-06

We have developed a tool Fab fragment of a rabbit monoclonal antibody that is useful for early evaluation in rabbit models of technologies for long acting delivery (LAD) of proteins to the eye. Using this Fab we show that vitreal clearance can be slowed through increased hydrodynamic size. Fab (G10rabFab) and Fab' (G10rabFab') fragments of a rabbit monoclonal antibody (G10rabIgG) were expressed in Chinese hamster ovary (CHO) cells and purified using antigen-based affinity chromatography. G10rabFab retains antigen-binding upon thermal stress (37 °C) for 8 weeks in phosphate-buffered saline (PBS) and can be detected in rabbit tissues using an antigen-based ELISA. Hydrodynamic radius, measured using quasi-elastic light scattering (QELS), was increased through site-specific modification of the G10rabFab' free cysteine with linear methoxy-polyethylene glycol(PEG)-maleimide of 20000 or 40000 molecular weight. Pharmacokinetic studies upon intravitreal dosing in New Zealand white rabbits were conducted on the G10rabFab and PEGylated G10rabFab'. Results of single and multidose pharmacokinetic experiments yield reproducible results and a vitreal half-life for G10rabFab of 3.2 days. Clearance from the eye is slowed through increased hydrodynamic size, with vitreal half-life showing a linear dependence on hydrodynamic radius (RH). A linear dependence of vitreal half-life on RH suggests that molecule diffusivity makes an important contribution to vitreal clearance. A method for prediction of vitreal half-life from RH measurements is proposed.

Radiolabelled monoclonal antibodies against alpha-fetoprotein for in vivo localization of human hepatocellular carcinoma by immunotomoscintigraphy

International Nuclear Information System (INIS)

Bergmann, J.F.; Lumbroso, J.D.; Manil, L.; Saccavini, J.C.; Rougier, P.; Assicot, M.; Mathieu, A.; Bellet, D.; Bohuon, C.

1987-01-01

Two high affinity monoclonal antibodies, designated AF01 and AF04, directed against distinct epitopes of human alpha-fetoprotein (AFP) and the Fab fragments of one of them, were labelled with 131 I and injected into 18 patients with AFP producing hepatocellular carcinoma (HCC) in order to carry out imaging studies by tomoscintigraphy. Twelve patients were injected with whole antibody, only three of seven patients injected with AF01 and two of five patients injected with AF04 had a positive scan. In contrast, five out of six patients injected with labelled Fab fragments of AF04 had positive imaging. These results confirm that tumour imaging of HCC using 131 I labelled monoclonal antibody against AFP is feasible. Moreover, utilization of tomoscintigraphy in place of linear scintigraphy and Fab fragments instead of whole immunoglobulin may improve the sensitivity of radioimmunolocalization. This technique provides useful information on the in vivo distribution of monoclonal antibodies directed against AFP and on the practicability of the eventual therapeutic use of anti-AFP antibodies in HCC. (orig.)

Preparation, biodistribution and dosimetry of copper-64-labeled anti-colorectal carcinoma monoclonal antibody fragments 1A3-F(ab')2

International Nuclear Information System (INIS)

Anderson, C.J.; Schwarz, S.W.; Connett, J.M.

1995-01-01

Antibody fragments labeled with a radiometal using bifunctional chelates generally undergo renal clearance followed by trapping of the metabolites, leading to high radiation doses to the kidneys. Copper-64-labeled BAT-2IT-1A3-F(ab') 2 was recently reported to accumulate in colorectal tumors in an animal model, however, kidney uptake was also high. In this study, the preparation of 64 Cu-BAT-2IT-1A3-F(ab') 2 was optimized to reduce the renal uptake. The bifunctional chelate 6-bromoacetamidobenzyl-1,4,8,11-tetraazacyclotetradecane-N,N',N double-prime,N'double-prime-tetraacetic acid (BAT) was conjugated to 1A3-F(ab') 2 using the linking agent 2-iminothiolane (2IT). The conjugation reaction produced 20% of a lower molecular weight impurity found to be TETA-1A3-Fab'. The conjugation procedure was optimized to include FPLC purification of the BAT-2IT-1A3-F(ab') 2 from TETA-1A3-Fab' after conjugation prior to labeling with 64 Cu. The biodistribution of 64 Cu-labeled FPLC-purified and unpurified conjugates was determined in normal Sprague-Dawley rats and tumor-bearing Golden Syrian hamsters. Human absorbed doses were calculated from rat biodistribution data and PET imaging of a baboon. Upon FPLC purification of the BAT-2IT-1A3-F(ab') 2 , the immunoreactivity of 64 Cu-labeled 1A3-F(ab') 2 was significantly improved over that of non-FPLC-purified 64 Cu-BAT-2IT-1A3-F(ab') 2 , and the kidney uptake was decreased in normal rats. The biodistribution in hamsters showed some improvement in both tumor uptake and kidney clearance with FPLC-purified 64 Cu-BAT-2IT-1A3-F(ab') 2 .The improved dosimetry of 64 Cu-labeled FPLC purified BAT-2IT-1A3-F(ab') 2 should more readily allow this agent to be investigated clinically to image colorectal cancer using PET. 33 refs., 7 figs., 3 tabs

Fragmentation, labeling and biodistribution studies of KS1/4, a monoclonal antibody

International Nuclear Information System (INIS)

Mohd, S.B.

1987-01-01

In this study, an IgG2a (KS1/4), a monoclonal antibody (MoAb) specific against a human lung adenocarcinoma (UCLA P-3) was successfully fragmented enzymatically to yield F(ab') 2 and Fab by using pepsin and papain, respectively. The kinetic of fragmentation of the MoAb was compared to that of human immunoglobulin G (IgG). A similar pattern of fragmentation was observed with both antibodies with a higher percentage yield of the F(ab') 2 and Fab obtained upon the fragmentation of the IgG by the enzymes. The KS1/4 and the two fragments were labeled with three different radionuclides, namely iodine-131, indium-111 and selenium-75. The radioiodination of the MoAb and the fragments was carried out by using a modified chloramine-T method. Radiometal labeling of the MoAb and the fragments with indium-111 was performed by using DTPA as a bifunctional chelating agent, while intrinsic labeling of the MoAb was done by culturing the hybridoma in the presence of 75 Se-methionine. The biodistribution of the radiolabeled MoAb, F(ab') 2 and Fab fragments were performed by injecting the preparations intravenously into nude mice bearing human lung adenocarcinoma

Experimental study on 211At labelled monoclonal antibody 3H11 and its Fab fragment radioimmunotherapy for human gastric cancer xenografts in nude mice

International Nuclear Information System (INIS)

Jin Jiannan; Liu Ning; Zhang Shuyuan; Zhang Shiyuan; Luo Deyuan; Zhou Maolun

1996-01-01

Experimental radioimmunotherapy investigation of α-emitting radionuclide 211 At labelled anti-gastric cancer monoclonal antibody 3H11 and its Fab fragment for nude mice carrying human gastric cancer xenografts was conducted. Three i.p. injections of 14.8 or 22.2 kBq/g mouse were given, once every 5 days. The results showed that the growth of tumor xenografts was inhibited efficiently. The most evident therapy effect was observed at 15 days after treatment, and the tumor inhibition rates were 65% and 72%, respectively. No radiation injury of important organs was found

Production and characterization of anti-human IgG F(ab')2 antibody fragment.

Science.gov (United States)

Valedkarimi, Zahra; Nasiri, Hadi; Aghebati-Maleki, Leili; Abdolalizadeh, Jalal; Esparvarinha, Mojghan; Majidi, Jafar

2018-04-10

In present study an optimized protocol for the separation of antibodies into antigen-binding fragments F(ab')2 using pepsin digestion was investigated. The production of these fragments is a consequential step in the development of medical research, treatment and diagnosis. For production of polyclonal antibody rabbit received antigen in four steps. The rabbit serum at 1/128000 dilution showed high absorbance in reaction with human IgG at the designed ELISA method. Rabbit IgG was purified by Ion-Exchange Chromatography (IEC) method. Purity was assessed by SDS-PAGE method. In non-reduced condition only one band was seen in about 150 kDa MW position and in reduced form, two bands were seen in 50 and 25 kDa MW positions. Rabbit IgG was digested by pepsin enzyme. The antibody fragments solution was applied to Gel filtration column to isolate the F(ab')2. Non-reduced SDS-PAGE for determining the purity of F(ab')2 fragment resulted in one band in 100 kDa corresponds to F(ab')2 fragment and a band in 150 kDa MW position corresponds to undigested IgG antibodies. The activities of FITC conjugated F(ab')2 fragment and commercial ones were compared using flowcytometry method. The activity results implied that the FITC conjugated- anti human F(ab')2 fragment worked as efficiently as the commercial one.

Crystallization and preliminary X-ray diffraction analysis of the Fab fragment of WO2, an antibody specific for the Aβ peptides associated with Alzheimer’s disease

Energy Technology Data Exchange (ETDEWEB)

Wun, Kwok S. [Biota Structural Biology Laboratory and Centre for Structural Neurobiology, St Vincent’s Institute of Medical Research, 41 Victoria Parade, Fitzroy, Victoria 3065 (Australia); Miles, Luke A. [Biota Structural Biology Laboratory and Centre for Structural Neurobiology, St Vincent’s Institute of Medical Research, 41 Victoria Parade, Fitzroy, Victoria 3065 (Australia); Department of Chemical and Biomolecular Engineering, The University of Melbourne, Victoria 3010 (Australia); Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010 (Australia); Crespi, Gabriela A. N. [Biota Structural Biology Laboratory and Centre for Structural Neurobiology, St Vincent’s Institute of Medical Research, 41 Victoria Parade, Fitzroy, Victoria 3065 (Australia); Wycherley, Kaye [WEHI Biotechnology Centre, La Trobe R& D Park, Bundoora, Victoria 3086 (Australia); Ascher, David B. [Biota Structural Biology Laboratory and Centre for Structural Neurobiology, St Vincent’s Institute of Medical Research, 41 Victoria Parade, Fitzroy, Victoria 3065 (Australia); Barnham, Kevin J.; Cappai, Roberto [Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010 (Australia); Department of Pathology, The University of Melbourne, Victoria 3010 (Australia); The Mental Health Research Institute of Victoria, Parkville, Victoria 3052 (Australia); Beyreuther, Konrad [ZMBH, University of Heidelberg, Heidelberg (Germany); Masters, Colin L. [Department of Pathology, The University of Melbourne, Victoria 3010 (Australia); The Mental Health Research Institute of Victoria, Parkville, Victoria 3052 (Australia); Parker, Michael W. [Biota Structural Biology Laboratory and Centre for Structural Neurobiology, St Vincent’s Institute of Medical Research, 41 Victoria Parade, Fitzroy, Victoria 3065 (Australia); Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010 (Australia); McKinstry, William J., E-mail: wjmckinstry@hotmail.com [Biota Structural Biology Laboratory and Centre for Structural Neurobiology, St Vincent’s Institute of Medical Research, 41 Victoria Parade, Fitzroy, Victoria 3065 (Australia); Department of Medicine (St Vincent’s Hospital), The University of Melbourne, 41 Victoria Parade, Fitzroy 3065 (Australia)

2008-05-01

Crystallization and X-ray diffraction data collection of the Fab fragment of the monoclonal antibody WO2 in the absence or presence of amyloid β peptides associated with Alzheimer’s disease are reported. The murine monoclonal antibody WO2 specifically binds the N-terminal region of the amyloid β peptide (Aβ) associated with Alzheimer’s disease. This region of Aβ has been shown to be the immunodominant B-cell epitope of the peptide and hence is considered to be a basis for the development of immunotherapeutic strategies against this prevalent cause of dementia. Structural studies have been undertaken in order to characterize the molecular basis for antibody recognition of this important epitope. Here, details of the crystallization and X-ray analysis of the Fab fragment of the unliganded WO2 antibody in two crystal forms and of the complexes that it forms with the truncated Aβ peptides Aβ{sub 1–16} and Aβ{sub 1–28} are presented. These crystals were all obtained using the hanging-drop vapour-diffusion method at 295 K. Crystals of WO2 Fab were grown in polyethylene glycol solutions containing ZnSO{sub 4}; they belonged to the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1} and diffracted to 1.6 Å resolution. The complexes of WO2 Fab with either Aβ{sub 1–@}@{sub 16} or Aβ{sub 1–28} were cocrystallized from polyethylene glycol solutions. These two complex crystals grew in the same space group, P2{sub 1}2{sub 1}2{sub 1}, and diffracted to 1.6 Å resolution. A second crystal form of WO2 Fab was grown in the presence of the sparingly soluble Aβ{sub 1–42} in PEG 550 MME. This second form belonged to space group P2{sub 1} and diffracted to 1.9 Å resolution.

Effect of Polysorbate 20 and Polysorbate 80 on the Higher-Order Structure of a Monoclonal Antibody and Its Fab and Fc Fragments Probed Using 2D Nuclear Magnetic Resonance Spectroscopy.

Science.gov (United States)

Singh, Surinder M; Bandi, Swati; Jones, David N M; Mallela, Krishna M G

2017-12-01

We examined how polysorbate 20 (PS20; Tween 20) and polysorbate 80 (PS80; Tween 80) affect the higher-order structure of a monoclonal antibody (mAb) and its antigen-binding (Fab) and crystallizable (Fc) fragments, using near-UV circular dichroism and 2D nuclear magnetic resonance (NMR). Both polysorbates bind to the mAb with submillimolar affinity. Binding causes significant changes in the tertiary structure of mAb with no changes in its secondary structure. 2D 13 C- 1 H methyl NMR indicates that with increasing concentration of polysorbates, the Fab region showed a decrease in crosspeak volumes. In addition to volume changes, PS20 caused significant changes in the chemical shifts compared to no changes in the case of PS80. No such changes in crosspeak volumes or chemical shifts were observed in the case of Fc region, indicating that polysorbates predominantly affect the Fab region compared to the Fc region. This differential effect of polysorbates on the Fab and Fc regions was because of the lesser thermodynamic stability of the Fab compared to the Fc. These results further indicate that PS80 is the preferred polysorbate for this mAb formulation, because it offers higher protection against aggregation, causes lesser structural perturbation, and has weaker binding affinity with fewer binding sites compared to PS20. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Monoclonal antibody hapten radiopharmaceutical delivery

International Nuclear Information System (INIS)

Goodwin, D.A.; McTigue, M.

1986-01-01

One hundred μg of monoclonal antibody (MoAb) CHA255 with a binding constant Kb of 4 x 10 9 was complexed with indium-111 labelled BLEDTA II, BLEDTA IV, benzyl EDTA, and an EDTA conjugate of Fab. The 24-h tumour and organ distribution of BALB/c mice bearing KHJJ tumours was studied for each compound alone, the antibody complex, and 3 h following a chelate chase of the antibody complex. Whole body biological half-life was measured for 7 days with and without a chelate chase for each antibody complex. The 24-h whole body counts dropped 20 to 60% and blood concentration fell over 89% within 3 h of administering the chelate chase. Theoretical equivalent human organ doses were calculated from the 24-h organ concentrations, effective half-life, and MIRD 11 S values (absorbed dose per cumulated activity). Liver and spleen were the target organs, with the dose ranging from 0.50 to 3.91 rads mCi -1 . The reduction in organ radiation dose varied up to 95% following the chelate chase. Rapid selective renal clearance of chelate labelled radiopharmaceuticals by competitive inhibition (chelate chase) of their reversible binding to monoclonal antibodies enhances tumour imaging and improves the radiation dosimetry. (author)

[Construction of human phage antibody library and screening for human monoclonal antibodies of amylin].

Science.gov (United States)

Gong, Qian; Li, Chang-ying; Chang, Ji-wu; Zhu, Tie-hong

2012-06-01

To screen monoclonal antibodies to amylin from a constructed human phage antibody library and identify their antigenic specificity and combining activities. The heavy chain Fd fragment and light chain of human immunoglobulin genes were amplified from peripheral blood lymphocytes of healthy donors using RT-PCR, and then inserted into phagemid pComb3XSS to generate a human phage antibody library. The insertion of light chain or heavy chain Fd genes were identified by PCR after the digestion of Sac I, Xba I, Xho Iand Spe I. One of positive clones was analyzed by DNA sequencing. The specific anti-amylin clones were screened from antibody library against human amylin antigens and then the positive clones were determined by Phage-ELISA analysis. A Fab phage antibody library with 0.8×10(8); members was constructed with the efficacy of about 70%. DNA sequence analysis indicated V(H); gene belonged to V(H);3 gene family and V(λ); gene belonged to the V(λ); gene family. Using human amylin as panning antigen, specific anti-amylin Fab antibodies were enriched by screening the library for three times. Phage-ELISA assay showed the positive clones had very good specificity to amylin antigen. The successful construction of a phage antibody library and the identification of anti-amylin Fab antibodies provide a basis for further study and preparation of human anti-amylin antibodies.

Antibodies to poliovirus detected by immunoradiometric assay with a monoclonal antibody

International Nuclear Information System (INIS)

Spitz, M.; Fossati, C.A.; Schild, G.C.; Spitz, L.; Brasher, M.

1982-01-01

An immunoradiometric assay (IRMA) for the assay of antibodies to poliovirus antigens is described. Dilutions of the test sera or whole (finger prick) blood samples were incubated with the poliovirus antigen bound to a solid phase and the specific antibody was detected by the addition of a mouse anti-human IgG monoclonal antibody (McAb), which was itself revealed by iodinated sheep IgG antimouse F(ab). The authors have shown that this technique is suitable for the estimation of IgG anti-poliovirus antibodies induced in children following polio vaccine. The present study shows that SPRIA provides a simple and inexpensive method for serological studies with poliovirus particularly for use in large-scale surveys. (Auth.)

Antibodies to poliovirus detected by immunoradiometric assay with a monoclonal antibody

Energy Technology Data Exchange (ETDEWEB)

Spitz, M.; Fossati, C.A.; Schild, G.C.; Spitz, L.; Brasher, M. (National Inst. for Biological Standards and Control, London (UK))

1982-10-01

An immunoradiometric assay (IRMA) for the assay of antibodies to poliovirus antigens is described. Dilutions of the test sera or whole (finger prick) blood samples were incubated with the poliovirus antigen bound to a solid phase and the specific antibody was detected by the addition of a mouse anti-human IgG monoclonal antibody (McAb), which was itself revealed by iodinated sheep IgG antimouse F(ab). The authors have shown that this technique is suitable for the estimation of IgG anti-poliovirus antibodies induced in children following polio vaccine. The present study shows that SPRIA provides a simple and inexpensive method for serological studies with poliovirus particularly for use in large-scale surveys.

Targeting human prostate cancer with 111In-labeled D2B IgG, F(ab')2 and Fab fragments in nude mice with PSMA-expressing xenografts.

Science.gov (United States)

Lütje, Susanne; van Rij, Catharina M; Franssen, Gerben M; Fracasso, Giulio; Helfrich, Wijnand; Eek, Annemarie; Oyen, Wim J; Colombatti, Marco; Boerman, Otto C

2015-01-01

D2B is a new monoclonal antibody directed against an extracellular domain of prostate-specific membrane antigen (PSMA), which is overexpressed in prostate cancer. The potential of D2B IgG, and F(ab')2 and Fab fragments of this antibody for targeting prostate cancer was determined in mice bearing subcutaneous prostate cancer xenografts. The optimal time point for imaging was determined in biodistribution and microSPECT imaging studies with (111)In-D2B IgG, (111)In-capromab pendetide, (111)In-D2B F(ab')2 and (111)In-D2B Fab fragments in mice with PSMA-expressing LNCaP and PSMA-negative PC3 tumors at several time points after injection. All (111)In-labeled antibody formats specifically accumulated in the LNCaP tumors, with highest uptake of (111)In-D2B IgG and (111)In-capromab pendetide at 168 h p.i. (94.8 ± 19.2% injected dose per gram (ID/g) and 16.7 ± 2.2% ID/g, respectively), whereas uptake of (111)In-D2B F(ab')2 and (111)In-D2B Fab fragments peaked at 24 h p.i. (12.1 ± 3.0% ID/g and 15.1 ± 2.9% ID/g, respectively). Maximum LNCaP tumor-to-blood ratios were 13.0 ± 2.3 (168 h p.i.), 6.2 ± 0.7 (24 h p.i.), 23.0 ± 4.0 (24 h p.i.) and 4.5 ± 0.6 (168 h p.i.) for (111)In-D2B IgG, (111)In-F(ab')2, (111)In-Fab and (111)In-capromab pendetide, respectively. LNCaP tumors were clearly visualized with microSPECT with all antibody formats. This study demonstrates the feasibility of D2B IgG, F(ab')2 and Fab fragments for targeting PSMA-expressing prostate cancer xenografts. Copyright © 2014 John Wiley & Sons, Ltd.

The importance of tumor marker titers for the indication of immunoscintigraphy with monoclonal antibodies anti-CEA and anti-CA 19.9

International Nuclear Information System (INIS)

Bouvier, J.F.; Charrie, A.; Fleury-Goyon, M.C.; Chauvot, P. et; Lahneche, B.E.

1986-01-01

In 18 patients operated for malignant tumors 20 immunoscintigraphies were done with a monoclonal antibody cocktail (anti-CEA F(ab') 2 and anti-CA 19.9 F(ab') 2 ). Immediately before scintigraphy tumor marker titers in plasma were determined in all cases. Tumor marker levels corresponding to positive or doubtful scintigraphies are analysed. (Author)

Evaluation of tumor targeting with radiolabeled F(ab2 fragment of a humanized monoclonal antibody

Directory of Open Access Journals (Sweden)

"Babaei MH

2002-08-01

Full Text Available Humanized monoclonal antibody U36 and its F(ab'2 fragment, radio labeled with 125I, were tested for tumor localization in nude mice bearing a squamous cell carcinoma xenograft line derived from a head and neck carcinoma. Monoclonal antibody IgG or F(ab'2 fragment were injected in parallel and at days 1, 2 and 3, mice were dissected for determination of isotope biodistribution. IgG as well as F(ab'2 showed highly specific localization in tumor tissue. The mean tumor uptake (n=3 is expressed as the percentage of the injected dose per gram of tumor tissue (%ID/g. %ID/g of IgG was 11.7% at day 1 and decreased to 10.9% at day 3 whereas %ID/g of F(ab'2 was 2.9% at day 1 and decreased on following days. Tumor to blood ratios (T/B at day 1 were 0.86 for IgG and 1.32 for F(ab'2 and reached a maximum at day 3 with values of 4.41 and 1.84 respectively. These findings suggest that the superior tumor to non-tumor ratios in the day of 1 render the F(ab'2 fragment more qualified for specific targeting radioisotopes to tumor xenografts in this exprimental setting.

Baculovirus display of functional antibody Fab fragments.

Science.gov (United States)

Takada, Shinya; Ogawa, Takafumi; Matsui, Kazusa; Suzuki, Tasuku; Katsuda, Tomohisa; Yamaji, Hideki

2015-08-01

The generation of a recombinant baculovirus that displays antibody Fab fragments on the surface was investigated. A recombinant baculovirus was engineered so that the heavy chain (Hc; Fd fragment) of a mouse Fab fragment was expressed as a fusion to the N-terminus of baculovirus gp64, while the light chain of the Fab fragment was simultaneously expressed as a secretory protein. Following infection of Sf9 insect cells with the recombinant baculovirus, the culture supernatant was analyzed by enzyme-linked immunosorbent assay using antigen-coated microplates and either an anti-mouse IgG or an anti-gp64 antibody. A relatively strong signal was obtained in each case, showing antigen-binding activity in the culture supernatant. In western blot analysis of the culture supernatant using the anti-gp64 antibody, specific protein bands were detected at an electrophoretic mobility that coincided with the molecular weight of the Hc-gp64 fusion protein as well as that of gp64. Flow cytometry using a fluorescein isothiocyanate-conjugated antibody specific to mouse IgG successfully detected the Fab fragments on the surface of the Sf9 cells. These results suggest that immunologically functional antibody Fab fragments can be displayed on the surface of baculovirus particles, and that a fluorescence-activated cell sorter with a fluorescence-labeled antigen can isolate baculoviruses displaying specific Fab fragments. This successful baculovirus display of antibody Fab fragments may offer a novel approach for the efficient selection of specific antibodies.

MINOR HUMAN-ANTIBODY RESPONSE TO A MOUSE AND CHIMERIC MONOCLONAL-ANTIBODY AFTER A SINGLE IV INFUSION IN OVARIAN-CARCINOMA PATIENTS - A COMPARISON OF 5 ASSAYS

NARCIS (Netherlands)

BUIST, MR; KENEMANS, P; VANKAMP, GJ; Haisma, Hidde

The human anti-(mouse Ig) antibody (HAMA) response was measured in serum of 52 patients suspected of having ovarian carcinoma who had received an i.v. injection of either the murine monoclonal antibody (mAb) OV-TL 3 F(ab')(2) (n = 28, 1 mg) or the chimeric mouse/human mAb MOv18 (cMOv18; n = 24, 3

Minor human antibody response to a mouse and chimeric monoclonal antibody after a single i.v. infusion in ovarian carcinoma patients: a comparison of five assays

NARCIS (Netherlands)

Buist, M. R.; Kenemans, P.; van Kamp, G. J.; Haisma, H. J.

1995-01-01

The human anti-(mouse Ig) antibody (HAMA) response was measured in serum of 52 patients suspected of having ovarian carcinoma who had received an i.v. injection of either the murine monoclonal antibody (mAb) OV-TL 3 F(ab')2 (n = 28, 1 mg) or the chimeric mouse/human mAb MOv18 (cMOv18; n = 24, 3 mg).

Direct labelling of monomeric antibody fragments Fab' with 99mTc

International Nuclear Information System (INIS)

Li Jun; Wang Shizhen; Yang Ziyi

1994-01-01

Direct labelling method and conditions of monomeric antibody Fab' with 99m Tc were investigated. Polyclonal antibody IgG was digested with ficin to produce dimeric fragments F(ab') 2 , which was subsequently reduced to monomeric fragments Fab' with 2-mercaptoethylamine. Finally, Fab' was incubated with sodium gluconate (Sn(II)) kit solution and 99m TcO 4 - eluted at room temperature to form 99m Tc-Fab'. The labelling efficiency was 85%-95%. The stability of labelled products was satisfactory and the elimination rate was faster than 99m Tc-IgG

Passive vaccination with a human monoclonal antibody: generation of antibodies and studies for efficacy in Bacillus anthracis infections.

Science.gov (United States)

vor dem Esche, Ulrich; Huber, Maria; Zgaga-Griesz, Andrea; Grunow, Roland; Beyer, Wolfgang; Hahn, Ulrike; Bessler, Wolfgang G

2011-07-01

A major difficulty in creating human monoclonal antibodies is the lack of a suitable myeloma cell line to be used for fusion experiments. In order to create fully human monoclonal antibodies for passive immunization, the human mouse heteromyeloma cell line CB-F7 was evaluated. Using this cell line, we generated human monoclonal antibodies against Bacillus anthracis toxin components. Antibodies against protective antigen (PA) and against lethal factor (LF) were obtained using peripheral blood lymphocytes (PBLs) from persons vaccinated with the UK anthrax vaccine. PBL were fused with the cell line CB-F7. We obtained several clones producing PA specific Ig and one clone (hLF1-SAN) producing a monoclonal antibody (hLF1) directed against LF. The LF binding antibody was able to neutralize Anthrax toxin activity in an in vitro neutralization assay, and preliminary in vivo studies in mice also indicated a trend towards protection. We mapped the epitope of the antibody binding to LF by dot blot analysis and ELIFA using 80 synthetic LF peptides of 20 amino acid lengths with an overlapping range of 10 amino acids. Our results suggest the binding of the monoclonal antibody to the peptide regions 121-150 or 451-470 of LF. The Fab-fragment of the antibody hLF1 was cloned in Escherichia coli and could be useful as part of a fully human monoclonal antibody for the treatment of Anthrax infections. In general, our studies show the applicability of the CB-F7 line to create fully human monoclonal antibodies for vaccination. Copyright © 2010 Elsevier GmbH. All rights reserved.

Crystallization and molecular-replacement studies of the monoclonal antibody mAbR310 specific for the (R)-HNE-modified protein

International Nuclear Information System (INIS)

Ito, Sohei; Tatsuda, Emi; Ishino, Kousuke; Suzuki, Kenichiro; Sakai, Hiroshi; Uchida, Koji

2006-01-01

Antigen-free Fab fragment of mAbR310, which recognizes (R)-HNE modified protein, has been crystallized. Initial phases have been obtained by molecular replacement. 4-Hydroxy-2-nonenal (HNE), a major racemic product of lipid peroxidation, reacts with histidine to form a stable HNE–histidine Michael addition-type adduct possessing three chiral centres in the cyclic hemiacetal structure. Monoclonal antibodies against HNE-modified protein have been widely used for assessing oxidative stress in vitro and in vivo. Here, the purification, crystallization and preliminary crystallographic analysis of a Fab fragment of novel monoclonal antibody R310 (mAbR310), which recognizes (R)-HNE-modified protein, are reported. The Fab fragment of mAbR310 was obtained by digestion with papain, purified and crystallized. Using hanging-drop vapour-diffusion crystallization techniques, crystals of mAbR310 Fab were obtained. The crystal belongs to the monoclinic space group C2 (unit-cell parameters a = 127.04, b = 65.31, c = 64.29 Å, β = 118.88°) and diffracted X-rays to a resolution of 1.84 Å. The asymmetric unit contains one molecule of mAbR310, with a corresponding crystal volume per protein weight of 2.51 Å 3 Da −1 and a solvent content of 51.0%

Label-free Fab and Fc affinity/avidity profiling of the antibody complex half-life for polyclonal and monoclonal efficacy screening.

Science.gov (United States)

Read, Thomas; Olkhov, Rouslan V; Williamson, E Diane; Shaw, Andrew M

2015-09-01

A unified approach to affinity screening for Fab and Fc interactions of an antibody for its antigen and FcγR receptor has been developed. An antigen array is used for the Fab affinity and cross-reactivity screening and protein A/G proxy is the FcγR receptor. The affinities are derived using a simple 1:1 binding model with a consistent error analysis. The association and dissociation kinetics are measured over optimised times for accurate determination. The Fab/Fc affinities are derived for ten antibodies: mAb-actin (mouse), pAb-BSA (sheep), pAb-collagen V (rabbit), pAb-CRP (goat), mAb-F1 (mouse), mAbs (mouse) 7.3, 12.3, 29.3, 36.3 and 46.3 raised against LcrV in Yersinia pestis. The rate of the dissociation of antigen-antibody complexes relates directly to their immunological function as does the Fc-FcγR complex and a new half-life plot has been defined with a Fab/Fc half-life range of 17-470 min. The upper half-life value points to surface avidity. Two antibodies that are protective as an immunotherapy define a Fab half-life >250 min and an Fc half-life >50 min as characteristics of ideal interactions which can form the basis of an antibody screen for immunotherapy.

Immobilization and functional reconstitution of antibody Fab fragment by solid-phase refolding.

Science.gov (United States)

Kumada, Yoichi; Hamasaki, Kyoto; Nakagawa, Aya; Sasaki, Eiju; Shirai, Tatsunori; Okumura, Masahiro; Inoue, Manami; Kishimoto, Michimasa

2013-12-31

In this study, we demonstrated the successful preparation of a Fab antibody-immobilized hydrophilic polystyrene (phi-PS) plate via one- and two-step solid-phase refolding methods. Both polystyrene-binding peptide (PS-tag)-fused Fd fragment of heavy chain (Fab H-PS) and full-length of light-chain (Fab L-PS) were individually produced in insoluble fractions of Escherichia coli cells, and they were highly purified in the presence of 8M of urea. Antigen-binding activities of Fab antibody immobilized were correctly recovered by the one-step solid-phase refolding method that a mixture of Fab H-PS and Fab L-PS was immobilized in the presence of 0.5-2M urea, followed by surface washing of the phi-PS plate with PBST. These results indicate that by genetic fusion of a PS-tag, a complex between Fab H and Fab L was efficiently immobilized on the surface of a phi-PS plate even in the presence of a low concentration of urea, and was then correctly refolded to retain its high antigen-binding activity via removal of the urea. A two-step solid-phase refolding method whereby Fab H-PS and Fab L-PS were successively refolded on the surface of a phi-PS plate also resulted in Fab antibody formation on the plate. Furthermore, both the binding affinity and the specificity of the Fab antibody produced by the two-step method were highly maintained, according to the results of sandwich ELISA and competitive ELISA using Fab antibody-immobilized plate via two-step solid-phase refolding. Thus, the solid-phase refolding method demonstrated in this study should be quite useful for the preparation of a Fab antibody-immobilized PS surface with high efficiency from individually produced Fab H-PS and Fab L-PS. This method will be applicable to the preparation of a large Fab antibody library on the surface of a PS plate for use in antibody screening. © 2013. Published by Elsevier B.V. All rights reserved.

Crystallization and preliminary X-ray analysis of birch-pollen allergen Bet v 1 in complex with a murine monoclonal IgG Fab' fragment

DEFF Research Database (Denmark)

Spangfort, M D; Mirza, Osman Asghar; Gajhede, M

1999-01-01

of the clinical symptoms of allergy. In order to study the structural basis of allergen-antibody interaction, a complex between the major birch-pollen allergen Bet v 1 and a Fab' fragment isolated from the murine monoclonal Bet v 1 antibody BV16 has been crystallized. Complex crystals belong to space group P1...

Immunomodulatory effects of intravenous bis-1 f(ab')(2) administration in renal-cell cancer-patients

NARCIS (Netherlands)

Janssen, R. A. J.; Kroesen, B. J.; Mesander, G.; Sleijfer, D. T.; The, T. Hauw; Mulder, N. H.; de Leij, L

We report the immunomodulatory effects of an intravenous treatment with F(ab')(2) fragments of the bispecific monoclonal antibody BIS-1 during subcutaneous recombinant interleukin 2 (rIL-2) therapy of renal cell cancer (RCC) patients. BIS-1 is directed against both the CD3 antigen on T cells and the

Noninvasive detection of cardiac repair after acute myocardial infarction in rats by 111In fab fragment of monoclonal antibody specific for tenascin-C

International Nuclear Information System (INIS)

Okada, Kenichi; Uehara, Tomoya; Arano, Yasushi

2008-01-01

Left ventricular (LV) remodeling after acute myocardial infarction (MI) causes heart failure, and thus it is important to evaluate cardiac repair as the early stage of LV remodeling. Tenascin-C (TNC), an extracellular matrix glycoprotein, is transiently and abundantly expressed in the heart during the early stage of tissue remodeling after MI. However, it is not expressed in healthy adult heart. This study was undertaken to develop a new noninvasive diagnostic technique to detect cardiac repair after acute MI using 111 In Fab fragment of a monoclonal antibody specific for TNC. 111 In-anti-TNC-Fab was injected intravenously in 13 rats at 1 (D1, n=3), 3 (D3, n=5), and 5 (D5, n=5) days after producing MI and in 5 sham-operated rats (S). We performed autoradiography and dual-isotope single-photon emission computed tomography imaging (SPECT) of 111 In-anti-TNC-Fab and 99m Tc methoxyisobutyl isonitrile (MIBI). The radioactivity in the heart was significantly higher in D (D1, 0.45±0.06% injected-dose/g; D3, 0.64±0.12; D5, 0.38±0.07) than S (0.27±0.06, P 111 In-anti-TNC-Fab, which was complementary to the perfusion image. The results of the present study indicated that we can localize the infarcted region in the heart by ex vivo and in vivo imaging methods using 111 In-anti-TNC-Fab, and suggested the potential usefulness of noninvasive detection of cardiac repair. (author)

Alterations in an indium-111 Fab' under conditions of utilization

International Nuclear Information System (INIS)

Halpern, S.E.; Sudora, E.; Tarburton, J.P.; Hagar, P.

1992-01-01

This study was conducted to investigate alterations that occur in an indium/111 Fab' of a monoclonal antibody following its in vivo administration. Patients were infused with 111 In-Fab' of the monoclonal antibody ZCE-025. Serum and urine specimens were collected from these pateients. Starting materials, serum, urine and controls samples were studied by electrophoresis. Animal distribution studies were performed in normal Balb/c mice and, in some cases, nude mice bearing a carcinoembryonic antigen (CEA)/producing human colon tumour since the antibody targets CEA. The studies indicated that the molecule circulated almost totally intact for at least 4 h and to a considerable extent for 24 h, with some evidence for in vivo fragmentation by 24 h. Evidence was also obtained suggesting the formation of a high molecular weight species in some patients. Shortly after infusion, some of the 111 In in the urine appeared as the intact Fab', but within hours the majority migrated electro-phoretically as low molecular weight species. We conclude that while the majority of the 111 In-Fab' of this particular antibody remains intact and immunoreactive following its administration, the molecule is structurally changed to some degree shortly after its infusion into humans. Since each monoclonal antibody is unique, the degree and rapidity of degradation of its Fab' in vivo could vary markedly from the above and possibly adversely effect its utility as a radiopharmaceutical. (orig.)

Structure of the extracellular domain of matrix protein 2 of influenza A virus in complex with a protective monoclonal antibody.

Science.gov (United States)

Cho, Ki Joon; Schepens, Bert; Seok, Jong Hyeon; Kim, Sella; Roose, Kenny; Lee, Ji-Hye; Gallardo, Rodrigo; Van Hamme, Evelien; Schymkowitz, Joost; Rousseau, Frederic; Fiers, Walter; Saelens, Xavier; Kim, Kyung Hyun

2015-04-01

The extracellular domain of influenza A virus matrix protein 2 (M2e) is conserved and is being evaluated as a quasiuniversal influenza A vaccine candidate. We describe the crystal structure at 1.6 Å resolution of M2e in complex with the Fab fragment of an M2e-specific monoclonal antibody that protects against influenza A virus challenge. This antibody binds M2 expressed on the surfaces of cells infected with influenza A virus. Five out of six complementary determining regions interact with M2e, and three highly conserved M2e residues are critical for this interaction. In this complex, M2e adopts a compact U-shaped conformation stabilized in the center by the highly conserved tryptophan residue in M2e. This is the first description of the three-dimensional structure of M2e. M2e of influenza A is under investigation as a universal influenza A vaccine, but its three-dimensional structure is unknown. We describe the structure of M2e stabilized with an M2e-specific monoclonal antibody that recognizes natural M2. We found that the conserved tryptophan is positioned in the center of the U-shaped structure of M2e and stabilizes its conformation. The structure also explains why previously reported in vivo escape viruses, selected with a similar monoclonal antibody, carried proline residue substitutions at position 10 in M2. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Fab-based bispecific antibody formats with robust biophysical properties and biological activity.

Science.gov (United States)

Wu, Xiufeng; Sereno, Arlene J; Huang, Flora; Lewis, Steven M; Lieu, Ricky L; Weldon, Caroline; Torres, Carina; Fine, Cody; Batt, Micheal A; Fitchett, Jonathan R; Glasebrook, Andrew L; Kuhlman, Brian; Demarest, Stephen J

2015-01-01

A myriad of innovative bispecific antibody (BsAb) platforms have been reported. Most require significant protein engineering to be viable from a development and manufacturing perspective. Single-chain variable fragments (scFvs) and diabodies that consist only of antibody variable domains have been used as building blocks for making BsAbs for decades. The drawback with Fv-only moieties is that they lack the native-like interactions with CH1/CL domains that make antibody Fab regions stable and soluble. Here, we utilize a redesigned Fab interface to explore 2 novel Fab-based BsAbs platforms. The redesigned Fab interface designs limit heavy and light chain mixing when 2 Fabs are co-expressed simultaneously, thus allowing the use of 2 different Fabs within a BsAb construct without the requirement of one or more scFvs. We describe the stability and activity of a HER2×HER2 IgG-Fab BsAb, and compare its biophysical and activity properties with those of an IgG-scFv that utilizes the variable domains of the same parental antibodies. We also generated an EGFR × CD3 tandem Fab protein with a similar format to a tandem scFv (otherwise known as a bispecific T cell engager or BiTE). We show that the Fab-based BsAbs have superior biophysical properties compared to the scFv-based BsAbs. Additionally, the Fab-based BsAbs do not simply recapitulate the activity of their scFv counterparts, but are shown to possess unique biological activity.

Antimelanoma monoclonal antibody 225-28S. Evaluation of toxicity in man

Energy Technology Data Exchange (ETDEWEB)

Cascinelli, N; Attili, A; Belli, F; Buraggi, G; Turrin, A; Gasparini, M; Terno, G; Vaglini, M

1988-01-01

To investigate possible undesirable due to the intravenous administration of a reagent of a xenogenic nature (monoclonal antibody 225-28S) in man, a toxicologic study was carried out on 85 patients with metastatic cutaneous melanoma. Two reagents were tested in this study: purified monoclonal antybody (MoAb) 225-28S and its F(ab')2 fragment. Purified MoAb was labelled with /sup 131/I and F(ab')2 fragment with /sup 131/I, or /sup 123/I, or /sup 111/In or /sup 99/Tc. The quantity of MoAb or F(ab')2 injected ranged from 14 to 750 ..mu..g, and the specific activity from 37.0 to 2116.4 MBqmg. The total radioactivity injected varied from 25.9 to 891.7 MBqmg. In addition to a careful clinical examination, the following tests were done to monitor possible adverse effects: blood glucose, azotemia, RBC WBC, platelet count, serum creatine, creatine clearence, plasma electrolyte levels, serum proteins, albuminglobulin ratio, serum bilirubin, SGOT, SgPT, /sub ..gamma../GT, and CPK. These tests were done before the injection and on days 7 and 14. No patient experienced adverse general effects like fever, nausea, vomiting or allergic reaction. None of the afore mentioned hematometric and biochemical tests showed significant variations compared with the initial values. It is concluded that a single injection of these reagents at the dosages tested is completely atoxic.

Directed Selection of Recombinant Human Monoclonal Antibodies to Herpes Simplex Virus Glycoproteins from Phage Display Libraries

Science.gov (United States)

Sanna, Pietro Paolo; Williamson, R. Anthony; de Logu, Alessandro; Bloom, Floyd E.; Burton, Dennis R.

1995-07-01

Human monoclonal antibodies have considerable potential in the prophylaxis and treatment of viral disease. However, only a few such antibodies suitable for clinical use have been produced to date. We have previously shown that large panels of human recombinant monoclonal antibodies against a plethora of infectious agents, including herpes simplex virus types 1 and 2, can be established from phage display libraries. Here we demonstrate that facile cloning of recombinant Fab fragments against specific viral proteins in their native conformation can be accomplished by panning phage display libraries against viral glycoproteins "captured" from infected cell extracts by specific monoclonal antibodies immobilized on ELISA plates. We have tested this strategy by isolating six neutralizing recombinant antibodies specific for herpes simplex glycoprotein gD or gB, some of which are against conformationally sensitive epitopes. By using defined monoclonal antibodies for the antigen-capture step, this method can be used for the isolation of antibodies to specific regions and epitopes within the target viral protein. For instance, monoclonal antibodies to a nonneutralizing epitope can be used in the capture step to clone antibodies to neutralizing epitopes, or antibodies to a neutralizing epitope can be used to clone antibodies to a different neutralizing epitope. Furthermore, by using capturing antibodies to more immunodominant epitopes, one can direct the cloning to less immunogenic ones. This method should be of value in generating antibodies to be used both in the prophylaxis and treatment of viral infections and in the characterization of the mechanisms of antibody protective actions at the molecular level.

The experimental study on biodistribution and radioimmunoimaging of 131I labeled anti-lymphoma Fab antibody in nude mice bearing human B cell lymphoma

International Nuclear Information System (INIS)

Yang Xiaochun; Zhang Meihua; Shen Junkang; Shen Yongmei; Shi Yizhen; Liu Zengli

2008-01-01

Objective: Radioimmunoimaging is still an interesting study in the domain of nuclear medicine. The aim of this study was to evaluate the biodistribution and radioimmunoimaging of 131 I-Fab anti- body in nude mice beating human B cell lymphoma. Methods: The immunoreactivity of Fab antibody to Raji cells was analyzed by immunohistochemistry and flow cytometry. Fab antibody and CD20 monoclonal antibody (as control) were labeled with 131 I using Iodogen method. 131 I-Fab antibody or 131 I-CD20 was injected into nude mice bearing B cell lymphoma via tail veins. The biodistribution and radioimmunoimaging results were obtained at 2, 4, 8 and 24 h postinjection, respectively. Results: The results of immunohistochemistry and flow cytometry indicated that both Fab antibody and 131 I-Fab antibody could bind strongly with membrane antigens on Raji cells, and the binding rate reached above 87%. Clear tumor image was obtained at 8 h after injection with 131 I-Fab and elimination was observed at 24 h postinjection. The clear tumor image for 131 I-CD20 antibody was obtained at 24 h post injection. The biodistribution in vivo showed that the percentage activities of injection dose per gram of tumor (% ID/g) of 131 I-Fab group at 2, 4, 8 h postinjection were higher than that of 131 I-CD20 antibody [(1.37±0.28), (1.84±0.13), (2.21±0.15)% ID/g vs (0.33±0.06), (0.62±0.08), (1.46±0.24)% ID/g, respectively; F=52.22, 278.42 and 29.00, all P 131 I-Fad and 131 I-CD20 groups at 2, 4, 8 and 24 h were [(0.22±0.03)-(5.44± 0.31)] vs[(0.04±0.01)-(3.10±0.29)], [(0.43±0.11) - (21.01±3.97)] vs [(0.11±0.05) - (7.99±1.81)], [(1.09±0.07) -(20.28±2.77)] vs [(0.48±0.06) - (23.55±1.69)], [(1.12± 0.02) - (10.29±1.78)] vs [(2.32 ± 0.34) - (33.23±6.83)], respectively. Conclusion: 131 I-Fab anti- body has advantages of small molecular weight, excellent targeting characteristics, early imaging and fast elimination, which indicates the potential application value in diagnosing B cell

Generation of HER2 monoclonal antibodies using epitopes of a rabbit polyclonal antibody.

Science.gov (United States)

Hu, Francis Jingxin; Uhlen, Mathias; Rockberg, Johan

2014-01-25

One of the issues in using polyclonal antibodies is the limited amount of reagent available from an immunisation, leading to batch-to-batch variation and difficulties in obtaining the same antibody performance when the same antigen is re-immunised into several separate animals. This led to the development of hybridoma technology allowing, at least theoretically, for an unlimited production of a specific binder. Nevertheless, polyclonal antibodies are widely used in research and diagnostics and there exists a need for robust methods to convert a polyclonal antibody with good binding performance into a renewable monoclonal with identical or similar binding specificity. Here we have used precise information regarding the functional recognition sequence (epitope) of a rabbit polyclonal antibody with attractive binding characteristics as the basis for generation of a renewable mouse monoclonal antibody. First, the original protein fragment antigen was used for immunisation and generation of mouse hybridoma, without obtaining binders to the same epitope region. Instead a peptide designed using the functional epitope and structural information was synthesised and used for hybridoma production. Several of the monoclonal antibodies generated were found to have similar binding characteristics to those of the original polyclonal antibody. These monoclonal antibodies detected native HER2 on cell lines and were also able to stain HER2 in immunohistochemistry using xenografted mice, as well as human normal and cancer tissues. Copyright © 2013 Elsevier B.V. All rights reserved.

Mining Naïve Rabbit Antibody Repertoires by Phage Display for Monoclonal Antibodies of Therapeutic Utility.

Science.gov (United States)

Peng, Haiyong; Nerreter, Thomas; Chang, Jing; Qi, Junpeng; Li, Xiuling; Karunadharma, Pabalu; Martinez, Gustavo J; Fallahi, Mohammad; Soden, Jo; Freeth, Jim; Beerli, Roger R; Grawunder, Ulf; Hudecek, Michael; Rader, Christoph

2017-09-15

Owing to their high affinities and specificities, rabbit monoclonal antibodies (mAbs) have demonstrated value and potential primarily as basic research and diagnostic reagents, but, in some cases, also as therapeutics. To accelerate access to rabbit mAbs bypassing immunization, we generated a large naïve rabbit antibody repertoire represented by a phage display library encompassing >10 billion independent antibodies in chimeric rabbit/human Fab format and validated it by next-generation sequencing. Panels of rabbit mAbs selected from this library against two emerging cancer targets, ROR1 and ROR2, revealed high diversity, affinity, and specificity. Moreover, ROR1- and ROR2-targeting rabbit mAbs demonstrated therapeutic utility as components of chimeric antigen receptor-engineered T cells, further corroborating the value of the naïve rabbit antibody library as a rich and virtually unlimited source of rabbit mAbs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nuclear medicine: Monoclonal antibodies

International Nuclear Information System (INIS)

Endo, K.; Sakahara, H.; Koizumi, M.; Kawamura, Y.; Torizuka, K.; Yokoyama, A.

1986-01-01

Antitumor monoclonal antibody was successfully labeled with Tc-99m by using dithiosemicarbazone (DTS) as a bifunctional chelating agent. In the first step, DTS was coupled to antibody without loss of immunoreactivity; the compound then efficiently formed a neutral 1:1 chelate with pentavalent or tetravalent Tc-99m. Imaging with Tc-99m-labeled monoclonal antibody to human osteosarcoma (OST-7) clearly displayed a small tumor in nude mice at 6 and 24 hours after intravenous administration. The tumor-to-blood ratio of the Tc-99m-labeled monoclonal antibody was higher than that of a radioiodinated antibody and similar to that of an In-111-labeled antibody. Thus, conjugation of DTS to monoclonal antibody followed by radiometalation is a simple and efficient method of preparing Tc-99m-labeled monoclonal antibody

A novel bispecific antibody, S-Fab, induces potent cancer cell killing.

Science.gov (United States)

Li, Li; He, Ping; Zhou, Changhua; Jing, Li; Dong, Bin; Chen, Siqi; Zhang, Ning; Liu, Yawei; Miao, Ji; Wang, Zhong; Li, Qing

2015-01-01

Bispecific antibodies that engage immune cells to kill cancer cells have been actively studied in cancer immunotherapy. In this study, we present a novel bispecific format, S-Fab, fabricated by linking a single-domain anti-carcinoembryonic antigen VHH to a conventional anti-CD3 Fab. In contrast to most bispecific antibodies, the S-Fab bispecific antibody can be efficiently expressed and purified from bacteria. The purified S-Fab is stable in serum and is able to recruit T cells to drive potent cancer cell killing. In xenograft models, the S-Fab antibody suppresses tumor growth in the presence of human immune cells. Our study suggested that the bispecific S-Fab format can be applied to a wide range of immunotherapies.

Monoclonal antibodies and cancer

International Nuclear Information System (INIS)

Haisma, H.J.

1987-01-01

The usefulness of radiolabeled monoclonal antibodies for imaging and treatment of human (ovarian) cancer was investigated. A review of tumor imaging with monoclonal antibodies is presented. Special attention is given to factors that influence the localization of the antibodies in tumors, isotope choice and methods of radiolabeling of the monoclonal antibodies. Two monoclonal antibodies, OC125 and OV-TL3, with high specificity for human epithelial ovarian cancer are characterized. A simple radio-iodination technique was developed for clinical application of the monoclonal antibodies. The behavior of monoclonal antibodies in human tumor xenograft systems and in man are described. Imaging of tumors is complicated because of high background levels of radioactivity in other sites than the tumor, especially in the bloodpool. A technique was developed to improve imaging of human tumor xenographs in nude mice, using subtraction of a specific and a non-specific antibody, radiolabeled with 111 In, 67 Ga and 131 I. To investigate the capability of the two monoclonal antibodies, to specifically localize in human ovarian carcinomas, distribution studies in mice bearing human ovarian carcinoma xenografts were performed. One of the antibodies, OC125, was used for distribution studies in ovarian cancer patients. OC125 was used because of availability and approval to use this antibody in patients. The same antibody was used to investigate the usefulness of radioimmunoimaging in ovarian cancer patients. The interaction of injected radiolabeled antibody OC125 with circulating antigen and an assay to measure the antibody response in ovarian cancer patients after injection of the antibody is described. 265 refs.; 30 figs.; 19 tabs

The strength of small: Improved targeting of Insulin-like Growth Factor-1 Receptor (IGF-1R) with F(ab')2-R1507 fragments in Ewing sarcomas

NARCIS (Netherlands)

Fleuren, Emmy D. G.; Versleijen-Jonkers, Yvonne M. H.; Heskamp, Sandra; Roeffen, Melissa H. S.; Bouwman, Wilbert H.; Molkenboer-Kuenen, Janneke D. M.; van Laarhoven, Hanneke W. M.; Oyen, Wim J. G.; Boerman, Otto C.; van der Graaf, Winette T. A.

2013-01-01

To investigate whether F(ab')2-fragments of the monoclonal Insulin-like Growth Factor-1 Receptor (IGF-1R) antibody R1507 (F(ab')2-R1507) can successfully target IGF-1R in Ewing sarcomas (ES). BALB/c nude mice were subcutaneously implanted with IGF-1R-expressing human ES xenografts (EW-5 and EW-8)

Antibodies and Selection of Monoclonal Antibodies.

Science.gov (United States)

Hanack, Katja; Messerschmidt, Katrin; Listek, Martin

Monoclonal antibodies are universal binding molecules with a high specificity for their target and are indispensable tools in research, diagnostics and therapy. The biotechnological generation of monoclonal antibodies was enabled by the hybridoma technology published in 1975 by Köhler and Milstein. Today monoclonal antibodies are used in a variety of applications as flow cytometry, magnetic cell sorting, immunoassays or therapeutic approaches. First step of the generation process is the immunization of the organism with appropriate antigen. After a positive immune response the spleen cells are isolated and fused with myeloma cells in order to generate stable, long-living antibody-producing cell lines - hybridoma cells. In the subsequent identification step the culture supernatants of all hybridoma cells are screened weekly for the production of the antibody of interest. Hybridoma cells producing the antibody of interest are cloned by limited dilution till a monoclonal hybridoma is found. This is a very time-consuming and laborious process and therefore different selection strategies were developed since 1975 in order to facilitate the generation of monoclonal antibodies. Apart from common automation of pipetting processes and ELISA testing there are some promising approaches to select the right monoclonal antibody very early in the process to reduce time and effort of the generation. In this chapter different selection strategies for antibody-producing hybridoma cells are presented and analysed regarding to their benefits compared to conventional limited dilution technology.

Development of 90Y-DOTA-nimotuzumab Fab fragment for radioimmunotherapy

International Nuclear Information System (INIS)

Alonso Martinez, L.M.; Marylaine Perez-Malo Cruz; Rene Leyva Montana; Calzada Falcon, V.N.; Minely Zamora Barrabi; Alejandro Arbesu Valdivia; Ignacio Hernandez Gonzalez; Mariela Leon Perez

2014-01-01

Yttrium-90-( 90 Y) labeled monoclonal antibodies prepared with a chelating agent, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), have been used for radioimmunotherapy of cancer. In the present work, the Fab fragment of anti-EGFR monoclonal antibody nimotuzumab was prepared with high purity, integrity and biological activity. The Fab fragment with high specific recognition of EGFR in NCI-H125 human lung adenocarcinoma cells was derivatized with DOTA-NHS applying a simple procedure. DOTA-nimotuzumab Fab fragment was successfully radiolabeled with 90 Y with high radiochemical yield. The in vitro stability of labeled product was optimal over 24 h in buffered solution at 37 deg C. Biodistribution and pharmacokinetic studies correctly evaluated the in vivo non-tumor uptake, dosage regimen and excretion pathway in normal Wistar rats. (author)

Selective disulfide reduction for labeling and enhancement of Fab antibody fragments.

Science.gov (United States)

Kirley, Terence L; Greis, Kenneth D; Norman, Andrew B

2016-11-25

Many methods have been developed for chemical labeling and enhancement of the properties of antibodies and their common fragments, including the Fab and F(ab') 2 fragments. Somewhat selective reduction of some antibody disulfide bonds has been previously achieved, yielding antibodies and antibody fragments that can be labeled at defined sites, enhancing their utility and properties. Selective reduction of the two hinge disulfide bonds present in F(ab') 2 fragments using mild reduction has been useful. However, such reduction is often not quantitative and results in the reduction of multiple disulfide bonds, and therefore subsequent multiple labeling or conjugation sites are neither homogenous nor stoichiometric. Here, a simple and efficient selective reduction of the single disulfide bond linking the partial heavy chain and the intact light chain which compose the Fab fragment is accomplished utilizing tris(2-carboxyethyl)phosphine (TCEP) immobilized on agarose beads. The resultant reduced cysteine residues were labeled with several cysteine-selective fluorescent reagents, as well as by cysteine-directed PEGylation. These two cysteine residues can also be re-ligated by means of a bifunctional cysteine cross-linking agent, dibromobimane, thereby both restoring a covalent linkage between the heavy and light chains at this site, far removed from the antigen binding site, and also introducing a fluorescent probe. There are many other research and clinical uses for these selectively partially reduced Fab fragments, including biotinylation, toxin and drug conjugation, and incorporation of radioisotopes, and this technique enables simple generation of very useful Fab fragment derivatives with many potential applications. Copyright © 2016 Elsevier Inc. All rights reserved.

The preparation of F(ab')2 fragment and it's application in tumor radioimmunoimaging

International Nuclear Information System (INIS)

Yang Ziyi

1991-01-01

Monoclonal antibody against lung cancer was digested into F(ab') 2 fragment by pepsin and papain digestion. The yields of pure F(ab') 2 were 32.3 ± 5.5% and 52.3 ± 12.0% respectively. The immunoreactivity of F(ab') 2 was based on the ELISA assay and the cell binding studies was retained well. In the localization experiments, radioiodinated F(ab') 2 was injected intraperitoneally into the nude mice bearing human xenografts of lung cancer. The highest radioactivity in tumors, 1.37% of injected dose per gram, was reached on the first day after injection; its T/NT ratios were higher than those of the intact IgG in all tissues except kidney. The localization index (LI) in tumors was 4.95, while the average LI value of normal tissues was 1.25. After the injection of 131 I-F(ab') 2 intraperitoneally into lung tumor-bearing nude mice, photo scintigraphy was performed at intervals of 12 hrs. The xenografts were visualized distinctly during 36 ∼ 48 hr, and the nonspecific background was very low at 48 hr

Re-188 labelling of DD-3B6/22 Fab' monoclonal antibody fragment for radio immuno therapy

International Nuclear Information System (INIS)

Schmidt, P.F.; Smith, S.V.; Bundesen, P.

1996-01-01

The chemical similarity of technetium and rhenium has created much interest in the nuclear medicine field to make a 'matched pair' of radiopharmaceuticals for radioimmuno- diagnosis and therapy. Clinical trials with the 99 mTc-DD-3B6/22 Fab' has shown promise in the diagnosis of ovarian cancer. The design of the analogous therapeutic agent with rhenium-188 (155 keV γ 15 % abundant, β E max 2.1 MeV, T 1/2 17 h) is under investigation. The present study describes the approach taken for direct radiolabelling of the DD-3B6/22 Fab' with carrier-free 188 Re and its biological evaluation in balb/c and nude mice. The effect of temperature, pH and antibody concentration on the amount and rate of transchelation was also evaluated. The final product had a specific activity of 35 mCi/mg with an immunoreactive fraction of 77%. Stability of the product was assessed under various conditions: temperature, presence and absence of an inert atmosphere and presence of ascorbic acid (stabilised). Pharmacokinetics of the final product was evaluated in balb/c and nude mice transplanted with both D-dimer (+Ve) and Glycine (-Ve) beads. Results show that 188 Re DD-3B6/22 Fab' clears rapidly from the blood (α = 2.4 hr, β = 3.5 hr) and is excreted through the renal system. Localisation to subcutaneous antigen beads shows specific uptake to the D-dimer (antigen) beads was achieved within 6 h (0.23% ID) and was maintained for 24 hour post injection. Specificity to antigen implants was 5:1 (P 99m Tc DD-3B6/22 Fab' in mice. The radiolabelling procedures are congenial for therapeutic levels and hence the authors believe that the 188 Re DD-3B6/22 Fab' has some potential for use in treatment of ovarian cancer

'Zipbody' leucine zipper-fused Fab in E. coli in vitro and in vivo expression systems.

Science.gov (United States)

Ojima-Kato, Teruyo; Fukui, Kansuke; Yamamoto, Hiroaki; Hashimura, Dai; Miyake, Shiro; Hirakawa, Yuki; Yamasaki, Tomomi; Kojima, Takaaki; Nakano, Hideo

2016-04-01

A small antibody fragment, fragment of antigen binding (Fab), is favorable for various immunological assays. However, production efficiency of active Fab in microorganisms depends considerably on the clones. In this study, leucine zipper-peptide pairs that dimerize in parallel (ACID-p1 (LZA)/BASE-p1 (LZB) or c-Jun/c-Fos) were fused to the C-terminus of heavy chain (Hc, VH-CH1) and light chain (Lc, VL-CL), respectively, to accelerate the association of Hc and Lc to form Fab in Escherichia coli in vivo and in vitro expression systems. The leucine zipper-fused Fab named 'Zipbody' was constructed using anti-E. coli O157 monoclonal antibody obtained from mouse hybridoma and produced in both in vitro and in vivo expression systems in an active form, whereas Fab without the leucine zipper fusion was not. Similarly, Zipbody of rabbit monoclonal antibody produced in in vitro expression showed significant activity. The purified, mouse Zipbody produced in the E. coli strain Shuffle T7 Express had specificity toward the antigen; in bio-layer interferometry analysis, the KD value was measured to be 1.5-2.0 × 10(-8) M. These results indicate that leucine zipper fusion to Fab C-termini markedly enhances active Fab formation in E. coli. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Structure of anti-FLAG M2 Fab domain and its use in the stabilization of engineered membrane proteins

International Nuclear Information System (INIS)

Roosild, Tarmo P.; Castronovo, Samantha; Choe, Senyon

2006-01-01

The X-ray crystallographic analysis of anti-FLAG M2 Fab is reported and the implications of the structure on FLAG epitope binding are described as a first step in the development of a tool for the structural and biophysical study of membrane proteins. The inherent difficulties of stabilizing detergent-solubilized integral membrane proteins for biophysical or structural analysis demand the development of new methodologies to improve success rates. One proven strategy is the use of antibody fragments to increase the ‘soluble’ portion of any membrane protein, but this approach is limited by the difficulties and expense associated with producing monoclonal antibodies to an appropriate exposed epitope on the target protein. Here, the stabilization of a detergent-solubilized K + channel protein, KvPae, by engineering a FLAG-binding epitope into a known loop region of the protein and creating a complex with Fab fragments from commercially available anti-FLAG M2 monoclonal antibodies is reported. Although well diffracting crystals of the complex have not yet been obtained, during the course of crystallization trials the structure of the anti-FLAG M2 Fab domain was solved to 1.86 Å resolution. This structure, which should aid future structure-determination efforts using this approach by facilitating molecular-replacement phasing, reveals that the binding pocket appears to be specific only for the first four amino acids of the traditional FLAG epitope, namely DYKD. Thus, the use of antibody fragments for improving the stability of target proteins can be rapidly applied to the study of membrane-protein structure by placing the short DKYD motif within a predicted peripheral loop of that protein and utilizing commercially available anti-FLAG M2 antibody fragments

Localization of tumors in vivo by scintigraphic identification of Clostridium butyricum using 131I-labelled antibodies and F(ab')2-antibody fragments

International Nuclear Information System (INIS)

Vogt, R.; Mehnert, W.H.; Schmidt, H.E.; Altenbrunn, H.J.; Akademie der Wissenschaften der DDR, Berlin-Buch. Zentralinstitut fuer Isotopen- und Strahlenforschung)

1979-01-01

Tumor-bearing mice injected with clostridial spores show enrichment and germination of the spores within the tumor. 131 I-labelled anti-Clostridium-antibodies and anti-Clostridium-F(ab') 2 -fragments were used for a possible localization of tumors in vivo by scintiscanning. The application of the antibody revealed increased radioactivity in the tumors of mice pretreated with spores as well as in animals without pretreatment. In using F(ab') 2 -fragments instead of total antibody neither the apparently unspecific increase of radioactivity in not pretreated mice nor the specific fixation of labelled F(ab') 2 -fragments to clostridial rods in the tumors of pretreated animals could be demonstrated. The results are discussed with respect to further investigation

Monoclonal antibodies to Herpes Simplex Virus Type 2

International Nuclear Information System (INIS)

McLean-Pieper, C.S.

1982-01-01

In this thesis the production and characterisation of monoclonal antibodies to Herpes Simplex Virus Type 2 is described. The development of a suitable radioimmunoassay for the detection of anti-HSV-2 antibodies, and the selection of an optimal immunisation schedule, is given. Three assay systems are described and their reliability and sensitivity compared. (Auth.)

Time resolved native ion-mobility mass spectrometry to monitor dynamics of IgG4 Fab arm exchange and "bispecific" monoclonal antibody formation.

Science.gov (United States)

Debaene, François; Wagner-Rousset, Elsa; Colas, Olivier; Ayoub, Daniel; Corvaïa, Nathalie; Van Dorsselaer, Alain; Beck, Alain; Cianférani, Sarah

2013-10-15

Monoclonal antibodies (mAbs) and derivatives such as antibody-drug conjugates (ADC) and bispecific antibodies (bsAb), are the fastest growing class of human therapeutics. Most of the therapeutic antibodies currently on the market and in clinical trials are chimeric, humanized, and human immunoglobulin G1 (IgG1). An increasing number of IgG2s and IgG4s that have distinct structural and functional properties are also investigated to develop products that lack or have diminished antibody effector functions compared to IgG1. Importantly, wild type IgG4 has been shown to form half molecules (one heavy chain and one light chain) that lack interheavy chain disulfide bonds and form intrachain disulfide bonds. Moreover, IgG4 undergoes a process of Fab-arm exchange (FAE) in which the heavy chains of antibodies of different specificities can dissociate and recombine in bispecific antibodies both in vitro and in vivo. Here, native mass spectrometry (MS) and time-resolved traveling wave ion mobility MS (TWIM-MS) were used for the first time for online monitoring of FAE and bsAb formation using Hz6F4-2v3 and natalizumab, two humanized IgG4s which bind to human Junctional Adhesion Molecule-A (JAM-A) and alpha4 integrin, respectively. In addition, native MS analysis of bsAb/JAM-A immune complexes revealed that bsAb can bind up to two antigen molecules, confirming that the Hz6F4 family preferentially binds dimeric JAM-A. Our results illustrate how IM-MS can rapidly assess bsAb structural heterogeneity and be easily implemented into MS workflows for bsAb production follow up and bsAb/antigen complex characterization. Altogether, these results provide new MS-based methodologies for in-depth FAE and bsAb formation monitoring. Native MS and IM-MS will play an increasing role in next generation biopharmaceutical product characterization like bsAbs, antibody mixtures, and antibody-drug conjugates (ADC) as well as for biosimilar and biobetter antibodies.

Structure of Rotavirus Outer-Layer Protein VP7 Bound with a Neutralizing Fab

Energy Technology Data Exchange (ETDEWEB)

Aoki, Scott T.; Settembre, Ethan C.; Trask, Shane D.; Greenberg, Harry B.; Harrison, Stephen C.; Dormitzer, Philip R.; (Stanford-MED); (CH-Boston)

2009-06-17

Rotavirus outer-layer protein VP7 is a principal target of protective antibodies. Removal of free calcium ions (Ca{sup 2+}) dissociates VP7 trimers into monomers, releasing VP7 from the virion, and initiates penetration-inducing conformational changes in the other outer-layer protein, VP4. We report the crystal structure at 3.4 angstrom resolution of VP7 bound with the Fab fragment of a neutralizing monoclonal antibody. The Fab binds across the outer surface of the intersubunit contact, which contains two Ca{sup 2+} sites. Mutations that escape neutralization by other antibodies suggest that the same region bears the epitopes of most neutralizing antibodies. The monovalent Fab is sufficient to neutralize infectivity. We propose that neutralizing antibodies against VP7 act by stabilizing the trimer, thereby inhibiting the uncoating trigger for VP4 rearrangement. A disulfide-linked trimer is a potential subunit immunogen.

99mTc-Labeling of Monoclonal Antibody to Carcinoembryonic Antigen and Biodistribution

International Nuclear Information System (INIS)

Moon, Dae Hyuk; Chung, June Key; Lee, Myu ng Chul; Koh, Chang Soon; Chung, Hong Keun; Park, Jae Gahb

1992-01-01

This study was designed to evaluate a direct method of 99m Tc labeling using β-mercaptoethanol as a reducing agent, and to investigate whether 99m Tc labeled specific monoclonal antibody against carcinoembryonic antigen (CEA-92) can be used for the scintigraphic localization of human colon cancer xenograft. Purified CEA-92 IgG was fragmented into F(ab') 2 and then labeled with 99m Tc by transchelation method using glucarate as a chelator. Labeling efficiency, immunological reactivity and in vitro stability of 99m Tc CEA-92 F(ab') 2 were measured and then injected intravenously into nude mice bearing human colon cancer (SNU-C4). Scintigrams were obtained at 24 hour after injection. Then nude mice were sacrificed and the radioactivity was measured. Labeling efficiency of injected 99m Tc CEA-92 F(ab') 2 , immunoreactive fraction and in vitro stability at 24 hour of injected 99m Tc CEA-92 F(ab') 2 was 45.2%, 32.8% and 57.4%, respectively. At 24 hour after injection, %ID/g in kidney (46.77) showed high uptake, but %ID/g in tumor (1.65) was significantly higher than spleen (0.69), muscle (0.16), intestine (0.45), stomach (0.75), heart (0.48) and blood(0.45). There was no significant difference between tumor and liver (1.81). Tumor contrast as quantitated by tumor to blood ratio of 99m Tc CEA-92 F(ab') 2 was increased significantly (p 131 I-CEA-92 F(ab') 2 . The scintigram demonstrated localization of radioactivity over transplanted tumor, but significant background radioactivity was also noted over kidney and abdomen. It is concluded that CEA-92 F(ab') 2 can be labeled with 99m Tc by a direct transchelation method using β-mercaptoethanol as a reducing agent and 99m Tc labeled CEA-92 F(ab') 2 can be used for the scintigraphic localization of human colon cancer xenograft in nude mice model.

Induction and characterization of monoclonal anti-idiotypic antibodies reactive with idiotopes of canine parvovirus neutralizing monoclonal antibodies.

NARCIS (Netherlands)

G.F. Rimmelzwaan (Guus); J. van Es (Johan); G.A. Drost; F.G.C.M. Uytdehaag (Fons); A.D.M.E. Osterhaus (Albert)

1991-01-01

textabstractMonoclonal anti-idiotypic (anti-Id) antibodies (Ab2) were generated against idiotypes (Id) of canine parvovirus (CPV) specific monoclonal antibodies (MoAbs). The binding of most of these anti-Id antibodies to their corresponding Id could be inhibited by antigen, thus classifying these

Experimental and clinical analysis of the characteristics of a chimeric monoclonal antibody, MOv18, reactive with an ovarian cancer-associated antigen

NARCIS (Netherlands)

Molthoff, C. F.; Buist, M. R.; Kenemans, P.; Pinedo, H. M.; Boven, E.

1992-01-01

Monoclonal antibody (Mab) MOv18 preferentially reacts with gynecological carcinomas. We have analyzed the characteristics of murine MOv18 (m-MOv18) and chimeric MOv18 (c-MOv18). We found no differences in affinity and binding to IGROV1 cells between c-MOv18 as IgG and F(ab')2 fragments and m-MOv18.

Efficient production of Trastuzumab Fab antibody fragments in Brevibacillus choshinensis expression system.

Science.gov (United States)

Mizukami, Makoto; Onishi, Hiromasa; Hanagata, Hiroshi; Miyauchi, Akira; Ito, Yuji; Tokunaga, Hiroko; Ishibashi, Matsujiro; Arakawa, Tsutomu; Tokunaga, Masao

2018-10-01

The Brevibacillus expression system has been successfully employed for the efficient productions of a variety of recombinant proteins, including enzymes, cytokines, antigens and antibody fragments. Here, we succeeded in secretory expression of Trastuzumab Fab antibody fragments using B. choshinensis/BIC (Brevibacillus in vivocloning) expression system. In the fed-batch high-density cell culture, recombinant Trastuzumab Fab with amino-terminal His-tag (His-BcFab) was secreted at high level, 1.25 g/liter, and Fab without His-tag (BcFab) at ∼145 mg/L of culture supernatant. His-BcFab and BcFab were purified to homogeneity using combination of conventional column chromatographies with a yield of 10-13%. This BcFab preparation exhibited native structure and functions evaluated by enzyme-linked immunosorbent assay, surface plasmon resonance, circular dichroism measurements and size exclusion chromatography. To our knowledge, this is the highest production of Fab antibody fragments in gram-positive bacterial expression/secretion systems. Copyright © 2018 Elsevier Inc. All rights reserved.

A human monoclonal antibody drug and target discovery platform for B-cell chronic lymphocytic leukemia based on allogeneic hematopoietic stem cell transplantation and phage display.

Science.gov (United States)

Baskar, Sivasubramanian; Suschak, Jessica M; Samija, Ivan; Srinivasan, Ramaprasad; Childs, Richard W; Pavletic, Steven Z; Bishop, Michael R; Rader, Christoph

2009-11-12

Allogeneic hematopoietic stem cell transplantation (alloHSCT) is the only potentially curative treatment available for patients with B-cell chronic lymphocytic leukemia (B-CLL). Here, we show that post-alloHSCT antibody repertoires can be mined for the discovery of fully human monoclonal antibodies to B-CLL cell-surface antigens. Sera collected from B-CLL patients at defined times after alloHSCT showed selective binding to primary B-CLL cells. Pre-alloHSCT sera, donor sera, and control sera were negative. To identify post-alloHSCT serum antibodies and subsequently B-CLL cell-surface antigens they recognize, we generated a human antibody-binding fragment (Fab) library from post-alloHSCT peripheral blood mononuclear cells and selected it on primary B-CLL cells by phage display. A panel of Fab with B-CLL cell-surface reactivity was strongly enriched. Selection was dominated by highly homologous Fab predicted to bind the same antigen. One Fab was converted to immunoglobulin G1 and analyzed for reactivity with peripheral blood mononuclear cells from B-CLL patients and healthy volunteers. Cell-surface antigen expression was restricted to primary B cells and up-regulated in primary B-CLL cells. Mining post-alloHSCT antibody repertoires offers a novel route to discover fully human monoclonal antibodies and identify antigens of potential therapeutic relevance to B-CLL and possibly other cancers. Trials described herein were registered at www.clinicaltrials.gov as nos. NCT00055744 and NCT00003838.

Binding of monoclonal antibody to protein antigen in fluid phase or bound to solid supports

Energy Technology Data Exchange (ETDEWEB)

Kennel, S J

1982-01-01

Rat monoclonal antibody (MoAb) to fragment D (FgD) of human fibrinogen was used to characterize the direct binding of antibody to protein in solution or bound to solid supports. Purified IgG, F(ab')/sub 2/ and Fab' were prepared from ascites fluid of hybridoma 104-14B which is a fusion product of spleen cells from a rat immunized with FgD and the mouse myeloma cell line, P3-X63-Ag8. Two-dimensional electrophoresis of radioiodinated antibody preparations demonstrated the presence of hybrid immunoglobulin molecules, but only structures having rat heavy and rat light chains had active antibody combinig sites. The affinity constant for IgG as well as F(ab')/sub 2/ and Fab', 6x10/sup 9/ M/sup -1/, was identical when tested using fluid phase antigen (/sup 125/I-labeled FgD). Affinity constants determined for direct binding of iodinated IgG using FgD immobilized on solid supports showed a slight dependence on the antigen concentration used in the measurement. These values ranged from 0.5x10/sup 9/ M/sup -1/ at high antigen concentrations (1.3x10/sup -7/ M) to 9x10/sup 9/ M/sup -1/ at low antigen concentration (1.3x10/sup -10/ M). Binding constants for F(ab')/sub 2/ and Fab' gave similar results indicating that binding was homogeneous and univalent. The capacity of solid state antigen to bind antibody varied with the method used to bind FgD to the solid support. FgD bound directly to polystyrene plates was least efficient at binding labeled antibody; FgD bound to plates through intermediate carriers poly(L-lysine) was only slightly more efficient, while antigen bound to Sepharose beads by cyanogen bromide activation was the most active.

At least two Fc Neu5Gc residues of monoclonal antibodies are required for binding to anti-Neu5Gc antibody

OpenAIRE

Yu, Chuanfei; Gao, Kai; Zhu, Lei; Wang, Wenbo; Wang, Lan; Zhang, Feng; Liu, Chunyu; Li, Meng; Wormald, Mark R.; Rudd, Pauline M.; Wang, Junzhi

2016-01-01

Two non-human glycan epitopes, galactose-Į-1,3-galactose (Į-gal) and Neu5Gc-Į-2-6-galactose (Neu5Gc) have been shown to be antigenic when attached to Fab oligosaccharides of monoclonal antibodies (mAbs) , while Į-gal attached to Fc glycans were not. However, the antigenicity of Neu5Gc on the Fc glycans remains unclear in the context that most mAbs carry only Fc glycans. After studying two clinical mAbs carrying significant amounts of Fc Neu5Gc, we show that their binding activity with anti-Ne...

Characterization of a monoclonal antibody that specifically inhibits triosephosphate isomerase activity of Taenia solium.

Science.gov (United States)

Víctor, Sanabria-Ayala; Yolanda, Medina-Flores; Araceli, Zavala-Carballo; Lucía, Jiménez; Abraham, Landa

2013-08-01

In the present study, we obtained and characterized partially a monoclonal antibody (4H11D10B11 mAb) against triosephosphate isomerase from Taenia solium (TTPI). This antibody recognized the enzyme by both ELISA and western blot and was able to inhibit its enzymatic activity in 74%. Moreover, the antigen-binding fragments (Fabs), products of digestion of the monoclonal antibody with papain, retained almost the same inhibitory effect. We determined the binding site by ELISA; synthetic peptides containing sequences from different non-conserved regions of the TTPI were confronted to the 4H11D10B11 mAb. The epitope recognized by the monoclonal antibody was located on peptide TTPI-56 (ATPAQAQEVHKVVRDWIRKHVDAGIADKARI), and an analysis of mimotopes, obtained with the 4H11D10B11 mAb, suggests that the epitope spans the sequence WIRKHVDAGIAD, residues 193-204 of the enzyme. This epitope is located within helix 6, next to loop 6, an essential active loop during catalysis. The antibody did not recognize triosephosphate isomerase from man and pig, definitive and intermediary hosts of T. solium, respectively. Furthermore, it did not bind to the catalytic site, since kinetic analysis demonstrated that inhibition had a non-competitive profile. Copyright © 2013 Elsevier Inc. All rights reserved.

Distribution and pharmacokinetics of radiolabeled monoclonal antibody OC 125 after intravenous and intraperitoneal administration in gynecologic tumors

International Nuclear Information System (INIS)

Haisma, H.J.; Moseley, K.R.; Battaile, A.; Griffiths, T.C.; Knapp, R.C.

1988-01-01

Radiolabeled monoclonal antibodies may be useful for radioimmunotherapy of gynecologic tumors. Iodine 131-labeled F(ab')2 fragments of a monoclonal antibody, OC 125, with specificity for ovarian carcinoma, were used to study the distribution and pharmacokinetics of this antibody in patients with gynecologic tumors. The radiolabeled antibody was injected intravenously or intraperitoneally into 10 patients suspected of having ovarian cancer. Blood and urine samples were used for pharmacokinetic studies, and biopsy specimens were examined for the uptake of antibody. The serum half-life of the labeled antibody was 30 hours after intravenous administration, with 20% of the injected dose per liter detected at 24 hours. After intraperitoneal injection, the appearance of antibody in serum was slow, with a maximum level of 1.4% of the injected dose per liter at 24 hours. Urinary excretion of the radiolabeled antibody was similar for intravenous and intraperitoneal administration, with approximately 50% of the injected dose excreted after 48 hours. Intraperitoneal administration of the radiolabeled antibody resulted in a higher uptake of antibody in the tumor and a lower uptake of antibody in normal tissues. On the basis of this limited study, intraperitoneal administration of radiolabeled antibody is preferred over intravenous administration for radioimmunotherapy of ovarian cancer

Production and purification of polyclonal antibody against F(ab')2 fragment of human immunoglobulin G

OpenAIRE

Nasiri, Hadi; Valedkarimi, Zahra; Aghebati-Maleki, Leili; Abdolalizadeh, Jalal; Kazemi, Tohid; Esparvarinha, Mojghan; Majidi, Jafar

2017-01-01

Antibodies are essential tools of biomedical and biochemical researches. Polyclonal antibodies are produced against different epitopes of antigens. Purified F(ab')2 can be used for animal’s immunization to produce polyclonal antibodies. Human immunoglobulin G (IgG) was purified by ion exchange chromatography method. In all stages verification method of the purified antibodies was sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Purified IgG was digested by pepsin enzyme a...

Charge-mediated Fab-Fc interactions in an IgG1 antibody induce reversible self-association, cluster formation, and elevated viscosity.

Science.gov (United States)

Arora, Jayant; Hu, Yue; Esfandiary, Reza; Sathish, Hasige A; Bishop, Steven M; Joshi, Sangeeta B; Middaugh, C Russell; Volkin, David B; Weis, David D

Concentration-dependent reversible self-association (RSA) of monoclonal antibodies (mAbs) poses a challenge to their pharmaceutical development as viable candidates for subcutaneous delivery. While the role of the antigen-binding fragment (Fab) in initiating RSA is well-established, little evidence supports the involvement of the crystallizable fragment (Fc). In this report, a variety of biophysical tools, including hydrogen exchange mass spectrometry, are used to elucidate the protein interface of such non-covalent protein-protein interactions. Using dynamic and static light scattering combined with viscosity measurements, we find that an IgG1 mAb (mAb-J) undergoes RSA primarily through electrostatic interactions and forms a monomer-dimer-tetramer equilibrium. We provide the first direct experimental mapping of the interface formed between the Fab and Fc domains of an antibody at high protein concentrations. Charge distribution heterogeneity between the positively charged interface spanning complementarity-determining regions CDR3H and CDR2L in the Fab and a negatively charged region in C H 3/Fc domain mediates the RSA of mAb-J. When arginine and NaCl are added, they disrupt RSA of mAb-J and decrease the solution viscosity. Fab-Fc domain interactions between mAb monomers may promote the formation of large transient antibody complexes that ultimately cause increases in solution viscosity. Our findings illustrate how limited specific arrangements of amino-acid residues can cause mAbs to undergo RSA at high protein concentrations and how conserved regions in the Fc portion of the antibody can also play an important role in initiating weak and transient protein-protein interactions.

Biodistribution of an anti-interleukin 2 receptor monoclonal antibody in rat recipients of a heart allograft, and its use as a rejection marker in gamma scintigraphy

International Nuclear Information System (INIS)

Thedrez, P.; Paineau, J.; Jacques, Y.; Chatal, J.F.; Pelegrin, A.; Bouchaud, C.; Soulillou, J.P.

1989-01-01

Anti-interleukin-2 receptor monoclonal antibodies have been shown to prevent allograft rejection. This paper reports on the biodistribution of a mouse MoAb directed at the 55 Kd alpha chain of rat interleukin-2 receptor (IL2-R) during allograft rejection. Only a low percentage (approximately 1%) of intact 125I-labeled MoAb was detected in the rejected graft, and irrelevant control IgG1 was found at a similar level. This suggests that most of the injected intact MoAb bound to graft tissue via its monomorphic Fc segment. In contrast, OX39 F(ab')2 fragments showed a preferential localization in the rejected allograft and did not bind to the LEW-to-LEW syngeneic heart graft. Irrelevant F(ab')2 did not concentrate in the allogeneic graft. Accordingly, F(ab')2 fragments from OX39 or irrelevant MoAb were used for gamma-scintigraphy on allograft recipients together with biodistribution studies. Results show that scintigraphy was able to detect allograft accumulation of 131I OX39 F(ab')2, whereas no imaging was obtained when OX39 F(ab')2 was used in the syngeneic combination or when irrelevant 131-IgG1 F(ab')2 was given to allograft recipients. This method, applied to the clinical situation, could be of interest for detection of early graft rejection episodes by immunoscintigraphy using reagents specific for activation determinants on lymphocyte membranes, such as anti-interleukin-2 receptor MoAb

Uses of monoclonal antibody 8H9

Science.gov (United States)

Cheung, Nai-Kong V.

2013-04-09

This invention provides a composition comprising an effective amount of monoclonal antibody 8H9 or a derivative thereof and a suitable carrier. This invention provides a pharmaceutical composition comprising an effective amount of monoclonal antibody 8H9 or a derivative thereof and a pharmaceutically acceptable carrier. This invention also provides an antibody other than the monoclonal antibody 8H9 comprising the complementary determining regions of monoclonal antibody 8H9 or a derivative thereof, capable of binding to the same antigen as the monoclonal antibody 8H9. This invention provides a substance capable of competitively inhibiting the binding of monoclonal antibody 8H9. This invention also provides an isolated scFv of monoclonal antibody 8H9 or a derivative thereof. This invention also provides the 8H9 antigen. This invention also provides different uses of the monoclonal antibody 8H9 or its derivative.

Radiolabeled monoclonal antibody 15 and its fragments for localization and imaging of xenografts of human lung cancer

International Nuclear Information System (INIS)

Endo, K.; Kamma, H.; Ogata, T.

1988-01-01

Monoclonal antibody (MAb) 15 and its F(ab')2 and Fab fragments were radioiodinated, and their biodistribution and imaging were compared in BALB/c nude mice bearing a xenograft of a human lung cancer (TKB-2). Association constants for 125I-labeled MAb 15 IgG, F(ab')2, and Fab were 1.9 X 10(9), 1.8 X 10(9), and 3.7 X 10(8) M-1, respectively. Immunoreactive fractions ranged from 0.59 to 0.50. Cultured TKB-2 cells expressed 1.1 X 10(4) binding sites/cell for MAb 15 IgG in vitro. The binding of a control antibody and the binding of its fragments to TKB-2 cells were less than 3% of the input doses. The mice with the TKB-2 tumors were given simultaneous injections of 10 microCi of 131I-labeled MAb 15 or its fragments and 10 microCi of 125I-labeled control IgG or its fragments. With MAb 15 IgG, the percentage of the injected dose bound per gram of tissue (ID/g) of the tumor was 3.68% at day 7, when the localization index (LI) was 4.38. At day 2 after MAb 15 F(ab')2 injection, 1.12% of the ID/g was localized in the tumor and the LI was 3.04. After MAb 15 Fab injection, the percentage of the ID/g of the tumor was 0.31% and the LI was 2.58 at day 1. MAb 15 IgG, F(ab')2, and Fab cleared from the blood early, with a half-life of 33, 16, and 9 hours, respectively. The distributions of MAb 15 and its fragments in the normal organs did not differ from those of the control. Radioimaging with 100 microCi of 131I-labeled MAb 15 and its fragments showed that 42%, 44%, and 32% of the total-body count were localized in the tumor with IgG at day 7, F(ab')2 at day 2, or Fab at day 1, respectively. Because the radioactivity remaining in the tumor with Fab was low, the image was insufficient. Throughout the period, less than 10% of the control IgG and its fragments remained in the tumor. Microautoradiography confirmed the binding of MAb 15 and its fragments to the tumor cells

Radioimmunotherapy of human colon cancer xenografts by using 131I labeled-CAb1 F(ab')2

International Nuclear Information System (INIS)

Li Ling; Xu Huiyun; Mi Li; Bian Huijie; Qin Jun; Xiong Hua; Feng Qiang; Wen Ning; Tian Rong; Xu Liqing; Shen Xiaomei; Tang Hao; Chen Zhinan

2006-01-01

Purpose: Therapeutic efficacy, suitable dose, and administration times of 131 I-CAb 1 F(ab') 2 , a new monoclonal antibody therapeutics specifically directed against a cell surface-associated glycoprotein of colon cancer, were investigated in this article. Methods and Materials: In human colon cancer xenografts, 131 I-CAb 1 F(ab') 2 at the dose of 125 μCi, 375 μCi, and 1125 μCi were administrated intraperitoneally on Days 6 and 18 after implantation of HR8348 cells with CAb 1 high reactivity. Survival time and tumor growth inhibition rate were used to evaluate the efficacy and safety of 131 I-CAb 1 F(ab') 2 in treatment of colon cancer xenografts. Results: Treatment of 125, 375, and 1125 μCi 131 I-CAb1 F(ab') 2 did not significantly decrease the mean survival time of nude mice when compared with nontreated groups (p = 0.276, 0.865, 0.582, respectively). Moreover, the mean survival times of nude mice receiving 375 μCi and 1125 μCi 131 I-CAb1 F(ab') 2 were significantly longer than that of 5-FU-treated groups (p 0.018 and 0.042). Tumor growth inhibition rates of the first therapy were 35.67% and 41.37%, with corresponding 131 I-labeled antibody dosage of 375 μCi and 1125 μCi. After single attack dosage, second reinforcement therapy may rise efficacy significantly. Tumor growth inhibition rates of 125 μCi, 375 μCi, and 1125 μCi 131 I-labeled antibody on Day 20 posttherapy were 42.65%, 56.56%, and 84.41%, respectively. Histopathology examination revealed that tissue necrosis of various degrees was found in 131 I-CAb1 F(ab') 2 -treated groups. Conclusion: 131 I-CAb 1 F(ab') 2 is safe and effective for colon cancer. It may be a novel and potentially adjuvant therapeutics for colon cancer

Production of Monoclonal Antibodies specific for Progesterone

OpenAIRE

YÜCEL, Fatıma

2014-01-01

Progesterone levels in milk and serum are indicators of pregnancy in cattle. The progesterone level reaches a peak on the 21 st and 22 nd days of pregnancy. Monoclonal antibodies specific to progesterone could be used for the immunodetection of milk and serum progesterone levels. We report here the development of hybrid cells prdoducing monoclonal antibodies specific for progesterone using hybridoma technology. Hybridoma cells secreting monoclonal antibodies against progesterone (MAM 2H1...

Selective disulfide reduction for labeling and enhancement of Fab antibody fragments

International Nuclear Information System (INIS)

Kirley, Terence L.; Greis, Kenneth D.; Norman, Andrew B.

2016-01-01

Many methods have been developed for chemical labeling and enhancement of the properties of antibodies and their common fragments, including the Fab and F(ab’) 2 fragments. Somewhat selective reduction of some antibody disulfide bonds has been previously achieved, yielding antibodies and antibody fragments that can be labeled at defined sites, enhancing their utility and properties. Selective reduction of the two hinge disulfide bonds present in F(ab’) 2 fragments using mild reduction has been useful. However, such reduction is often not quantitative and results in the reduction of multiple disulfide bonds, and therefore subsequent multiple labeling or conjugation sites are neither homogenous nor stoichiometric. Here, a simple and efficient selective reduction of the single disulfide bond linking the partial heavy chain and the intact light chain which compose the Fab fragment is accomplished utilizing tris(2-carboxyethyl)phosphine (TCEP) immobilized on agarose beads. The resultant reduced cysteine residues were labeled with several cysteine-selective fluorescent reagents, as well as by cysteine-directed PEGylation. These two cysteine residues can also be re-ligated by means of a bifunctional cysteine cross-linking agent, dibromobimane, thereby both restoring a covalent linkage between the heavy and light chains at this site, far removed from the antigen binding site, and also introducing a fluorescent probe. There are many other research and clinical uses for these selectively partially reduced Fab fragments, including biotinylation, toxin and drug conjugation, and incorporation of radioisotopes, and this technique enables simple generation of very useful Fab fragment derivatives with many potential applications. - Highlights: • TCEP agarose is effective for selective reduction of a single Fab disulfide bond. • This disulfide is solvent accessible and distant from the antigen binding site. • A variety of buffers of varying pHs can be used, simplifying

Optimization of IGF-1R SPECT/CT Imaging Using In-111-Labeled F(ab ')(2) and Fab Fragments of Article the Monoclonal Antibody R1507

NARCIS (Netherlands)

Heskamp, Sandra; van Laarhoven, Hanneke W. M.; Molkenboer-Kuenen, Janneke D. M.; Bouwman, Wilbert H.; van der Graaf, Winette T. A.; Oyen, Wim J. G.; Boerman, Otto C.

2012-01-01

The insulin-like growth factor 1 receptor (IGF-1R) is a potential new target for the treatment of breast cancer. Patients with breast cancer lesions that express IGF-1R may benefit from treatment with anti-IGF-IR antibodies. IGF-1R expression can be visualized using radiolabeled R1507, a monoclonal

Uses of monoclonal antibody 8H9

Energy Technology Data Exchange (ETDEWEB)

Cheung, Nai-Kong V.

2018-04-10

This invention provides a composition comprising an effective amount of monoclonal antibody 8H9 or a derivative thereof and a suitable carrier. This invention provides a pharmaceutical composition comprising an effective amount of monoclonal antibody 8H9 or a derivative thereof and a pharmaceutically acceptable carrier. This invention also provides an antibody other than the monoclonal antibody 8H9 comprising the complementary determining regions of monoclonal antibody 8H9 or a derivative thereof, capable of binding to the same antigen as the monoclonal antibody 8H9. This invention provides a substance capable of competitively inhibiting the binding of monoclonal antibody 8H9. This invention also provides an isolated scFv of monoclonal antibody 8H9 or a derivative thereof. This invention also provides the 8H9 antigen. This invention also provides a method of inhibiting the growth of tumor cells comprising contacting said tumor cells with an appropriate amount of monoclonal antibody 8H9 or a derivative thereof.

Current diagnostic efficacy of Tc-99m-labeled antitumor antibodies

International Nuclear Information System (INIS)

Morrison, R.T.; Lyster, D.M.; Szasz, I.; Alcorn, L.N.; Rhodes, B.A.; Breslow, K.; Burchiel, S.W.

1983-01-01

The authors have recently evaluated technetium 99 labeled antibodies specific to human chorionic gonadotropin (hCG) for the in vivo detection of a variety of human tumors. Both mouse monoclonal and sheep polyclonal antibodies were evaluated in this study. Another antibody specific to hCG studied, is an antigen-agglutinating monoclonal F(ab') 2 fragment. Some preliminary results are reported

N-succinimidyl 4-methyl-3-(tri-n-butylstannyl)benzoate: synthesis and potential utility for the radioiodination of monoclonal antibodies

International Nuclear Information System (INIS)

Garg, P.K.; Garg, S.; Zalutsky, M.R.

1993-01-01

N-Succinimidyl 4-methyl-3-(tri-n-butylstannyl)benzoate (MATE) was synthesized in two steps from 4-methyl-3-iodobenzoic acid. Radioiododestannylation of MATE proceeded more slowly than N-succinimidyl 3-(tri-n-butylstannyl)benzoate (ATE), but for reaction periods of 10 min, identical yields were obtained. Paired-label biodistribution studies were performed in mice with an intact monoclonal antibody and an F(ab') 2 fragment labeled using MATE, ATE and Iodogen. Thyroid uptake with MATE was low, comparable to that seen with ATE, and considerably lower than that observed when the Iodogen method was used. With the F(ab') 2 fragment, kidney uptake using MATE was 8-fold higher than that observed when either the ATE or Iodogen methods were used. (Author)

Monoclonal antibodies to Pneumocystis carinii

DEFF Research Database (Denmark)

Kovacs, J A; Halpern, J L; Lundgren, B

1989-01-01

To increase understanding of the antigenic structure of Pneumocystis carinii, we developed monoclonal antibodies to rat and human P. carinii. The specificity of the antibodies was demonstrated by immunofluorescence and immunoblot studies. Only one of five monoclonal antibodies to rat P. carinii r...

Higher cytotoxicity of divalent antibody-toxins than monovalent antibody-toxins

International Nuclear Information System (INIS)

Won, JaeSeon; Nam, PilWon; Lee, YongChan; Choe, MuHyeon

2009-01-01

Recombinant antibody-toxins are constructed via the fusion of a 'carcinoma-specific' antibody fragment to a toxin. Due to the high affinity and high selectivity of the antibody fragments, antibody-toxins can bind to surface antigens on cancer cells and kill them without harming normal cells [L.H. Pai, J.K. Batra, D.J. FitzGerald, M.C. Willingham, I. Pastan, Anti-tumor activities of immunotoxins made of monoclonal antibody B3 and various forms of Pseudomonas exotoxin, Proc. Natl. Acad. Sci. USA 88 (1991) 3358-3362]. In this study, we constructed the antibody-toxin, Fab-SWn-PE38, with SWn (n = 3, 6, 9) sequences containing n-time repeated (G 4 S) between the Fab fragment and PE38 (38 kDa truncated form of Pseudomonas exotoxin A). The SWn sequence also harbored one cysteine residue that could form a disulfide bridge between two Fab-SWn-PE38 monomers. We assessed the cytotoxicity of the monovalent (Fab-SWn-PE38), and divalent ([Fab-SWn-PE38] 2 ) antibody-toxins. The cytotoxicity of the dimer against the CRL1739 cell line was approximately 18.8-fold higher than that of the monomer on the ng/ml scale, which was approximately 37.6-fold higher on the pM scale. These results strongly indicate that divalency provides higher cytotoxicity for an antibody-toxin.

Protein crystallization with microseed matrix screening: application to human germline antibody Fabs

International Nuclear Information System (INIS)

Obmolova, Galina; Malia, Thomas J.; Teplyakov, Alexey; Sweet, Raymond W.; Gilliland, Gary L.

2014-01-01

The power of microseed matrix screening is demonstrated in the crystallization of a panel of antibody Fab fragments. The crystallization of 16 human antibody Fab fragments constructed from all pairs of four different heavy chains and four different light chains was enabled by employing microseed matrix screening (MMS). In initial screening, diffraction-quality crystals were obtained for only three Fabs, while many Fabs produced hits that required optimization. Application of MMS, using the initial screens and/or refinement screens, resulted in diffraction-quality crystals of these Fabs. Five Fabs that failed to give hits in the initial screen were crystallized by cross-seeding MMS followed by MMS optimization. The crystallization protocols and strategies that resulted in structure determination of all 16 Fabs are presented. These results illustrate the power of MMS and provide a basis for developing future strategies for macromolecular crystallization

Pre- and Posttransplant IgA Anti-Fab Antibodies to Predict Long-term Kidney Graft Survival.

Science.gov (United States)

Amirzargar, M A; Amirzargar, A; Basiri, A; Hajilooi, M; Roshanaei, G; Rajabi, G; Solgi, G

2015-05-01

Immunologic factors are reliable markers for allograft monitoring, because of their seminal role in rejection process. One of these factors is the immunoglobulin (Ig)A anti-Fab of the IgG antibody. This study aimed to evaluate the predictive value of pre- and posttransplant levels of this marker for kidney allograft function and survival. Sera samples of 59 living unrelated donor kidney recipients were collected before and after transplantation (days 7, 14, and 30) and investigated for IgA anti-Fab of IgG antibody levels using enzyme-linked immunosorbent assay in relation with allograft outcome. Among 59 patients, 15 cases (25%) including 10 with acute rejection and 5 with chronic rejection episodes showed graft failure during a mean of 5 years of follow-up. High posttransplant levels of IgA anti-Fab antibodies were observed more frequently in patients with stable graft function (SGF) compared with patients with graft failure (P = 2 × 10(-6)). None of patients with acute or chronic rejection episodes had high levels of IgA anti-Fab antibodies at day 30 posttransplant compared with the SGF group (P = 10(-6) and P = .01, respectively). In addition, high levels of IgA anti-Fab antibody correlated with lesser concentration of serum creatinine at 1 month posttransplantation (P = .01). Five-year graft survival was associated with high levels of pre- and posttransplant IgA anti-Fab antibodies (P = .02 and P = .003, respectively). Our findings indicate the protective effect of higher levels of IgA anti-Fab antibodies regarding to kidney allograft outcomes and long-term graft survival. Copyright © 2015 Elsevier Inc. All rights reserved.

A novel human Fab antibody for Trop2 inhibits breast cancer growth in vitro and in vivo.

Science.gov (United States)

Lin, Hong; Zhang, Huiling; Wang, Jun; Lu, Meiping; Zheng, Feng; Wang, Changjun; Tang, Xiaojun; Xu, Ning; Chen, Renjie; Zhang, Dawei; Zhao, Ping; Zhu, Jin; Mao, Yuan; Feng, Zhenqing

2014-03-01

Human trophoblastic cell surface antigen 2 (Trop2) has been suggested as an oncogene, which is associated with the different types of tumors. In this study, a human Fab antibody against Trop2 extracellular domain was isolated from phage library by phage display technology, and characterized by ELISA, FACS, fluorescence staining and Western blotting analysis. MTT, apoptosis assay and wound healing assay were employed to evaluate the inhibitory effects of Trop2 Fab on breast cancer cell growth in vitro, while tumor-xenograft model was employed to evaluate the inhibitory effects on breast cancer growth in vivo. The results showed that Trop2 Fab inhibited the proliferation, induced the apoptosis and suspended the migration of MDA-MB-231 cells in a dose dependent manner. The expression caspase-3 was activated, and the expression of Bcl-2 was reduced while that of Bax was elevated in MDA-MB-231 cells by treating with Trop2 Fab. In addition, Trop2 Fab inhibited the growth of breast cancer xenografts and the expression of Bcl-2 was reduced while that of Bax was elevated in xenografts. Trop2 Fab, which was isolated successfully in this research, is a promising therapeutic agent for the treatment of Trop2 expressing breast cancer. © 2013 UICC.

Tumor detection using radiolabeled monoclonal antibodies

International Nuclear Information System (INIS)

Moldofsky, P.J.; Powe, J.; Hammond, N.D.

1987-01-01

Radioisotope conjugated to monoclonal antibody products has been used for imaging tumors targeted by the antibody. As imaging progresses, new sets of procedural and technical questions arise. In this chapter, we discuss several current problems in imaging tumor with radiolabeled monoclonal antibody. These include (1) methods for selection of specific antibody and, once the particular antibody is selected, which fragment form is to be used; (2) imaging procedures: what are the optimum imaging parameters, such as optimum time for imaging after administration of tracer and considerations regarding background subtraction; and (3) noninvasive quantitative techniques: quantitation of localization of antibody indirectly from quantitative information in the images.100 references

Therapeutic Recombinant Monoclonal Antibodies

Science.gov (United States)

Bakhtiar, Ray

2012-01-01

During the last two decades, the rapid growth of biotechnology-derived techniques has led to a myriad of therapeutic recombinant monoclonal antibodies with significant clinical benefits. Recombinant monoclonal antibodies can be obtained from a number of natural sources such as animal cell cultures using recombinant DNA engineering. In contrast to…

Crystal structure of the antigen-binding fragment of a monoclonal antibody specific for the multidrug-resistance-linked ABC transporter human P-glycoprotein

Energy Technology Data Exchange (ETDEWEB)

Esser, Lothar; Shukla, Suneet; Zhou, Fei; Ambudkar, Suresh V.; Xia, Di

2016-07-27

P-glycoprotein (P-gp) is a polyspecific ATP-dependent transporter linked to multidrug resistance in cancers that plays important roles in the pharmacokinetics of a large number of drugs. The drug-resistance phenotype of P-gp can be modulated by the monoclonal antibody UIC2, which specifically recognizes human P-gp in a conformation-dependent manner. Here, the purification, sequence determination and high-resolution structure of the Fab fragment of UIC2 (UIC2/Fab) are reported. Purified UIC2/Fab binds human P-gp with a 1:1 stoichiometry. Crystals of UIC2/Fab are triclinic (space groupP1), with unit-cell parametersa= 40.67,b= 44.91,c= 58.09 Å, α = 97.62, β = 99.10, γ = 94.09°, and diffracted X-rays to 1.6 Å resolution. The structure was determined by molecular replacement and refined to 1.65 Å resolution. The asymmetric unit contains one molecule of UIC2/Fab, which exhibits a positively charged antigen-binding surface, suggesting that it might recognize an oppositely charged extracellular epitope of P-gp.

Monoclonal antibodies in oncology

International Nuclear Information System (INIS)

Chan, S.Y.T.; Sikora, K.

1986-01-01

Monoclonal antibodies (MCAs) can be used to differentiate between normal and neoplastic cells and thus exploited for diagnostic and, ultimately, therapeutic gain. The evidence for the existence of human tumour antigens is reviewed. Several areas of diagnosis are already benefiting from the application of the monoclonal technology. Immunohistology can help the pathologist with difficult diagnostic problems. New classifications of lymphoma and leukaemia can be based on specific surface molecules. Similarly, the detection of shed tumour antigens is already established as part of the routine assessment of many patients with common solid tumours. Isotopically labeled monoclonal antibodies have been used to localise primary and metastatic tumours. The use of antibodies in this way is not only a promising diagnostic tool but also the first step in studying the possibility of arming antibodies to provide therapeutic agents. Such trials are currently in progress. (Auth.)

Phage-display libraries of murine and human antibody Fab fragments

DEFF Research Database (Denmark)

Engberg, J; Andersen, P S; Nielsen, L K

1996-01-01

We provide efficient and detailed procedures for construction, expression, and screening of comprehensive libraries of murine or human antibody Fab fragments displayed on the surface of filamentous phage. In addition, protocols for producing and using ultra-electrocompetent cells, for producing Fab...

Potent neutralization of VEGF biological activities with a fully human antibody Fab fragment directed against VEGF receptor 2

International Nuclear Information System (INIS)

Miao, H.-Q.; Hu, Kun; Jimenez, Xenia; Navarro, Elizabeth; Zhang, Haifan; Lu Dan; Ludwig, Dale L.; Balderes, Paul; Zhu Zhenping

2006-01-01

Compelling evidence suggest that vascular endothelial growth factor (VEGF) and its receptors, especially receptor 2 (VEGFR2, or kinase insert domain-containing receptor, KDR), play a critical role in angiogenesis under both physiological and pathological conditions, including cancer and angiogenic retinopathies such as age-related macular degeneration (AMD). To this end, inhibition of angiogenesis with antagonists to either VEGF or KDR has yielded significant therapeutic efficacy both in preclinical studies in animal models and in clinical trials in patients with cancer and AMD. We previously reported the identification of a high affinity, fully human anti-KDR antibody fragment, 1121B Fab, through a highly stringent affinity maturation process with a Fab originally isolated from a naive human antibody phage display library. In this study, we demonstrate that 1121B Fab is able to strongly block KDR/VEGF interaction, resulting in potent inhibition of an array of biological activities of VEGF, including activation of the receptor and its signaling pathway, intracellular calcium mobilization, and migration and proliferation of endothelial cells. Taken together, our data lend strong support to the further development of 1121B Fab fragment as an anti-angiogenesis agent in both cancer and angiogenic retinopathies

Chelate chase of radiopharmaceuticals reversibly bound to monoclonal antibodies improves dosimetry

International Nuclear Information System (INIS)

Goodwin, D.A.; Smith, S.I.; Meares, C.F.; David, G.S.; McTigue, M.; Finston, R.A.

1986-01-01

One hundred micrograms of monoclonal antibody (MoAb) CHA 255 with a binding constant Kb of 4 x 10 9 was complexed with indium-111 labeled BLEDTA II, GLEDTA IV, benzyl EDTA, and an EDTA conjugate of Fab. The 24-hour tumor and organ distribution in BALB/c mice bearing KHJJ tumors was studied for each compound alone, the antibody complex, and 3 hours following a chelate chase of the antibody complex. Whole-body biological half-life was measured for 7 days with and without a chelate chase for each antibody complex. The 24-hour whole-body counts dropped 20-60% within 3 hours of administering the chelate chase. Blood concentration fell over 89% within 3 hours of administering the chase and there was a decrease in concentration in all organs, except the kidneys, of 10 to 85%. Theoretical equivalent human doses were calculated from the 24-hour organ concentrations, effective half-life, and MIRD 11 S values (absorbed dose per cumulated activity). Liver and spleen were the target organs, with the dose ranging from 0.50 to 3.91 rads per millicurie. The reduction in organ radiation dose varied up to 95% following the chelate chase. Rapid selective renal clearance of chelate labeled radiopharmaceuticals by competitive inhibition (chelate chase) of their reversible binding to monoclonal antibodies, greatly improves the radiation dosimetry of tumor imaging agents. 28 references, 5 figures, 5 tables

Monoclonal antibody PAL-E specific for endothelium

NARCIS (Netherlands)

Schlingemann, R. O.; Dingjan, G. M.; Emeis, J. J.; Blok, J.; Warnaar, S. O.; Ruiter, D. J.

1985-01-01

A monoclonal antibody, PAL-E, is described that is specific for endothelial cells. The monoclonal antibody, an IgG2a, markedly stains endothelium of capillaries, medium-sized and small veins, and venules in frozen sections of human and some animal tissues tested. It reacts not at all or only weakly

Acute myocardial infarct imaging with indium-111-labeled monoclonal antimyosin Fab

International Nuclear Information System (INIS)

Khaw, B.A.; Yasuda, T.; Gold, H.K.; Leinbach, R.C.; Johns, J.A.; Kanke, M.; Barlai-Kovach, M.; Strauss, H.W.; Haber, E.

1987-01-01

Indium-111 monoclonal antimyosin Fab scintigraphy was used to detect myocardial necrosis in 52 of 54 patients (96.3%) with acute myocardial infarction. Infarcts were visualized when coronary arteries were persistently occluded (n = 10), became patent after thrombolysis (n = 33), or became patent after spontaneous reperfusion (n = 7). Posteroinferolateral visualizations were obtained in two patients with clinical and enzymatic evidence of infarction but normal electrocardiograms. Of the two patients in whom no infarcts were visualized, one had an anterior myocardial infarct. This patient underwent successful thrombolytic therapy, with attendant minimization of creatine kinase release. The other patient had a small, nonreperfused inferior myocardial infarct. Five patients with a history of remote infarction and acute necrosis showed antimyosin uptake only in regions concordant with the acute episodes of infarction, and radiolabeled antimyosin Fab localized in neither old infarcts nor normal, noninfarcted myocardium. Antimyosin Fab scintigraphy, thus, appears to be a highly specific means of delineating necrotic myocardium, at least in this limited and selected group of patients

Effect of the route of administration on the biodistribution of radioiodinated OV-TL 3 F(ab')2 in experimental ovarian cancer

International Nuclear Information System (INIS)

Tibben, J.G.; Massuger, L.F.A.G.; Boerman, O.C.; Borm, G.F.; Claessens, R.A.M.J.; Corstens, F.H.M.

1994-01-01

The effect of the route administration on the distribution of radioiodinated OV-TL 3 F(ab') 2 was studied in Balb/c female mice with intraperitoneal or subcutaneous ovarian carcinoma xenografts. In the intraperitoneal tumour model in which both ascites and solid tumour deposits were present, intraperitoneal administration resulted in a lower estimated radiation dose to blood as compared with intravenous administration. In this model normalization to equal estimated radiation doses to blood for both routes of administration indicated that a twice as high estimated radiation dose can be guided to solid intraperitoneal tumour deposits following intraperitoneal administration. Evacuation of ascitic tumour cells prior to monoclonal antibody injection further increased the estimated radiation dose to solid intraperitoneal tumour deposits following intraperitoneal delivery. Following simultaneous intravenous and intraperitoneal injection of the monoclonal antibody, tissue uptake showed no relevant differences in the subcutaneous tumour model. Overall, the intraperitoneal route of administration was found to be the best choice for therapeutic delivery of iodine-131 labelled monoclonal antibodies. (orig.)

High contrast tumor imaging with radio-labeled antibody Fab fragments tailored for optimized pharmacokinetics via PASylation.

Science.gov (United States)

Mendler, Claudia T; Friedrich, Lars; Laitinen, Iina; Schlapschy, Martin; Schwaiger, Markus; Wester, Hans-Jürgen; Skerra, Arne

2015-01-01

Although antigen-binding fragments (Fabs) of antibodies constitute established tracers for in vivo radiodiagnostics, their functionality is hampered by a very short circulation half-life. PASylation, the genetic fusion with a long, conformationally disordered amino acid chain comprising Pro, Ala and Ser, provides a convenient way to expand protein size and, consequently, retard renal filtration. Humanized αHER2 and αCD20 Fabs were systematically fused with 100 to 600 PAS residues and produced in E. coli. Cytofluorimetric titration analysis on tumor cell lines confirmed that antigen-binding activities of the parental antibodies were retained. The radio-iodinated PASylated Fabs were studied by positron emission tomography (PET) imaging and biodistribution analysis in mouse tumor xenograft models. While the unmodified αHER2 and αCD20 Fabs showed weak tumor uptake (0.8% and 0.2% ID/g, respectively; 24 h p.i.) tumor-associated radioactivity was boosted with increasing PAS length (up to 9 and 26-fold, respectively), approaching an optimum for Fab-PAS400. Remarkably, 6- and 5-fold higher tumor-to-blood ratios compared with the unmodified Fabs were measured in the biodistribution analysis (48 h p.i.) for αHER2 Fab-PAS100 and Fab-PAS200, respectively. These findings were confirmed by PET studies, showing high imaging contrast in line with tumor-to-blood ratios of 12.2 and 5.7 (24 h p.i.) for αHER2 Fab-PAS100 and Fab-PAS200. Even stronger tumor signals were obtained with the corresponding αCD20 Fabs, both in PET imaging and biodistribution analysis, with an uptake of 2.8% ID/g for Fab-PAS100 vs. 0.24% ID/g for the unmodified Fab. Hence, by engineering Fabs via PASylation, plasma half-life can be tailored to significantly improve tracer uptake and tumor contrast, thus optimally matching reagent/target interactions.

Comparative study of intact A7 MoAc and F(ab')2 fragments for radioimmunoimaging of human colon cancer in nude mice

International Nuclear Information System (INIS)

Kojima, Shuji; Suzuki, Naomi; Shimura, Noriko; Kubodera, Akiko; Kubota, Kazuhiko; Yamaguchi, Toshiharu; Takahashi, Toshio; Oyamada, Hiyoshimaru

1993-01-01

Differences of pharmacokinetics and tumor imaging ability between intact monoclonal antibody A7 (A7 MoAb) and F(ab) 2 fragments were studied in human colon cancer (LS-174T)-bearing nude mice. The authors examined the yield and the immunoreactivity of F(ab) 2 fragments after treatment with ficin as a function of time. The yield of F(ab) 2 fragments reached about 50% after ficin treatment for 8 h, and the F(ab) 2 retained about 80% of the immunoreactivity of the corresponding MoAb. Longer digestion with ficin produced smaller fragments (less than 92 kDa) with a lower yield and most of the immunoreactivity was lost. In pharmacokinetics studies, the F(ab') 2 was preferentially taken up by the tumor, cleared more rapidly from the blood circulation and seemed to have less non-specific tissue binding than intact A7 MoAb. The tumor image obtained at an early time using 131 I-F(ab') 2 was much superior in quality to that with intact 131 I-A7 MoAb. The use of F(ab') 2 fragments may be effective for tumor diagnosis and therapy. (author)

Immunoscintigraphy of Colorectal and Other Gastrointestinal Cancers with Radioactive Monoclonal Antibodies to CEA and CA 19 - 9

International Nuclear Information System (INIS)

Jang, Dae Hwan; Choi, Duck Joo; Lee, Bum Woo; Park, Won; Han, Chang Soon; Kim, Hak San; Kim, Chong Soon

1988-01-01

The cocktails of two 131 I labeled Monoclonal antibody (MCAB) (Anti CA 19-9 F(ab') 2 +Anti CEA F(ab') 2 fragment), which react specially, with human gastrointestinal cancers, were administered to 10 patients with colorectal (7), stomach (2) and pancreas (l) cancer for scintigraphic detection. All patients were known or postoperatively recurrent cases, and serum tumor markers, CA 19-9 and CEA, were measured with immunoradiometric assay, just before immunoscintigraphy (ISG). The tumor marker's level in serum is not correlated with positive tumor uptake in ISG. The sensitivity and specificity of ISG in detection of 21 tumor sites, based on surgery, CT, ultrasonography and pathology, were 90.5% and 100%. One case of colon cancer showed gall bladder metastasis, which was neglected on CT study. Tumor/non tumor uptake ratio of radiolabelled antibody were progressively increased from day 3 to day 7 during study. We summarized as follows: 1) The use of cocktails of CEA and CA 19-9 MCAB F(ab') 2 increased sensitivity and specificity in ISG. 2) Delayed imaging (later than 5 days) increases sensitivity and specificity due to exclusion of nonspecific iodine accumulation in stomach and lung. 3) Second tracer technique is essential for anatomical landmark by use of a double isotope scan, but subtraction technique, a possible source of artifacts, is no longer necessary when delayed imaging is performed. 4) It may be possible to use two MCAB cocktails of CA 19-9 and CEA in Radioimmunodetection of stomach and pancreas cancer. In conclusion, ISG using MCAB cocktails, F(ab') 2 fragment of anti CA 19-9 and Anti CEA, provide additional opportunity for tumor localization and detection of colorectal and other G-I cancer, such as stomach and pancreas.

Comparison of the C-mediating killing activity and C-activating properties of mouse monoclonal and polyclonal antibodies against Trypanosoma cruzi

Directory of Open Access Journals (Sweden)

T. L. Kipnis

1992-01-01

Full Text Available A Mouse polyclonal antiserum against Trypanosoma cruzi or its IgG and IgM fractions and five monoclonal antibodies (two IgM, two IgG1 and one IgG2a recognize and combine with membrane components of trypomastigote forms of the parasite as revealed by immunofluorescence. Although all these antibodies sensitize trypomastigotes and prepare them to activate the complement (C system, as measured by consumption of total C, C4, B and C3, only the polyclonal antiserum or its IgG, IgM and Fabμ fragments were able to induce trypanosome lysis by the alternative C pathway.

Use of AN Eosinophil Specific Monoclonal Antibody in Assessing Eosinophil Function.

Science.gov (United States)

Minkoff, Marjorie Sue

A monoclonal antibody to an eosinophil specific determinant is very important in assessing eosinophil function during helminthic infection. Eosinophils induced by Schistosoma mansoni infection in BALB/c mice were used to induce C57B1/6 immunocytes for production of hybridomas secreting eosinophil monoclonal antibodies. These antibodies were shown to react with an eosinophil surface epitope but not with neutrophils or macrophages as determined by ELISA, immunodiffusion, immunofluorescence, and immunoblot assay. Affinity chromatography with eosinophil chemotactic factor-sepharose consistently selected out a { rm M_ R} 67,000 protein from solubilized eosinophil membrane antigens but not from neutrophil and macrophage antigens. In vitro studies showed that the eosinophil-specific monoclonal antibodies abrogated antibody-dependent eosinophil -mediated killing of S. mansoni schistosomula using mouse, rat or human eosinophils. Neutrophil and macrophage killing activities were unaffected. The monoclonal antibodies effected complement-dependent lysis of mouse and rat eosinophils but not of human eosinophils. ECF-treated eosinophils showed enhanced killing of schistosomula which was blocked by the monoclonal antibody. Murine and human eosinophils preincubated with monoclonal antibody exhibited decreased chemotaxis to ECF at optimal chemotactic concentrations. The monoclonal antibody also blocked eosinophil binding to ECF- sepharose beads. In vivo induction of peripheral blood eosinophilia by injection of S. mansoni eggs was suppressed by injections of monoclonal antibodies 2CD13 and 2QD45 in mouse and rat experimental models. Eosinophilia induced by keyhole limpet hemocyanin- cyclophosphamide treatment was also suppressed by monoclonal antibody in both murine and rat systems. Pulmonary granulomas in mice given egg injection and monoclonal antibody were smaller and contained fewer eosinophils than those granulomas from mice given eggs only. In immuno-biochemical studies, the

Human Cell Line-Derived Monoclonal IgA Antibodies for Cancer Immunotherapy

Directory of Open Access Journals (Sweden)

Felix Hart

2017-05-01

Full Text Available IgA antibodies have great potential to improve the functional diversity of current IgG antibody-based cancer immunotherapy options. However, IgA production and purification is not well established, which can at least in part be attributed to the more complex glycosylation as compared to IgG antibodies. IgA antibodies possess up to five N-glycosylation sites within their constant region of the heavy chain as compared to one site for IgG antibodies. The human GlycoExpress expression system was developed to produce biotherapeutics with optimized glycosylation and used here to generate a panel of IgA isotype antibodies directed against targets for solid (TA-mucin 1, Her2, EGFR, Thomsen–Friedenreich and hematological (CD20 cancer indications. The feasibility of good manufacturing practice was shown by the production of 11 g IgA within 35 days in a one liter perfusion bioreactor, and IgA antibodies in high purity were obtained after purification. The monoclonal IgA antibodies possessed a high sialylation degree, and no non-human glycan structures were detected. Kinetic analysis revealed increased avidity antigen binding for IgA dimers as compared to monomeric antibodies. The IgA antibodies exhibited potent Fab- and Fc-mediated functionalities against cancer cell lines, whereby especially granulocytes are recruited. Therefore, for patients who do not sufficiently benefit from therapeutic IgG antibodies, IgA antibodies may complement current regiment options and represent a promising strategy for cancer immunotherapy. In conclusion, a panel of novel biofunctional IgA antibodies with human glycosylation was successfully generated.

Isolation of human anti-serum albumin Fab antibodies with an extended serum-half life.

Science.gov (United States)

Kang, Hyeon-Ju; Kim, Hye-Jin; Cha, Sang-Hoon

2016-01-01

The serum albumin (SA) has been exploited to generate long-acting biotherapeutics by taking advantage of the FcRn-mediated recycling mechanism in a direct or an indirect way. Since Fab fragments have been proven to be clinically safe for human usage, we assumed that human anti-SA Fab antibodies could have a great potential as a carrier molecule to extend the serum half-life of therapeutic proteins. We, herein, had attempted to isolate anti-SA Fab antibodies from HuDVFab-8L antibody library via a phage display technology, and identified eight discrete human Fab antibodies. One of the Fab antibodies, SL335, showed the strongest binding reactivity to human SA with nM range of affinity at both pH 6 and pH 7.4, and cross-reacted to SAs from various species including rat, mouse, canine and monkey. The in vivo pharmacokinetic assay using a rat model indicated that SL335 has approximately 10 fold longer serum half-life and 26 to 44-fold increase in AUC0 → ∞ compared to the negative control Fab molecule in both intravenous and subcutaneous administrations. Knowing that Fabs have proven to be safe in clinics for a long time, SL335 seems to have a great potential in generating long-acting protein drugs by tagging effector molecules with either chemical conjugation or genetic fusion. Copyright © 2015 Elsevier B.V. All rights reserved.

Monoclonal antibodies to drosophila cytochrome P-450's

International Nuclear Information System (INIS)

Sundseth, S.S.; Kennel, S.J.; Waters, L.C.

1987-01-01

Hybridomas producing monoclonal antibodies were prepared by the fusion of SP2/0 myeloma cells and spleen cells from a female BALB/c mouse immunized by cytochrome P-450-A and P-450-B purified from Drosophila Hikone-R (BG) microsomes. P-450-A and P-450-B are electrophoretically distinct subsets of Drosophila P-450. P-450-A is ubiquitous among strains tested, while P-450-B is present in only a few strains displaying unique enzyme activities and increased insecticide resistance. The Oregon-R strain contains only cytochromes P-450-A and is susceptible to insecticides. The authors Hikone-R (BG) strain expresses both cytochromes P-450-A and P-450-B and is insecticide resistant. Antibody producing hybridomas were detected in a solid-phase radioimmunoassay (RIA) by binding to Hikone-R (BG) or Oregon-R microsomes. Four independent hybridomas were identified as producing monoclonal antibodies that recognized proteins in the P-450 complex by immunoblot experiments. Three monoclonal antibodies recognized P-450-A proteins, while one monoclonal antibody bound predominantly P-450-B. This monoclonal antibody also recognized southern armyworm (Spodoptera eridania, Cramer) microsomal proteins

Nonspecific bowel activity in imaging inflammation with Tc-99m labelled monoclonal anti-NCA-90 Fab' fragment MN3

International Nuclear Information System (INIS)

Ivancevic, V.; Wolter, A.; Munz, D.L.

2001-01-01

Since the Tc-99m labelled monoclonal anti-NCA 90 granulocyte antibody Fab' fragment MN3 (MN3 Fab') might be of interest for imaging abdominal inflammation which could be hampered by nonspecific bowel activity, we prospectively investigated the appearance of bowel activity in MN3 Fab' imaging. Methods: Eighty consecutive patients (age range 12-85 years) referred for suspected nonabdominal, mostly musculoskeletal infection, were included. Abdominal inflammation was excluded clinically and there were no signs of inflammatory bowel disease in the patients' histories. One, 5, and 24 hours after introvenous injection of up to 1.1 GBq of MN3 Fab' planar images of the abdomen were performed. Bowel activity was graded visually using a 5-point scale. Results: The one (N = 80), 5 (N = 79), and 24 (N = 52) hour images revealed 46 (10%), 162 (34%), and 173 (55%) accumulating bowel segments, respectively, in 37 (46%), 69 (87%), and 52 (100%) patients. The mean intensity score per accumulating segment was 1.1, 1.8 and 2.7 (p = 0), respectively. Relative frequencies of appearance of the small intestine were 38%, 57%, and 21%, ileocaecal region 6%, 53%, and 48%, ascending colon 5%, 67%, and 89%, transverse colon 1%, 9%, and 69%, descending colon 8%, 15%, and 67%, and rectosigmoid 0%, 4%, and 38%, respectively. Follow-up investigations in 13 patients revealed diverging uptake patterns. Conclusion: Nonspecific bowel activity is often present in the early and almost always and more intense, in the delayed images. Early imaging at one hour after administration seems feasible, but a loss in sensitivity has to be considered. Thus, nonspecific bowel activity can be anticipated to be a pitfall in imaging abdominal inflammation with MN3 Fab'. (orig.) [de

Mapping the Binding Interface of VEGF and a Monoclonal Antibody Fab-1 Fragment with Fast Photochemical Oxidation of Proteins (FPOP) and Mass Spectrometry

Science.gov (United States)

Zhang, Ying; Wecksler, Aaron T.; Molina, Patricia; Deperalta, Galahad; Gross, Michael L.

2017-05-01

We previously analyzed the Fab-1:VEGF (vascular endothelial growth factor) system described in this work, with both native top-down mass spectrometry and bottom-up mass spectrometry (carboxyl-group or GEE footprinting) techniques. This work continues bottom-up mass spectrometry analysis using a fast photochemical oxidation of proteins (FPOP) platform to map the solution binding interface of VEGF and a fragment antigen binding region of an antibody (Fab-1). In this study, we use FPOP to compare the changes in solvent accessibility by quantitating the extent of oxidative modification in the unbound versus bound states. Determining the changes in solvent accessibility enables the inference of the protein binding sites (epitope and paratopes) and a comparison to the previously published Fab-1:VEGF crystal structure, adding to the top-down and bottom-up data. Using this method, we investigated peptide-level and residue-level changes in solvent accessibility between the unbound proteins and bound complex. Mapping these data onto the Fab-1:VEGF crystal structure enabled successful characterization of both the binding region and regions of remote conformation changes. These data, coupled with our previous higher order structure (HOS) studies, demonstrate the value of a comprehensive toolbox of methods for identifying the putative epitopes and paratopes for biotherapeutic antibodies.

Evaluation of iodovinyl antibody conjugates: Comparison with a p-iodobenzoyl conjugate and direct radioiodination

International Nuclear Information System (INIS)

Hadley, S.W.; Wilbur, D.S.

1990-01-01

The preparations and conjugations of 2,3,5,6-tetrafluorophenyl 5-[125I/131I]iodo-4-pentenoate (7a) and 2,3,5,6-tetrafluorophenyl 3,3-dimethyl-5-[125I/131I]iodo-4-pentenoate (7b) to monoclonal antibodies are reported. Reagents 7a and 7b were prepared in high radiochemical yield by iododestannylation of their corresponding 5-tri-n-butylstannyl precursors. Radioiodinated antibody conjugates were prepared by reaction of 7a or 7b with the protein at basic pH. Evaluation of these conjugates by several in vitro procedures demonstrated that the radiolabel was attached to the antibody in a stable manner and that the conjugates maintained immunoreactivity. Comparative dual-isotope biodistribution studies of a monoclonal antibody Fab fragment conjugate of 7a and 7b with the same Fab fragment labeled with N-succinimidyl p-[131I]iodobenzoate (PIB, p-iodobenzoate, 2) or directly radioiodinated have been carried out in tumor-bearing nude mice. Coinjection of the Fab conjugate of 7a with the Fab conjugate of 2 demonstrated that the biodistributions were similar in most organs, except the neck tissue (thyroid-containing) and the stomach, which contained substantially increased levels of the 7a label. Coinjection of the Fab conjugate of 7a with the Fab fragment radioiodinated by using the chloramine-T method demonstrated that the biodistributions were remarkably similar, suggesting roughly equivalent in vivo deiodination of these labeled antibody fragments. Coinjection of the Fab conjugate of 7a with the Fab conjugate of 7b indicated that there was ∼ a 2-fold reduction in the amount of in vivo deiodination of the 7b conjugate as compared to the 7a conjugate

Radiolabeled monoclonal antibodies: a review

International Nuclear Information System (INIS)

Toledo e Souza, I.T. de; Okada, H.

1990-05-01

Since the description by Kohler and Milstein 1975 of their technique for producing monoclonal antibodies of predefined specificity, it has become a mainstay in most laboratories that utilize immunochemical techniques to study problems in basic, applied or clinical research. Paradoxically, the very success of monoclonal antibodies has generated a literature which is now so vast and scattered that it has become difficult to obtain a perspective. This brief review represents the distillation of many publications relating to the production and use of monoclonaal antibodies as radiopharmaceuticals. Significant advances were made possible in the last few years by combined developments in the fields of tumor-associated antigens and of monoclonal antibodies. In fact monoclonal antibodies against some well defined tumor-associated antigens, has led to significantly greater practical possibilities for producing highly specific radiolabeled antibodies as radiopharmaceuticals for diagnosis and therapy of human tumors. One of the main requirements of this methodology is the availability of stable radiopharmaceutical reagents which after labeling in vivo injection retain the capacity of specific interaction with the defined antigen and their molecular integrity. Since injection into human is the objetive of this kind of study all the specifications of radiopharmaceutical have to be fulfilled e.g. sterility, apirogenicity and absence of toxicity. (author) [pt

Production, purification, crystallization and preliminary X-ray diffraction analysis of the HIV-2-neutralizing V3 loop-specific Fab fragment 7C8

International Nuclear Information System (INIS)

Uchtenhagen, Hannes; Sourial, Samer; Friemann, Rosmarie; Ehnlund, Mariethe; Spetz, Anna-Lena; Harris, Robert A.; Madhurantakam, Chaithanya; Achour, Adnane

2009-01-01

Neutralizing Fab fragments of the HIV-2-binding murine antibody 7C8 were generated after purification from hybridoma cell-culture supernatant. Crystallization conditions were determined and diffraction data were collected to 2.7 Å resolution. 7C8 is a mouse monoclonal antibody that is specific for the third hypervariable loop (V3 loop) of the human immunodeficiency virus type 2 (HIV-2) associated protein gp125. Fab fragments of 7C8 effectively neutralize HIV-2. 7C8 was expressed and purified from a hybridoma cell line in order to establish the molecular basis underlying the specificity of the 7C8 antibody for the V3 loop as well as the specific role of the elongated third complementarity-determining region of the heavy chain (CDRH3). The antibody was digested with papain and Fab fragments were purified using size-exclusion chromatography. Hanging-drop vapour-diffusion crystallization techniques were employed and the protein was crystallized in 50 mM ammonium sulfate, 100 mM Tris–HCl pH 8.5, 25%(w/v) PEG 8000 and 2.5%(w/v) PEG 400 at 275 K. The analysed crystals belonged to the rhombohedral space group P3 2 21, with unit-cell parameters a = b = 100.1, c = 196.8 Å, and diffracted to 2.7 Å resolution

Locking the Elbow: Improved Antibody Fab Fragments as Chaperones for Structure Determination.

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Bailey, Lucas J; Sheehy, Kimberly M; Dominik, Pawel K; Liang, Wenguang G; Rui, Huan; Clark, Michael; Jaskolowski, Mateusz; Kim, Yejoon; Deneka, Dawid; Tang, Wei-Jen; Kossiakoff, Anthony A

2018-02-02

Antibody Fab fragments have been exploited with significant success to facilitate the structure determination of challenging macromolecules as crystallization chaperones and as molecular fiducial marks for single particle cryo-electron microscopy approaches. However, the inherent flexibility of the "elbow" regions, which link the constant and variable domains of the Fab, can introduce disorder and thus diminish their effectiveness. We have developed a phage display engineering strategy to generate synthetic Fab variants that significantly reduces elbow flexibility, while maintaining their high affinity and stability. This strategy was validated using previously recalcitrant Fab-antigen complexes where introduction of an engineered elbow region enhanced crystallization and diffraction resolution. Furthermore, incorporation of the mutations appears to be generally portable to other synthetic antibodies and may serve as a universal strategy to enhance the success rates of Fabs as structure determination chaperones. Copyright © 2017 Elsevier Ltd. All rights reserved.

Identifying Monoclonal Antibodies that Potently Inhibit MERS-CoV | Center for Cancer Research

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The Middle East respiratory syndrome coronavirus (MERS-CoV), first isolated in September 2012, infects cells lining the human airway, causing severe flu-like symptoms that, in some cases, lead to death. As of July 2, 2014, 824 confirmed cases of MERS-CoV infection, including at least 286 related deaths, have been reported to the World Health Organization. While there are currently no effective therapies against the virus, monoclonal antibodies (MAbs) may be a promising candidate. Having previously developed MAbs against other viruses, including the related severe acute respiratory syndrome coronavirus or SARS-CoV, Dimiter Dimitrov, Ph.D., of CCR’s Laboratory of Experimental Immunology (LEI), and his colleagues decided to pan a library of antigen binding fragments (Fab) for activity against MERS-CoV.

Fab fragments of ovine antibody to colchicine enhance its clearance in the rat.

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Peake, Philip W; Pianta, Timothy J; Succar, Lena; Fernando, Mangalee; Buckley, Nicholas A; Endre, Zoltan H

2015-06-01

Colchicine is an anti-inflammatory alkaloid used for the treatment of acute gout, but has a narrow therapeutic index. Colchicine overdoses are relatively rare, but have high mortality requiring rapid treatment. To evaluate the ability of a newly available ovine fragment antigen-binding (Fab) antibody to colchicine (ColchiFab(™)) to protect rats against renal and other injury 24 h after colchicine ingestion. Rats were gavaged with colchicine (5 mg/kg), then 2 h later injected intraperitoneally with 5 ml of sterile saline, or Fab anti-colchicine, a newly available ovine antibody to colchicine. Samples of blood were taken at 1, 2, 5 and 24 h after gavage, and urine was collected from 5 to 24 h after gavage. Concentrations of colchicine in tissue, blood and urine were measured by liquid chromatography/mass spectrometry, concentrations of Fab anti-colchicine, urinary neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 or KIM-1 by enzyme-linked immunosorbent assay or ELISA, while concentrations of creatine kinase and creatinine (Cr) were measured enzymatically. Colchicine equilibrated rapidly throughout the body and increased serum creatine kinase. Fab anti-colchicine also rapidly redistributed to the blood and remained at high concentrations over 24 h. Fab anti-colchicine caused a rapid 7.1-fold increase in serum colchicine level, followed by excretion of both colchicine and Fab anti-colchicine through the urine. This was associated with the accumulation of colchicine in the kidney, a reversal of colchicine-induced diarrhoea, and increasing urinary NGAL level; from 168 ± 48 to 477 ± 255 ng/mmol Cr [mean ± standard deviation or SD]. Fab anti-colchicine greatly increased the clearance of colchicine, although increasing NGAL level suggested the presence of mild kidney damage. These data suggest clinical utility for Fab anti-colchicine in the treatment of colchicine overdose.

Chimpanzee-Human Monoclonal Antibodies for Treatment of Chronic Poliovirus Excretors and Emergency Postexposure Prophylaxis▿‡

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Chen, Zhaochun; Chumakov, Konstantin; Dragunsky, Eugenia; Kouiavskaia, Diana; Makiya, Michelle; Neverov, Alexander; Rezapkin, Gennady; Sebrell, Andrew; Purcell, Robert

2011-01-01

Six poliovirus-neutralizing Fabs were recovered from a combinatorial Fab phage display library constructed from bone marrow-derived lymphocytes of immunized chimpanzees. The chimeric chimpanzee-human full-length IgGs (hereinafter called monoclonal antibodies [MAbs]) were generated by combining a chimpanzee IgG light chain and a variable domain of heavy chain with a human constant Fc region. The six MAbs neutralized vaccine strains and virulent strains of poliovirus. Five MAbs were serotype specific, while one MAb cross-neutralized serotypes 1 and 2. Epitope mapping performed by selecting and sequencing antibody-resistant viral variants indicated that the cross-neutralizing MAb bound between antigenic sites 1 and 2, thereby covering the canyon region containing the receptor-binding site. Another serotype 1-specific MAb recognized a region located between antigenic sites 2 and 3 that included parts of capsid proteins VP1 and VP3. Both serotype 2-specific antibodies recognized antigenic site 1. No escape mutants to serotype 3-specific MAbs could be generated. The administration of a serotype 1-specific MAb to transgenic mice susceptible to poliovirus at a dose of 5 μg/mouse completely protected them from paralysis after challenge with a lethal dose of wild-type poliovirus. Moreover, MAb injection 6 or 12 h after virus infection provided significant protection. The MAbs described here could be tested in clinical trials to determine whether they might be useful for treatment of immunocompromised chronic virus excretors and for emergency protection of contacts of a paralytic poliomyelitis case. PMID:21345966

Discovery and characterization of antibody variants using mass spectrometry-based comparative analysis for biosimilar candidates of monoclonal antibody drugs.

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Li, Wenhua; Yang, Bin; Zhou, Dongmei; Xu, Jun; Ke, Zhi; Suen, Wen-Chen

2016-07-01

Liquid chromatography mass spectrometry (LC-MS) is the most commonly used technique for the characterization of antibody variants. MAb-X and mAb-Y are two approved IgG1 subtype monoclonal antibody drugs recombinantly produced in Chinese hamster ovary (CHO) cells. We report here that two unexpected and rare antibody variants have been discovered during cell culture process development of biosimilars for these two approved drugs through intact mass analysis. We then used comprehensive mass spectrometry-based comparative analysis including reduced light, heavy chains, and domain-specific mass as well as peptide mapping analysis to fully characterize the observed antibody variants. The "middle-up" mass comparative analysis demonstrated that the antibody variant from mAb-X biosimilar candidate was caused by mass variation of antibody crystalline fragment (Fc), whereas a different variant with mass variation in antibody antigen-binding fragment (Fab) from mAb-Y biosimilar candidate was identified. Endoproteinase Lys-C digested peptide mapping and tandem mass spectrometry analysis further revealed that a leucine to glutamine change in N-terminal 402 site of heavy chain was responsible for the generation of mAb-X antibody variant. Lys-C and trypsin coupled non-reduced and reduced peptide mapping comparative analysis showed that the formation of the light-heavy interchain trisulfide bond resulted in the mAb-Y antibody variant. These two cases confirmed that mass spectrometry-based comparative analysis plays a critical role for the characterization of monoclonal antibody variants, and biosimilar developers should start with a comprehensive structural assessment and comparative analysis to decrease the risk of the process development for biosimilars. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparation of monoclonal antibodies against cardiac myosin and some radiolabelling studies

International Nuclear Information System (INIS)

Bapat, K.; Venkatesh, M.; Pillai, M.R.A.; Sarma, H.D.; Sainis, K.B.

1998-01-01

Monoclonal antibodies were raised against myosin, a specific indicator of myocardial infarction and labelled with 125 I and 99m Tc. Human cardiac myosin was isolated from normal human heart and was used for raising the monoclonal antibodies by the hybridoma technique. Antibody producing clones were identified by ELISA and cloning was done by the limiting dilution technique. Of the 13 clones obtained, 4 were deemed suitable for further studies. The antibodies were grown in ascites, purified, isotyped and their cross reactions with other forms of myosin were estimated. All the clones showed negligible cross reaction with rabbit myosin, but reacted to different extents with bovine skeletal myosin. The most avid antibody Mab-4G4 was chosen for further labelling studies. Mab-4G4 was labelled with 125 I using different oxidising agents such as iodogen, chloramine-T and lactoperoxidase. Purified radioiodinated antibody with radiochemical purity >95% could be obtained by gel filtration. Immunoreactivity was retained as tested by binding to myosin immobilised on a solid support. Mab-4G4 was also labelled with 99m Tc using stannous tartrate as the reducing agent. Radiolabelling yield was ∼60%, the purity was >95% and the immunoreactivity was retained. Both the labelled preparations were tested for bio-distribution in normal and infarcted rats. The activity accumulation in the infarcted region was ∼ 1.5 and 3.5 times as that in normal heart muscle for 125 I and 99m Tc labelled Mab-4G4 respectively. The major problem with the iodinated antibody was the in vivo deiodination resulting in very high percentage of activity in the thyroid. Although the fraction of the total activity associated with the infarcted heart is not very impressive, the fact that the activities with the infarcted and normal hearths are significantly different is heartening. With further optimisation of labelling and use of F(ab)'2 fragments, better delineation of the infarct sites is aspired. (author)

Rat Monoclonal Antibodies Specific for LST1 Proteins

OpenAIRE

Schiller, Christian; Nitschké, Maximilian J. E.; Seidl, Alexander; Kremmer, Elisabeth; Weiss, Elisabeth H.

2009-01-01

The LST1 gene is located in the human MHC class III region and encodes transmembrane and soluble isoforms that have been suggested to play a role in the regulation of the immune response and are associated with inflammatory diseases such as rheumatoid arthritis. Here we describe the generation and characterization of the first monoclonal antibodies against LST1. Two hybridoma lines secreting monoclonal antibodies designated 7E2 and 8D12 were established. The 7E2 antibody detects recombinant a...

Preliminary studies of monoclonal antibody lymphoscintigraphy in malignant melanoma

International Nuclear Information System (INIS)

Nelp, W.B.; Eary, J.F.; Jones, R.F.; Hellstrom, K.E.; Hellstrom, I.; Beaumier, P.L.; Krohn, K.A.

1987-01-01

Lymphoscintigraphy was performed at 3 and 20 hr following subcutaneous injection of 131 I anti-melanoma antibody (Fab) in 11 patients who had surgical resection of lymph nodes (neck, axilla, groin) at 24 hr for suspected metastatic melanoma. Comparable amounts of 125 I nonspecific control antibody (Fab) were co-administered. Six patients had nodal metastases and three showed positive images at both time periods. Five patients had no metastases though one was image positive. Four other nondiseased inguinal node groups were image negative. A total of 28 tumored nodes and 110 normal nodes were removed, counted and histologically examined. All metastatic tumors expressed antigen against which the specific Fab was directed. The concentrations of both specific and nonspecific Fab were similar in tumored nodes and both were significantly greater than in normal nodes showed essentially identical intranodal spatial distribution of the specific and control Fab in areas containing tumor. These preliminary results suggest the increased concentration of murine immunoglobulin (Fab) retained in diseased nodes was a nonspecific phenomenon

Dual Constant Domain-Fab: A novel strategy to improve half-life and potency of a Met therapeutic antibody.

Science.gov (United States)

Cignetto, Simona; Modica, Chiara; Chiriaco, Cristina; Fontani, Lara; Milla, Paola; Michieli, Paolo; Comoglio, Paolo M; Vigna, Elisa

2016-06-01

The kinase receptor encoded by the Met oncogene is a sensible target for cancer therapy. The chimeric monovalent Fab fragment of the DN30 monoclonal antibody (MvDN30) has an odd mechanism of action, based on cell surface removal of Met via activation of specific plasma membrane proteases. However, the short half-life of the Fab, due to its low molecular weight, is a severe limitation for the deployment in therapy. This issue was addressed by increasing the Fab molecular weight above the glomerular filtration threshold through the duplication of the constant domains, in tandem (DCD-1) or reciprocally swapped (DCD-2). The two newly engineered molecules showed biochemical properties comparable to the original MvDN30 in vitro, acting as full Met antagonists, impairing Met phosphorylation and activation of downstream signaling pathways. As a consequence, Met-mediated biological responses were inhibited, including anchorage-dependent and -independent cell growth. In vivo DCD-1 and DCD-2 showed a pharmacokinetic profile significantly improved over the original MvDN30, doubling the circulating half-life and reducing the clearance. In pre-clinical models of cancer, generated by injection of tumor cells or implant of patient-derived samples, systemic administration of the engineered molecules inhibited the growth of Met-addicted tumors. Copyright © 2016 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Human Monoclonal Antibodies Targeting Glypican-2 in Neuroblastoma | NCI Technology Transfer Center | TTC

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Researchers at the National Cancer Institute’s Laboratory of Molecular Biology (NCI LMB) have developed and isolated several single domain monoclonal human antibodies against GPC2. NCI seeks parties interested in licensing or co-developing GPC2 antibodies and/or conjugates.

Ablation of human colon carcinoma in nude mice by 131I-labeled monoclonal anti-carcinoembryonic antigen antibody F(ab')2 fragments

International Nuclear Information System (INIS)

Buchegger, F.; Pfister, C.; Fournier, K.; Prevel, F.; Schreyer, M.; Carrel, S.; Mach, J.P.

1989-01-01

Pooled F(ab')2 fragments of three MAbs against distinct epitopes of carcinoembryonic antigen (CEA) were used for radioimmunotherapy of nude mice bearing a subcutaneous human colon carcinoma xenograft. 9-10 d after transplantation when tumor nodules were in exponential growth, 36 mice were treated by intravenous injection of different amounts of 131 I-labeled MAb F(ab')2. All 14 mice injected with a single dose of 2,200 (n = 10) or 2,800 microCi (n = 4) showed complete tumor remission. 8 of the 10 mice treated with 2,200 microCi survived in good health for 1 yr when they were killed and shown to be tumor free. Four of nine other mice treated with four fractionated doses of 400 microCi showed no tumor relapse for more than 9 mo. In contrast, all 15 mice injected with 1,600-3,000 microCi 131 I-control IgG F(ab')2 showed tumor growth retardation of only 1-4 wk, and 15 of 16 mice injected with unlabeled anti-CEA MAb F(ab')2 showed unmodified tumor progression as compared with untreated mice. From tissue radioactivity distributions it was calculated that by an injection of 2,200 microCi 131 I-MAb F(ab')2 a mean dose of 8,335 rad was selectively delivered to the tumor, while the tissue-absorbed radiation doses for the normal organs were: peripheral blood, 2,093; stomach, 1,668; kidney, 1,289; lung, 1,185; liver, 617; spleen, 501; small intestine, 427; large intestine, 367; bone, 337; and muscle, 198. These treatments were well tolerated since out of 19 mice with complete tumor remission only 4 required bone marrow transplantation and 17 were in good health for 6-12 mo of observation

Reorienting the Fab domains of trastuzumab results in potent HER2 activators.

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Justin M Scheer

Full Text Available The structure of the Fab region of antibodies is critical to their function. By introducing single cysteine substitutions into various positions of the heavy and light chains of the Fab region of trastuzumab, a potent antagonist of HER2, and using thiol chemistry to link the different Fabs together, we produced a variety of monospecific F(ab'(2-like molecules with activities spanning from activation to inhibition of breast tumor cell growth. These isomers (or bis-Fabs of trastuzumab, with varying relative spatial arrangements between the Fv-regions, were able to either promote or inhibit cell-signaling activities through the PI3K/AKT and MAPK pathways. A quantitative phosphorylation mapping of HER2 indicated that the agonistic isomers produced a distinct phosphorylation pattern associated with activation. This study suggests that antibody geometric isomers, found both in nature and during synthetic antibody development, can have profoundly different biological activities independent of their affinities for their target molecules.

Polyclonal and monoclonal antibodies in clinic.

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Wootla, Bharath; Denic, Aleksandar; Rodriguez, Moses

2014-01-01

Immunoglobulins (Ig) or antibodies are heavy plasma proteins, with sugar chains added to amino-acid residues by N-linked glycosylation and occasionally by O-linked glycosylation. The versatility of antibodies is demonstrated by the various functions that they mediate such as neutralization, agglutination, fixation with activation of complement and activation of effector cells. Naturally occurring antibodies protect the organism against harmful pathogens, viruses and infections. In addition, almost any organic chemical induces antibody production of antibodies that would bind specifically to the chemical. These antibodies are often produced from multiple B cell clones and referred to as polyclonal antibodies. In recent years, scientists have exploited the highly evolved machinery of the immune system to produce structurally and functionally complex molecules such as antibodies from a single B clone, heralding the era of monoclonal antibodies. Most of the antibodies currently in the clinic, target components of the immune system, are not curative and seek to alleviate symptoms rather than cure disease. Our group used a novel strategy to identify reparative human monoclonal antibodies distinct from conventional antibodies. In this chapter, we discuss the therapeutic relevance of both polyclonal and monoclonal antibodies in clinic.

Critical epitopes in the nucleocapsid protein of SFTS virus recognized by a panel of SFTS patients derived human monoclonal antibodies.

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Li Yu

Full Text Available BACKGROUND: SFTS virus (SFTSV is a newly discovered pathogen to cause severe fever with thrombocytopenia syndrome (SFTS in human. Successful control of SFTSV epidemic requires better understanding of the antigen target in humoral immune responses to the new bunyavirus infection. METHODOLOGY/PRINCIPAL FINDINGS: We have generated a combinatorial Fab antibody phage library from two SFTS patients recovered from SFTSV infection. To date, 94 unique human antibodies have been generated and characterized from over 1200 Fab antibody clones obtained by screening the library with SFTS purified virions. All those monoclonal antibodies (MAbs recognized the nucleocapsid (N protein of SFTSV while none of them were reactive to the viral glycoproteins Gn or Gc. Furthermore, over screening 1000 mouse monoclonal antibody clones derived from SFTSV virions immunization, 462 clones reacted with N protein, while only 16 clones were reactive to glycoprotein. Furthermore, epitope mapping of SFTSV N protein was performed through molecular simulation, site mutation and competitive ELISA, and we found that at least 4 distinct antigenic epitopes within N protein were recognized by those human and mouse MAbs, in particular mutation of Glu10 to Ala10 abolished or significantly reduced the binding activity of nearly most SFTS patients derived MAbs. CONCLUSIONS/SIGNIFICANCE: The large number of human recombinant MAbs derived from SFTS patients recognized the viral N protein indicated the important role of the N protein in humoral responses to SFTSV infection, and the critical epitopes we defined in this study provided molecular basis for detection and diagnosis of SFTSV infection.

Incomplete Antibodies May Reduce ABO Cross-Match Incompatibility: A Pilot Study

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Mehmet Özen

2018-02-01

Full Text Available Objective: Any erythrocyte transfusion among humans having type A or B blood groups is impossible due to antibodies causing fatal transfusion complications. A cross-match test is performed to prevent immune transfusion complications before transfusion. Our hypothesis is that the fragment antibody (Fab part of the antibody (incomplete antibody may be used to prevent an immune stimulus related to the complete antibody. Therefore, we designed a pilot study to evaluate the effectiveness of these incomplete antibodies using cross-match tests. Materials and Methods: Pepsin enzyme and staphylococcal protein A columns were used to cut anti-A and anti-B monoclonal antibodies and purify their Fab (2 fragments, respectively. An Rh-positive erythrocyte suspension with purified anti-A Fab (2 solution and B Rh-positive erythrocyte suspension with purified anti-B Fab (2 solution were combined correspondingly. Cross-match tests were performed by tube and gel centrifugation methods. The agglutination levels due to the anti-A and anti-B Fab (2 antibodies and their effects on the agglutination normally observed with complete antibodies were then measured. Results: No agglutination for the purified incomplete anti-A Fab (2 with A Rh+ erythrocyte and anti-B Fab (2 with B Rh+ erythrocyte combinations was observed in the tube cross-match tests. These agglutination levels were 1+ in two wells in the gel centrifugation cross-match tests. Fab (2-treated erythrocytes were also resistant to the agglutination that normally occurs with complete antibodies. Conclusion: We determined that the Fab (2 fragments of antibodies may not only be used to obtain a mild or negative reaction when compared to complete antibodies, but they might also be used for decreasing ABO incompatibility. Incomplete antibodies might be a therapeutic option in autoimmune hemolytic anemia and they may also be used in solid organ or hematopoietic stem cell transplantation. Therefore, we have planned an

Utilisation of tracer monoclonal antibodies for the immunoscintigraphic detection of human colorectal cancers

International Nuclear Information System (INIS)

Chatal, J.F.; Douillard, J.Y.; Kremer, M.; Curtet, C.; Le Mevel, B.; Fumoleau, P.; Bourdoiseau, M.

1983-01-01

Two monoclonal antibodies, 17-1A and 19-9, with recognized human gastrointestinal cancers in cell cultures, were labeled with iodine 131 for immunoscintigraphic application. With the intact 131 I-17-1A antibody, 21 out of 35 (60%) primary or secondary colorectal cancer sites were visualized, whereas all 21 nonepitheliomatous colic cancer sites or noncolic cancer sites were negative. With F(ab') 2 fragments of the 19-9 antibody, 18 out of 27 (67%) colorectal cancer sites were positive. With both radioantibodies, the bestly contrasted tumor images were late, 4 to 5 days after injection. A study with paired-label technique, associating a specific iodine-131-labeled antibody with a non-specific iodine-125-labeled immunoglobulin, demonstrated, that tumor uptake was indeed specific for the 17-1A or 19-9 antibody in tumor and normal colon fragments obtained during operations on 4 patients. A preliminary prospective study showed that only immunoscintigraphy was able to confirm and localize a recurrence of rectal cancer in one patient. A larger series will be necessary to validate the clinical benefit of the technique, as compared with the results of other diagnostic techniques, before immunoscintigraphy can be proposed for routine clinical use [fr

New Insights into the Functional Behavior of Antibodies as Revealed by Binding Studies on an Anti-Uranium Monoclonal Antibody

International Nuclear Information System (INIS)

Blake, Diane A.; Xia Li; Haini Yu; Blake, Robert C.

2004-01-01

As part of an ongoing effort to develop immunoassays for chelated uranium(VI) on a hand-held flow fluorimeter, an anti-uranium monoclonal antibody designated as 8A11 was fluorescently labeled using two different strategies. When 8A11 was coupled via reactive lysines to either ALEXATM 488 or Cy5TM, the resulting fluorescent antibody conjugate exhibited positive cooperativity in the presence of its antigen, U(VI) chelated with 2,9-dicarboxy-1,10-phenanthroline (U(VI)-DCP). That is, when one of the two binding sites on the covalently modified 8A11 was occupied with bound antigen, the affinity of the remaining site on the antibody for U(VI)-DCP appeared to increase. Unmodified 8A11 bound U(VI)-DCP with the expected hyperbolic dependence on the concentration of antigen, consistent with independent and equal binding of ligand at both sites. Proteolytic cleavage of the fluorescently conjugated 8A11 to produce the fluorescent monovalent Fab fragment yielded an active preparation that now bound U(VI)-DCP with no evidence of positive cooperativity. Although, in principle, any divalent antibody has the potential to exhibit positive cooperativity in its binding interactions with its antigen, very little literature precedent for this type of behavior exists. Native 8A11 was also noncovalently labeled with highly fluorescent ZENONTM reagents. These reagents are fluorescently-labeled Fab fragments of goat anti-mouse antibodies that bind to the Fc portion of 8A11. These high-affinity, monovalent fluorescent reagents permitted the intact 8A11 mouse antibody to be labeled in situ with no covalent modifications. Incubation of the 8A11 with ZENON 647 produced a fluorescent protein complex that showed an 8-fold higher affinity for U(VI)-DCP than did the free 8A11 alone. Again, very few literature precedents exist for this phenomenon, where agents that bind to the Fc portion of an intact antibody change the affinity of the antibody for the antigen at the structurally distant Fab portion

Radioimmunodetection of human melanoma tumor xenografts with human monoclonal antibodies

International Nuclear Information System (INIS)

Gomibuchi, Makoto; Saxton, R.E.; Lake, R.R.; Katano, Mitsuo; Irie, R.F.

1986-01-01

A human IgM monoclonal antibody has been established that defines a tumor-associated membrane antigen expressed on human melanoma cells. The antigen has been identified as the ganglioside GD2. In this paper, the authors describe the potential usefulness of the human monoclonal antibody for radioimaging. Nude mice bearing tumors derived from a human melanoma cell line were used as a model. Antibody activity was degradated significantly after labeling with 131 I by the use of a modified chloramine-T method. After testing various concentrations, labeled antibody of a specific activity of 2.8μCi/μg produced the best results. Balb/c nude mice bearing a GD2-positive M14 melanoma cell line were injected with 10-30μg of labeled antibody, and its radiolocalization in different organs and in the whole body were evaluated. The best tumor image was obtained on Day 6. The labeled antibody uptake ratio between tumor and muscle was 9.2:1; the ratio between tumor and liver was 1.4:1. These studies represent the first report of experimental tumor imaging with human monoclonal antibody. Human monoclonals will probably prove to be superior reagents for tumor imaging in melanoma patients if the problem of anti-body radiolysis is resolved. (author)

Structural Basis for Recognition of Human Enterovirus 71 by a Bivalent Broadly Neutralizing Monoclonal Antibody.

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Xiaohua Ye

2016-03-01

Full Text Available Enterovirus 71 (EV71 is the main pathogen responsible for hand, foot and mouth disease with severe neurological complications and even death in young children. We have recently identified a highly potent anti-EV71 neutralizing monoclonal antibody, termed D5. Here we investigated the structural basis for recognition of EV71 by the antibody D5. Four three-dimensional structures of EV71 particles in complex with IgG or Fab of D5 were reconstructed by cryo-electron microscopy (cryo-EM single particle analysis all at subnanometer resolutions. The most critical EV71 mature virion-Fab structure was resolved to a resolution of 4.8 Å, which is rare in cryo-EM studies of virus-antibody complex so far. The structures reveal a bivalent binding pattern of D5 antibody across the icosahedral 2-fold axis on mature virion, suggesting that D5 binding may rigidify virions to prevent their conformational changes required for subsequent RNA release. Moreover, we also identified that the complementary determining region 3 (CDR3 of D5 heavy chain directly interacts with the extremely conserved VP1 GH-loop of EV71, which was validated by biochemical and virological assays. We further showed that D5 is indeed able to neutralize a variety of EV71 genotypes and strains. Moreover, D5 could potently confer protection in a mouse model of EV71 infection. Since the conserved VP1 GH-loop is involved in EV71 binding with its uncoating receptor, the scavenger receptor class B, member 2 (SCARB2, the broadly neutralizing ability of D5 might attribute to its inhibition of EV71 from binding SCARB2. Altogether, our results elucidate the structural basis for the binding and neutralization of EV71 by the broadly neutralizing antibody D5, thereby enhancing our understanding of antibody-based protection against EV71 infection.

Monoclonal antibodies for treating cancer

International Nuclear Information System (INIS)

Dillman, R.O.

1989-01-01

The purpose of this study is to assess the current status of in-vivo use of monoclonal antibodies for treating cancer. Publications appearing between 1980 and 1988 were identified by computer searches using MEDLINE and CANCERLIT, by reviewing the table of contents of recently published journals, and by searching bibliographies of identified books and articles. More than 700 articles, including peer-reviewed articles and book chapters, were identified and selected for analysis. The literature was reviewed and 235 articles were selected as relevant and representative of the current issues and future applications for in-vivo monoclonal antibodies for cancer therapy and of the toxicity and efficacy which has been associated with clinical trials. Approaches include using antibody alone (interacting with complement or effector cells or binding directly with certain cell receptors) and immunoconjugates (antibody coupled to radioisotopes, drugs, toxins, or other biologicals). Most experience has been with murine antibodies. Trials of antibody alone and radiolabeled antibodies have confirmed the feasibility of this approach and the in-vivo trafficking of antibodies to tumor cells. However, tumor cell heterogeneity, lack of cytotoxicity, and the development of human antimouse antibodies have limited clinical efficacy. Although the immunoconjugates are very promising, heterogeneity and the antimouse immune response have hampered this approach as has the additional challenge of chemically or genetically coupling antibody to cytotoxic agents. As a therapeutic modality, monoclonal antibodies are still promising but their general use will be delayed for several years. New approaches using human antibodies and reducing the human antiglobulin response should facilitate treatment. 235 references

Agonistic effects of a monoclonal antibody specific for the interleukin-2 receptor

International Nuclear Information System (INIS)

Eardley, D.D.; Makrides, V.

1986-01-01

Interleukin-2 (IL-2) mediated immune responses can be blocked by monoclonal antibodies to the IL-2 receptor. The monoclonal antibody, M720, is defined as specific for the IL-2 receptor because it blocks 35 S-IL-2 binding to Con A blasts, reacts with lymphoblasts but not resting splenocytes, and inhibits IL-2 induced proliferation to mitogen, antigen, or allogeneic stimuli. Under appropriate culture conditions, the IL-2 receptor-specific antibody can act like IL-2 in that it will induce proliferation in T cells in the absence of additional antigen or mitogen. This agonistic effect is dependent on time, dose of antibody, and requires fetal calf serum (FCS) in the media. Because the FCS is not mitogenic by itself, the authors propose that the FCS components act as incomplete mitogen to induce appearance of IL-2 receptors but lack a factor which would push the majority of the cells into the S phase of the cell cycle. This factor is usually IL-2, but in the authors experiments, the IL-2 receptor-specific antibody can provide the same stimulus. These data indicate that factors like FCS can induce IL-2 receptors, but without additional IL-2 or receptor triggering, the cells will not proceed through the synthetic and proliferative phases of cell growth

Comparing domain interactions within antibody Fabs with kappa and lambda light chains.

Science.gov (United States)

Toughiri, Raheleh; Wu, Xiufeng; Ruiz, Diana; Huang, Flora; Crissman, John W; Dickey, Mark; Froning, Karen; Conner, Elaine M; Cujec, Thomas P; Demarest, Stephen J

2016-10-01

IgG antibodies are multi-domain proteins with complex inter-domain interactions. Human IgG heavy chains (HCs) associate with light chains (LCs) of the κ or λ isotype to form mature antibodies capable of binding antigen. The HC/LC interaction involves 4 domains: VH and CH1 from the HC and VL and CL from the LC. Human Fabs with κ LCs have been well characterized for their unfolding behaviors and demonstrate a significant level of cooperativity and stabilization when all 4 domains are intact. Very little is known regarding the thermodynamic properties of human Fabs with λ LCs. Here, we dissect the domain contributions to Fab stability for both κ and λ LC-containing Fabs. We find the cooperativity of unfolding between the constant domains, CH1/Cλ, and variable domains, VH/Vλ, within λ LC-containing Fabs is significantly weaker than that of κ LC-containing Fabs. The data suggests there may not be an evolutionary necessity for strong variable/constant domain cooperativity within λ LC-containing Fabs. After investigating the biophysical properties of Fabs with mismatched variable and constant domain subunits (e.g., VH/Vκ paired with CH1/Cλ or T cell receptor Cα/Cβ), the major role of the constant domains for both κ- and λ-containing Fabs may be to reduce the hydrophobic exposure at the VH/VL interface. Even though Fabs with these non-native pairings were thermodynamically less stable, they secreted well from mammalian cells as well behaved monodisperse proteins, which was in contrast to what was observed with the VH/Vκ and VH/Vλ scFvs that secreted as a mixture of monomer and aggregates.

Studies of a murine monoclonal antibody directed against DARC: reappraisal of its specificity.

Directory of Open Access Journals (Sweden)

Dorota Smolarek

Full Text Available Duffy Antigen Receptor for Chemokines (DARC plays multiple roles in human health as a blood group antigen, a receptor for chemokines and the only known receptor for Plasmodium vivax merozoites. It is the target of the murine anti-Fy6 monoclonal antibody 2C3 which binds to the first extracellular domain (ECD1, but exact nature of the recognized epitope was a subject of contradictory reports. Here, using a set of complex experiments which include expression of DARC with amino acid substitutions within the Fy6 epitope in E. coli and K562 cells, ELISA, surface plasmon resonance (SPR and flow cytometry, we have resolved discrepancies between previously published reports and show that the basic epitope recognized by 2C3 antibody is 22FEDVW26, with 22F and 26W being the most important residues. In addition, we demonstrated that 30Y plays an auxiliary role in binding, particularly when the residue is sulfated. The STD-NMR studies performed using 2C3-derived Fab and synthetic peptide corroborated most of these results, and together with the molecular modelling suggested that 25V is not involved in direct interactions with the antibody, but determines folding of the epitope backbone.

Immunogenicity of anti-tumor necrosis factor antibodies-toward improved methods of anti-antibody measurement.

Science.gov (United States)

Aarden, Lucien; Ruuls, Sigrid R; Wolbink, Gertjan

2008-08-01

To date, millions of people have been treated with therapeutic monoclonal antibodies (TmAbs) for various indications. It is becoming increasingly clear that TmAbs can be immunogenic, which may reduce efficacy or induce adverse effects. Over the years, the importance of antibody formation has been questioned and sometimes minimized, as few antibody responses to TmAbs (HACA or HAHA) were reported. However, the methods to detect and quantify such antibodies used in the past have been problematic. Only recently, methods have been developed that have adequate sensitivity and are not seriously disturbed by false-positive reactions caused by rheumatoid factors, natural antibodies to Fab or F(ab')2 fragments, or Fc interactions of IgG4. The large number of treated patients, in combination with these new assays, presents a unique opportunity to study the anti-antibody immune response in man, possibly allowing us to manipulate immunogenicity in the future.

[International classification of various types of monoclonal antibodies].

Science.gov (United States)

Scheen, A J

2009-01-01

Significant advances in the development of monoclonal antibodies ("mabs") have been acknowledged during the last two decades. Successive developments led to the marketing of murine antibodies ("o-mab" first, followed by chimeric antibodies ("xi-mab"), humanised antibodies ("zu-mab") and, finally, human monoclonal antibodies ("u-mab"). In order to facilitate the distinction between the various monoclonal antibodies used in clinical practice, an international nomenclature has been proposed with the use of a specific suffix corresponding to the origine/source of "mabs" preceded by an infix referring to the medicine's target. The efforts in developing new types of monoclonal antibodies aimed at improving their pharmacokinetics (longer half-life), pharmacodynamics (better efficacy because of stronger affinity to human receptor), and safety profile (less antigenic and immunogenic reactions). These progresses could be obtained thanks to the remarkable development of molecular biotechnology.

Distribution and dosimetry of indium-111 labeled F(ab')2 fragments in humans

International Nuclear Information System (INIS)

Doherty, P.; Schwinger, R.; King, M.; Gionet, M.

1986-01-01

The purpose of this study was to obtain quantitative biodistribution data in patients injected with the indium-111 labeled F(ab') 2 fragments of mouse monoclonal antibody. From this data dosimetric calculations were made for the individual organs. The authors also evaluated the quantitative properties of SPECT in this application and compared it with the more conventional two view planar technique in both phantom and patient studies. For one antibody (19-9) the mean dose in rads/mCi for the organs of highest accumulation, namely, the liver and kidneys was 3.2 and 2.6 respectively. Preliminary data from another antibody (OC 125) showed much higher blood levels and a significantly lower liver dose of 2.3 indicating that antibody type is another significant determinant in dosimetry. The SPECT approach particularly in the presence of background activity, was more accurate in the phantom studies and resulted in larger estimated doses in the patient studies. Also, SPECT has the added advantage of providing an index of organ volume, which has to be balanced with the fact the planar is more rapid, and does not require special hardware. 24 references, 5 figures, 1 table

Enhancement of retroviral infection in vitro by anti-Le(y) IgG: reversal by humanization of monoclonal mouse antibody

DEFF Research Database (Denmark)

Hansen, J E; Sørensen, A M; Arendrup, M

1993-01-01

Monoclonal mouse IgG3 antibody (ABL 364) against the carbohydrate Le(y) antigen enhanced infection in vitro with HTLV-1 and with HIV-1 when propagated in both transformed and normal lymphocytes. Enhancement was independent of complement, occurred with both lymphocytes and monocytes as target cells...... with no indication of any alternative pathway of infection, as evidenced by abrogation of enhancement by anti-CD4 MAb or soluble recombinant CD4, and also the inability of anti-Le(y) MAb to mediate HIV infection of HSB-2 cells in which HTLV-1/HIV pseudovirus infection was enhanced. While F(ab)2 fragments of ABL 364...

A sensitive radioimmunoassay for the detection of monoclonal anti-idiotype antibodies

International Nuclear Information System (INIS)

Morahan, G.

1983-01-01

A radioimmunoassay was developed in order to detect anti-idiotypic antibodies in the supernatants of hybrid cells. This assay is both sensitive and specific for anti-idiotypic (but not anti-allotypic) antibodies. Monoclonal antibodies present in test supernatants are bound by an anti-immunoglobulin coated solid phase. Subsequent incubation with a source of mouse immunoglobulin 'blocks' unreacted anti-immunoglobulin antibodies on the solid phase. Anti-idiotypic antibodies are then detected by their ability to bind 125 I-labelled idiotype-bearing antibody. This paper describes the use of this assay to detect monoclonal anti-idiotypic antibodies in 2 systems; the cross-reactive idiotype of A/J anti-ABA antibodies, and the idiotype expressed by the myeloma protein HOPC 8. Similarly, 125 I-labelled anti-idiotype antibodies may be used in this assay to detect monoclonal idiotype-bearing antibodies. Further modifications are described which would allow the detection of monoclonal anti-allotype antibodies. (Auth.)

Fab-dsFv: A bispecific antibody format with extended serum half-life through albumin binding.

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Davé, Emma; Adams, Ralph; Zaccheo, Oliver; Carrington, Bruce; Compson, Joanne E; Dugdale, Sarah; Airey, Michael; Malcolm, Sarah; Hailu, Hanna; Wild, Gavin; Turner, Alison; Heads, James; Sarkar, Kaushik; Ventom, Andrew; Marshall, Diane; Jairaj, Mark; Kopotsha, Tim; Christodoulou, Louis; Zamacona, Miren; Lawson, Alastair D; Heywood, Sam; Humphreys, David P

2016-10-01

An antibody format, termed Fab-dsFv, has been designed for clinical indications that require monovalent target binding in the absence of direct Fc receptor (FcR) binding while retaining substantial serum presence. The variable fragment (Fv) domain of a humanized albumin-binding antibody was fused to the C-termini of Fab constant domains, such that the VL and VH domains were individually connected to the Cκ and CH1 domains by peptide linkers, respectively. The anti-albumin Fv was selected for properties thought to be desirable to ensure a durable serum half-life mediated via FcRn. The Fv domain was further stabilized by an inter-domain disulfide bond. The bispecific format was shown to be thermodynamically and biophysically stable, and retained good affinity and efficacy to both antigens simultaneously. In in vivo studies, the serum half-life of Fab-dsFv, 2.6 d in mice and 7.9 d in cynomolgus monkeys, was equivalent to Fab'-PEG.

Clearance of 131I-labeled murine monoclonal antibody from patients' blood by intravenous human anti-murine immunoglobulin antibody

International Nuclear Information System (INIS)

Stewart, J.S.; Sivolapenko, G.B.; Hird, V.; Davies, K.A.; Walport, M.; Ritter, M.A.; Epenetos, A.A.

1990-01-01

Five patients treated with intraperitoneal 131I-labeled mouse monoclonal antibody for ovarian cancer also received i.v. exogenous polyclonal human anti-murine immunoglobulin antibody. The pharmacokinetics of 131I-labeled monoclonal antibody in these patients were compared with those of 28 other patients receiving i.p.-radiolabeled monoclonal antibody for the first time without exogenous human anti-murine immunoglobulin, and who had no preexisting endogenous human anti-murine immunoglobulin antibody. Patients receiving i.v. human anti-murine immunoglobulin antibody demonstrated a rapid clearance of 131I-labeled monoclonal antibody from their circulation. The (mean) maximum 131I blood content was 11.4% of the injected activity in patients receiving human anti-murine immunoglobulin antibody compared to 23.3% in patients not given human anti-murine immunoglobulin antibody. Intravenous human anti-murine immunoglobulin antibody decreased the radiation dose to bone marrow (from 131I-labeled monoclonal antibody in the vascular compartment) 4-fold. Following the injection of human anti-murine immunoglobulin antibody, 131I-monoclonal/human anti-murine immunoglobulin antibody immune complexes were rapidly transported to the liver. Antibody dehalogenation in the liver was rapid, with 87% of the injected 131I excreted in 5 days. Despite the efficient hepatic uptake of immune complexes, dehalogenation of monoclonal antibody was so rapid that the radiation dose to liver parenchyma from circulating 131I was decreased 4-fold rather than increased. All patients developed endogenous human anti-murine immunoglobulin antibody 2 to 3 weeks after treatment

Development and Characterization of Canine Distemper Virus Monoclonal Antibodies.

Science.gov (United States)

Liu, Yuxiu; Hao, Liying; Li, Xiangdong; Wang, Linxiao; Zhang, Jianpo; Deng, Junhua; Tian, Kegong

2017-06-01

Five canine distemper virus monoclonal antibodies were developed by immunizing BALB/c mice with a traditional vaccine strain Snyder Hill. Among these monoclonal antibodies, four antibodies recognized both field and vaccine strains of canine distemper virus without neutralizing ability. One monoclonal antibody, 1A4, against hemagglutinin protein of canine distemper virus was found to react only with vaccine strain virus but not field isolates, and showed neutralizing activity to vaccine strain virus. These monoclonal antibodies could be very useful tools in the study of the pathogenesis of canine distemper virus and the development of diagnostic reagents.

Reorienting the Fab Domains of Trastuzumab Results in Potent HER2 Activators

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Scheer, Justin M.; Sandoval, Wendy; Elliott, J. Michael; Shao, Lily; Luis, Elizabeth; Lewin-Koh, Sock-Cheng; Schaefer, Gabriele; Vandlen, Richard

2012-01-01

The structure of the Fab region of antibodies is critical to their function. By introducing single cysteine substitutions into various positions of the heavy and light chains of the Fab region of trastuzumab, a potent antagonist of HER2, and using thiol chemistry to link the different Fabs together, we produced a variety of monospecific F(ab′)2-like molecules with activities spanning from activation to inhibition of breast tumor cell growth. These isomers (or bis-Fabs) of trastuzumab, with varying relative spatial arrangements between the Fv-regions, were able to either promote or inhibit cell-signaling activities through the PI3K/AKT and MAPK pathways. A quantitative phosphorylation mapping of HER2 indicated that the agonistic isomers produced a distinct phosphorylation pattern associated with activation. This study suggests that antibody geometric isomers, found both in nature and during synthetic antibody development, can have profoundly different biological activities independent of their affinities for their target molecules. PMID:23284778

Glomerular filtration rate after alpha-radioimmunotherapy with 211At-MX35-F(ab')2: a long-term study of renal function in nude mice

DEFF Research Database (Denmark)

Back, T.; Haraldsson, B.; Hultborn, R

2009-01-01

of the glomerular filtration rate (GFR). The renal toxicity was evaluated at levels close to the dose limit for the bone marrow and well within the range for therapeutic efficacy on tumors. Astatinated MX35-F(ab')(2) monoclonal antibodies were administered intravenously to nude mice. Both non-tumor-bearing animals...... manifested late. Examination of the kidney sections showed histologic changes that were overall subdued. Following alpha-RIT with (211)At-MX35-F(ab')(2) at levels close to the dose limit of severe myelotoxicity, the effects found on renal function were relatively small, with only minor to moderate reductions...... in GFR. These results suggest that a mean absorbed dose to the kidneys of approximately 10 Gy is acceptable, and that the kidneys would not be the primary dose-limiting organ in systemic alpha-RIT when using (211)At-MX35-F(ab')(2) Udgivelsesdato: 2009/12...

Preclinical and phase I studies of monoclonal antibodies in melanoma: Application to boron neutron capture therapy of melanoma

International Nuclear Information System (INIS)

Hersey, P.

1989-01-01

Monoclonal antibodies (MAbs) provide an attractive method of selectively localizing sufficient boron atoms around tumour cells to capture neutrons. Assuming that 10(8)-10(10) 10B atoms are needed for one capture event and that 10(3)-10(4) atoms can be coupled to each antibody molecule, then 10(5)-10(6) antibody molecules gathered on an individual cell will destroy that cell. Binding to normal tissues, on the other hand, would need to be at least 20-fold less than that to tumour tissues to avoid toxic effects of neutrons on surrounding tissues. Preclinical studies in animals show that several MAbs may bind to melanoma cells in sufficient quantities in vitro to localize the required amount of boron per cell. Whether this will occur in vivo, however, may depend not only on antigen density but a variety of other properties of the tumour cells and MAbs. These include the Ig class and affinity of the antibody and whether the antibody is internalized into the tumour cell. The ratio of uptake between tumour and normal tissue is governed by such factors as the percentage of tumour cells within a tumour expressing the antigen and whether the MAb react with normal tissues. Use of Fab or F(ab)2 preparations of the MAb may increase the uptake ratio by preventing uptake of MAb by cells with Fc receptors. In contrast to preclinical animal studies, tumour/normal tissue uptake ratios in phase I studies in humans have been disappointingly low.80 references

Development of an immunoassay for determination of 2,4-dichlorophenoxyacetic acid (2,4-D) based upon the recombinant Fab fragment of 2,4-D specific antibody

Science.gov (United States)

Nguyen, Van C.; Nguyen, Thi D. T.; Dau, Hung A.; Tham, Thu N.; Quyen, Dinh T.; Bachmman, Till; Schmid, Rolf D.

2001-09-01

To develop an immunoassay and further an immunosensor for 2,4-D based upon recombinant antibody, the Fab fragments of 2,4-D specific antibody were expressed in E. coli. Western blotting analysis of the periplasmic cell fractions shown that under the non-reducing condition only a single protein band at a molecular mass of 45-kDa, corresponding to the whole Fab fragment was detected. Antigen binding activity for 2,4-D was found only in the extract of cells bearing the 2,4-D plasmid. An immunoassay based on the competitive reaction of 2,4-D and enzyme tracer with 2,4-D Fab fragments immobilized on micro titer plates via rabbit anti-mouse IgC was developed. Using this assay, 2,4-D could be detected at concentration range of 0.5 (mu) g/1 to 10(mu) g/1. The center point of the 2,4-D test was found at a concentration of 5 (mu) g/l. The assay was applied for detection of 2,4-D in spiked orange samples, resulting in recovery rate of 90 percent. The immunoassay could be applied to monitor human exposure to 2,4-D from contamination in fruit samples.

Human anti-plague monoclonal antibodies protect mice from Yersinia pestis in a bubonic plague model.

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Xiaodong Xiao

2010-10-01

Full Text Available Yersinia pestis is the etiologic agent of plague that has killed more than 200 million people throughout the recorded history of mankind. Antibiotics may provide little immediate relief to patients who have a high bacteremia or to patients infected with an antibiotic resistant strain of plague. Two virulent factors of Y. pestis are the capsid F1 protein and the low-calcium response (Lcr V-protein or V-antigen that have been proven to be the targets for both active and passive immunization. There are mouse monoclonal antibodies (mAbs against the F1- and V-antigens that can passively protect mice in a murine model of plague; however, there are no anti-Yersinia pestis monoclonal antibodies available for prophylactic or therapeutic treatment in humans. We identified one anti-F1-specific human mAb (m252 and two anti-V-specific human mAb (m253, m254 by panning a naïve phage-displayed Fab library against the F1- and V-antigens. The Fabs were converted to IgG1s and their binding and protective activities were evaluated. M252 bound weakly to peptides located at the F1 N-terminus where a protective mouse anti-F1 mAb also binds. M253 bound strongly to a V-antigen peptide indicating a linear epitope; m254 did not bind to any peptide from a panel of 53 peptides suggesting that its epitope may be conformational. M252 showed better protection than m253 and m254 against a Y, pestis challenge in a plague mouse model. A synergistic effect was observed when the three antibodies were combined. Incomplete to complete protection was achieved when m252 was given at different times post-challenge. These antibodies can be further studied to determine their potential as therapeutics or prophylactics in Y. pestis infection in humans.

Crystal structure and size-dependent neutralization properties of HK20, a human monoclonal antibody binding to the highly conserved heptad repeat 1 of gp41.

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Sabin, Charles; Corti, Davide; Buzon, Victor; Seaman, Mike S; Lutje Hulsik, David; Hinz, Andreas; Vanzetta, Fabrizia; Agatic, Gloria; Silacci, Chiara; Mainetti, Lara; Scarlatti, Gabriella; Sallusto, Federica; Weiss, Robin; Lanzavecchia, Antonio; Weissenhorn, Winfried

2010-11-18

The human monoclonal antibody (mAb) HK20 neutralizes a broad spectrum of primary HIV-1 isolates by targeting the highly conserved heptad repeat 1 (HR1) of gp41, which is transiently exposed during HIV-1 entry. Here we present the crystal structure of the HK20 Fab in complex with a gp41 mimetic 5-Helix at 2.3 Å resolution. HK20 employs its heavy chain CDR H2 and H3 loops to bind into a conserved hydrophobic HR1 pocket that is occupied by HR2 residues in the gp41 post fusion conformation. Compared to the previously described HR1-specific mAb D5, HK20 approaches its epitope with a different angle which might favor epitope access and thus contribute to its higher neutralization breadth and potency. Comparison of the neutralization activities of HK20 IgG, Fab and scFv employing both single cycle and multiple cycle neutralization assays revealed much higher potencies for the smaller Fab and scFv over IgG, implying that the target site is difficult to access for complete antibodies. Nevertheless, two thirds of sera from HIV-1 infected individuals contain significant titers of HK20-inhibiting antibodies. The breadth of neutralization of primary isolates across all clades, the higher potencies for C-clade viruses and the targeting of a distinct site as compared to the fusion inhibitor T-20 demonstrate the potential of HK20 scFv as a therapeutic tool.

Generation of a Monoclonal Antibody against Mycoplasma spp. following Accidental Contamination during Production of a Monoclonal Antibody against Lawsonia intracellularis

OpenAIRE

Hwang, Jeong-Min; Lee, Ji-Hye; Yeh, Jung-Yong

2012-01-01

This report describes Mycoplasma contamination of Lawsonia intracellularis cultures that led to the unintended acquisition of a monoclonal antibody against Mycoplasma spp. during the attempted generation of a monoclonal antibody against L. intracellularis.

Lymphoma, melanoma, colon cancer: diagnosis and treatment with radiolabeled monoclonal antibodies. The 1986 Eugene P. Pendergrass New Horizons Lecture

International Nuclear Information System (INIS)

Larson, S.M.

1987-01-01

The development of monoclonal antibodies for use as in vivo carriers of radioactivity for diagnosis and therapy of malignant neoplasms is proceeding rapidly within academic and commercial sectors. The author and his colleagues studied anticancer antibodies formed against tumors of both somatic and hematopoietic origins. Several general principles have been established with the work with somatic tumors, including the following: Improved tumor-to-normal-tissue ratios can be achieved with Fab fragments as opposed to whole IgG; each antitumor antibody has a characteristic biodistribution in humans that cannot be readily predicted from tissue or small animal studies; and for many antibodies, there is a strong dependency of tumor uptake on total mass amount of antibody administered (greater uptake with greater mass dose). Initial work with iodine-131 labeled Fab fragments of the antimelanoma antibodies, 96.5 and 48-7, documented that tumor uptake was broadly proportional to antigen content of the tumors and that under optimal conditions, some tumors were sufficiently loaded with radiolabeled antibody to serve as radiation therapy. The antitumor antibody B-72.3, as IgG, has been particularly promising when administered intraperitoneally. In ten patients who were administered I-131 B-72.3 via a Tenkhoff catheter, the sensitivity and specificity of tumor location were excellent for peritoneal implants, and in three of these patients, surgically confirmed tumor was seen with the radiolabeled antibody technique when abdominal computed tomography and magnetic resonance studies were negative

Novel anti-HER2 monoclonal antibodies: synergy and antagonism with tumor necrosis factor-α

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Ceran Ceyhan

2012-10-01

Full Text Available Abstract Background One-third of breast cancers display amplifications of the ERBB2 gene encoding the HER2 kinase receptor. Trastuzumab, a humanized antibody directed against an epitope on subdomain IV of the extracellular domain of HER2 is used for therapy of HER2-overexpressing mammary tumors. However, many tumors are either natively resistant or acquire resistance against Trastuzumab. Antibodies directed to different epitopes on the extracellular domain of HER2 are promising candidates for replacement or combinatorial therapy. For example, Pertuzumab that binds to subdomain II of HER2 extracellular domain and inhibits receptor dimerization is under clinical trial. Alternative antibodies directed to novel HER2 epitopes may serve as additional tools for breast cancer therapy. Our aim was to generate novel anti-HER2 monoclonal antibodies inhibiting the growth of breast cancer cells, either alone or in combination with tumor necrosis factor-α (TNF-α. Methods Mice were immunized against SK-BR-3 cells and recombinant HER2 extracellular domain protein to produce monoclonal antibodies. Anti-HER2 antibodies were characterized with breast cancer cell lines using immunofluorescence, flow cytometry, immunoprecipitation, western blot techniques. Antibody epitopes were localized using plasmids encoding recombinant HER2 protein variants. Antibodies, either alone or in combination with TNF-α, were tested for their effects on breast cancer cell proliferation. Results We produced five new anti-HER2 monoclonal antibodies, all directed against conformational epitope or epitopes restricted to the native form of the extracellular domain. When tested alone, some antibodies inhibited modestly but significantly the growth of SK-BR-3, BT-474 and MDA-MB-361 cells displaying ERBB2 amplification. They had no detectable effect on MCF-7 and T47D cells lacking ERBB2 amplification. When tested in combination with TNF-α, antibodies acted synergistically on SK-BR-3 cells

Monoclonal antibodies in oncology. Review article

Energy Technology Data Exchange (ETDEWEB)

Chan, S Y.T.; Sikora, K

1986-05-01

Monoclonal antibodies (MCAs) can be used to differentiate between normal and neoplastic cells and thus exploited for diagnostic and, ultimately, therapeutic gain. The evidence for the existence of human tumour antigens is reviewed. Several areas of diagnosis are already benefiting from the application of the monoclonal technology. Immunohistology can help the pathologist with difficult diagnostic problems. New classifications of lymphoma and leukaemia can be based on specific surface molecules. Similarly, the detection of shed tumour antigens is already established as part of the routine assessment of many patients with common solid tumours. Isotopically labeled monoclonal antibodies have been used to localise primary and metastatic tumours. The use of antibodies in this way is not only a promising diagnostic tool but also the first step in studying the possibility of arming antibodies to provide therapeutic agents. Such trials are currently in progress. 69 refs.; 7 figs.; 3 tabs.

Near-Atomic Resolution Structure of a Highly Neutralizing Fab Bound to Canine Parvovirus.

Science.gov (United States)

Organtini, Lindsey J; Lee, Hyunwook; Iketani, Sho; Huang, Kai; Ashley, Robert E; Makhov, Alexander M; Conway, James F; Parrish, Colin R; Hafenstein, Susan

2016-11-01

Canine parvovirus (CPV) is a highly contagious pathogen that causes severe disease in dogs and wildlife. Previously, a panel of neutralizing monoclonal antibodies (MAb) raised against CPV was characterized. An antibody fragment (Fab) of MAb E was found to neutralize the virus at low molar ratios. Using recent advances in cryo-electron microscopy (cryo-EM), we determined the structure of CPV in complex with Fab E to 4.1 Å resolution, which allowed de novo building of the Fab structure. The footprint identified was significantly different from the footprint obtained previously from models fitted into lower-resolution maps. Using single-chain variable fragments, we tested antibody residues that control capsid binding. The near-atomic structure also revealed that Fab binding had caused capsid destabilization in regions containing key residues conferring receptor binding and tropism, which suggests a mechanism for efficient virus neutralization by antibody. Furthermore, a general technical approach to solving the structures of small molecules is demonstrated, as binding the Fab to the capsid allowed us to determine the 50-kDa Fab structure by cryo-EM. Using cryo-electron microscopy and new direct electron detector technology, we have solved the 4 Å resolution structure of a Fab molecule bound to a picornavirus capsid. The Fab induced conformational changes in regions of the virus capsid that control receptor binding. The antibody footprint is markedly different from the previous one identified by using a 12 Å structure. This work emphasizes the need for a high-resolution structure to guide mutational analysis and cautions against relying on older low-resolution structures even though they were interpreted with the best methodology available at the time. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Studies of nontarget-mediated distribution of human full-length IgG1 antibody and its FAb fragment in cardiovascular and metabolic-related tissues.

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Davidsson, Pia; Söderling, Ann-Sofi; Svensson, Lena; Ahnmark, Andrea; Flodin, Christine; Wanag, Ewa; Screpanti-Sundqvist, Valentina; Gennemark, Peter

2015-05-01

Tissue distribution and pharmacokinetics (PK) of full-length nontargeted antibody and its antigen-binding fragment (FAb) were evaluated for a range of tissues primarily of interest for cardiovascular and metabolic diseases. Mice were intravenously injected with a dose of 10 mg/kg of either human IgG1or its FAb fragment; perfused tissues were collected at a range of time points over 3 weeks for the human IgG1 antibody and 1 week for the human FAb antibody. Tissues were homogenized and antibody concentrations were measured by specific immunoassays on the Gyros system. Exposure in terms of maximum concentration (Cmax ) and area under the curve was assessed for all nine tissues. Tissue exposure of full-length antibody relative to plasma exposure was found to be between 1% and 10%, except for brain (0.2%). Relative concentrations of FAb antibody were the same, except for kidney tissue, where the antibody concentration was found to be ten times higher than in plasma. However, the absolute tissue uptake of full-length IgG was significantly higher than the absolute tissue uptake of the FAb antibody. This study provides a reference PK state for full-length whole and FAb antibodies in tissues related to cardiovascular and metabolic diseases that do not include antigen or antibody binding. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Fast conversion of scFv to Fab antibodies using type IIs restriction enzymes.

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Sanmark, Hanna; Huovinen, Tuomas; Matikka, Tero; Pettersson, Tiina; Lahti, Maria; Lamminmäki, Urpo

2015-11-01

Single chain variable fragment (scFv) antibody libraries are widely used for developing novel bioaffinity reagents, although Fab or IgG molecules are the preferred antibody formats in many final applications. Therefore, rapid conversion methods for combining multiple DNA fragments are needed to attach constant domains to the scFv derived variable domains. In this study we describe a fast and easy cloning method for the conversion of single framework scFv fragments to Fab fragments using type IIS restriction enzymes. All cloning steps excluding plating of the Fab transformants can be done in 96 well plates and the procedure can be completed in one working day. The concept was tested by converting 69 scFv clones into Fab format on 96 well plates, which resulted in 93% success rate. The method is particularly useful as a high-throughput tool for the conversion of the chosen scFv clones into Fab molecules in order to analyze them as early as possible, as the conversion can significantly affect the binding properties of the chosen clones. Copyright © 2015 Elsevier B.V. All rights reserved.

Cationization increases brain distribution of an amyloid-beta protofibril selective F(ab')2 fragment

OpenAIRE

Syvänen, Stina; Edén, Desireé; Sehlin, Dag

2017-01-01

Antibodies and fragments thereof are, because of high selectivity for their targets, considered as potential therapeutics and biomarkers for several neurological disorders. However, due to their large molecular size, antibodies/fragments do not easily penetrate into the brain. The aim of the present study was to improve the brain distribution via adsorptive-mediated transcytosis of an amyloid-beta (A beta) protofibril selective F(ab')2 fragment (F(ab')2-h158). F(ab')2-h158 was cationized to d...

Enhanced antibody-dependent cellular phagocytosis by chimeric monoclonal antibodies with tandemly repeated Fc domains.

Science.gov (United States)

Nagashima, Hiroaki; Ootsubo, Michiko; Fukazawa, Mizuki; Motoi, Sotaro; Konakahara, Shu; Masuho, Yasuhiko

2011-04-01

We previously reported that chimeric monoclonal antibodies (mAbs) with tandemly repeated Fc domains, which were developed by introducing tandem repeats of Fc domains downstream of 2 Fab domains, augmented binding avidities for all Fcγ receptors, resulting in enhanced antibody (Ab)-dependent cellular cytotoxicity. Here we investigated regarding Ab-dependent cellular phagocytosis (ADCP) mediated by these chimeric mAbs, which is considered one of the most important mechanisms that kills tumor cells, using two-color flow cytometric methods. ADCP mediated by T3-Ab, a chimeric mAb with 3 tandemly repeated Fc domains, was 5 times more potent than that by native anti-CD20 M-Ab (M-Ab hereafter). Furthermore, T3-Ab-mediated ADCP was resistant to competitive inhibition by intravenous Ig (IVIG), although M-Ab-mediated ADCP decreased in the presence of IVIG. An Fcγ receptor-blocking study demonstrated that T3-Ab mediated ADCP via both FcγRIA and FcγRIIA, whereas M-Ab mediated ADCP exclusively via FcγRIA. These results suggest that chimeric mAbs with tandemly repeated Fc domains enhance ADCP as well as ADCC, and that Fc multimerization may significantly enhance the efficacy of therapeutic Abs. Copyright © 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Monoclonal antibodies to DNA modified with cis- or trans-diamminedichloroplatinum(II)

International Nuclear Information System (INIS)

Sundquist, W.I.; Lippard, S.J.; Stollar, B.D.

1987-01-01

Murine monoclonal antibodies that bind selectively to adducts formed on DNA by the antitumor drug cis-diamminedichloroplatinum(II), cis-DDP, or to the chemothrapeutically inactive trans isomer trans-DDP were elicited by immunization with calf thymus DNA modified with either cis- or trans-DDP at ratios of bound platinum per nucleotide, (D/N)/sub b/, of 0.06-0.08. The binding of two monoclonal antibodies to cis-DDP-modified DNA was competitively inhibited in an enzyme-linked immunosorbent assay (ELISA) by 4-6 nM concentrations of cis-DDP bound to DNA. Adducts formed by cis-DDP on other synthetic DNA polymers did not inhibit antibody binding to cis-DDP-DNA. The biologically active compounds [Pt(en)Cl 2 ], [Pt(dach)Cl 2 ], and [Pt(NH 3 ) 2 (cbdca)] (carboplatin) all formed antibody-detectable adducts on DNA, whereas the inactive platinum complexes trans-DDP and [Pt(dien)Cl]Cl (dien, diethylenetriamine) did not. The monoclonal antibodies therefore recognize a bifunctional Pt-DNA adduct with cis stereochemistry in which platinum is coordinated by two adjacent guanines or, to a lesser degree, by adjacent adenine and guanine. A monoclonal antibody raised against trans-DDP-DNA was competitively inhibited in an ELISA by 40 nM trans-DDP bound to DNA. This antibody crossreacted with unmodified, denatured DNA. The recognition of cis- or trans-DDP-modified DNAs by monoclonal antibodies thus parallels the known modes of DNA binding of these compounds and may correlate with their biological activities

[Molecular dynamics of immune complex of photoadduct-containing DNA with Fab-Anti-DNA antibody fragment].

Science.gov (United States)

Akberova, N I; Zhmurov, A A; Nevzorova, T A; Litvinov, R I

2016-01-01

Antibodies to DNA play an important role in the pathogenesis of autoimmune diseases. The elucidation of structural mechanisms of both the antigen recognition and the interaction of anti-DNA antibodies with DNA will help to understand the role of DNA-containing immune complexes in various pathologies and can provide a basis for new treatment modalities. Moreover, the DNA-antibody complex is an analog of specific intracellular DNA-protein interactions. In this work, we used in silico molecular dynamic simulations of bimolecular complexes of the dsDNA segment containing the Fab fragment of an anti-DNA antibody to obtain the detailed thermodynamic and structural characteristics of dynamic intermolecular interactions. Using computationally modified crystal structure of the Fab-DNA complex (PDB ID: 3VW3), we studied the equilibrium molecular dynamics of the 64M-5 antibody Fab fragment associated with the dsDNA fragment containing the thymine dimer, the product of DNA photodamage. Amino acid residues that constitute paratopes and the complementary nucleotide epitopes for the Fab-DNA construct were identified. Stacking and electrostatic interactions were found to play the main role in mediating the most specific antibody-dsDNA contacts, while hydrogen bonds were less significant. These findings may shed light on the formation and properties of pathogenic anti-DNA antibodies in autoimmune diseases, such as systemic lupus erythematosus associated with skin photosensitivity and DNA photodamage.

[Biotechnological advances in monoclonal antibody therapy: the RANK ligand inhibitor antibody].

Science.gov (United States)

Kiss, Emese; Kuluncsics, Zénó; Kiss, Zoltán; Poór, Gyula

2010-12-26

Biological drugs have been used since the middle of the last century in medicine. Nowadays we are witnesses of the intensive development and wider administration of these drugs in clinical practice. Around 250 biological drugs are available and more than 350 million patients have been treated since their marketed authorization. Among the biologics there are protein based macromolecules, which mass production can be performed with the help of biotechnology. This term referring to the use of living organisms for production of molecules, was introduced by the Hungarian engineer, Károly Ereky. The present review focuses on the research, production and development of monoclonal antibodies manufactured by biotechnology. Some steps of this development have changed our immunological knowledge and the outcome of several diseases. The development of antibodies was highly recognized by two Nobel prizes. Authors detail the structure and functions of immunoglobulins, and their development, including fully human monoclonal antibodies. The RANKL inhibitor denosumab, a fully human IgG2 monoclonal antibody belongs to this latter group and it is available for treatment of osteoporosis. Authors also summarize the basic process of bone metabolism and the benefits of RANK ligand inhibition.

Detection of experimental thrombi in rabbits with an 131I-labelled fibrin-specific monoclonal antibody

International Nuclear Information System (INIS)

Walker, K.Z.; Milner, L.J.; Boniface, G.R.

1990-01-01

The detection of thrombi in rabbits has been investigated with 131 I-labelled DD-3B6/22, a monoclonal antibody (Mab) reactive at high affinity (Kd=2.68x10 -10 M) with human D Dimer (DD). DD-3B6/22 bound well to both 'fresh' and 'aged' human clots in an in vitro assay but showed poor binding to rabbit clots. However, reactivity was restored to rabbit blood if it was seeded, before clotting, with human DD covalently coupled to Sepharose beads. Thus, a rabbit model was developed in which blood was allowed to clot around DD-Sepharose beads introduced into the jugular vein. Gamma camera imaging showed that intact 131 I-labelled DD-3B6/22 localised to these clots within 24 h. Uptake at this time was 0.202%±0.012% injected dose per gram (%ID/g) compared with 0.086±0.018%ID/g after injection of control antibody. 131 I-labelled F(ab') 2 fragments of DD-3B6/22 allowed earlier scintigraphic detection of the clot which was evident 4 h after injection. Uptake in the clot at 24 h was 0.154±0.038% ID/g compared with 0.109±0.027% ID/g for a control F(ab') 2 . As antigen levels in the clot are estimated to be less than 300 μg DD, thus representing a very small human clot, the DD-3B6/22 Mab would appear to have a good potential for the sensitive detection of thrombi in a clinical setting. (orig.)

Molecular characterization of monoclonal antibodies that inhibit acetylcholinesterase by targeting the peripheral site and backdoor region.

Directory of Open Access Journals (Sweden)

Yves Bourne

Full Text Available The inhibition properties and target sites of monoclonal antibodies (mAbs Elec403, Elec408 and Elec410, generated against Electrophorus electricus acetylcholinesterase (AChE, have been defined previously using biochemical and mutagenesis approaches. Elec403 and Elec410, which bind competitively with each other and with the peptidic toxin inhibitor fasciculin, are directed toward distinctive albeit overlapping epitopes located at the AChE peripheral anionic site, which surrounds the entrance of the active site gorge. Elec408, which is not competitive with the other two mAbs nor fasciculin, targets a second epitope located in the backdoor region, distant from the gorge entrance. To characterize the molecular determinants dictating their binding site specificity, we cloned and sequenced the mAbs; generated antigen-binding fragments (Fab retaining the parental inhibition properties; and explored their structure-function relationships using complementary x-ray crystallography, homology modeling and flexible docking approaches. Hypermutation of one Elec403 complementarity-determining region suggests occurrence of antigen-driven selection towards recognition of the AChE peripheral site. Comparative analysis of the 1.9Å-resolution structure of Fab408 and of theoretical models of its Fab403 and Fab410 congeners evidences distinctive surface topographies and anisotropic repartitions of charges, consistent with their respective target sites and inhibition properties. Finally, a validated, data-driven docking model of the Fab403-AChE complex suggests a mode of binding at the PAS that fully correlates with the functional data. This comprehensive study documents the molecular peculiarities of Fab403 and Fab410, as the largest peptidic inhibitors directed towards the peripheral site, and those of Fab408, as the first inhibitor directed toward the backdoor region of an AChE and a unique template for the design of new, specific modulators of AChE catalysis.

Perfusion of tumor-bearing kidneys as a model for scintigraphic screening of monoclonal antibodies

International Nuclear Information System (INIS)

van Dijk, J.; Oosterwijk, E.; van Kroonenburgh, M.J.; Jonas, U.; Fleuren, G.J.; Pauwels, E.K.; Warnaar, S.O.

1988-01-01

Tumor-bearing human kidneys were used in an ex vivo perfusion model to screen monoclonal antibodies, recognizing renal cell carcinoma-associated antigens for diagnostic potential in vivo. Perfusion of tumor-bearing kidneys with /sup 99m/Tc-labeled G250 and RC38 antibody resulted in visualization of the tumor, whereas perfusion with two other monoclonal antibodies, RC2 and RC4, did not lead to tumor visualization. Uptake of radiolabel in normal kidney tissue was low for G250 and RC38 antibody. Tumor-to-kidney tissue ratios after perfusion with G250 and RC38 antibody were 2.7 and 2.2, respectively. After rinsing for 3 hr with unlabeled perfusion fluid the tumor-to-kidney tissue ratios increased to 8.6 for G250 antibody and to 2.7 for RC38 antibody. We conclude that perfusion of tumor-bearing human kidneys with radiolabeled monoclonal antibodies is a relatively simple way to evaluate renal cell carcinoma associated monoclonal antibodies as diagnostic agents in vivo

Monoclonal antibodies to human chorionic gonadotropin and their application to two-site sandwich radioimmunoassay

International Nuclear Information System (INIS)

Mizuchi, A.; Iio, M.; Miyachi, Y.

1984-01-01

Monoclonal antibodies were prepared against human chorionic gonadotropin (HCG). One monoclonal antibody recognized a conformational determinant expressed only on native HCG molecule and another monoclonal antibody had the specificity for the epitopes located on the β-subunit of HCG. Monoclonal antibodies reacting with different antigenic determinants on the HCG molecule were used to develop a simplified 2-site sandwich radioimmunoassay in which one monoclonal antibody was immobilized and another labeled with 125 iodine. This assay was highly specific for HCG and there was no cross-reactivity with α,β-subunit of HCG, luteinizing hormone and follicle stimulating hormone. (Auth.)

Comparison of the efficiency of antibody selection from semi-synthetic scFv and non-immune Fab phage display libraries against protein targets for rapid development of diagnostic immunoassays.

Science.gov (United States)

Chan, Conrad E Z; Chan, Annie H Y; Lim, Angeline P C; Hanson, Brendon J

2011-10-28

Rapid development of diagnostic immunoassays against novel emerging or genetically modified pathogens in an emergency situation is dependent on the timely isolation of specific antibodies. Non-immune antibody phage display libraries are an efficient in vitro method for selecting monoclonal antibodies and hence ideal in these circumstances. Such libraries can be constructed from a variety of sources e.g. B cell cDNA or synthetically generated, and use a variety of antibody formats, typically scFv or Fab. However, antibody source and format can impact on the quality of antibodies generated and hence the effectiveness of this methodology for the timely production of antibodies. We have carried out a comparative screening of two antibody libraries, a semi-synthetic scFv library and a human-derived Fab library against the protective antigen toxin component of Bacillus anthracis and the epsilon toxin of Clostridium botulinum. We have shown that while the synthetic library produced a diverse collection of specific scFv-phage, these contained a high frequency of unnatural amber stops and glycosylation sites which limited their conversion to IgG, and also a high number which lost specificity when expressed as IgG. In contrast, these limitations were overcome by the use of a natural human library. Antibodies from both libraries could be used to develop sandwich ELISA assays with similar sensitivity. However, the ease and speed with which full-length IgG could be generated from the human-derived Fab library makes screening this type of library the preferable method for rapid antibody generation for diagnostic assay development. Copyright © 2011 Elsevier B.V. All rights reserved.

Pharmacological efficacy of anti-IL-1β scFv, Fab and full-length antibodies in treatment of rheumatoid arthritis.

Science.gov (United States)

Qi, Jianying; Ye, Xianlong; Ren, Guiping; Kan, Fangming; Zhang, Yu; Guo, Mo; Zhang, Zhiyi; Li, Deshan

2014-02-01

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease that mainly causes the synovial joint inflammation and cartilage destruction. Interleukin-1β (IL-1β) is an important proinflammatory cytokine involved in the pathogenesis of RA. In this study, we constructed and expressed anti-IL-1β-full-length antibody in CHO-K1-SV, anti-IL-1β-Fab and anti-IL-1β-scFv in Rosetta. We compared the therapeutic efficacy of three anti-IL-1β antibodies for CIA mice. Mice with CIA were subcutaneously injected with humanized anti-IL-1β-scFv, anti-IL-1β-Fab or anti-IL-1β-full-length antibody. The effects of treatment were determined by arthritis severity score, autoreactive humoral, cellular immune responses, histological lesion and cytokines production. Compared with anti-IL-1β-scFv treatments, anti-IL-1β-Fab and anti-IL-1β-full-length antibody therapy resulted in more significant effect in alleviating the severity of arthritis by preventing bone damage and cartilage destruction, reducing humoral and cellular immune responses, and down-regulating the expression of IL-1β, IL-6, IL-2, IFN-γ, TNF-α and MMP-3 in inflammatory tissue. The therapeutic effects of anti-IL-1β-Fab and anti-IL-1β-full-length antibodies on CIA mice had no significant difference. However, production of anti-IL-1β-full-length antibody in eukaryotic system is, in general, time-consuming and more expensive than that of anti-IL-1β-Fab in prokaryotic systems. In conclusion, as a small molecule antibody, anti-IL-1β-Fab is an ideal candidate for RA therapy. Copyright © 2013 Elsevier Ltd. All rights reserved.

Development and validation of an antigen-binding capture ELISA for native and putrescine-modified anti-tetanus F(ab')2 fragments for the assessment of the cellular uptake and plasma kinetics of the antibodies.

Science.gov (United States)

Welfringer, Frédéric; d'Athis, Philippe; Scherrmann, Jean-Michel; Hervé, Françoise

2005-12-20

Cationization is a strategy to enhance the permeability of antibodies to physiological membranes for potential therapeutic and diagnostic applications of these proteins, with one of its crucial points being the retention of antigen binding activity. Here, we describe the cationization of horse polyclonal anti-tetanus F(ab')(2) fragments and the development and validation of an ELISA for quantitative measurements of the binding activity of the native and cationized F(ab')(2) in cell lysates and rat plasma samples, assessing the cellular uptake and plasma kinetics of these antibodies, respectively. The method used tetanus anatoxin coated on microtitre plates as capture antigen to bind sample or standard F(ab')(2), the amount of antibody binding being quantified using, first, a secondary biotinylated anti-horse antibody/streptavidin-alkaline phosphatase complex in situ and then a measurement of the substrate product. Cationization of the F(ab')(2) was performed with putrescine at pH 4.5 using soluble carbodiimide as carboxyl activator. The average substitution ratio was determined at 3 putrescine molecules per F(ab')(2) molecule. The cationized F(ab')(2) retained roughly 80% of the initial antigen binding activity and was stable over a 1 year period of storage at -20 degrees C. The ELISA validation data showed that the method was linear for both the native and cationized F(ab')(2) using Hanks' balanced saline solution with 0.2% bovine serum albumin as assay diluent for the cell lysate samples. The useful F(ab')(2) concentration range was 2.5-25 ng/ml and the limit of quantification was 2.5 ng/ml. With rat blank plasma used as assay diluent for the rat plasma samples the useful F(ab')(2) concentration range was 3.5-25 ng/ml and the limit of quantification was 3.5 ng/ml. Specific requirements for the limits of quantification were fulfilled: precision tetanus F(ab')(2) in an HL 60 cell model, and of plasma kinetics after i.v. administration to rats.

Chimeric rabbit/human Fab antibodies against the hepatitis Be-antigen and their potential applications in assays, characterization, and therapy.

Science.gov (United States)

Zhuang, Xiaolei; Watts, Norman R; Palmer, Ira W; Kaufman, Joshua D; Dearborn, Altaira D; Trenbeath, Joni L; Eren, Elif; Steven, Alasdair C; Rader, Christoph; Wingfield, Paul T

2017-10-06

Hepatitis B virus (HBV) infection afflicts millions worldwide, causing cirrhosis and liver cancer. HBV e-antigen (HBeAg), a clinical marker for disease severity, is a soluble variant of the viral capsid protein. HBeAg is not required for viral replication but is implicated in establishing immune tolerance and chronic infection. The structure of recombinant e-antigen (rHBeAg) was recently determined, yet to date, the exact nature and quantitation of HBeAg still remain uncertain. Here, to further characterize HBeAg, we used phage display to produce a panel of chimeric rabbit/human monoclonal antibody fragments (both Fab and scFv) against rHBeAg. Several of the Fab/scFv, expressed in Escherichia coli , had unprecedentedly high binding affinities ( K d ∼10 -12 m) and high specificity. We used Fab/scFv in the context of an enzyme-linked immunosorbent assay (ELISA) for HBeAg quantification, which we compared with commercially available kits and verified with seroconversion panels, the WHO HBeAg standard, rHBeAg, and patient plasma samples. We found that the specificity and sensitivity are superior to those of existing commercial assays. To identify potential fine differences between rHBeAg and HBeAg, we used these Fabs in microscale immunoaffinity chromatography to purify HBeAg from individual patient plasmas. Western blotting and MS results indicated that rHBeAg and HBeAg are essentially structurally identical, although HBeAg from different patients exhibits minor carboxyl-terminal heterogeneity. We discuss several potential applications for the humanized Fab/scFv.

Crystal structure and size-dependent neutralization properties of HK20, a human monoclonal antibody binding to the highly conserved heptad repeat 1 of gp41.

Directory of Open Access Journals (Sweden)

Charles Sabin

Full Text Available The human monoclonal antibody (mAb HK20 neutralizes a broad spectrum of primary HIV-1 isolates by targeting the highly conserved heptad repeat 1 (HR1 of gp41, which is transiently exposed during HIV-1 entry. Here we present the crystal structure of the HK20 Fab in complex with a gp41 mimetic 5-Helix at 2.3 Å resolution. HK20 employs its heavy chain CDR H2 and H3 loops to bind into a conserved hydrophobic HR1 pocket that is occupied by HR2 residues in the gp41 post fusion conformation. Compared to the previously described HR1-specific mAb D5, HK20 approaches its epitope with a different angle which might favor epitope access and thus contribute to its higher neutralization breadth and potency. Comparison of the neutralization activities of HK20 IgG, Fab and scFv employing both single cycle and multiple cycle neutralization assays revealed much higher potencies for the smaller Fab and scFv over IgG, implying that the target site is difficult to access for complete antibodies. Nevertheless, two thirds of sera from HIV-1 infected individuals contain significant titers of HK20-inhibiting antibodies. The breadth of neutralization of primary isolates across all clades, the higher potencies for C-clade viruses and the targeting of a distinct site as compared to the fusion inhibitor T-20 demonstrate the potential of HK20 scFv as a therapeutic tool.

Development of a Recombinant Antibody with Specificity for Chelated Uranyl Ions

International Nuclear Information System (INIS)

X. Li; A.M. Kriegel; T.C. Bishop; R.C. Blake; E. Figueiredo; H. Yu; D.A. Blake

2005-01-01

The goal of our project is to continue the development of new techniques for rapid, automated identification of radionuclides, metals, and chelators that may contaminant sur face and groundwater at DOE sites. One of the four specific aims of the present project is to develop new technologies in antibody engineering that will enhance our immunosensor program. Recombinant antibodies have potential advantages over monoclonal antibodies produced by standard hybridoma technology. The cloned genes represent a stable, recoverable source for antibody production. In addition, the recombinant format offers opportunities for protein engineering that enhances antibody performance and for studies that relate antibody sequence to binding activity. In this study, a hybridoma that synthesized an antibody (12F6) that recognized a 1:1 complex between 2,9-dicarboxyl-1,10- phenanthroline (DCP) and UO 2 2+ was used as a source of RNA for the development of a recombinant (Fab) 2 fragment. RNA was isolated from the 12F6 hybridoma and the cDNA encoding the entire κ light chain and the linked VH and C1 portions of the heavy chain were amplified from total RNA. cDNA sequences were verified by comparison with the N-terminal amino acid sequences of the light and heavy chains of the native 12F6 monoclonal antibody. A leader sequence and appropriate restriction sites were added to each chain, and the fragments were ligated into a commercial dicistronic vector (pBudCE4.1, Invitrogen, Inc.). COS-1 cells were transfected with this vector and the culture supernatant was assayed for activity and the (Fab) 2 protein. Cells transfected with vector containing 12F6 cDNA synthesized and secreted recombinant (Fab) 2 fragments that bound to the UO 2 2+ -DCP complex with an affinity indistinguishable from that of a (Fab) 2 fragment prepared from the native antibody. Molecular models of the heavy and light chain variable domains were constructed according to the canonical structures method detailed by Morea

Making Recombinant Monoclonal Antibody And Radiolabelling For Medical Purpose

International Nuclear Information System (INIS)

Nguyen Thi Thu; Duong Van Dong; Vo Thi Cam Hoa; Bui Van Cuong; Chu Van Khoa; Vu Bich Huong; Le Quang Huan

2008-01-01

Recombinant monoclonal antibody labeling with 131 I specific to tumor cell has been studied and prepared for treatment of Hodgkin lymphoma. In this study, a recombinant monoclonal antibody with two specific properties is a hybrid molecule created by coupling an antibody variable fragments with peptide melittin. The gene coding the antibody fragment has been obtained from human synthetic Fv libraries using for panning and screening on populations of lymphocytes fragmented from human blood cells with Hodgkin diseases. The gene encoding peptit melittin has been cloned from honeybee Apis cerana DNA. The gene coding recombinant monoclonal antibody has been expressed in E.coli BL21 (DE3) at 37 o C and was induced with 0.6 mM IPTG. The recombinant compound has been purified by affinity chromatography with HiTrap affinity column. The obtained recombinant monoclonal antibody has showed cytolytic activities when added to cell culture medium for LU cancer cell line with the amount of 100 - 200 mg/ml. This monoclonal antibody is labeled with 131 I using chloramine T procedure. ChT mass for the oxidation of 50 μg monoclonal antibody in 76 MBq was 10 μg. Sodium metabisulfite was used as a reducing agent. Reaction time was above 3 mins. The radiochemical purity was determined using electrophoresis and TLC methods. Radiochemical yield was > 97%. Radiochemical purity after purification was > 99%. Nuclear purity was > 99%. Stability of the label antibody was 12 days. This is the product promise potential used in the diagnostic and therapeutic of Hodgkin lymphoma. (author)

Characterization of crystals of an antibody-recognition fragment of the cancer differentiation antigen mesothelin in complex with the therapeutic antibody MORAb-009

International Nuclear Information System (INIS)

Ma, Jichun; Tang, Wai Kwan; Esser, Lothar; Pastan, Ira; Xia, Di

2012-01-01

The therapeutic antibody MORAb-009 disrupts the interaction of mesothelin and the ovarian cancer antigen CA-125. Crystals have been grown of the Fab fragment derived from MORAb-009 and of its complex with an N-terminal fragment of mesothelin. The mesothelin-specific monoclonal antibody MORAb-009 is capable of blocking the binding of mesothelin to CA-125 and displays promising anticancer potential. It is currently undergoing clinical trials. In order to understand the basis of the interaction between MORAb-009 and mesothelin at atomic resolution, both the Fab fragment of MORAb-009 and the complex between the Fab and an N-terminal fragment of mesothelin (residues 7–64) were crystallized. The crystals of the Fab diffracted X-rays to 1.75 Å resolution and had the symmetry of space group P4 1 2 1 2, with unit-cell parameters a = b = 140.6, c = 282.0 Å. The crystals of the mesothelin–Fab complex diffracted to 2.6 Å resolution and belonged to the hexagonal space group P6 4 , with unit-cell parameters a = b = 146.2, c = 80.9 Å. Structural analyses of these molecules are in progress

Boronated monoclonal antibody conjugates for neutron capture therapy

International Nuclear Information System (INIS)

Borg, D.C.; Elmore, J.J. Jr.; Ferrone, S.

1986-01-01

This paper describes the effectiveness of 10 B-labeled monoclonal antibodies against Colo-38 human melanoma in vitro. The authors obtained high boron to antibody ratios while maintaining antibody activity by using dextran intermediate carriers to link 10 B to the antibody. They developed a double cell quasi-competitive binding bioassay to minimize the effects of nonspecific binding of boronated complexes to cells. 1 fig., 2 tabs

Fab antibody fragment-functionalized liposomes for specific targeting of antigen-positive cells

Czech Academy of Sciences Publication Activity Database

Ohradanova-Repic, A.; Nogueira, E.; Hartl, I.; Gomes, A.C.; Preto, A.; Steinhuber, E.; Muehlgrabner, V.; Repic, M.; Kuttke, M.; Zwirzitz, A.; Prouza, M.; Suchánek, M.; Wozniak-Knopp, G.; Hořejší, Václav; Schabbauer, G.; Cavaco-Paulo, A.; Stockinger, H.

2018-01-01

Roč. 14, č. 1 (2018), s. 123-130 ISSN 1549-9634 Institutional support: RVO:68378050 Keywords : Active targeting * Liposome functionalization * Immunoliposome * Antibody engineering * Recombinant Fab antibody fragment Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Cell biology Impact factor: 5.720, year: 2016

Crossreactivity of boar sperm monoclonal antibodies with human ...

African Journals Online (AJOL)

Monoclonal antibodies against the head (H mabs) and tail (Tmabs) of boar spermatozoa were produced. Spermatozoa from boar, stallion, bull, human, ram, goat and rabbit were independently incubated with the monoclonal antibodies and later stained by immunofluorescence method. There were positive reactions of the ...

Identification and typing of herpes simplex viruses with monoclonal antibodies.

OpenAIRE

Balachandran, N; Frame, B; Chernesky, M; Kraiselburd, E; Kouri, Y; Garcia, D; Lavery, C; Rawls, W E

1982-01-01

Monoclonal antibodies which reacted with type-specific antigens of herpes simplex virus type 2 or with antigens shared by herpes simplex virus types 1 and 2 were used in an indirect immunofluorescence assay to type virus isolates and to detect viral antigens in cells obtained from herpetic lesions. Complete concordance was obtained for 42 isolates typed by endonuclease restriction analysis of viral DNA and by indirect immunofluorescence with monoclonal antibodies. Examination of a limited num...

Technetium-99m-labelled monoclonal antibody fragment (99mTc-DD-3B6/22Fab') for ovarian cancer

International Nuclear Information System (INIS)

Fernandes, V.; Donaghy, T.; Prabakaran, K.; Smith, S.; Clingan, P.; Bartolo, N.; Bundesen, P.; Hillyard, C.

1998-01-01

Full text: This study is the first to assess 99m Tc-DD-3B6/22Fab'' as an agent for detecting OC recurrence. Five informed consenting volunteers with stages 3 or 4 OC (mean age 54.2 y) and with negative skin prick test to Fab'' were recruited. All had suspicion of OC recurrence, with elevated serum tumour marker CA125, and in some, OC confirmation on CT scans. Aggressive treatment was continued so that tumour regression was possible prior to 99m Tc-DD-3B6/22Fab''scan. CA125, FBC, biochemical and clot markers were measured pre-and post-study. All received IV 600-800 MBq of 99 mTc-DD-3B6/22Fab''. Temperature, pulse and BP were monitored for one hour. Data were acquired with a single head LFOV gamma camera and HIRES collimator at 1,4,6 and 24 hours. Studies were read for OC lesions which were scored as probably normal (PN) or abnormal (PAb), definitely abnormal (DAb). The gold standard was CA125 immediately post-scan and, when possible, confirmation with CT. Of 5 patients, 1 was disease negative with 99 mTc-DD-3B6/22Fab'', CA125 suggesting remission, and 4 were positive on all modalities (Sensitivity, specificity, 100% respectively). 99 mTc-DD-3B6/22Fab'' identified 15 lesions (100% DAb). CT detected 7 lesions (71% Dab) pre- 99 mTc-DD-3B6/22Fab''. Repeat CT detected 8 (100% DAb). Correlation with CA125 levels was best with 99 mTc-DD3B6/22Fab''. No side effects or adverse change in serum markers were noted. 99 mTc-DD-3B6/22Fab'' is sensitive and specific for detecting OC recurrence

Rapid screening of monoclonal antibodies: new 'microstick' radioimmunoassay

International Nuclear Information System (INIS)

Scheinberg, D.A.; Strand, M.; Wilsnack, R.

1983-01-01

A new system for assaying monoclonal antibodies consisting of an 8 x 12 array of sticks which fits into a 96-well microtiter plate is described. Tests using virus specific monoclonal antibodies and virus proteins demonstrated sensitivity equivalent to the conventional microtiter plate assay. Antibody production, antigen specific antibody, and immunoglobulin isotypes could be measured under sterile conditions directly in the original fusion mixture wells and much greater rapidity than with the microtiter plate assay. (Auth.)

Assay for the specificity of monoclonal antibodies in crossed immunoelectrophoresis

DEFF Research Database (Denmark)

Skjødt, K; Schou, C; Koch, C

1984-01-01

A method is described based on crossed immunoelectrophoresis of a complex antigen mixture in agarose gel followed by incubation of the gel with the monoclonal antibody. The bound monoclonal antibody is detected by the use of a secondary enzyme-labelled antibody. Using this technique we have been ...... I molecules. In other experiments using the same technique we demonstrated the reaction of a monoclonal antibody specific for chicken Ig light chains. Udgivelsesdato: 1984-Aug-3...

[Study of anti-idiotype antibodies to human monoclonal antibody].

Science.gov (United States)

Harada, R; Takahashi, N; Owaki, I; Kannagi, R; Endo, N; Morita, N; Inoue, M

1992-02-01

A human monoclonal antibody, ll-50 (IgM, lambda), was generated, which reacted specifically with a major of glycolipid present in LS174T colon cancer cells. The glycolipid antigen which reacted with the ll-50 antibody was expected to four sugar residues from its TLC mobility, and it was ascertained that the glycolipid antigen which reacted with ll-50 antibody might be Lc4 antigen [Gal beta 1----3 GLcNAc beta 1----3 Gal beta 1----4 Glc beta 1----1 Cer] judging from TLC immunostaining and ELISA when the reactivity of ll-50 antibody was tested using various pure glycolipids in 3-5 sugar residues as an antigen. Sera in patients with malignant disorders and healthy individuals were analyzed by Sandwich assay of immobilized and biotinylated ll-50 antibody. The serum of the Lc4 antigen recognized by ll-50 antibody was significantly higher in patients with malignant disorders than that in healthy individuals (p less than 0.05). Three mouse monoclonal anti-idiotype antibodies, G3, B3 and C5 (all IgG1), were generated by the immunization of BALB/c mice with ll-50 antibody. These anti-idiotype antibodies specifically bound to to human monoclonal antibody, ll-50 and had a significant inhibitory activity towards the binding of ll-50 antibody to the Lc4 antigen. This indicated that these anti-idiotype antibodies, G3, B3, and C5, were paratope-related anti-idiotype antibodies. G3, B3, and C5 were expected to define the nearest idiotope because they could mutually inhibit ll-50 antibody. Sera in patients with malignant disorders and healthy individuals were analyzed by Sandwich assay of immobilized and biotinylated anti-idiotype antibodies, G3, B3, and C5. As to the ll-50 like antibodies defined by C5 (Id-C5+), the mean serum level in patients with malignant disorders was significantly higher than that in healthy individuals (p less than 0.05). As to the ll-50 like antibodies defined by B3 (Id-B3+), the mean serum level in patients with malignant disorders was significantly higher

Crystallization and preliminary X-ray diffraction analysis of prion protein bound to the Fab fragment of the POM1 antibody

International Nuclear Information System (INIS)

Baral, Pravas Kumar; Wieland, Barbara; Swayampakula, Mridula; Polymenidou, Magdalini; Aguzzi, Adriano; Kav, Nat N. V.; James, Michael N. G.

2011-01-01

The complex of MoPrP(120–232) and Fab POM1 has been crystallized (space group C2, unit-cell parameters a = 83.68, b = 106.9, c = 76.25 Å, β = 95.6°). Diffraction data to 2.30 Å resolution have been collected using synchrotron radiation. Prion diseases are neurodegenerative diseases that are characterized by the conversion of the cellular prion protein PrP c to the pathogenic isoform PrP sc . Several antibodies are known to interact with the cellular prion protein and to inhibit this transition. An antibody Fab fragment, Fab POM1, was produced that recognizes a structural motif of the C-terminal domain of mouse prion protein. To study the mechanism by which Fab POM1 recognizes and binds the prion molecule, the complex between Fab POM1 and the C-terminal domain of mouse prion (residues 120–232) was prepared and crystallized. Crystals of this binary complex belonged to the monoclinic space group C2, with unit-cell parameters a = 83.68, b = 106.9, c = 76.25 Å, β = 95.6°

TdT activity in acute myeloid leukemias defined by monoclonal antibodies.

Science.gov (United States)

San Miguel, J F; González, M; Cañizo, M C; Anta, J P; Portero, J A; López-Borrasca, A

1986-09-01

Blast cells from eight out of 71 patients diagnosed with acute myeloid leukemia (AML) by morphological, cytochemical, and immunological criteria showed TdT activity. Their distribution according to the FAB classification was one M1, one M2, one M4, two M5a, one M5b, one M6, and one undifferentiated case. The TdT+ AML cases did not show major clinical and hematological differences when compared with the classical TdT- AML patients. Other phenotypical aberrations in the expression of membrane antigens, apart from the presence of nuclear TdT, were not observed in these TdT+ cases after study with a large panel of monoclonal antibodies. A higher incidence of TdT+ cases was found among the monocytic variants of AML (M4 and M5)--four cases--than in the granulocytic variants (M1, M2, and M3)--2 cases. These TdT+ cases should be distinguished from mixed leukemias by double labeling techniques, assessing in the TdT+ AML the coexpression of TdT and myeloid markers in individual cells as shown in four of our cases.

Human/murine chimeric 81C6 F(ab')2 fragment: preclinical evaluation of a potential construct for the targeted radiotherapy of malignant glioma

International Nuclear Information System (INIS)

Boskovitz, Abraham; Akabani, Gamal H.; Pegram, Charles N.; Bigner, Darrell D.; Zalutsky, Michael R.

2004-01-01

We have obtained encouraging responses in recent Phase I studies evaluating 131 I-labeled human/murine chimeric 81C6 anti-tenascin monoclonal antibody (ch81C6) administered into surgically-created tumor resection cavities in brain tumor patients. However, because the blood clearance is slow, hematologic toxicity has been higher than seen with murine 81C6 (mu81C6). In the current study, a series of paired-label experiments were performed in athymic mice bearing subcutaneous D-245 MG human glioma xenografts to compare the biodistribution of the fragment ch81C6 F(ab') 2 labeled using Iodogen to a) intact ch81C6, b) mu81C6, and c) ch81C6 F(ab') 2 labeled using N-succinimidyl 3-[ 131 I]iodobenzoate. Tumor retention of radioiodine activity for the F(ab') 2 fragment was comparable to that for intact ch81C6 for the first 24 h and to that for mu81C6 for the first 48 h; as expected, blood and other normal tissue levels declined faster for ch81C6 F(ab') 2. Radiation dosimetry calculations suggest that 131 I-labeled ch81C6 F(ab') 2 may warrant further evaluation as a targeted radiotherapeutic for the treatment of brain tumors

[Production of monoclonal antibodies against a wild strain of rabies virus].

Science.gov (United States)

Akacem, O; Benmansour, A; Coulon, P; Brahimi, M; Benhassine, M

1992-01-01

Production of monoclonal antibodies against a wild strain of rabies virus. Cell fusion of SP 2/O, a murine myeloma against a wild strain of rabies virus has originated five monoclonal antibodies (M.A.) specific for virus nucleocapsid , one M.A. specific for virus glycoprotein and one M.A. specific for a viral membrane protein.

Comparative tumour localization properties of radiolabelled monoclonal antibody preparations of defined immunoreactivities

International Nuclear Information System (INIS)

Pimm, M.V.; Baldwin, R.W.

1987-01-01

The immunoreactive fraction of an anti-CEA monoclonal antibody preparation has been progressively decreased by the addition of increasing proportions of impurity in the form of immunologically inert mouse immunoglobulin. Following radioiodination, the immunoreactive fractions of the preparations were determined and their localization in a human tumour xenograft in nude mice was assessed. There was a progressive decline in tumour localization, from tumour to blood ratios of 2:1 with unadulterated antibody to 0.6:1 with preparations only 15% with respect to the initial antibody. These findings demonstrate that the immunoreactive fraction of monoclonal antibody preparations is a major limiting factor in tumour localization and this has implications for experimental and clinical applications of monoclonal antibodies. (orig.)

Development of radioinmunoconjugate 90Y-DOTA-nimotuzumab-Fab for therapy of EGFR over expressing tumors

International Nuclear Information System (INIS)

Rodriguez, A. M.; Alonso, L. M.; Gongora, M.; Leyva, R.; Solana, A.

2015-01-01

Many monoclonal antibodies conjugated with 1,4,7,10-tetraaza cyclododecane-N, N', N'', N'''-tetraacetic acid (DOTA) and radiolabeled with 90 Y, have been used for radioimmunotherapy. As know IgG molecules are heavy proteins with a molecular weight of approximately 150 kDa. Accordingly, intact IgG antibodies may have significant slow kinetics biodistribution and severely limited properties of tissue penetration. Antibody fragments labeled with radio metals could be promising radiopharmaceuticals for imaging and non-invasive therapy due to its high affinity to the tumor, the lack of effector function and rapid pharmacokinetic. In this work, the nimotuzumab Fab fragment was obtained by cleavage with papain in molar excess. After separating the reaction mixture in three steps using affinity, size exclusion and ion exchange chromatography; the Fab fragment showed high values of purity, integrity and identity. The Fab fragment was derivatized with DOTA and labeled with 90 Y. The radioimmunoconjugate with high radiochemical yield was assessed by in vitro stability with an excess of 50mM DTPA. The development of 90 Y-DOTA-Nimotuzumab-Fab radioimmunoconjugate allows to count on as a potential agent for radioimmunotherapy. (Author)

Production of monoclonal antibodies against Mycobacterium leprae and armadillo-derived mycobacteria

NARCIS (Netherlands)

Kolk, A. H.; Ho, M. L.; Klatser, P. R.; Eggelte, T. A.; Portaels, F.

1985-01-01

Six monoclonal antibodies to Mycobacterium leprae and armadillo-derived mycobacteria were produced. The monoclonal antibodies were characterized by an immunofluorescence assay using 22 mycobacterial strains. One monoclonal antibody, F47-21-3, reacted only with M. leprae; two, F45-9 and F45-15,

Efficient generation of monoclonal antibodies from single rhesus macaque antibody secreting cells.

Science.gov (United States)

Meng, Weixu; Li, Leike; Xiong, Wei; Fan, Xuejun; Deng, Hui; Bett, Andrew J; Chen, Zhifeng; Tang, Aimin; Cox, Kara S; Joyce, Joseph G; Freed, Daniel C; Thoryk, Elizabeth; Fu, Tong-Ming; Casimiro, Danilo R; Zhang, Ningyan; A Vora, Kalpit; An, Zhiqiang

2015-01-01

Nonhuman primates (NHPs) are used as a preclinical model for vaccine development, and the antibody profiles to experimental vaccines in NHPs can provide critical information for both vaccine design and translation to clinical efficacy. However, an efficient protocol for generating monoclonal antibodies from single antibody secreting cells of NHPs is currently lacking. In this study we established a robust protocol for cloning immunoglobulin (IG) variable domain genes from single rhesus macaque (Macaca mulatta) antibody secreting cells. A sorting strategy was developed using a panel of molecular markers (CD3, CD19, CD20, surface IgG, intracellular IgG, CD27, Ki67 and CD38) to identify the kinetics of B cell response after vaccination. Specific primers for the rhesus macaque IG genes were designed and validated using cDNA isolated from macaque peripheral blood mononuclear cells. Cloning efficiency was averaged at 90% for variable heavy (VH) and light (VL) domains, and 78.5% of the clones (n = 335) were matched VH and VL pairs. Sequence analysis revealed that diverse IGHV subgroups (for VH) and IGKV and IGLV subgroups (for VL) were represented in the cloned antibodies. The protocol was tested in a study using an experimental dengue vaccine candidate. About 26.6% of the monoclonal antibodies cloned from the vaccinated rhesus macaques react with the dengue vaccine antigens. These results validate the protocol for cloning monoclonal antibodies in response to vaccination from single macaque antibody secreting cells, which have general applicability for determining monoclonal antibody profiles in response to other immunogens or vaccine studies of interest in NHPs.

Quantitative imaging with radiolabeled monoclonal antibodies

International Nuclear Information System (INIS)

Moldofsky, P.J.; Hammond, N.D.

1988-01-01

The ability to image tumor by using radiolabeled monoclonal antibody products has been widely demonstrated. The questions of safety and efficacy remain open and require further experience, but at least in some clinical situations radioimmunoimaging has provided clinically useful information. Imaging tumor with radiolabeled monoclonal and polyclonal antibodies has been widely reported, and several summaries have recently appeared. For extensive review of recent clinical imaging the reader is referred to these excellent sources. Having demonstrated the possibility of imaging tumor with radiolabeled antibody, the question now apparent is: will the imaging modality provide information new and different from the already available with established techniques in computed tomography, magnetic resonance imaging, and standard nuclear medicine?

Monoclonal anti-melanoma antibodies and their possible clinical use

International Nuclear Information System (INIS)

Hellstroem, K.E.; Hellstroem, Ingegerd; Washington Univ., Seattle; Washington Univ., Seattle

1985-01-01

Cell surface antigens of human melanoma, as defined by monoclonal antibodies, are discussed and in particular the three antigens p97, a GD3 ganglioside and a proteoglycan. The potential diagnostic uses of antibodies to melanoma antigens are reviewed including in vitro diagnosis by immuno-histology, in vitro diagnosis by serum assays and in vivo diagnosis by tumour imaging using radioactively labelled antibodies. The potential therapeutic uses of monoclonal antibodies to melanoma antigens are also reviewed including targets for antibody therapy, the use of antibodies alone, radiolabelled antibodies, antibody-toxin conjugates, antibody-drug conjugates, anti-idiotypic antibodies and vaccines. (UK)

Approaches to lung cancer treatment using the CD3E x GP-2-directed bispecific monoclonal antibody BIS-1

NARCIS (Netherlands)

Kroesen, BJ; Nieken, J; Sleijfer, DT; Molema, G; deVries, EGE; Groen, HJM; Helfrich, W; The, TH; Mulder, NH; deLeij, L

1997-01-01

The bispecific monoclonal antibody (bsAb) BIS-1 combines a monoclonal-antibody(mAb)-defined specificity for the CD3 complex, as present on all T lymphocytes, with a mAb-defined specificity for the pancarcinoma/epithelium associated glycoprotein EGP-2. In vitro studies indicate that BIS-1 can direct

MONOCLONAL ANTIBODIES TO IDENTIFY TOMATO MOSAIC TOBAMOVIRUS (TOMV

Directory of Open Access Journals (Sweden)

Duarte Keila M.R.

2001-01-01

Full Text Available Monoclonal antibodies were obtained against Tomato mosaic tobamovirus (ToMV isolated in Brazil. One antibody (8G7G2 isotyped as IgG2b (kappa light chain showed strong specificity and very low cross reaction with the Tobacco mosaic virus (TMV. It can be used in identification of tomato mosaic virus (ToMV.

Introduction of a glycosylation site in the constant region decreases the aggregation of adalimumab Fab.

Science.gov (United States)

Nakamura, Hitomi; Oda-Ueda, Naoko; Ueda, Tadashi; Ohkuri, Takatoshi

2018-06-18

The production of therapeutic monoclonal antibodies is costly; therefore, antigen-binding fragments (Fabs) can be used instead. However, their tendency toward aggregation can reduce the half-life in the plasma and the therapeutic effectiveness. To examine the effect of glycosylation on the properties of the Fab of a therapeutic antibody, an N-glycosylation site was introduced at position 178 of the H-chain constant region of adalimumab Fab through site-directed mutagenesis of L178 N (H:L178 N Fab), and then H:L178 N Fab was expressed in Pichia pastoris. SDS-PAGE analysis with treatment of N-glycosidase F or periodic acid-Schiff reagent showed that H:L178 N Fab contained a relatively low glycan level. Moreover, the H:L178 N mutation did not decrease the binding activity and thermal stability of Fab, and H:L178 N Fab was more resistant to protease digestion than wild-type Fab. The aggregation of Fab induced by pH-shift stress was measured by monitoring the optical density at 350 nm. Although the wild-type Fab showed a large increase in optical density with an increase of protein concentration, no such increase of turbidity during aggregation was found in H:L178 N Fab. These results demonstrated that glycosylation at position 178 of the H-chain constant region of adalimumab Fab can prevent protein aggregation, and therefore serve as a potentially effective platform for drug development. Copyright © 2018. Published by Elsevier Inc.

Antibody deposition in tumor in relation to blood clearance using a nephrectomized mouse model

International Nuclear Information System (INIS)

Nelp, W.B.; Eary, J.F.; Beaumier, P.; Krohn, K.A.; Hellstrom, K.E.; Hellstrom, I.

1985-01-01

The purpose of this experiment was to study tumor deposition of monoclonal anti-p97 melanoma antibody (Fab) as a function of its blood concentration over time. I-131-anti-p97 Fab and I-125 non-specific Fab were injected I.V. into 28 control athymic (nude) mice (CM) bearing human xenografted malignant melanoma containing p-97 antigen. Fab (M.W. 50,000) is rapidly excreted by kidney and >90% excretion occurred in 24 hr. To create maximum sustained high blood concentrations of Fab 10 similar mice were likewise injected 1 hr after acute nephrectomy (NM). In this case 24 hr. body excretion was <1%. Blood clearance in CM was biexponential with initial T-1/2 0.4 hr. (80%) a second T-1/2 of 4.4 hr. In NM clearance was monoexponential with a T-1/2 of 29.6 hr. Blood concentrations at 4 hrs. were 2 vs. 19% dose/gm (CM vs NM) and 0.15 vs 12 at 24 hrs. This tumor binding resembled a 2nd order phenomenon. Such information may be useful in predicting the effect of dosage manipulations (multiple bolus or sustained infusions) designed to increase Fab blood levels and enhance tumor labeling with Fab. The NM model should be useful to study the kinetics of antibody tumor deposition with various antibodies

Radioimmunological imaging of metastatic prostatic cancer with 111indium-labeled monoclonal antibody PAY 276

International Nuclear Information System (INIS)

Babaian, R.J.; Murray, J.L.; Lamki, L.M.

1987-01-01

A total of 25 patients with histologically proved adenocarcinoma of the prostate, whose disease was staged clinically as D2 by appropriate radiographic and nuclear medicine studies, received increasing doses of PAY 276, an antiprostatic acid phosphatase monoclonal antibody for radioimmunological imaging. The patients were divided into 5 groups of 5. Groups 1 through 5 received an infusion of 5, 10, 20, 40 or 80 mg. monoclonal antibody, respectively, 1 mg. of which was labeled to 5 mCi. of 111 indium, while stable monoclonal antibody was added to achieve the desired antibody concentration. No patient had an allergic reaction, and no significant change in serial hemoglobin levels, platelet count, chemistry profile or results of urinalyses was noted. The monoclonal antibody scan visualized at least 1 lesion in 19 of 25 patients (76 per cent): 4 in groups 1 and 2, and all 15 in groups 3 to 5. With results of conventional radiography and bone scintigraphy considered definitive for metastases, monoclonal antibody scans detected 7 of 32 metastases (21.8 per cent) in group 3 (20 mg.), 31 of 58 (53.4 per cent) in group 4 (40 mg.) and 101 of 134 (75.4 per cent) in group 5 (80 mg). In group 5 the incidence of false positive and false negative scans was 2.3 per cent (3 of 132) and 24.6 per cent (33 of 134), respectively. The detection of metastatic lesions increased as the concentration of unlabeled monoclonal antibody increased. Radioimmunological imaging of prostatic cancer with antiprostatic acid phosphatase monoclonal antibody seems to be feasible

Isolation of a human anti-epidermal growth factor receptor Fab antibody, EG-19-11, with subnanomolar affinity from naïve immunoglobulin repertoires using a hierarchical antibody library system.

Science.gov (United States)

Hur, Byung-ung; Yoon, Jae-bong; Liu, Li-Kun; Cha, Sang-hoon

2010-11-30

Specific antibodies that possess a subnanomolar affinity are very difficult to obtain from human naïve immunoglobulin repertoires without the use of lengthy affinity optimization procedures. Here, we designed a hierarchical phage-displayed antibody library system to generate an enormous diversity of combinatorial Fab fragments (6×10(17)) and attempted to isolate high-affinity Fabs against the human epidermal growth factor receptor (EGFR). A primary antibody library, designated HuDVFab-8L, comprising 4.5×10(9) human naïve heavy chains and eight unspecified human naïve light chains was selected against the EGFR-Fc protein by biopanning, and four anti-EGFR Fab clones were isolated. Because one of the Fab clones, denoted EG-L2-11, recognized a native EGFR expressed on A431 cells, the heavy chain of the Fab was shuffled with a human naïve light chain repertoire with a diversity of 1.4×10(8) and selected a second time against the EGFR-Fc protein again. One EG-L2-11 variant, denoted EG-19-11, recognized an EGFR epitope that was almost the same as that bound by cetuximab and had a K(D) of approximately 540 pM for soluble EGFR, which is about 7-fold higher than that of the FabC225 derived from cetuximab. This variant was also internalized by A431 cells, likely via receptor-mediated endocytosis, and it efficiently inhibited EGF-mediated tyrosine phosphorylation of the EGFR. These results demonstrate that the use of our hierarchical antibody library system is advantageous in generating fully human antibodies especially with a therapeutic purpose. Copyright © 2010 Elsevier B.V. All rights reserved.

Exploration of novel strategies to enhance monoclonal antibodies targeting

International Nuclear Information System (INIS)

Khawli, L.A.; Epstein, A.L.

1997-01-01

This paper highlights the major obstacles and prospects of antibody targeting for the radio imaging and therapy of human malignant lymphomas and more challenging solid tumors. To improve the therapeutic potential of monoclonal antibodies, the authors have focused their attention on the development of new and successful methods to augment antibody uptake in the tumor. These approaches include the use of radiolabeled streptavidin to target biotinylated monoclonal antibodies already bound to tumor, pretreatment with vasoactive immunoconjugates, and the use of chemically modified antibodies. Because of the promising preclinical data obtained with these three newer approaches, plans are underway to test them in the clinic. More generally, these approaches are applicable to the use of other monoclonal antibody/tumor systems for the diagnosis and therapy of human cancers and related diseases

Biodistribution mechanisms of therapeutic monoclonal antibodies in health and disease.

Science.gov (United States)

Tabrizi, Mohammad; Bornstein, Gadi Gazit; Suria, Hamza

2010-03-01

The monoclonal antibody market continues to witness an impressive rate of growth and has become the leading source of expansion in the biologic segment within the pharmaceutical industry. Currently marketed monoclonal antibodies target a diverse array of antigens. These antigens are distributed in a variety of tissues such as tumors, lungs, synovial fluid, psoriatic plaques, and lymph nodes. As the concentration of drug at the proximity of the biological receptor determines the magnitude of the observed pharmacological responses, a significant consideration in effective therapeutic application of monoclonal antibodies is a thorough understanding of the processes that regulate antibody biodistribution. Monoclonal antibody distribution is affected by factors such as molecular weight, blood flow, tissue and tumor heterogeneity, structure and porosity, target antigen density, turnover rate, and the target antigen expression profile.

Generation of human Fab antibody libraries: PCR amplification and assembly of light- and heavy-chain coding sequences.

Science.gov (United States)

Andris-Widhopf, Jennifer; Steinberger, Peter; Fuller, Roberta; Rader, Christoph; Barbas, Carlos F

2011-09-01

The development of therapeutic antibodies for use in the treatment of human diseases has long been a goal for many researchers in the antibody field. One way to obtain these antibodies is through phage-display libraries constructed from human lymphocytes. This protocol describes the construction of human Fab (fragment antigen binding) antibody libraries. In this method, the individual rearranged heavy- and light-chain variable regions are amplified separately and are linked through a series of overlap polymerase chain reaction (PCR) steps to give the final Fab products that are used for cloning.

Monoclonal Antibody Therapy for Advanced Neuroblastoma

Science.gov (United States)

NCI is sponsoring two clinical trials of a monoclonal antibody called ch14.18, in combination with other drugs, to see if the antibody may be helpful for children or young adults (up to age 21) with relapsed or refractory neuroblastoma.

At least two Fc Neu5Gc residues of monoclonal antibodies are required for binding to anti-Neu5Gc antibody.

Science.gov (United States)

Yu, Chuanfei; Gao, Kai; Zhu, Lei; Wang, Wenbo; Wang, Lan; Zhang, Feng; Liu, Chunyu; Li, Meng; Wormald, Mark R; Rudd, Pauline M; Wang, Junzhi

2016-01-29

Two non-human glycan epitopes, galactose-α-1,3-galactose (α-gal) and Neu5Gc-α-2-6-galactose (Neu5Gc) have been shown to be antigenic when attached to Fab oligosaccharides of monoclonal antibodies (mAbs) , while α-gal attached to Fc glycans was not. However, the antigenicity of Neu5Gc on the Fc glycans remains unclear in the context that most mAbs carry only Fc glycans. After studying two clinical mAbs carrying significant amounts of Fc Neu5Gc, we show that their binding activity with anti-Neu5Gc antibody resided in a small subset of mAbs carrying two or more Fc Neu5Gc, while mAbs harboring only one Neu5Gc showed no reactivity. Since most Neu5Gc epitopes were distributed singly on the Fc of mAbs, our results suggest that the potential antigenicity of Fc Neu5Gc is low. Our study could be referenced in the process design and optimization of mAb production in murine myeloma cells and in the quality control of mAbs for industries and regulatory authorities.

Effect of kinase inhibitors on the therapeutic properties of monoclonal antibodies.

Science.gov (United States)

Duong, Minh Ngoc; Matera, Eva-Laure; Mathé, Doriane; Evesque, Anne; Valsesia-Wittmann, Sandrine; Clémenceau, Béatrice; Dumontet, Charles

2015-01-01

Targeted therapies of malignancies currently consist of therapeutic monoclonal antibodies and small molecule kinase inhibitors. The combination of these novel agents raises the issue of potential antagonisms. We evaluated the potential effect of 4 kinase inhibitors, including the Bruton tyrosine kinase inhibitor ibrutinib, and 3 PI3K inhibitors idelalisib, NVP-BEZ235 and LY294002, on the effects of the 3 monoclonal antibodies, rituximab and obinutuzumab (directed against CD20) and trastuzumab (directed against HER2). We found that ibrutinib potently inhibits antibody-dependent cell-mediated cytotoxicity exerted by all antibodies, with a 50% inhibitory concentration of 0.2 microM for trastuzumab, 0.5 microM for rituximab and 2 microM for obinutuzumab, suggesting a lesser effect in combination with obinutuzumab than with rituximab. The 4 kinase inhibitors were found to inhibit phagocytosis by fresh human neutrophils, as well as antibody-dependent cellular phagocytosis induced by the 3 antibodies. Conversely co-administration of ibrutinib with rituximab, obinutuzumab or trastuzumab did not demonstrate any inhibitory effect of ibrutinib in vivo in murine xenograft models. In conclusion, some kinase inhibitors, in particular, ibrutinib, are likely to exert inhibitory effects on innate immune cells. However, these effects do not compromise the antitumor activity of monoclonal antibodies in vivo in the models that were evaluated.

Isolation of Osteosarcoma-Associated Human Antibodies from a Combinatorial Fab Phage Display Library

Directory of Open Access Journals (Sweden)

Carmela Dantas-Barbosa

2009-01-01

Full Text Available Osteosarcoma, a highly malignant disease, is the most common primary bone tumor and is frequently found in children and adolescents. In order to isolate antibodies against osteosarcoma antigens, a combinatorial osteosarcoma Fab library displayed on the surface of phages was used. After three rounds of selection on the surface of tumor cells, several osteosarcoma-reactive Fabs were detected. From these Fabs, five were better characterized, and despite having differences in their VH (heavy chain variable domain and Vκ (kappa chain variable domain regions, they all bound to a protein with the same molecular mass. Further analysis by cell ELISA and immunocytochemistry suggested that the Fabs recognize a membrane-associated tumor antigen expressed in higher amounts in neoplasic cells than in normal tissue. These results suggest that the human Fabs selected in this work are a valuable tool for the study of this neoplasia.

Use of commercially available rabbit monoclonal antibodies for immunofluorescence double staining

DEFF Research Database (Denmark)

Bzorek, M.; Stamp, I.M.; Frederiksen, L.

2008-01-01

Immunohistochemistry, that is, the use of polyclonal and monoclonal antibodies to detect cell and tissue antigens at a microscopical level is a powerful tool for both research and diagnostic purposes. Especially in the field of hematologic disease, there is often a need to detect several antigens...... synchronously, and we report here a fast and easy technique for demonstrating more than 1 antigen in 1 slide using immunofluorescence. We have used commercially available rabbit monoclonal antibodies (Cyclin D1, CD3, CD5, CD23, etc.) paired with mouse monoclonal antibodies (CD7, CD20, CD79a, Pax-5, etc.......) for double immunofluorescence labeling on paraffin-embedded tissue sections. Commercially available rabbit monoclonal antibodies in combination with mouse monoclonal antibodies proved useful in double immunofluorescence labeling on paraffin-embedded tissue, and all combinations used yielded excellent results...

Antitumor activity of anti-C-ERC/mesothelin monoclonal antibody in vivo.

Science.gov (United States)

Inami, Koichi; Abe, Masaaki; Takeda, Kazuyoshi; Hagiwara, Yoshiaki; Maeda, Masahiro; Segawa, Tatsuya; Suyama, Masafumi; Watanabe, Sumio; Hino, Okio

2010-04-01

Mesothelioma is an aggressive cancer often caused by chronic asbestos exposure, and its prognosis is very poor despite the therapies currently used. Due to the long latency period between asbestos exposure and tumor development, the worldwide incidence will increase substantially in the next decades. Thus, novel effective therapies are warranted to improve the prognosis. The ERC/mesothelin gene (MSLN) is expressed in wide variety of human cancers, including mesotheliomas, and encodes a precursor protein cleaved by proteases to generate C-ERC/mesothelin and N-ERC/mesothelin. In this study, we investigated the antitumor activity of C-ERC/mesothelin-specific mouse monoclonal antibody, 22A31, against tumors derived from a human mesothelioma cell line, ACC-MESO-4, in a xenograft experimental model using female BALB/c athymic nude mice. Treatment with 22A31 did not inhibit cell proliferation of ACC-MESO-4 in vitro; however, therapeutic treatment with 22A31 drastically inhibited tumor growth in vivo. 22A31 induced antibody-dependent cell-mediated cytotoxicity by natural killer (NK) cells, but not macrophages, in vitro. Consistently, the F(ab')(2) fragment of 22A31 did not inhibit tumor growth in vivo, nor did it induce antibody-dependent cell mediated cytotoxicity (ADCC) in vitro. Moreover, NK cell depletion diminished the antitumor effect of 22A31. Thus, 22A31 induced NK cell-mediated ADCC and exerted antitumor activity in vivo. 22A31 could have potential as a therapeutic tool to treat C-ERC/mesothelin-expressing cancers including mesothelioma.

Human monoclonal antibodies: the residual challenge of antibody immunogenicity.

Science.gov (United States)

Waldmann, Herman

2014-01-01

One of the major reasons for seeking human monoclonal antibodies has been to eliminate immunogenicity seen with rodent antibodies. Thus far, there has yet been no approach which absolutely abolishes that risk for cell-binding antibodies. In this short article, I draw attention to classical work which shows that monomeric immunoglobulins are intrinsically tolerogenic if they can be prevented from creating aggregates or immune complexes. Based on these classical studies two approaches for active tolerization to therapeutic antibodies are described.

Taking aim at cancer with monoclonal antibodies

International Nuclear Information System (INIS)

Klausner, A.

1986-01-01

Conjugating radioisotopes to monoclonal antibodies could have certain advantages in cancer therapy. Radioactive compounds have the double-edged ability to kill cells that are up to centimeter or more away. This is a plausible way to overcome tumor heterogeneity, but it also means that normal cells near the tumor could be affected. Hybritech (San Diego, CA) has been supplying antibody linked to the radioisotope yttrium-90 for a number of clinical trials. Work at Johns Hopkins University (Baltimore, MD) has focused on polyclonal antibodies to hepatoma. Monoclonal antibodies will be used there soon, and trials could be expanded eventually to include breast, lung, and prostate cancer as well. Hybritech also expects that the yttrium-antibody conjugates developed with NCI will enter the clinic later this year for treating leukemia and lymphoma systems; treatments for melanomas should follow

The detection of ovarian cancer using 123I monoclonal antibody

International Nuclear Information System (INIS)

Granowska, M.; Britton, K.E.; Shepherd, J.

1984-01-01

The technique of the production of monoclonal antibodies is described. Antibodies show reactivity with epithelial surfaces of cancer of breast, colon and ovary. The iodogen reaction is used for labelling monoclonal antibodies with 123 I. Description of labelling technique and quality control. After intravenous injection of 74 MBq 123 I-labelled monoclonal antibody (0.5 mg) static camera images of the abdomen were recorded at 10 min, 4 and 22 hours in anterior and posterior position. 20 out of 22 patients with ovarian cancer with and without metastases were correctly diagnosed and confirmed at surgery. (author)

Drug delivery systems--2. Site-specific drug delivery utilizing monoclonal antibodies.

Science.gov (United States)

Ranade, V V

1989-10-01

Monoclonal antibodies (MAbs) are purified antibodies produced by a single clone of cells. They are engineered to recognize and bind to a single specific antigen. Accordingly, when administered, MAbs home in on a particular circulating protein or on cells that bear the correct antigenic signature on their surfaces. It is the specificity of MAbs that has made them valuable tools for health professions. Following the discovery of Kohler and Milstein regarding the method of somatic cell hybridization, a number of investigators have successfully adopted this technique to obtain T-lymphocyte hybrid cell lines by fusion of activated T (thymus derived) lymphocytes with a T lymphoma cell line leading to an immortalization of a specific differentiated function. The hybrids thus obtained were subsequently shown to produce homogeneous effector molecules with a wide variety of immune functions such as enhancement or suppression of antibody responses, generation of helper T cells, suppressor T cells and cytotoxic T cells. Study of these regulatory molecules has been further shown to provide a greater insight into the genetic, biochemical and molecular mechanisms responsible for cellular development, and the interaction and triggering of various cell types. The successful application of hybridoma technology has now resulted into several advances in the understanding the mechanism and treatment of diseases, especially cancer and development of vaccines, promotion of organ transplantation and therapy against parasites as well. Since monoclonal antibodies could be made in unlimited supply, they have been used in genetic studies such as mRNA and gene isolation, chromosomal isolation of specific genes, immunoglobulin structure, detection of new or rare immunoglobulin gene products, structural studies of enzymes and other proteins and structural and population studies of protein polymorphisms. In some instances, the monoclonal antibodies have been found to replace conventional antisera

Radioimmunoscintigraphy of colorectal carcinoma using technetium-99m-labeled, totally human monoclonal antibody 88BV59H21-2.

Science.gov (United States)

Gulec, S A; Serafini, A N; Moffat, F L; Vargas-Cuba, R D; Sfakianakis, G N; Franceschi, D; Crichton, V Z; Subramanian, R; Klein, J L; De Jager, R L

1995-12-01

Radioimmunoscintigraphy (RIS) using human monoclonal antibodies offers the important clinical advantage of repeated imaging over murine monoclonal antibodies by eliminating the cross-species antibody response. This article reports a Phase I-II clinical trial with Tc-99m-labeled, totally human monoclonal antibody 88BV59H21-2 in patients with colorectal carcinoma. The study population consisted of 34 patients with colorectal cancer (20 men and 14 women; age range, 44-81 years). Patients were administered 5-10 mg antibody labeled with 21-41 mCi Tc-99m by the i.v. route and imaged at 3-10 and 16-24 h after infusion using planar and single-photon emission computed tomographic (CT) techniques. Pathological confirmation was obtained in 25 patients who underwent surgery. Human antihuman antibody (HAHA) titers were checked prior to and 1 and 3 months after the infusion. RIS with Tc-99m-labeled 88BV59H21-2 revealed a better detection rate in the abdomen-pelvis region compared with axial CT. The combined use of both modalities increased the sensitivity in both the liver and abdomen-pelvis regions. Ten patients developed mild adverse reactions (chills and fever). No HAHA response was detected in this series. Tc-99m-labeled human monoclonal antibody 88BV59H21-2 RIS shows promise as a useful diagnostic modality in patients with colorectal cancer. RIS alone or in combination with CT is more sensitive than CT in detecting tumor within the abdomen and pelvis. Repeated RIS studies may be possible, due to the lack of a HAHA response.

Efficacy of Wnt-1 monoclonal antibody in sarcoma cells

International Nuclear Information System (INIS)

Mikami, Iwao; Koizumi, Kiyoshi; Jablons, David M; You, Liang; He, Biao; Xu, Zhidong; Batra, Sonny; Lee, Amie Y; Mazieres, Julien; Reguart, Noemi; Uematsu, Kazutsugu

2005-01-01

Sarcomas are one of the most refractory diseases among malignant tumors. More effective therapies based on an increased understanding of the molecular biology of sarcomas are needed as current forms of therapy remain inadequate. Recently, it has been reported that Wnt-1/β-catenin signaling inhibits apoptosis in several cancers. In this study, we investigated the efficacy of a monoclonal anti-Wnt-1 antibody in sarcoma cells. We treated cell lines A-204, SJSA-1, and fresh primary cultures of lung metastasis of sarcoma with a monoclonal anti-Wnt-1 antibody. Wnt-1 siRNA treatment was carried out in A-204. We assessed cell death using Crystal Violet staining. Apoptosis induction was estimated by flow cytometry analysis (Annexin V and PI staining). Cell signaling changes were determined by western blotting analysis. We detected Wnt-1 expression in all tissue samples and cell lines. Significant apoptosis induction was found in monoclonal anti-Wnt-1 antibody treated cells compared to control monoclonal antibody treated cells (p < 0.02). Similarly, we observed increased apoptosis in Wnt-1 siRNA treated cells. Blockade of Wnt-1 signaling in both experiments was confirmed by analyzing intracellular levels of Dishevelled-3 and of cytosolic β-catenin. Furthermore, the monoclonal anti-Wnt-1 antibody also induced cell death in fresh primary cultures of metastatic sarcoma in which Wnt-1 signaling was active. Our results indicate that Wnt-1 blockade by either monoclonal antibody or siRNA induces cell death in sarcoma cells. These data suggest that Wnt-1 may be a novel therapeutic target for the treatment of a subset of sarcoma cells in which Wnt-1/β-catenin signaling is active

Generation and characterization of rat and mouse monoclonal antibodies specific for MeCP2 and their use in X-inactivation studies.

Directory of Open Access Journals (Sweden)

K Laurence Jost

Full Text Available Methyl CpG binding protein 2 (MeCP2 binds DNA, and has a preference for methylated CpGs and, hence, in cells, it accumulates in heterochromatin. Even though it is expressed ubiquitously MeCP2 is particularly important during neuronal maturation. This is underscored by the fact that in Rett syndrome, a neurological disease, 80% of patients carry a mutation in the MECP2 gene. Since the MECP2 gene lies on the X chromosome and is subjected to X chromosome inactivation, affected patients are usually chimeric for wild type and mutant MeCP2. Here, we present the generation and characterization of the first rat monoclonal MeCP2 specific antibodies as well as mouse monoclonal antibodies and a rabbit polyclonal antibody. We demonstrate that our antibodies are suitable for immunoblotting, (chromatin immunoprecipitation and immunofluorescence of endogenous and ectopically expressed MeCP2. Epitope mapping revealed that most of the MeCP2 monoclonal antibodies recognize the C-terminal domain and one the N-terminal domain of MeCP2. Using slot blot analysis, we determined a high sensitivity of all antibodies, detecting amounts as low as 1 ng of MeCP2 protein. Moreover, the antibodies recognize MeCP2 from different species, including human, mouse, rat and pig. Lastly, we have validated their use by analyzing and quantifying X chromosome inactivation skewing using brain tissue of MeCP2 heterozygous null female mice. The new MeCP2 specific monoclonal antibodies described here perform well in a large variety of immunological applications making them a very valuable set of tools for studies of MeCP2 pathophysiology in situ and in vitro.

Monoclonal antibodies and Fc fragments for treating solid tumors

Directory of Open Access Journals (Sweden)

Eisenbeis AM

2012-01-01

Full Text Available Andrea M Eisenbeis, Stefan J GrauDepartment of Neurosurgery, University Hospital of Cologne, Cologne, GermanyAbstract: Advances in biotechnology, better understanding of pathophysiological processes, as well as the identification of an increasing number of molecular markers have facilitated the use of monoclonal antibodies and Fc fragments in various fields in medicine. In this context, a rapidly growing number of these substances have also emerged in the field of oncology. This review will summarize the currently approved monoclonal antibodies used for the treatment of solid tumors with a focus on their clinical application, biological background, and currently ongoing trials.Keywords: targeted therapy, monoclonal antibodies, cancer, biological therapy

Two-site sandwich radioimmunoassay of human gamma interferon with monoclonal antibodies

Energy Technology Data Exchange (ETDEWEB)

Tanaka, E; Imai, M; Usuda, S; Tachibana, K; Okamoto, H; Ohike, Y; Nakamura, T; Miyakawa, Y; Mayumi, M [Jichi Medical School, Minamikawachi, Tochigi (Japan)

1985-03-18

Two monoclonal antibodies were raised against human gamma interferon (IFN-..gamma..) derived from E. coli harboring the recombinant cDNA for IFN-..gamma.., and one against a synthetic peptide representing its C-terminus amino acid sequence of 20 residues. The monoclonal antibody against the synthetic peptide reacted either with IFN-..gamma.. or the synthetic peptide. One monoclonal anti-IFN-..gamma.. did not react with the synthetic peptide, while the other showed a weak binding with the peptide. A 2-site '1-step' radioimmunoassay was developed. The assay was rapid with a sensitivity capable of detecting a few ng/ml of IFN-..gamma...

Dissecting Immunogenicity of Monoclonal Antibodies

National Research Council Canada - National Science Library

Snyder, Christopher

2003-01-01

The potential of monoclonal antibodies, (mAbs), for use in therapeutic and diagnostic applications has not been fully realized in part due to counter-immune responses that often arise in patient recipients of mAb...

Generation of a haptoglobin-hemoglobin complex-specific Fab antibody blocking the binding of the complex to CD163

DEFF Research Database (Denmark)

Horn, Ivo R; Nielsen, Marianne Jensby; Madsen, Mette

2003-01-01

During intravascular hemolysis hemoglobin (Hb) binds to haptoglobin (Hp) leading to endocytosis of the complex by the macrophage receptor, CD163. In the present study, we used a phage-display Fab antibody strategy to explore if the complex formation between Hp and Hb leads to exposure of antigenic...... epitopes specific for the complex. By Hp-Hb-affinity screening of a phage-Fab library, we isolated a phage clone against the ligand complex. Surface plasmon resonance analyses of the Fab part expressed as a recombinant protein revealed a high affinity binding (KD = 3.9 nm) to Hp-Hb, whereas no binding...... was measured for non-complexed Hp or Hb. The Fab antibody completely inhibited the binding of 125I-labeled Hp-Hb complexes to CD163 and blocked their uptake in CD163-transfected cells. In conclusion, we have raised a receptor-blocking antibody specifically recognizing the Hp-Hb complex. In addition to provide...

Tuning the specificity of a Two-in-One Fab against three angiogenic antigens by fully utilizing the information of deep mutational scanning.

Science.gov (United States)

Koenig, Patrick; Sanowar, Sarah; Lee, Chingwei V; Fuh, Germaine

Monoclonal antibodies developed for therapeutic or diagnostic purposes need to demonstrate highly defined binding specificity profiles. Engineering of an antibody to enhance or reduce binding to related antigens is often needed to achieve the desired biologic activity without safety concern. Here, we describe a deep sequencing-aided engineering strategy to fine-tune the specificity of an angiopoietin-2 (Ang2)/vascular endothelial growth factor (VEGF) dual action Fab, 5A12.1 for the treatment of age-related macular degeneration. This antibody utilizes overlapping complementarity-determining region (CDR) sites for dual Ang2/VEGF interaction with K D in the sub-nanomolar range. However, it also exhibits significant (K D of 4 nM) binding to angiopoietin-1, which has high sequence identity with Ang2. We generated a large phage-displayed library of 5A12.1 Fab variants with all possible single mutations in the 6 CDRs. By tracking the change of prevalence of each mutation during various selection conditions, we identified 35 mutations predicted to decrease the affinity for Ang1 while maintaining the affinity for Ang2 and VEGF. We confirmed the specificity profiles for 25 of these single mutations as Fab protein. Structural analysis showed that some of the Fab mutations cluster near a potential Ang1/2 epitope residue that differs in the 2 proteins, while others are up to 15 Å away from the antigen-binding site and likely influence the binding interaction remotely. The approach presented here provides a robust and efficient method for specificity engineering that does not require prior knowledge of the antigen antibody interaction and can be broadly applied to antibody specificity engineering projects.

Conversion of a Mouse Fab into a Whole Humanized IgG Antibody for Detecting Botulinum Toxin

National Research Council Canada - National Science Library

Palys, Thomas J; Schmid, Kara E; Scherer, John M; Schoepp, Randal J

2006-01-01

Antibodies serve as the gold standard in most immunodiagnostic assays. Recent advances in recombinant DNA technology have offered the production of antibody fragments or Fabs as promising alternatives...

Strain differentiation of polioviruses with monoclonal antibodies.

NARCIS (Netherlands)

A.D.M.E. Osterhaus (Albert); A.L. van Wezel; A.J.H. Stegmann; J.A.A.M. van Asten (Jack)

1984-01-01

textabstractPanels of monoclonal antibodies raised against different poliovirus type 1, 2 and 3 strains, were tested in a micro-neutralization test and in a micro-enzyme linked immunosorbent assay against a large number of poliovirus strains. The results were compared with those obtained with the

Human peripheral blood monocytes display surface antigens recognized by monoclonal antinuclear antibodies

International Nuclear Information System (INIS)

Holers, V.M.; Kotzin, B.L.

1985-01-01

The authors used monoclonal anti-nuclear autoantibodies and indirect immunofluorescence to examine normal human peripheral blood mononuclear leukocytes for the presence of cell surface nuclear antigens. Only one monoclonal anti-histone antibody (MH-2) was found to bind to freshly isolated PBL, staining approximately 10% of large cells. However, after cells were placed into culture for 16-24 h, a high percentage (up to 60%) of large-sized cells were recognized by an anti-DNA (BWD-1) and several different antihistone monoclonal antibodies (BWH-1, MH-1, and MH-2). These antibodies recognize separate antigenic determinants on chromatin and histones extracted from chromatin. The histone antigen-positive cells were viable, and the monoclonal antibodies could be shown to be binding to the cell surface and not to the nucleus. Using monoclonal antibodies specific for monocytes and T cells, and complement-mediated cytotoxicity, the cells bearing histone antigens were shown to be primarily monocytes. The appearance of histone and DNA antigen-positive cells was nearly completely inhibited by the addition of low concentrations of cycloheximide at initiation of the cultures. In contrast, little effect on the percentage of positive cells was detected if cells were exposed to high doses of gamma irradiation before culture. These data further support the existence of cell surface nuclear antigens on selected cell subsets, which may provide insight into the immunopathogenesis of systemic lupus erythematosus and related autoimmune diseases

Generation and Characterization of Novel Human IRAS Monoclonal Antibodies

Directory of Open Access Journals (Sweden)

Bo Wang

2009-01-01

Full Text Available Imidazoline receptors were first proposed by Bousquet et al., when they studied antihypertensive effect of clonidine. A strong candidate for I1R, known as imidazoline receptor antisera-selected protein (IRAS, has been cloned from human hippocampus. We reported that IRAS mediated agmatine-induced inhibition of opioid dependence in morphine-dependent cells. To elucidate the functional and structure properties of I1R, we developed the newly monoclonal antibody against the N-terminal hIRAS region including the PX domain (10–120aa through immunization of BALB/c mice with the NusA-IRAS fusion protein containing an IRAS N-terminal (10–120aa. Stable hybridoma cell lines were established and monoclonal antibodies specifically recognized full-length IRAS proteins in their native state by immunoblotting and immunoprecipitation. Monoclonal antibodies stained in a predominantly punctate cytoplasmic pattern when applied to IRAS-transfected HEK293 cells by indirect immunofluorescence assays and demonstrated excellent reactivity in flow immunocytometry. These monoclonal antibodies will provide powerful reagents for the further investigation of hIRAS protein functions.

Demonstration of two distinct antigenic determinants on hepatitis B e antigen by monoclonal antibodies

International Nuclear Information System (INIS)

Imai, M.; Nomura, M.; Gotanda, T.; Sano, T.; Tachibana, K.; Miyamoto, H.; Takahashi, K.; Toyama, S.; Miyakawa, Y.; Mayumi, M.

1982-01-01

Mice were immunized against hepatitis B e antigen (HBeAg) isolated from sera of asymptomatic carriers of hepatitis B virus. Their spleen cells were fused with mouse myeloma (NS-1) cells, and 5 clones of hybridoma cells secreting antibody against HBeAg (anti-HBe) were isolated. For the production of anti-HBe in large scale, cells were cultivated both in vitro and in the peritoneal cavity of ascitic mice. Although monoclonal antibodies produced by these clones showed a strong reactivity of anti-HBe in hemagglutination tests, individual monoclonal anti-HBe did not reveal any precipitin line in immunodiffusion. When 2 of the 5 monoclonal antibodies were mixed together, however, some combinations showed a precipitin line against HBeAg, whereas others did not. Utilizing solid-phase radioimmunoassay involving a number of combinations of monoclonal antibodies used for solid-phase and radiolabeling, the 5 antibodies were classified into 2 groups. Three of the anti-HBe antibodies were found to be directed to 1 determinant of HBeAg (determinant a); the remaining 2 to the other determinant (determinant b). Determinants a and b were detected on HBeAg in the serum, as well as on the polypeptide of 19,000 daltons (P19) derived from the nucleocapsid of hepatitis B virus. Monoclonal anti-HBe antibodies with different specificities may provide useful tools in delineating the antigenic structure of HBeAg and also in evaluating immune responses of the host directed to its subdeterminants

Neutralisation and binding of VHS virus by monovalent antibody fragments

DEFF Research Database (Denmark)

Cupit, P.M.; Lorenzen, Niels; Strachan, G.

2001-01-01

We have previously reported the cloning and characterisation of the heavy and light chain variable domain genes encoding three monoclonal antibodies (Mabs) that bind viral haemorrhagic septicaemia virus (VHSV). Two of these antibodies, 3F1H10 and 3F1A2 both neutralised the virus though 3F1A2...... appeared to recognise a broader range of virus isolates. The variable domains of these two antibodies differ by only four residues (Lorenzen et al., 2000a. Fish Shellfish Immunol. 10, 129-142). To further study the mechanism of neutralisation, Fab fragments as well as a series of recombinant bacterial...... single chain antibody (scAb) fragments were generated from the three anti-VHSV Mabs and their variable domain genes, respectively. Fabs and scAbs derived from the neutralising Mabs were both able to neutralise the VHSV type 1 isolate DK-F1. In addition, a series of scAb fragments were produced using...

Monoclonal antibodies in myeloma

DEFF Research Database (Denmark)

Sondergeld, P.; van de Donk, N. W. C. J.; Richardson, P. G.

2015-01-01

The development of monoclonal antibodies (mAbs) for the treatment of disease goes back to the vision of Paul Ehrlich in the late 19th century; however, the first successful treatment with a mAb was not until 1982, in a lymphoma patient. In multiple myeloma, mAbs are a very recent and exciting add...

Optimizing Production of Antigens and Fabs in the Context of Generating Recombinant Antibodies to Human Proteins.

Directory of Open Access Journals (Sweden)

Nan Zhong

Full Text Available We developed and optimized a high-throughput project workflow to generate renewable recombinant antibodies to human proteins involved in epigenetic signalling. Three different strategies to produce phage display compatible protein antigens in bacterial systems were compared, and we found that in vivo biotinylation through the use of an Avi tag was the most productive method. Phage display selections were performed on 265 in vivo biotinylated antigen domains. High-affinity Fabs (<20nM were obtained for 196. We constructed and optimized a new expression vector to produce in vivo biotinylated Fabs in E. coli. This increased average yields up to 10-fold, with an average yield of 4 mg/L. For 118 antigens, we identified Fabs that could immunoprecipitate their full-length endogenous targets from mammalian cell lysates. One Fab for each antigen was converted to a recombinant IgG and produced in mammalian cells, with an average yield of 15 mg/L. In summary, we have optimized each step of the pipeline to produce recombinant antibodies, significantly increasing both efficiency and yield, and also showed that these Fabs and IgGs can be generally useful for chromatin immunoprecipitation (ChIP protocols.

Lymphocyte antibody-dependent cytotoxicity test for evaluation of clinical role of monoclonal anti-D-antibodies for prevention of rhesus sensitization.

Science.gov (United States)

Olovnikova, N I; Belkina, E V; Nikolaeva, T L; Miterev, G Yu; Chertkov, I L

2006-01-01

Monoclonal antibodies to D antigen were studied in the reaction of antibody-dependent cytotoxicity for evaluation of the possibility of using these antibodies for preventing rhesus sensitization. High hemolytic activity of four anti-D-monoclonal antibodies in the antibody-dependent cytotoxicity test, mediated by their interaction with FcgammaRI, and the capacity to accelerate elimination of D+ erythrocytes from circulation did not provide the immunosuppressive effect. It was hypothesized that monoclonal antibodies for prevention of rhesus sensitization should interact with FcgammaRIII on lymphocytes. These monoclonal antibodies are extremely rare: only 4 of 125 studied antibodies mediated hemolysis in the antibody-dependent cytotoxicity test with lymphocytes, while all polyclonal anti-D-preparations exhibited this activity.

F(ab'2 antibody fragments against Trypanosoma cruzi calreticulin inhibit its interaction with the first component of human complement

Directory of Open Access Journals (Sweden)

LORENA AGUILAR

2005-01-01

Full Text Available Trypanosoma cruzi calreticulin (TcCRT, described in our laboratory, retains several important functional features from its vertebrate homologues. We have shown that recombinant TcCRT inhibits the human complement system when it binds to the collagenous portion of C1q. The generation of classical pathway convertases and membrane attack complexes is thus strongly inhibited. In most T. cruzi-infected individuals, TcCRT is immunogenic and mediates the generation of specific antibodies. By reverting the C1q / TcCRT interaction, a parasite immune evasion strategy, these antibodies contribute to the host / parasite equilibrium. In an in vitro correlate of this situation, we show that the C1q / TcCRT interaction is inhibited by F(ab'2 polyclonal anti-TcCRT IgG fragments. It is therefore feasible that in infected humans anti-TcCRT antibodies participate in reverting an important parasite strategy aimed at inhibiting the classical complement pathway. Thus, membrane-bound TcCRT interacts with the collagenous portion C1q, and this C1q is recognized by the CD91-bound host cell CRT, thus facilitating parasite internalization. Based on our in vitro results, it could be proposed that the in vivo interaction between TcCRT and vertebrate C1q could be inhibited by F(ab'2 fragments anti-rTcCRT or against its S functional domain, thus interfering with the internalization process

Aggregates in monoclonal antibody manufacturing processes.

Science.gov (United States)

Vázquez-Rey, María; Lang, Dietmar A

2011-07-01

Monoclonal antibodies have proved to be a highly successful class of therapeutic products. Large-scale manufacturing of pharmaceutical antibodies is a complex activity that requires considerable effort in both process and analytical development. If a therapeutic protein cannot be stabilized adequately, it will lose partially or totally its therapeutic properties or even cause immunogenic reactions thus potentially further endangering the patients' health. The phenomenon of protein aggregation is a common issue that compromises the quality, safety, and efficacy of antibodies and can happen at different steps of the manufacturing process, including fermentation, purification, final formulation, and storage. Aggregate levels in drug substance and final drug product are a key factor when assessing quality attributes of the molecule, since aggregation might impact biological activity of the biopharmaceutical. In this review it is analyzed how aggregates are formed during monoclonal antibody industrial production, why they have to be removed and the manufacturing process steps that are designed to either minimize or remove aggregates in the final product. Copyright © 2011 Wiley Periodicals, Inc.

Enhancement of tumor contrast on radioimmunoscans by using mixtures of monoclonal antibody F(ab')2 fragements

International Nuclear Information System (INIS)

Munz, D.L.; Alavi, A.; Koprowski, H.; Herlyn, D.; Pennsylvania Univ., Philadelphia

1986-01-01

F(ab') 2 fragments of MAbs GA 73-3 (IgG 2 a) and CO 29.11 (IgG 1), which detect distinct antigenic determinants on adenocarcinoma cells of the gastrointestinal tract, were labeled with 131 I using the iodogen method. 41 nude mice bearing SW-948 CRC tumores were injected either with a mixture of 100 μCi (11 μg) each (n=9) of the two 131 I-F(ab') 2 fragments or with either fragment alone at various doses (each group consisting of 8 mice): GA 73-3, 100 μCi (11 μg) and 200 μCi (25 μg); CO 29.11, 100 μCi (11 μg) and 200 μCi (26 μg). Whole-body images of the mice were obtained daily for up to six days after injection. Ratios of cpm/pixel in the tumor to those in the rest of the body (rob), representing tumor contrast, were significantly (p 1/2 biol. ) f the mixture (44.8±14.5 h) in the CRC tumors was significantly (p 1/2 biol. determined in the groups given either fragment alone. T 1/2 biol. in the rob was similar in all groups of mice examined. (orig.) [de

An Anti-C1s Monoclonal, TNT003, Inhibits Complement Activation Induced by Antibodies Against HLA.

Science.gov (United States)

Thomas, K A; Valenzuela, N M; Gjertson, D; Mulder, A; Fishbein, M C; Parry, G C; Panicker, S; Reed, E F

2015-08-01

Antibody-mediated rejection (AMR) of solid organ transplants (SOT) is characterized by damage triggered by donor-specific antibodies (DSA) binding donor Class I and II HLA (HLA-I and HLA-II) expressed on endothelial cells. While F(ab')2 portions of DSA cause cellular activation and proliferation, Fc regions activate the classical complement cascade, resulting in complement deposition and leukocyte recruitment, both hallmark features of AMR. We characterized the ability of an anti-C1s monoclonal antibody, TNT003, to inhibit HLA antibody (HLA-Ab)-induced complement activation. Complement deposition induced by HLA-Ab was evaluated using novel cell- and bead-based assays. Human aortic endothelial cells (HAEC) were cultured with HLA-Ab and human complement; production of activated complement proteins was measured by flow cytometry. Additionally, C3d deposition was measured on single antigen beads (SAB) mixed with HLA-Ab and human complement. TNT003 inhibited HLA-Ab mediated complement deposition on HAEC in a concentration-dependent manner; C3a, C4a and C5a anaphylatoxin production was also diminished by TNT003. Finally, TNT003 blocked C3d deposition induced by Class I (HLAI-Ab)- and Class II (HLAII-Ab)-specific antibodies on SAB. These data suggest TNT003 may be useful for modulating the effects of DSA, as TNT003 inhibits complement deposition and split product formation generated by HLA-I/II-Ab in vitro. © 2015 The Authors. American Journal of Transplantation Published by Wiley Periodicals, Inc.

Generation of monoclonal antibodies against peptidylarginine deiminase 2 (PAD2) and development of a PAD2-specific enzyme-linked immunosorbent assay

DEFF Research Database (Denmark)

Damgaard, Dres; Palarasah, Yaseelan; Skjødt, Karsten

2014-01-01

The enzyme peptidylarginine deiminase 2 (PAD2) has been associated with inflammatory diseases, such as rheumatoid arthritis and neurodegenerative diseases including multiple sclerosis. To investigate the association of various diseases with extracellular PAD2, we raised monoclonal antibodies (m......Abs) against rabbit PAD2 and evaluated their cross-reactivity with human PAD2 by indirect enzyme-linked immunosorbent assay (ELISA), western blotting and immunohistological staining of inflamed synovial tissue. Moreover, we established a sandwich ELISA detecting human PAD2, based on two different monoclonal...... diseases....

A monoclonal antibody that specifically recognizes m6A nucleoside

OpenAIRE

Espuny, Ruth; Castro, Ana; Codony, Carles; Eritja Casadellà, Ramón; Bach-Elias, Montse

1998-01-01

A hybridoma against the nucleoside m6A has been obtained from mouse spleen. This hybridoma was named H65 and it secretes monoclonal antibodies anti-m6A. The competition assays showed that the monoclonal antibody was highly specific for m6A nucleoside.

Identification of antibody glycosylation structures that predict monoclonal antibody Fc-effector function.

Science.gov (United States)

Chung, Amy W; Crispin, Max; Pritchard, Laura; Robinson, Hannah; Gorny, Miroslaw K; Yu, Xiaojie; Bailey-Kellogg, Chris; Ackerman, Margaret E; Scanlan, Chris; Zolla-Pazner, Susan; Alter, Galit

2014-11-13

To determine monoclonal antibody (mAb) features that predict fragment crystalizable (Fc)-mediated effector functions against HIV. Monoclonal antibodies, derived from Chinese hamster ovary cells or Epstein-Barr virus-immortalized mouse heteromyelomas, with specificity to key regions of the HIV envelope including gp120-V2, gp120-V3 loop, gp120-CD4(+) binding site, and gp41-specific antibodies, were functionally profiled to determine the relative contribution of the variable and constant domain features of the antibodies in driving robust Fc-effector functions. Each mAb was assayed for antibody-binding affinity to gp140(SR162), antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP) and for the ability to bind to FcγRIIa, FcγRIIb and FcγRIIIa receptors. Antibody glycan profiles were determined by HPLC. Neither the specificity nor the affinity of the mAbs determined the potency of Fc-effector function. FcγRIIIa binding strongly predicted ADCC and decreased galactose content inversely correlated with ADCP, whereas N-glycolylneuraminic acid-containing structures exhibited enhanced ADCP. Additionally, the bi-antenary glycan arm onto which galactose was added predicted enhanced binding to FcγRIIIa and ADCC activity, independent of the specificity of the mAb. Our studies point to the specific Fc-glycan structures that can selectively promote Fc-effector functions independently of the antibody specificity. Furthermore, we demonstrated antibody glycan structures associated with enhanced ADCP activity, an emerging Fc-effector function that may aid in the control and clearance of HIV infection.

Application of murine monoclonal antibodies to the serodiagnosis of tuberculosis

International Nuclear Information System (INIS)

Ivanyl, J.; Coates, A.R.M.; Krambovitis, E.

1982-01-01

The immune response during infectious diseases leads to a rise in antibody titre to the various different antigenic determinants of the causative organism. The response is further complicated by the fact that it is relatively unusual for one individual to respond to all antigenic components of an organism. Demonstration of the specific immune response of an infected host by serological tests is often hampered by the broad cross-reactivity between several bacterial antigens. The authors report on a serodiagnostic application of murine monoclonal antibodies (MAB), specific for a human pathogen, M. tuberculosis by a technique which is applicable in principle to the serodiagnosis of many other infectious diseases. The serum diagnostic test is based on the competitive inhibition by human sera of the binding of 125 I-labelled murine monoclonal antibodies to M. tuberculosis-coated polyvinyl plates. Five monoclonal antibodies binding to distinct antigenic determinants of the organism were used as structural probes which conferred their stringent combining site specificities to the polyclonal mixture of antibodies from patients' sera. When compared with healthy controls, increased titres of inhibitory antibodies were found in about 70% of patients with active tuberculosis. The diagnostic value of the individual monoclonal antibodies as well as the benefit from the use of multiple specificity probes has been qualified

Isolation and functional effects of monoclonal antibodies binding to thymidylate synthase.

Science.gov (United States)

Jastreboff, M M; Todd, M B; Malech, H L; Bertino, J R

1985-01-29

Monoclonal antibodies against electrophoretically pure thymidylate synthase from HeLa cells have been produced. Antibodies (M-TS-4 and M-TS-9) from hybridoma clones were shown by enzyme-linked immunoassay to recognize thymidylate synthase from a variety of human cell lines, but they did not bind to thymidylate synthase from mouse cell lines. The strongest binding of antibodies was observed to enzyme from HeLa cells. These two monoclonal antibodies bind simultaneously to different antigenic sites on thymidylate synthase purified from HeLa cells, as reflected by a high additivity index and results of cross-linked radioimmunoassay. Both monoclonal antibodies inhibit the activity of thymidylate synthase from human cell lines. The strongest inhibition was observed with thymidylate synthase from HeLa cells. Monoclonal antibody M-TS-9 (IgM subclass) decreased the rate of binding of [3H]FdUMP to thymidylate synthase in the presence of 5,10-methylenetetrahydrofolate while M-TS-4 (IgG1) did not change the rate of ternary complex formation. These data indicate that the antibodies recognize different epitopes on the enzyme molecule.

Monoclonal antibodies: an overview of their advantages and limitations in nuclear medicine

International Nuclear Information System (INIS)

Revillard, J.P.; Cohen, J.

1982-01-01

The following topics were reviewed: antigen recognition by the immune system; development of immunoassays for antigenic components of biological fluids; monoclonal antibodies against infectious agents; monochonal antibodies against tumor and differentiation antigens; human monoclonal antibodies

Monoclonal antibodies in animal production : their use in diagnostics and passive immunization

NARCIS (Netherlands)

Booman, P.

1989-01-01

One of the landmarks in immunology was the invention and development of monoclonal antibody-secreting hybridomas by Milstein and his coworkers. The enormous promise of monoclonal antibody technology, which became apparent soon after its discovery, may explain the unusual speed with which monoclonal

Structural characterization of POM6 Fab and mouse prion protein complex identifies key regions for prions conformational conversion.

Science.gov (United States)

Baral, Pravas Kumar; Swayampakula, Mridula; Aguzzi, Adriano; James, Michael N G

2018-05-01

Conversion of the cellular prion protein PrP C into its pathogenic isoform PrP S c is the hallmark of prion diseases, fatal neurodegenerative diseases affecting many mammalian species including humans. Anti-prion monoclonal antibodies can arrest the progression of prion diseases by stabilizing the cellular form of the prion protein. Here, we present the crystal structure of the POM6 Fab fragment, in complex with the mouse prion protein (moPrP). The prion epitope of POM6 is in close proximity to the epitope recognized by the purportedly toxic antibody fragment, POM1 Fab also complexed with moPrP. The POM6 Fab recognizes a larger binding interface indicating a likely stronger binding compared to POM1. POM6 and POM1 exhibit distinct biological responses. Structural comparisons of the bound mouse prion proteins from the POM6 Fab:moPrP and POM1 Fab:moPrP complexes reveal several key regions of the prion protein that might be involved in initiating mis-folding events. The structural data of moPrP:POM6 Fab complex are available in the PDB under the accession number www.rcsb.org/pdb/search/structidSearch.do?structureId=6AQ7. © 2018 Federation of European Biochemical Societies.

[Preparation and application of monoclonal antibodies against DR region of Na+-K+-ATPase α1 subunit].

Science.gov (United States)

Yan, Xiaofei; Wu, Litao; DU, Xiaojuan; Li, Jing; Zhang, Fujun; Han, Yan; Lyu, Shemin; Li, Dongmin

2016-12-01

Objective To prepare monoclonal antibodies against DR region (897DVEDSYGQQWTYEQR911) of Na + -K + -ATPase α1 subunit and identify their properties. Methods BALB/c mice were immunized with DR-keyholelimpet hemocyanin (KLH). Splenocytes from the immunized mice were collected and subsequently fused with SP2/0 mouse myeloma cells. Positive hybridoma clones were obtained after cell fusion and selection. ELISA was used to detect DR antibody titer in the cell supernatants. DR region-specific monoclonal antibodies were analyzed by dot blotting, Western blotting and immunofluorescence assay. Na + -K + -ATPase activity was detected by SensoLyte R FDP Protein Phosphatase Assay Kit and the protective effect of the monoclonal antibody against high glucose-induced cell injury was assessed in H9c2 cells. Results Three hybridoma cell lines which secreted stable DR monoclonal antibody were obtained. The strongest positive cell line, named DRm217, was selected to prepare ascites. Dot blotting, Western blotting and immunofluorescence assay showed that DRm217 recognized specially DR region of Na + -K + -ATPase and bound on H9c2 cell membranes. DRm217 stimulated Na + -K + -ATPase activity and alleviated high glucose-induced H9c2 cells injury. Conclusion The monoclonal antibodies against DR region of Na + -K + -ATPase α1 subunit is prepared.

Isolation of Mal d 1 and Api g 1 - specific recombinant antibodies from mouse IgG Fab fragment libraries - Mal d 1-specific antibody exhibits cross-reactivity against Bet v 1.

Science.gov (United States)

Haka, Jaana; Niemi, Merja H; Iljin, Kristiina; Reddy, Vanga Siva; Takkinen, Kristiina; Laukkanen, Marja-Leena

2015-05-27

Around 3-5% of the population suffer from IgE-mediated food allergies in Western countries and the number of food-allergenic people is increasing. Individuals with certain pollen allergies may also suffer from a sensitisation to proteins in the food products. As an example a person sensitised to the major birch pollen allergen, Bet v 1, is often sensitised to its homologues, such as the major allergens of apple, Mal d 1, and celery, Api g 1, as well. Development of tools for the reliable, sensitive and quick detection of allergens present in various food products is essential for allergic persons to prevent the consumption of substances causing mild and even life-threatening immune responses. The use of monoclonal antibodies would ensure the specific detection of the harmful food content for a sensitised person. Mouse IgG antibody libraries were constructed from immunised mice and specific recombinant antibodies for Mal d 1 and Api g 1 were isolated from the libraries by phage display. More detailed characterisation of the resulting antibodies was carried out using ELISA, SPR experiments and immunoprecipitation assays. The allergen-specific Fab fragments exhibited high affinity towards the target recombinant allergens. Furthermore, the Fab fragments also recognised native allergens from natural sources. Interestingly, isolated Mal d 1-specific antibody bound also to Bet v 1, the main allergen eliciting the cross-reactivity syndrome between the birch pollen and apple. Despite the similarities in Api g 1 and Bet v 1 tertiary structures, the isolated Api g 1-specific antibodies showed no cross-reactivity to Bet v 1. Here, high-affinity allergen-specific recombinant antibodies were isolated with interesting binding properties. With further development, these antibodies can be utilised as tools for the specific and reliable detection of allergens from different consumable products. This study gives new preliminary insights to elucidate the mechanism behind the pollen

Conjugation of 10 kDa Linear PEG onto Trastuzumab Fab' Is Sufficient to Significantly Enhance Lymphatic Exposure while Preserving in Vitro Biological Activity.

Science.gov (United States)

Chan, Linda J; Ascher, David B; Yadav, Rajbharan; Bulitta, Jürgen B; Williams, Charlotte C; Porter, Christopher J H; Landersdorfer, Cornelia B; Kaminskas, Lisa M

2016-04-04

The lymphatic system is a major conduit by which many diseases spread and proliferate. There is therefore increasing interest in promoting better lymphatic drug targeting. Further, antibody fragments such as Fabs have several advantages over full length monoclonal antibodies but are subject to rapid plasma clearance, which can limit the lymphatic exposure and activity of Fabs against lymph-resident diseases. This study therefore explored ideal PEGylation strategies to maximize biological activity and lymphatic exposure using trastuzumab Fab' as a model. Specifically, the Fab' was conjugated with single linear 10 or 40 kDa PEG chains at the hinge region. PEGylation led to a 3-4-fold reduction in binding affinity to HER2, but antiproliferative activity against HER2-expressing BT474 cells was preserved. Lymphatic pharmacokinetics were then examined in thoracic lymph duct cannulated rats after intravenous and subcutaneous dosing at 2 mg/kg, and the data were evaluated via population pharmacokinetic modeling. The Fab' displayed limited lymphatic exposure, but conjugation of 10 kDa PEG improved exposure by approximately 11- and 5-fold after intravenous (15% dose collected in thoracic lymph over 30 h) and subcutaneous (9%) administration, respectively. Increasing the molecular weight of the PEG to 40 kDa, however, had no significant impact on lymphatic exposure after intravenous (14%) administration and only doubled lymphatic exposure after subcutaneous administration (18%) when compared to 10 kDa PEG-Fab'. The data therefore suggests that minimal PEGylation has the potential to enhance the exposure and activity of Fab's against lymph-resident diseases, while no significant benefit is achieved with very large PEGs.

Homology of ab1 and ab3 monoclonal antibodies that neutralize Semliki Forest virus

NARCIS (Netherlands)

Fernandez, IM; Bos, NA; Harmsen, M; Verheul, AFM; Snippe, H; Kraaijeveld, CA

2001-01-01

A noninternal image monoclonal antiidiotypic antibody (ab2 mAb), designated 1,13A321, that had proved its efficacy as vaccine against infection with Semliki Forest virus (SFV) in BALB/c mice, was used as immunogen to generate a panel of SFV-neutralizing monoclonal anti-anti-idiotypic antibodies (ab3

Monoclonal antibodies specific for the organophosphate pesticide azinphos-methyl

NARCIS (Netherlands)

Jones, WT; Harvey, D; Jones, SD; Ryan, GB; Wynberg, H; TenHoeve, W; Reynolds, PHS

1995-01-01

2-(2-Mercapto-5-methyl-1,3,2-dioxaphosphorinan-5-yl,2-sulphide) methoxyacetic acid has been synthesized and used to prepare an azinphos hapten and protein conjugates. Monoclonal antibodies of high affinity against the pesticide azinphos-methyl were prepared from mice immunized with the

Monoclonal antibodies and recombinant immunoglobulins for the treatment of multiple sclerosis.

Science.gov (United States)

Gensicke, Henrik; Leppert, David; Yaldizli, Özgür; Lindberg, Raija L P; Mehling, Matthias; Kappos, Ludwig; Kuhle, Jens

2012-01-01

Multiple sclerosis (MS) is an inflammatory and degenerative disease leading to demyelination and axonal damage in the CNS. Autoimmunity plays a central role in MS pathogenesis. Per definition, monoclonal antibodies are recombinant biological compounds with a well defined target, thus carrying the promise of targeting pathogenic cells or molecules with high specificity, avoiding undesired off-target effects. Natalizumab was the first monoclonal antibody to be approved for the treatment of MS. Several other monoclonal antibodies are in development and have demonstrated promising efficacy in phase II studies. They can be categorized according to their mode of action into compounds targeting (i) leukocyte migration into the CNS (natalizumab); (ii) cytolytic antibodies (rituximab, ocrelizumab, ofatumumab, alemtuzumab); or (iii) antibodies and recombinant proteins targeting cytokines and chemokines and their receptors (daclizumab, ustekinumab, atacicept, tabalumab [Ly-2127399], secukinumab [AIN457]). In this review, we discuss the specific molecular targets, clinical efficacy and safety of these compounds and discuss criteria to anticipate the position of monoclonal antibodies in the diversifying armamentarium of MS therapy in the coming years.

New tools for immunochemistry: internally labelled monoclonal antibodies

International Nuclear Information System (INIS)

Galfre, G.; Cuello, A.C.

1981-01-01

Labelled antibodies are routinely used in a wide variety of immunochemical methods. Over the years several labelling techniques have been developed and the discussion of some of them forms a substantial part of this course. Common to all the procedures is the need to purify the antibodies. The labelling itself consists of coupling the antibodies to a ''label'' molecule by means of a chemical reaction. Preparation in vitro of monoclonal antibodies offers the unique possibility to internally label them. Although this is restricted to radiolabelling, and the specific activity achieved is limited, the procedure is extremely simple, does not require purification prior to labelling and chemical manipulation is not necessary as the antibodies themselves are synthesized from radioactive amino acids. Moreover, different labels can be used ( 14 C, 35 S, 3 H) which have a much longer half-life than 125 I. The choice of labelled amino acid precurors and labelling procedure is discussed. The uses of internally-labelled monoclonal antibodies are indicated. (Auth.)

Monkey-derived monoclonal antibodies against Plasmodium falciparum

International Nuclear Information System (INIS)

Stanley, H.A.; Reese, R.T.

1985-01-01

A system has been developed that allows efficient production of monkey monoclonal antibodies from owl monkeys. Splenocytes or peripheral blood lymphocytes from monkeys immune to the human malarial parasite, Plasmodium falciparum, were fused with P3X63 Ag8.653 mouse myelomas. The resulting hybridomas were screened by an indirect fluorescent antibody test for the production of monkey monoclonal antibodies (mAb) reactive with P. falciparum. Most of the mAb reacted with the P. falciparum merozoites and immunoprecipitated a parasite-derived glycoprotein having a relative molecular weight of 185,000. These mAb gave a minimum of five different immunoprecipitation patterns, thus demonstrating that a large number of polypeptides obtained when parasitized erythrocytes are solubilized share epitopes with this large glycoprotein. In addition, mAb were obtained that reacted with antigens associated with the infected erythrocyte membrane. One of these mAb bound a M/sub r/ 95,000 antigen. Radioimmunoprecipitation assays using 125 T-antibodies were done

Safety, pharmacokinetic and dosimetry evaluation of the proposed thrombus imaging agent 99mTc-DI-DD-3B6/22-80B3 Fab'

International Nuclear Information System (INIS)

Macfarlane, David J.; Smart, Richard C.; Tsui, Wendy W.; Gerometta, Michael; Eisenberg, Paul R.; Scott, Andrew M.

2006-01-01

99m Tc-DI-DD-3B6/22-80B3 (Thromboview, hereafter abbreviated to 99m Tc-DI-80B3 Fab') is a humanised, radiolabelled monoclonal antibody Fab' fragment with high affinity and specificity for the D-dimer domain of cross-linked fibrin. The purpose of this study was to evaluate the safety, pharmacokinetics and dosimetry of four increasing doses of 99m Tc-DI-80B3 Fab' in healthy volunteers. Thirty-two healthy volunteers (18-70 years; 16 male, 16 female) received a single intravenous injection of 0.5, 1.0, 2.0 or 4.0 mg of 99m Tc-DI-80B3 Fab'. Safety outcomes (vital signs, electrocardiography, haematology, biochemistry, adverse events and development of human anti-human antibodies) were assessed up to 30 days post injection. Blood and urine samples were collected up to 48 h post injection. Gamma camera images were acquired at 0.5, 1, 2, 4, 6 and 24 h post injection. Dosimetry was performed using standard MIRD methodology. No adverse events considered to be drug related were observed. Human anti-human antibody was not detectable in any subject during the follow-up period. 99m Tc-DI-80B3 Fab' had a rapid initial plasma clearance (t 1/2 α=1 h). The pharmacokinetic profile of the Fab' fragment was generally linear across the four dose cohorts. By 24 h, 30-35% of the administered radioactivity appeared in the urine. There was marked renal accumulation with time, but no specific uptake was identified within other normal tissues. The effective dose was 9 mSv/750 MBq. (orig.)

Recent Advances in Monoclonal Antibody Therapies for Multiple Sclerosis

Science.gov (United States)

Stavropoulos, Nikolaos; Wittenberg, Nathan J.; Dasari, Harika; Abdelrahim, Murtada A.; Henley, John R.; Oh, Sang-Hyun; Warrington, Arthur E.; Rodriguez, Moses

2016-01-01

Introduction Multiple sclerosis (MS) is the most common chronic inflammatory, demyelinating disease of the CNS and results in neurological disability. Existing immunomodulatory and immunosuppressive approaches lower the number of relapses but do not cure or reverse existing deficits nor improve long-term disability in MS patients. Areas Covered Monogenic antibodies were described as treatment options for MS, however the immunogenicity of mouse antibodies hampered the efficacy of potential therapeutics in humans. Availability of improved antibody production technologies resulted in a paradigm shift in MS treatment strategies. In this review, an overview of immunotherapies for MS that use conventional monoclonal antibodies reactive to immune system and their properties and mechanisms of action will be discussed, including recent advances in MS therapeutics and highlight natural autoantibodies (NAbs) that directly target CNS cells. Expert Opinion Recent challenges for MS therapy are the identification of relevant molecular and cellular targets, time frame of treatment, and antibody toxicity profiles to identify safe treatment options for MS patients. The application of monoclonal antibody therapies with better biological efficacy associated with minimum side effects possesses huge clinical potential. Advances in monoclonal antibody technologies that directly target cells of nervous system may promote the CNS regeneration field from bench to bedside. PMID:26914737

Monoclonal antibody form and function: manufacturing the right antibodies for treating drug abuse.

Science.gov (United States)

Peterson, Eric; Owens, S Michael; Henry, Ralph L

2006-05-26

Drug abuse continues to be a major national and worldwide problem, and effective treatment strategies are badly needed. Antibodies are promising therapies for the treatment of medical problems caused by drug abuse, with several candidates in preclinical and early clinical trials. Monoclonal antibodies can be designed that have customized affinity and specificity against drugs of abuse, and because antibodies can be designed in various forms, in vivo pharmacokinetic characteristics can be tailored to suit specific clinical applications (eg, long-acting for relapse prevention, or short-acting for overdose). Passive immunization with antibodies against drugs of abuse has several advantages over active immunization, but because large doses of monoclonal antibodies may be needed for each patient, efficient antibody production technology is essential. In this minireview we discuss some of the antibody forms that may be effective clinical treatments for drug abuse, as well as several current and emerging production systems that could bridge the gap from discovery to patient use.

Current status of cancer immunodetection with radiolabeled human monoclonal antibodies.

Science.gov (United States)

De Jager, R; Abdel-Nabi, H; Serafini, A; Pecking, A; Klein, J L; Hanna, M G

1993-04-01

The use of radiolabeled murine monoclonal antibodies (MoAbs) for cancer immunodetection has been limited by the development of human antimouse antibodies (HAMA). Human monoclonal antibodies do not elicit a significant human antihuman (HAHA) response. The generation and production of human monoclonal antibodies met with technical difficulties that resulted in delaying their clinical testing. Human monoclonal antibodies of all isotypes have been obtained. Most were immunoglobulin (Ig) M directed against intracellular antigens. Two antibodies, 16.88 (IgM) and 88BV59 (IgG3k), recognize different epitopes on a tumor-associated antigen, CTA 16.88, homologous to cytokeratins 8, 18, and 19. CTA 16.88 is expressed by most epithelial-derived tumors including carcinomas of the colon, pancreas, breast, ovary, and lung. The in vivo targeting by these antibodies is related to their localization in nonnecrotic areas of tumors. Repeated administration of 16.88 over 5 weeks to a cumulative dose of 1,000 mg did not elicit a HAHA response. Two of 53 patients developed a low titer of HAHA 1 to 3 months after a single administration of 88BV59. Planar imaging of colorectal cancer with Iodine-131 (131I)-16.88 was positive in two studies in 9 of 12 and 16 of 20 patients preselected by immunohistochemistry. Tumors less than 2 cm in diameter are usually not detected. The lack of immunogenicity and long tumor residence time (average = 17 days) makes 16.88 a good candidate for therapy. Radioimmunlymphoscintigraphy with indium-111 (111In)-LiLo-16.88 administered by an intramammary route was used in the presurgical staging of primary breast cancer. The negative predictive value of lymph node metastases for tumors less than 3 cm was 90.5%. Planar and single photon emission computed tomography imaging of colorectal carcinoma with technetium-99m (99mTc) 88BV59 was compared with computed tomography (CT) scan in 36 surgical patients. The antibody scan was more sensitive than the CT scan in detecting

Monoclonal antibodies for radioimmunodetection of tumours and for targeting

International Nuclear Information System (INIS)

Baldwin, R.W.; Embleton, M.J.; Pimm, M.V.

1983-01-01

A monoclonal antibody 791T/36 prepared against human osteogenic sarcoma has been used to detect primary and metastatic colorectal carcinomas by external imaging of patients following injection of 131 I-labelled antibody. In 10 of 11 patients radiolabelled 791T/36 antibody localized in tumours, the tumour/non tumour ratio of radioactivity ranging from 1.5:1 to 8.1. 791T/36 antibody was also evaluated for its potential for targeting anti-tumour agents including cytotoxic drugs (Vindesine) and immunomodulating agents (interferon). Vindesine-791T/36 conjugates were preferentially cytotoxic in vitro for target cells expressing the 791T/36 anti-body defined antigen. Also interferon conjugated to 791T/36 antibody, like free interferon activated peripheral blood natural killer cell activity. These in vitro tests together with related studies on antibody localization in vivo indicate the potential of monoclonal antibody targeting of anti-tumour agents

Application of Tryptophan Fluorescence Bandwidth-Maximum Plot in Analysis of Monoclonal Antibody Structure.

Science.gov (United States)

Huang, Cheng-Yen; Hsieh, Ming-Ching; Zhou, Qinwei

2017-04-01

Monoclonal antibodies have become the fastest growing protein therapeutics in recent years. The stability and heterogeneity pertaining to its physical and chemical structures remain a big challenge. Tryptophan fluorescence has been proven to be a versatile tool to monitor protein tertiary structure. By modeling the tryptophan fluorescence emission envelope with log-normal distribution curves, the quantitative measure can be exercised for the routine characterization of monoclonal antibody overall tertiary structure. Furthermore, the log-normal deconvolution results can be presented as a two-dimensional plot with tryptophan emission bandwidth vs. emission maximum to enhance the resolution when comparing samples or as a function of applied perturbations. We demonstrate this by studying four different monoclonal antibodies, which show the distinction on emission bandwidth-maximum plot despite their similarity in overall amino acid sequences and tertiary structures. This strategy is also used to demonstrate the tertiary structure comparability between different lots manufactured for one of the monoclonal antibodies (mAb2). In addition, in the unfolding transition studies of mAb2 as a function of guanidine hydrochloride concentration, the evolution of the tertiary structure can be clearly traced in the emission bandwidth-maximum plot.

Monoclonal antibodies reactive with hairy cell leukemia

NARCIS (Netherlands)

Visser, L; Shaw, A; Slupsky, J; Vos, H; Poppema, S

Monoclonal antibodies reactive with hairy cell leukemia were developed to aid in the diagnosis of this subtype of B cell chronic lymphocytic leukemia and to gain better insight into the origin of hairy cells. Three antibodies were found to be of value in the diagnosis of hairy cell leukemia.

Generation of monoclonal antibodies against highly conserved antigens.

Directory of Open Access Journals (Sweden)

Hongzhe Zhou

Full Text Available BACKGROUND: Therapeutic antibody development is one of the fastest growing areas of the pharmaceutical industry. Generating high-quality monoclonal antibodies against a given therapeutic target is very crucial for the success of the drug development. However, due to immune tolerance, some proteins that are highly conserved between mice and humans are not very immunogenic in mice, making it difficult to generate antibodies using a conventional approach. METHODOLOGY/PRINCIPAL FINDINGS: In this report, the impaired immune tolerance of NZB/W mice was exploited to generate monoclonal antibodies against highly conserved or self-antigens. Using two highly conserved human antigens (MIF and HMGB1 and one mouse self-antigen (TNF-alpha as examples, we demonstrate here that multiple clones of high affinity, highly specific antibodies with desired biological activities can be generated, using the NZB/W mouse as the immunization host and a T cell-specific tag fused to a recombinant antigen to stimulate the immune system. CONCLUSIONS/SIGNIFICANCE: We developed an efficient and universal method for generating surrogate or therapeutic antibodies against "difficult antigens" to facilitate the development of therapeutic antibodies.

Development of radiolabelling techniques of anti-CEA monoclonal antibody

International Nuclear Information System (INIS)

Castiglia, S.G. de

1998-01-01

The purpose of this work was to label monoclonal and polyclonal antibodies with 99 Tc m such as the ior-CEA-1 antibody and polyclonal IgG using a direct method, to check the radiochemical and biological behavior of labelled products, to prepare it under sterile and apyrogenic conditions as a lyophilized kit and to employ it in clinical trials. In addition, a photoactivation method was used to label polyclonal IgG with 99 Tc m and to compare with the established method using mercaptoethanol (2-ME) as the reducing agent. Finally polyclonal IgG was labelled using an indirect method in which a chelator was covalently attached to the protein and the 99 Tc m added as glucoheptonate complex. The properties of 99 Tc m when labelled with monoclonal and polyclonal antibodies by different methods were assessed by in vitro and in vivo studies

Monoclonal antibody-based immunoassays.

Science.gov (United States)

Appleby, P; Reischl, U

1998-01-01

An immunoassay may be defined as an assay that employs an immunological reagent, usually an antibody, to confer specificity for the ligand being measured. As a corollary to this, the discovery, and subsequent development, of monoclonal antibodies (MAbs) has greatly expanded the application and use of immunoassays. Polyclonal reagents, with their associated problems of specificity and quality control, have now been largely replaced by readily available MAbs of potential immortality and well-defined specificity and affinity. This has resulted, in the last two decades, in a great expansion in the range of immunoassays available and also a significant improvement in their reproducibility and reliability.

Radioimmunolocalization and selective delivery of radiation in a rat model system: comparison of intact and fragmented antibody

International Nuclear Information System (INIS)

Walker, K.Z.; Seymour-Munn, K.; Axiak, S.M.; Raison, R.L.; Basten, A.; Towson, J.E.; Bautovitch, G.J.; Morris, J.

1988-01-01

Monoclonal antibody (MoAb) fragments are known to have advantages over intact immunoglobulins for radioimmunoscintigraphy. It is less clear whether they are as effective in the delivery of radioimmunotherapy. The imaging and dosimetric properties of an intact MoAb, K-1-21, reactive against human kappa light chains (LC) were compared with that of its F(ab') 2 and Fab fragments using a normal rat model system. Two days after injection of 131 I-K-1-21 into rats bearing antigen-sepharose implants, gamma camera images showed specific localization of the MoAb to the target (kappa LC) but not to the control (lambda LC) implant. Better images were obtained with K-1-21 F(ab') 2 than with Fab or intact antibody. Mean kappa implant: blood ratios were 8.6 ± 3.9 for Fab, 7.9 ± 1.8 for F(ab') 2 and 2.0 ± 0.3 for intact K-1-21. The improvement associated with the use of 131 I-K-1-21 fragments was, however, achieved at the expense of lower absolute values of activity at the target site. Thus the absorbed dose delivered to the implant by the intact K-1-21 was double that delivered with F(ab') 2 and six times that delivered with Fab. As intact K-1-21 also delivered a greater radiation dose to normal tissues, F(ab') 2 fragments may have the greatest overall advantages for therapy with radionuclide MoAb conjugates. (author)

ERBB oncogene proteins as targets for monoclonal antibodies.

Science.gov (United States)

Polanovski, O L; Lebedenko, E N; Deyev, S M

2012-03-01

General properties of the family of tyrosine kinase ERBB receptors are considered in connection with their role in the generation of cascades of signal transduction in normal and tumor cells. Causes of acquisition of oncogene features by genes encoding these receptors and their role in tumorigenesis are analyzed. Anti-ERBB monoclonal antibodies approved for therapy are described in detail, and mechanisms of their antitumor activity and development of resistance to them are reviewed. The existing and the most promising strategies for creating and using monoclonal antibodies and their derivatives for therapy of cancer are discussed.

The development of glioblastoma multiforme reactive monoclonal antibodies and their use in drug targeting

International Nuclear Information System (INIS)

Klaich, G.M.

1989-01-01

The objectives of this project were to develop monoclonal antibodies reactive with the tumor glioblastoma multiforme and to use them to study and develop new treatment modalities for this disease. A tumor antigen enriched immunogen, prepared by immunoaffinity chromatography, was compared to a whole tumor homogenate immunogen with the difference in the yield of tumor reactive, normal brain unreactive monoclonal antibodies proving to be significant. Monoclonal antibody A7, reactive with tumor tissue but unreactive with normal tissue, was isotyped to be an IgG2a immunoglobulin and could be purified to electrophoretic homogeneity by using serum-free culture conditions and protein A sepharose chromatography. Monoclonal antibody A7 is noncytotoxic as measured by the 3 H-nicotinamide release assay and binds to a 138 kd membrane antigen which is not internalized. Localization studies using 14 C-labeled monoclonal antibody A7 and the U-87 MG nude mouse xenograft model resulted in a tumor:serum ratio of 1.25:1.0 as compared to 0.29:1.0 for the negative control. A monoclonal antibody A7-doxorubicin immunoconjugate proved to be more cytotoxic than free doxorubicin in vitro while lethality studies using Swiss mice demonstrated the lack of toxicity of the immunoconjugate as compared to free doxorubicin. In vivo chemotherapy studies using the U-87 MG nude mouse xenograft failed to demonstrate any immunoconjugate anti-tumor activity which may be attributable to the route of administration

Identification of antigen-specific human monoclonal antibodies using high-throughput sequencing of the antibody repertoire.

Science.gov (United States)

Liu, Ju; Li, Ruihua; Liu, Kun; Li, Liangliang; Zai, Xiaodong; Chi, Xiangyang; Fu, Ling; Xu, Junjie; Chen, Wei

2016-04-22

High-throughput sequencing of the antibody repertoire provides a large number of antibody variable region sequences that can be used to generate human monoclonal antibodies. However, current screening methods for identifying antigen-specific antibodies are inefficient. In the present study, we developed an antibody clone screening strategy based on clone dynamics and relative frequency, and used it to identify antigen-specific human monoclonal antibodies. Enzyme-linked immunosorbent assay showed that at least 52% of putative positive immunoglobulin heavy chains composed antigen-specific antibodies. Combining information on dynamics and relative frequency improved identification of positive clones and elimination of negative clones. and increase the credibility of putative positive clones. Therefore the screening strategy could simplify the subsequent experimental screening and may facilitate the generation of antigen-specific antibodies. Copyright © 2016 Elsevier Inc. All rights reserved.

Expression of deleted, atoxic atypical recombinant beta2 toxin in a baculovirus system and production of polyclonal and monoclonal antibodies.

Science.gov (United States)

Serroni, Anna; Magistrali, Chiara Francesca; Pezzotti, Giovanni; Bano, Luca; Pellegrini, Martina; Severi, Giulio; Di Pancrazio, Chiara; Luciani, Mirella; Tittarelli, Manuela; Tofani, Silvia; De Giuseppe, Antonio

2017-05-25

Clostridium perfringens is an important animal and human pathogen that can produce more than 16 different major and minor toxins. The beta-2 minor toxin (CPB2), comprising atypical and consensus variants, appears to be involved in both human and animal enterotoxaemia syndrome. The exact role of CPB2 in pathogenesis is poorly investigated, and its mechanism of action at the molecular level is still unknown because of the lack of specific reagents such as monoclonal antibodies against the CPB2 protein and/or the availability of a highly purified antigen. Previous studies have reported that purified wild-type or recombinant CPB2 toxin, expressed in a heterologous system, presented cytotoxic effects on human intestinal cell lines. Undoubtedly, for this reason, to date, these purified proteins have not yet been used for the production of monoclonal antibodies (MAbs). Recently, monoclonal antibodies against CPB2 were generated using peptides designed on predicted antigenic epitopes of this toxin. In this paper we report, for the first time, the expression in a baculovirus system of a deleted recombinant C-terminal 6xHis-tagged atypical CPB2 toxin (rCPB2 Δ1-25 -His 6 ) lacking the 25 amino acids (aa) of the N-terminal putative signal sequence. A high level of purified recombinant rCPB2 Δ1-25 -His 6 was obtained after purification by Ni 2+ affinity chromatography. The purified product showed no in vitro and in vivo toxicity. Polyclonal antibodies and twenty hybridoma-secreting Mabs were generated using purified rCPB2 Δ1-25 -His 6 . Finally, the reactivity and specificity of the new antibodies were tested against both recombinant and wild-type CPB2 toxins. The high-throughput of purified atoxic recombinant CPB2 produced in insect cells, allowed to obtain monoclonal and polyclonal antibodies. The availability of these molecules could contribute to develop immunoenzymatic methods and/or to perform studies about the biological activity of CPB2 toxin.

Monoclonal antibodies: potential role in radiation therapy and oncology

International Nuclear Information System (INIS)

Order, S.E.

1982-01-01

Specificity, which is a hallmark of the immune system, will be used in radiation oncology in both diagnosis and therapy through the application of radiolabelled monoclonal and polyclonal antibodies. Antigenic specificities, antibody preparations, and the tumor as a target for radiolabelled antibody is reviewed. Several clinical situations, i.e. single tumor cell suspensions, intraperitoneal single cells and masses, and solid tumors are reviewed in regard to both immune antibody targeting and specific differences between tumors in these regions. The concentration of tumor associated antigens is introductory to radiolabelled antibodies in diagnosis. In the radiation therapy of solid tumors, data regarding tumor dose, tumor effective half-life, varied antibody preparations, and the use of radiolabelled antibody as a method of tumor implantation is discussed using antiferritin 131 I-IgG as a model in hepatoma. The theoretical applications of monoclonal antibody integrated in cancer therapy are then presented as a new goal for future development

Clinical assay stage I clinical trial with the murine monoclonal antibody IOR-T1: Pharmacokinetic and immune answers

International Nuclear Information System (INIS)

Faxas Garcia, Maria E.; Guerra Yi, Marta E.; Alvarez, Alejandro; Calderon, Carlos

2003-01-01

As part of the stage I clinical trial with the murine monoclonal antibody IOR-T1 at repeated doses (200-800 mg) in patients carriers of cutaneous T-cell lymphoma, the pharmacokinetics and the response against the mouse protein (HAMA) were studied in the 10 patients under treatment. It was observed a great individual variation in the maximum concentration in serum, which was estimated at 2 hours. The mean life time of the monoclonal antibody was between 13.93 and 19.6 hours. Most of the patients developed antibodies against the monoclonal antibody IOR-T1. The presence of this second antibody did not alter significantly the pharmacokinetics of the administered monoclonal antibody

Isolation and characterization of a monoclonal anti CK-2 alpha subunit antibody of the IgG1 subclass

DEFF Research Database (Denmark)

Schmidt-Spaniol, I; Boldyreff, B; Issinger, O G

1992-01-01

A monoclonal antibody was produced against the recombinant human alpha subunit of CK-2. The antibody was of the IgG1 subclass and it was isolated from serum-free cell culture media and purified by affinity chromatography on Protein G Sepharose. The antibody can be used to detect specifically the CK......-2 alpha subunit in immunoblots from tissue extracts. An ELISA detection test was also established which also allows the identification of the CK-2 alpha subunit....

A rapid one-step radiometric assay for hepatitis B surface antigen utilising monoclonal antibodies

International Nuclear Information System (INIS)

Goodall, A.H.; Meek, F.L.; Waters, J.A.; Miescher, G.C.; Janossy, G.; Thomas, H.C.

1982-01-01

A two-site antigen assay for HBsAg has been developed that employs 3 monoclonal antibodies. The antibodies were selected for their high affinity and their particular epitope specificity to establish an assay with a sensitivity for the antigen comparable with that of a conventional assay with heterologous antisera. In addition, by selecting a monoclonal antibody for use as a tracer which does not compete for antigenic binding sites with the solid-phase monoclonal antibodies, it has been possible to perform a two-site assay in a single 1 h incubation step, achieving the same degree of sensitivity. This principle of using monoclonal antibodies in a one-step assay therefore gives advantages of speed and simplicity over assays using heterologous antisera and would be applicable to a variety of antigen assays for which appropriate monoclonal antibodies are available. (Auth.)

An ELISA-inhibition test using monoclonal antibody for the serology of leprosy

NARCIS (Netherlands)

Klatser, P. R.; de Wit, M. Y.; Kolk, A. H.

1985-01-01

In this study a mouse monoclonal antibody (47-9) is described, which recognized an epitope on the 36 kD protein antigen of M. leprae. The monoclonal antibody showed specificity for M. leprae. An ELISA-inhibition test based on the competitive inhibition by antibodies from human test sera of the

Characterization of monoclonal antibodies against human thyrotropin and use in an immunoradiometric assay and immunohistochemistry

International Nuclear Information System (INIS)

Benkirane, M.; Bon, D.; Bellot, F.; Prince, P.; Delori, P.; Hassoun, J.; Carayon, P.

1987-01-01

Monoclonal antibodies were prepared against human thyrotropin. 13 different antibodies were characterized. Ten antibodies were of the IgG1 subclass. The affinities of the antibodies were in the range 10 9 -10 11 mol -1 .l. Four of them were specific for hTSH and did not react with hLH, hFSH, hCG or αhCG. Four reacted with these hormones and recognized the α subunit of hCG. One cross-reacted only with HFSH. The remaining four antibodies recognized the holo-hTSH only, and thus were designated as anti-conformational determinants. Monoclonal antibodies reacting with different antigenic determinants on the hTSH molecule defined seven clusters. Two of them were used to develop a simplified two-site sandwich radioimmunoassay in which one monoclonal antibody was immobilized on tubes (anti-βTSH) and another (anti-α) labelled with 125 I. This assay was highly specific and demonstrated a sensitivity level of 0.1 μIU/ml. Two monoclonal antibodies were used in immunohistochemistry and their quality and specificity was assessed in the detection of hTSH immunoreactivity in human pituitary biological sections. 20 refs.; 6 figs.; 2 tabs

Mammalian tissue distribution of a large heparan sulfate proteoglycan detected by monoclonal antibodies

DEFF Research Database (Denmark)

Couchman, J R; Ljubimov, A V

1989-01-01

muscle, endothelia, peripheral nerve fibers and epithelia so far examined. In addition, two of the monoclonal antibodies show cross-species reactivity, staining bovine and human basement membranes, and immunoprecipitating proteoglycans from human endothelial cell cultures. These antibodies do not......A panel of nine monoclonal antibodies has been characterized, all of which have reactivity with the core protein of a large heparan sulfate proteoglycan derived from the murine EHS tumor matrix. These rat monoclonal antibodies stained mouse basement membranes intensely, including those of all...

Topographic antigenic determinants recognized by monoclonal antibodies on human choriogonadotropin beta-subunit

International Nuclear Information System (INIS)

Bidart, J.M.; Troalen, F.; Salesse, R.; Bousfield, G.R.; Bohuon, C.J.; Bellet, D.H.

1987-01-01

We describe a first attempt to study the antibody-combining sites recognized by monoclonal antibodies raised against the beta-subunit of human choriogonadotropin (hCG). Two groups of antibodies were first defined by their ability to recognize only the free beta-subunit or the free and combined subunit. Antibodies FBT-11 and FBT-11-L bind only to hCG beta-subunit but not to hCG, whereas antibodies FBT-10 and D1E8 bind to both the beta-subunit and the hormone. In both cases, the antigenic determinants were localized to the core of the protein (residues 1-112), indicating the weak immunogenicity of the specific carboxyl-terminal extension of hCG-beta. Nine synthetic peptides spanning different regions of hCG-beta and lutropin-beta were assessed for their capacity to inhibit antibody binding. A synthetic peptide inclusive of the NH2-terminal region (residues 1-7) of the hCG beta-subunit was found to inhibit binding to the radiolabeled subunit of a monoclonal antibody specific for free hCG-beta (FBT-11). Further delineation of the antigenic site recognized by this antibody provided evidence for the involvement of fragment 82-92. Moreover, monoclonal antibody FBT-11 inhibited the recombination of hCG-beta to hCG-alpha, indicating that its antigenic determinant might be located nearby or in the hCG-beta portion interacting with the alpha-subunit. Binding of monoclonal antibody FBT-10, corresponding to the second antigenic determinant, was weakly inhibited by fragment 82-105 and did not impair the recombination of the hCG beta-subunit to the hCG alpha-subunit. Its combining site appeared to be located in a region of the intact native choriogonadotropin present at the surface of the hormone-receptor complex

Single-reagent one-step procedures for the purification of ovine IgG, F(ab')2 and Fab antivenoms by caprylic acid.

Science.gov (United States)

Al-Abdulla, Ibrahim; Casewell, Nicholas R; Landon, John

2014-01-15

Antivenoms are typically produced in horses or sheep and often purified using salt precipitation of immunoglobulins or F(ab')2 fragments. Caprylic (octanoic) acid fractionation of antiserum has the advantage of not precipitating the desired antibodies, thereby avoiding potential degradation that can lead to the formation of aggregates, which may be the cause of some adverse reactions to antivenoms. Here we report that when optimising the purification of immunoglobulins from ovine antiserum raised against snake venom, caprylic acid was found to have no effect on the activity of the enzymes pepsin and papain, which are employed in antivenom manufacturing to digest immunoglobulins to obtain F(ab')2 and Fab fragments, respectively. A "single-reagent" method was developed for the production of F(ab')2 antivenom whereby whole ovine antiserum was mixed with both caprylic acid and pepsin and incubated for 4h at 37°C. For ovine Fab antivenom production from whole antiserum, the "single reagent" comprised of caprylic acid, papain and l-cysteine; after incubation at 37°C for 18-20h, iodoacetamide was added to stop the reaction. Caprylic acid facilitated the precipitation of albumin, resulting in a reduced protein load presented to the digestion enzymes, culminating in substantial reductions in processing time. The ovine IgG, F(ab')2 and Fab products obtained using these novel caprylic acid methods were comparable in terms of yield, purity and specific activity to those obtained by multi-step conventional salt fractionation with sodium sulphate. Copyright © 2013 Elsevier B.V. All rights reserved.

Targeting of indium 111-labeled bivalent hapten to human melanoma mediated by bispecific monoclonal antibody conjugates: Imaging of tumors hosted in nude mice

International Nuclear Information System (INIS)

Le Doussal, J.M.; Gruaz-Guyon, A.; Martin, M.; Gautherot, E.; Delaage, M.; Barbet, J.

1990-01-01

Antibody conjugates were prepared by coupling F(ab')2 or Fab' fragments of an antibody specific for the human high molecular weight-melanoma associated antigen to Fab' fragments of an antibody specific for indium-diethylenetriaminepentaacetate complexes. Monovalent and bivalent haptens were synthesized by reacting the dipeptide tyrosyl-lysine with diethylenetriaminepentaacetic cyclic anhydride. In vitro, the antibody conjugate mediated binding of the 111In-labeled haptens to melanoma cells. In vivo, it allowed specific localization of the haptens in A375 tumors. The bivalent hapten exhibited much higher efficiency at targeting 111In onto cells, both in vitro and in vivo. Antibody conjugate and hapten doses (2 micrograms and 1 pmol, respectively) and the delay between antibody conjugate and tracer injections (24 h) were adjusted to maximize tumor uptake (4% injected dose/g) and tumor to normal tissue contrast (greater than 3) obtained 3 h after injection of the 111In-labeled bivalent hapten. This two-step technique, when compared to direct targeting of 111In-labeled F(ab')2 fragments, provided lower localization of injected activity into the tumor (x 0.25), but higher tumor/tissue ratios, especially with respect to liver (x 7), spleen (x 8), and kidneys (x 10). In addition, high contrast images were obtained within 3 hours, instead of days. Thus, antibody conjugate-mediated targeting of small bivalent haptens, labeled with short half-life isotopes, is proposed as a general method for improving tumor radioimmunolocalization

High throughput production of mouse monoclonal antibodies using antigen microarrays

DEFF Research Database (Denmark)

De Masi, Federico; Chiarella, P.; Wilhelm, H.

2005-01-01

Recent advances in proteomics research underscore the increasing need for high-affinity monoclonal antibodies, which are still generated with lengthy, low-throughput antibody production techniques. Here we present a semi-automated, high-throughput method of hybridoma generation and identification....... Monoclonal antibodies were raised to different targets in single batch runs of 6-10 wk using multiplexed immunisations, automated fusion and cell-culture, and a novel antigen-coated microarray-screening assay. In a large-scale experiment, where eight mice were immunized with ten antigens each, we generated...

Discovery of functional monoclonal antibodies targeting G-protein-coupled receptors and ion channels.

Science.gov (United States)

Wilkinson, Trevor C I

2016-06-15

The development of recombinant antibody therapeutics is a significant area of growth in the pharmaceutical industry with almost 50 approved monoclonal antibodies on the market in the US and Europe. Despite this growth, however, certain classes of important molecular targets have remained intractable to therapeutic antibodies due to complexity of the target molecules. These complex target molecules include G-protein-coupled receptors and ion channels which represent a large potential target class for therapeutic intervention with monoclonal antibodies. Although these targets have typically been addressed by small molecule approaches, the exquisite specificity of antibodies provides a significant opportunity to provide selective modulation of these target proteins. Given this opportunity, substantial effort has been applied to address the technical challenges of targeting these complex membrane proteins with monoclonal antibodies. In this review recent progress made in the strategies for discovery of functional monoclonal antibodies for these challenging membrane protein targets is addressed. © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

Boronated monoclonal antibody 225.28S for potential use in neutron capture therapy of malignant melanoma

International Nuclear Information System (INIS)

Tamat, S.R.; Moore, D.E.; Patwardhan, A.; Hersey, P.

1989-01-01

The concept of conjugating boron cluster compounds to monoclonal antibodies has been examined by several groups of research workers in boron neutron capture therapy (BNCT). The procedures reported to date for boronation of monoclonal antibodies resulted in either an inadequate level of boron incorporation, the precipitation of the conjugates, or a loss of immunological activity. The present report describes the conjugation of dicesium-mercapto-undecahydrododecaborate (Cs2B12H11SH) to 225.28S monoclonal antibody directed against high molecular weight melanoma-associated antigens (HMW-MAA), using poly-L-ornithine as a bridge to increase the carrying capacity of the antibody and to minimize change in the conformational structure of antibody. The method produces a boron content of 1,300 to 1,700 B atoms per molecule 225.28S while retaining the immunoreactivity. Characterization in terms of the homogeneity of the conjugation of the boron-monoclonal antibody conjugates has been studied by gel electrophoresis and ion-exchange HPLC

Microbials for the production of monoclonal antibodies and antibody fragments.

Science.gov (United States)

Spadiut, Oliver; Capone, Simona; Krainer, Florian; Glieder, Anton; Herwig, Christoph

2014-01-01

Monoclonal antibodies (mAbs) and antibody fragments represent the most important biopharmaceutical products today. Because full length antibodies are glycosylated, mammalian cells, which allow human-like N-glycosylation, are currently used for their production. However, mammalian cells have several drawbacks when it comes to bioprocessing and scale-up, resulting in long processing times and elevated costs. By contrast, antibody fragments, that are not glycosylated but still exhibit antigen binding properties, can be produced in microbial organisms, which are easy to manipulate and cultivate. In this review, we summarize recent advances in the expression systems, strain engineering, and production processes for the three main microbials used in antibody and antibody fragment production, namely Saccharomyces cerevisiae, Pichia pastoris, and Escherichia coli. Copyright © 2013 Elsevier Ltd. All rights reserved.

Monoclonal Antibodies for Non-Hodgkin's Lymphoma: State of the Art and Perspectives

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Giulia Motta

2010-01-01

Full Text Available Monoclonal antibodies have been the most successful therapeutics ever brought to cancer treatment by immune technologies. The use of monoclonal antibodies in B-cell Non-Hodgkin's lymphomas (NHL represents the greatest example of these advances, as the introduction of the anti-CD20 antibody rituximab has had a dramatic impact on how we treat this group of diseases today. Despite this success, several questions about how to optimize the use of monoclonal antibodies in NHL remain open. The best administration schedules, as well as the optimal duration of rituximab treatment, have yet to be determined. A deeper knowledge of the mechanisms underlying resistance to rituximab is also necessary in order to improve the activity of this and of similar therapeutics. Finally, new antibodies and biological agents are entering the scene and their advantages over rituximab will have to be assessed. We will discuss these issues and present an overview of the most significant clinical studies with monoclonal antibodies for NHL treatment carried out to date.

Immunotherapy for the treatment of colorectal tumors: focus on approved and in-clinical-trial monoclonal antibodies

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Françoso A

2017-01-01

Full Text Available Alex Françoso,1 Patricia Ucelli Simioni1–3 1Department of Biomedical Science, Faculty of Americana, Americana, 2Department of Genetics, Evolution and Bioagents, Institute of Biology, University of Campinas, Campinas, 3Department of Biochemistry and Microbiology, Institute of Biosciences, Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil Abstract: Colorectal cancer is considered a disease of the elderly population. Since the number of geriatric patients continues to rise, monoclonal antibody therapy is the most promising therapy in the recent research. Presently, the monoclonal antibodies most frequently used in the treatment of colorectal tumors are bevacizumab, cetuximab, panitumumab, and ramucirumab. Bevacizumab is a monoclonal antibody that acts on VEGF. Cetuximab and panitumumab act on EGFR. Ramucirumab binds directly to the ligand-binding pocket of VEGFR-2 to block the binding of VEGF-A, VEGF-C, and VEGF-D. These monoclonal antibodies, alone or in association with radiotherapy or chemotherapy, are presenting good results and are increasing patient survival, despite the side effects. Due to the limited number of molecules available, several studies are trying to develop new monoclonal antibodies for the treatment of colorectal tumors. Among those being studied, some recent molecules are in phase I and/or II trials and are yielding advantageous results, such as anti-DR5, anti-Fn14, anti-IGF-1R, anti-EGFR, anti-NRP1, and anti-A33 antibodies. This has been successful in reducing side effects and in treating nonresponsive patients. Keywords: monoclonal antibodies, colorectal tumor, bevacizumab, cetuximab, panitumumab, ramucirumab

Mass-Production and Characterization of Anti-CD20 Monoclonal Antibody in Peritoneum of Balb/c Mice

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Leili Aghebati

2013-02-01

Full Text Available Purpose: Monoclonal antibodies are important tools are used in basic research as well as, in diagnosis, imaging and treatment of immunodeficiency diseases, infections and cancers. The purpose of this study was to produce large scale of monoclonal antibody against CD20 in order to diagnostic application in leukemia and lymphomas disorders. Methods: Hybridoma cells that produce monoclonal antibody against human CD20 were administered into the peritoneum of the Balb/c mice which have previously been primed with 0.5 ml Pristane. After twelve days, approximately 7 ml ascetic fluid was harvested from the peritoneum of each mouse. Evaluation of mAb titration was assessed by ELISA method. In the present study, we describe a protocol for large scale production of MAbs. Results: We prepared monoclonal antibodies (mAbs with high specificity and sensitivity against human CD20 by hybridoma method and characterized them by ELISA. The subclass of antibody was IgG2a and its light chain was kappa. Ascetic fluid was purified by Protein-A Sepharose affinity chromatography and the purified monoclonal antibody was conjugated with FITC and Immunofluorescence was done for confirming the specific binding. Conclusion: The conjugated monoclonal antibody could have application in diagnosis B-cell lymphomas, hairy cell leukemia, B-cell chronic lymphocytic leukemia, and melanoma cancer stem cells.

Mass-Production and Characterization of Anti-CD20 Monoclonal Antibody in Peritoneum of Balb/c Mice

Science.gov (United States)

Sineh sepehr, Koushan; Baradaran, Behzad; Majidi, Jafar; Abdolalizadeh, Jalal; Aghebati, leili; Zare Shahneh, Fatemeh

2013-01-01

Purpose: Monoclonal antibodies are important tools are used in basic research as well as, in diagnosis, imaging and treatment of immunodeficiency diseases, infections and cancers. The purpose of this study was to produce large scale of monoclonal antibody against CD20 in order to diagnostic application in leukemia and lymphomas disorders. Methods: Hybridoma cells that produce monoclonal antibody against human CD20 were administered into the peritoneum of the Balb/c mice which have previously been primed with 0.5 ml Pristane. After twelve days, approximately 7 ml ascetic fluid was harvested from the peritoneum of each mouse. Evaluation of mAb titration was assessed by ELISA method. In the present study, we describe a protocol for large scale production of MAbs. Results: We prepared monoclonal antibodies (mAbs) with high specificity and sensitivity against human CD20 by hybridoma method and characterized them by ELISA. The subclass of antibody was IgG2a and its light chain was kappa. Ascetic fluid was purified by Protein-A Sepharose affinity chromatography and the purified monoclonal antibody was conjugated with FITC and Immunofluorescence was done for confirming the specific binding. Conclusion: The conjugated monoclonal antibody could have application in diagnosis B-cell lymphomas, hairy cell leukemia, B-cell chronic lymphocytic leukemia, and melanoma cancer stem cells. PMID:24312821

Production and radioiodination of monoclonal antibodies and its applications in nuclear medicine

International Nuclear Information System (INIS)

Toledo e Souza, I.T. de; Okada, H.

1988-12-01

The basis of the monoclonal antibody production methodology, some immunological concepts which are important for the understanding of what is a Monoclonal Antibody, its radioiodination and acceptance as receptor-specific radiopharmaceuticals in nuclear medicine are reviewed. (author) [pt

Identification of endogenous opioid receptor components in rat brain using a monoclonal antibody

Energy Technology Data Exchange (ETDEWEB)

Bero, L.A.; Roy, S.; Lee, N.M.

1988-11-01

A monoclonal antibody generated against the tertiary structure of a partially purified opioid binding protein was used to probe the structure of the dynorphin and beta-endorphin receptors. The Fab fragment 3B4F11 inhibited completely the binding of 125I-beta-endorphin and (3H)dynorphin to rat brain P2 membranes with IC50 values of 26 ng/ml and 40 ng/ml, respectively. To explore further the interaction of 3B4F11 with the beta-endorphin receptor, the effect of the Fab fragment on 125I-beta-endorphin cross-linking to rat brain membranes was examined. 125I-beta-endorphin was covalently bound to three major species of approximate molecular weights 108,000, 73,000, and 49,000. The delta-selective ligand D-Pen2, D-pen5enkephalin was least effective at inhibiting the cross-linking of beta-endorphin, whereas the micro-selective ligand Tyr-D-Ala-Gly-NMe-Phe-Gly-ol and kappa-selective ligand U50488 inhibited beta-endorphin cross-linking to the 108,000 and 73,000 Da species. Both 3B4F11 and beta-endorphin prevented the covalent binding of 125I-beta-endorphin to all three labeled species. These findings suggest that micro and kappa receptor types might have some structural similarities, whereas the delta receptor type might differ in molecular size. In addition, the micro, kappa, and delta ligands might have different primary sequences, whereas their tertiary structures might share regions of molecular homology with all three receptor constituents labeled by 125I-beta-endorphin. 3B4F11 will be a valuable tool for the purification and isolation of the several components of the beta-endorphin receptor complex.

Radioimmunoimaging in malignant melanoma with 111In-labeled monoclonal antibody 96.5

International Nuclear Information System (INIS)

Murray, J.L.; Rosenblum, M.G.; Sobol, R.E.

1985-01-01

A radiolabeled monoclonal antibody (96.5) reactive with an Mr 97,000 antigen found on over 80% of melanoma cell lines and tissue extracts was examined for its ability to detect malignant melanoma metastases in vivo. For imaging purposes, it was conjugated with diethyltriaminepentaacetic acid and subsequently labeled with 111 In by chelation. Thirty-one patients with metastatic melanoma received single injections of monoclonal antibody 96.5 at concentrations ranging from 0.5 to 20 mg and at specific activities of 111 In ranging from 0.125 to 4 mCi/mg. Total-body scans were performed at various time intervals following administration. No serious side effects were observed. Of a total of 100 previously documented metastatic sites, 50 imaged for a specificity of 50%. The number of sites imaged increased significantly as the amount of antibody administered increased relative to the average radiation dose. Considerable background uptake of isotope was observed in blood pool and other organs with gradual acquisition of label in tumor sites by 48 to 72 h. Hence, tumor imaging of melanoma using 111 In-labeled monoclonal antibody 96.5 appeared feasible, especially at antibody doses above 2 mg

The development of methods for obtaining monoclonal antibody-producing cells

Directory of Open Access Journals (Sweden)

Michał Skowicki

2016-04-01

Full Text Available Monoclonal antibodies (mAbs are biomolecules of great scientific and practical significance. In contrast to polyclonal antibodies from immune sera, they are homogeneous and monospecific, since they are produced by hybridoma cells representing a clone arising from a single cell. The successful technology was described for the first time in 1975; the inventors were later awarded the Nobel Prize. Currently, mAbs are broadly used as a research tool, in diagnostics and medicine in particular for the treatment of cancer or in transplantology. About 47 therapeutics based on monoclonal antibodies are now available in the US and Europe, and the number is still growing. Production of monoclonal antibodies is a multistage, time-consuming and costly process. Growing demand for these molecules creates space for research focused on improvements in hybridoma technology. Lower costs, human labor, and time are important goals of these attempts. In this article, a brief review of current methods and their advances is given.

A fully synthetic human Fab antibody library based on fixed VH/VL framework pairings with favorable biophysical properties

Science.gov (United States)

Tiller, Thomas; Schuster, Ingrid; Deppe, Dorothée; Siegers, Katja; Strohner, Ralf; Herrmann, Tanja; Berenguer, Marion; Poujol, Dominique; Stehle, Jennifer; Stark, Yvonne; Heßling, Martin; Daubert, Daniela; Felderer, Karin; Kaden, Stefan; Kölln, Johanna; Enzelberger, Markus; Urlinger, Stefanie

2013-01-01

This report describes the design, generation and testing of Ylanthia, a fully synthetic human Fab antibody library with 1.3E+11 clones. Ylanthia comprises 36 fixed immunoglobulin (Ig) variable heavy (VH)/variable light (VL) chain pairs, which cover a broad range of canonical complementarity-determining region (CDR) structures. The variable Ig heavy and Ig light (VH/VL) chain pairs were selected for biophysical characteristics favorable to manufacturing and development. The selection process included multiple parameters, e.g., assessment of protein expression yield, thermal stability and aggregation propensity in fragment antigen binding (Fab) and IgG1 formats, and relative Fab display rate on phage. The framework regions are fixed and the diversified CDRs were designed based on a systematic analysis of a large set of rearranged human antibody sequences. Care was taken to minimize the occurrence of potential posttranslational modification sites within the CDRs. Phage selection was performed against various antigens and unique antibodies with excellent biophysical properties were isolated. Our results confirm that quality can be built into an antibody library by prudent selection of unmodified, fully human VH/VL pairs as scaffolds. PMID:23571156

Effect of monoclonal antibodies on limited proteolysis of native glycoprotein gD of herpes simplex virus type 1

International Nuclear Information System (INIS)

Eisenberg, R.J.; Long, D.; Pereira, L.; Hampar, B.; Zweig, M.; Cohen, G.H.

1982-01-01

We examined the properties of 17 monoclonal antibodies to glycoprotein gD of herpes simplex type 1 (HSV-1) (gD-1) and HSV-2 (gD-2). The antibodies recognized eight separate determinants of gD, based on differences in radioimmuno-precipitation and neutralization assays. The determinants were distributed as follows: three were gD-1 specific, one was gD-2 specific, and four were type common. Several type-specific and type-common determinants appeared to be involved in neutralization. We developed a procedure for examining the effect that binding of monoclonal antibody has on proteolysis of native gD-1 by Staphylococcus aureus protease V8. We showed that several different patterns of protease V8 cleavage were obtained, depending on the monoclonal antibody used. The proteolysis patterns were generally consistent with the immunological groupings. With four groups of antibodies, we found that fragments of gD-1 remained bound to antibody after V8 treatment. A 38,000-dalton fragment remained bound to antibodies in three different groups of monoclonal antibodies. This fragment appeared to contain one type-common and two type-specific determinants. A 12,000-dalton fragment remained bound to antibodies belonging to one type-common group of monoclonal antibodies. Tryptic peptide analysis revealed that the 12,000-dalton fragment represented a portion of the 38,000-dalton fragment and was enriched in a type-common arginine tryptic peptide

Pharmacokinetics of internally labeled monoclonal antibodies as a gold standard: comparison of biodistribution of 75Se-, 111In-, and 125I-labeled monoclonal antibodies in osteogenic sarcoma xenografts in nude mice

International Nuclear Information System (INIS)

Koizumi, M.; Endo, K.; Watanabe, Y.; Saga, T.; Sakahara, H.; Konishi, J.; Yamamuro, T.; Toyama, S.

1989-01-01

In order to know the true biodistribution of anti-tumor monoclonal antibodies, three monoclonal antibodies (OST6, OST7, and OST15) against human osteosarcoma and control antibody were internally labeled with 75Se by incubating [75Se]methionine and hybridoma cells. 75Se-labeled monoclonal antibodies were evaluated both in vitro and in vivo using the human osteogenic sarcoma cell line KT005, and the results were compared with those of 125I- and 111In-labeled antibodies. 75Se-, 125I- and 111In-labeled monoclonal antibodies had identical binding activities to KT005 cells, and the immunoreactivity was in the decreasing order of OST6, OST7, and OST15. On the contrary, in vivo tumor uptake (% injected dose/g) of 75Se- and 125I-labeled antibodies assessed using nude mice bearing human osteosarcoma KT005 was in the order of OST7, OST6, and OST15. In the case of 111In, the order was OST6, OST7, and OST15. High liver uptake was similarly seen with 75Se- and 111In-labeled antibodies, whereas 125I-labeled antibodies showed the lowest tumor and liver uptake. These data indicate that tumor targeting of antibody conjugates are not always predictable from cell binding studies due to the difference of blood clearance of labeled antibodies. Furthermore, biodistribution of both 111In- and 125I-labeled antibodies are not identical with internally labeled antibody. Admitting that internally labeled antibody is a ''gold standard'' of biodistribution of monoclonal antibody, high liver uptake of 111In-radiolabeled antibodies may be inherent to antibodies. Little, if any, increase in tumor-to-normal tissue ratios of antibody conjugates will be expected compared to those of 111In-labeled antibodies if stably coupled conjugates are administered i.v

On-line immunoaffinity solid-phase extraction capillary electrophoresis mass spectrometry using Fab´antibody fragments for the analysis of serum transthyretin.

Science.gov (United States)

Pont, Laura; Benavente, Fernando; Barbosa, José; Sanz-Nebot, Victoria

2017-08-01

This paper describes an on-line immunoaffinity solid-phase extraction capillary electrophoresis mass spectrometry (IA-SPE-CE-MS) method using an immunoaffinity sorbent with Fab' antibody fragments (Fab'-IA) for the analysis of serum transthyretin (TTR), a homotetrameric protein (M r ~56,000) involved in different types of amyloidosis. The IA sorbent was prepared by covalent attachment of Fab' fragments obtained from a polyclonal IgG antibody against TTR to succinimidyl silica particles. The Fab'-IA-SPE-CE-MS methodology was first established analyzing TTR standard solutions. Under optimized conditions, repeatability and reproducibility were acceptable, the method was linear between 1 and 25µgmL -1 , limits of detection (LODs) were around 0.5µgmL -1 (50-fold lower than by CE-MS, ~25µgmL -1 ) and different TTR conformations were observed (folded and unfolded). The applicability of the developed method to screen for familial amyloidotic polyneuropathy type I (FAP-I), which is the most common hereditary systemic amyloidosis, was evaluated analyzing serum samples from healthy controls and FAP-I patients. For the analysis of sera, the most abundant proteins were precipitated with 5% (v/v) of phenol before Fab'-IA-SPE-CE-MS. The current method enhanced our previous results for the analysis of TTR using intact antibodies immobilized on magnetic beads. It allowed a slight improvement on LODs (2-fold), the detection of proteoforms found at lower concentrations and the preparation of microcartridges with extended durability. Copyright © 2017. Published by Elsevier B.V.

A novel engineered interchain disulfide bond in the constant region enhances the thermostability of adalimumab Fab.

Science.gov (United States)

Nakamura, Hitomi; Oda-Ueda, Naoko; Ueda, Tadashi; Ohkuri, Takatoshi

2018-01-01

We constructed a system for expressing the Fab of the therapeutic human monoclonal antibody adalimumab at a yield of 20 mg/L in the methylotrophic yeast Pichia pastoris. To examine the contribution of interchain disulfide bonds to conformational stability, we prepared adalimumab Fab from which the interchain disulfide bond at the C-terminal region at both the CH 1 and CL domains was deleted by substitution of Cys with Ala (Fab ΔSS ). DSC measurements showed that the Tm values of Fab ΔSS were approximately 5 °C lower than those of wild-type Fab, suggesting that the interchain disulfide bond contributes to conformational thermostability. Using computer simulations, we designed a novel interchain disulfide bond outside the C-terminal region to increase the stability of Fab ΔSS . The resulting Fab (mutSS Fab ΔSS ) had the mutations H:V177C and L:Q160C in Fab ΔSS , confirming the formation of the disulfide bond between CH 1 and CL. The thermostability of mutSS Fab ΔSS was approximately 5 °C higher than that of Fab ΔSS . Therefore, the introduction of the designed interchain disulfide bond enhanced the thermostability of Fab ΔSS and mitigated the destabilization caused by partial reduction of the interchain disulfide bond at the C-terminal region, which occurs in site-specific modification such as PEGylation. Copyright © 2017 Elsevier Inc. All rights reserved.

Localisation of metastatic carcinoma by a radiolabelled monoclonal antibody

Energy Technology Data Exchange (ETDEWEB)

Smedley, H M; Ritson, A; Wraight, P; Sikora, K [Addenbrooke' s Hospital, Cambridge (UK); Hinchingbrooke Hospital, Huntingdon (UK)); Finan, P [St. James Hospital, Leeds (UK); Lennox, E S; Takei, F [Medical Research Council, Cambridge (UK)

1983-02-01

Rat monoclonal antibodies were prepared by immunising rats with human colorectal carcinoma cell membranes and fusing splenic lymphocytes with a rat myeloma. Hybridoma supernatants were screened by binding assays on membranes prepared from colorectal carcinoma tissue. One hybridoma supernatant, containing a monoclonal antibody with high binding activity on malignant compared to normal colon sections, was grown in large quantities in serum-free medium. After ammonium sulphate precipitation the antibody was purified by ion-exchange chromatography and labelled with /sup 131/I. Radiolabelled antibody was administered i.v. to 27 patients with colonic and other tumours. Scintigrams were obtained at 48 h. Computerised subtraction of the blood pool image revealed localised areas of uptake corresponding with areas of known disease in 13/16 patients with colorectal carcinoma and 3/4 patients with breast cancer.

Effect of bovine pellucid zone 3 monoclonal antibodies on B cell lymphoma 2 expressions of granulosa cell and mice (Mus musculus follicle diameter

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Heti Ira Ayue

2017-01-01

Full Text Available Objective: To evaluate the effects of pellucid zone 3 monoclonal antibodies against B-cell lymphoma 2 (BCL-2 expression and mice follicle diameter at various time periods.Methods: The animal model of this study was 36 Balb/c mice (Mus musculus. A true experimental design was used with a post-test only control group approach. BCL-2 expression was observed using immunohistochemistry, while the follicle diameter was observed by haematoxylin-eosin staining. The data was analyzed using nested ANOVA to compare the results of the mean expression of BCL-2 on the 5th and 20th day of observation in the pre-antral and antral follicle between the control and treatment groups.Results: No significant differences were found in BCL-2 gene expression. There were also no significant differences in BCL-2 expression on the 10th day of pre-antral follicle analysis. Moreover, there were no significant differences between the mean follicle diameter on the 5th, 10th, and 20th day of pre-antral and antral follicle development between the control and treatment groups. The addition of bovine pellucid zone 3 (bZP3 monoclonal antibodies on the 5th and 20th day of observation did not decrease the expression of BCL-2 gene in the pre-antral and antral follicle of mice. Administering bZP3 monoclonal antibodies on the 10th day of observation did not affect BCL-2 expression in the pre-antral follicle but did decrease BCL-2 expression in the antral follicle. Supplying bZP3 monoclonal antibodies on the 5th, 10th and 20th day did not affect the diameter of pre-antral and antral follicles of the mice.Conclusion: The monoclonal antibodies bovine zona pelusida 3 has the potential to be developed as a safe immunocontraception preparation.

Improving food and agricultural production. Thailand. Application on monoclonal antibodies for progesterone measurement

International Nuclear Information System (INIS)

Butcher, G.W.

1991-01-01

The duties of the mission were to provide instructions on the maintenance of hybridoma cell lines and their culture and the harvesting of monoclonal antibodies; to assist the counterparts in Thailand to develop work plans for the use of monoclonal antibodies in radioimmunoassay measurements of progesterone; and to assess the need for and feasibility of establishing a laboratory for producing monoclonal antibodies directed against progesterone. The report contains a summary of the activities performed in fulfillment of these duties

Isolation of highly active monoclonal antibodies against multiresistant gram-positive bacteria.

Directory of Open Access Journals (Sweden)

Friederike S Rossmann

Full Text Available Multiresistant nosocomial pathogens often cause life-threatening infections that are sometimes untreatable with currently available antibiotics. Staphylococci and enterococci are the predominant Gram-positive species associated with hospital-acquired infections. These infections often lead to extended hospital stay and excess mortality. In this study, a panel of fully human monoclonal antibodies was isolated from a healthy individual by selection of B-cells producing antibodies with high opsonic killing against E. faecalis 12030. Variable domains (VH and VL of these immunoglobulin genes were amplified by PCR and cloned into an eukaryotic expression vector containing the constant domains of a human IgG1 molecule and the human lambda constant domain. These constructs were transfected into CHO cells and culture supernatants were collected and tested by opsonophagocytic assay against E. faecalis and S. aureus strains (including MRSA. At concentrations of 600 pg/ml, opsonic killing was between 40% and 70% against all strains tested. Monoclonal antibodies were also evaluated in a mouse sepsis model (using S. aureus LAC and E. faecium, a mouse peritonitis model (using S. aureus Newman and LAC and a rat endocarditis model (using E. faecalis 12030 and were shown to provide protection in all models at a concentration of 4 μg/kg per animal. Here we present a method to produce fully human IgG1 monoclonal antibodies that are opsonic in vitro and protective in vivo against several multiresistant Gram-positive bacteria. The monoclonal antibodies presented in this study are significantly more effective compared to another monoclonal antibody currently in clinical trials.

Therapeutic IgG4 antibodies engage in Fab-arm exchange with endogenous human IgG4 in vivo

NARCIS (Netherlands)

Labrijn, Aran F.; Buijsse, Antonio Ortiz; van den Bremer, Ewald T. J.; Verwilligen, Annemiek Y. W.; Bleeker, Wim K.; Thorpe, Susan J.; Killestein, Joep; Polman, Chris H.; Aalberse, Rob C.; Schuurman, Janine; van de Winkel, Jan G. J.; Parren, Paul W. H. I.

Two humanized IgG4 antibodies, natalizumab and gemtuzumab, are approved for human use, and several others, like TGN1412, are or have been in clinical development. Although IgG4 antibodies can dynamically exchange half-molecules(1), Fab-arm exchange with therapeutic antibodies has not been

Therapeutic IgG4 antibodies engage in Fab-arm exchange with endogenous human IgG4 in vivo

NARCIS (Netherlands)

Labrijn, Aran F.; Buijsse, Antonio Ortiz; van den Bremer, Ewald T. J.; Verwilligen, Annemiek Y. W.; Bleeker, Wim K.; Thorpe, Susan J.; Killestein, Joep; Polman, Chris H.; Aalberse, Rob C.; Schuurman, Janine; van de Winkel, Jan G. J.; Parren, Paul W. H. I.

2009-01-01

Two humanized IgG4 antibodies, natalizumab and gemtuzumab, are approved for human use, and several others, like TGN1412, are or have been in clinical development. Although IgG4 antibodies can dynamically exchange half-molecules, Fab-arm exchange with therapeutic antibodies has not been demonstrated

Sequences of 12 monoclonal anti-dinitrophenyl spin-label antibodies for NMR studies

International Nuclear Information System (INIS)

Leahy, D.J.; Rule, G.S.; Whittaker, M.M.; McConnell, H.M.

1988-01-01

Eleven monoclonal antibodies specific for a spin-labeled dinitrophenyl hapten (DNP-SL) have been produces for use in NMR studies. They have been named AN01 and ANO3-AN12. The stability constants for the association of these antibodies with DNP-SL and related haptens were measured by fluorescence quenching. cDNA clones coding for the heavy and light chains of each antibody and of an additional anti-DNP-SL monoclonal antibody, ANO2, have been isolated. The nucleic acid sequence of the 5' end of each clone has been determined, and the amino acid sequence of the variable regions of each antibody has been deduced from the cDNA sequence. The sequences are relatively heterogeneous, but both the heavy and the light chains of ANO1 and ANO3 are derived from the same variable-region gene families as those of the ANO2 antibody. ANO7 has a heavy chain that is related to that of ANO2, and ANO9 has a related light chain. ANO5 and ANO6 are unrelated to ANO2 but share virtually identical heavy and light chains. Preliminary NMR difference spectra comparing related antibodies show that sequence-specific assignment of resonances is possible. Such spectra also provide a measure of structural relatedness

Multicompartmental analysis of the kinetics of monoclonal antibody in cancer patients

International Nuclear Information System (INIS)

Koizumi, K.; De Nardo, G.L.; De Nardo, S.J.; Peng, J.S.; Macey, D.J.; Hisada, K.; Tonami, N.

1985-01-01

Multicompartmental models were applied for analysis of kinetics of iodide labeled monoclonal antibody in cancer patients. About 14 compartments such as intravascular antibody pool, interstitial antibody pool, antibody processors, tumor antigen site, intravascular immune complex pool, intravascular iodide pool, and urine iodide pool were assumed. This model accounts for three molecular species, the antibody, and antibody complex, and free iodide or iodinated peptides. Patients were injected with I-123-Lym-1 IgG2a (anti B cell lymphoma antibody). After injection, blood and urine samples were sequentially collected. Plasma and urine were separated by HPLC into fractions of intact antibody, immune complex, and free iodide. This information was used for input data in the theoretical model. SAAM computer program was used to solve these compartmental models. Published linear rate constants for human serum albumin and human non-immune IgG were initially used. However, data calculated from the model differed from observed curves in several respects. The kinetics of mouse monoclonal antibody, a foreign protein in a patient, were significantly different from those reported for human IgG. When a nonlinear, saturable hepatic processor was incorporated in the model, calculated data fit the observed data better. This kinetic model provides a basis for calculating radiation doses for radioiodinated antibodies