• G P Talwar

      Articles written in Journal of Biosciences

    • Properties and characteristics of an anti-human chorionic gonadotropin monoclonal antibody

      S K Gupta S Ramakrishnan G P Talwar

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      The product of a hybrid cell clone, P3W80, obtained as ascites fluid from mouse peritoneal cavity had high titres of anti-human chorionic gonadotropin antibodies e.g. 30 to 40% binding of125I-human chorionic gonadotropin at 107 dilution in a radioimmunoassay. The antiserum SB6 (raised against Β-human chorionic gonadotropin distributed by National Institutes of Health, USA gave similar binding at 5000 dilution in parallel runs. The monoclonal antibody recognized best human chorionic gonadotropin (0.3 mlU of hormone/tube withB/B0 75%), but also bound Β and a subunits of human chorionic gonadotropin, 12 and 800 folds lower than human chorionic gonadotropin respectively No binding was observed with carboxy terminal peptides of Β-human chorionic gonadotropin ranging from 93 to 145 amino acid residues, indicating the lack of recognition of the C-terminal region. No cross-reaction with human leutinizing hormone was obtained at the physiological surge levels, a significant competition (B/B075 %. obtainable only at 60 mlU of LER 960 human leutinizing hormone/ tube. The antibody had heavy chain of IgG1 and light chain of kappa type. It neutralized the bio-activity of human chorionic gonadotropin bothin vitro and invivo.

    • Diversity of antigenic determinants of porcine zona pellucida revealed by monoclonal antibodies

      A K Bamezai A Bhattacharya A H Band Suman G P Talwar

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      Monoclonal antibodies derived from ten hybrid cell clones, generated against porcine zona pellucida gave strong immunofluorescence with zona but the pattern varied from patchy, thin rim to heavy precipitation type of rim. Five of the 6 monoclonals studied prevented the binding of the porcine epididymal sperm to homologous oocytesin vitro, whereas the sixth one was partially effective. All of the 6 monoclonale of this batch inhibited the lysis of zonae by proteolytic enzymes even at dilutions up to 1 × 10−3. Three of the four monoclonals prepared in a subsequent batch gave strong immunofluorescent reactions and had high titres as determined by enzyme immunoassay. These monoclonals did not, however, protect the zonae against lysis by proteolytic enzymes. These properties are suggestive of the heterogeneity of the antigenic determinants in zona and emphasize the employment of appropriate bioassays for screening and selection of bioeffective antibodies.

    • Cloning of Y derived DNA sequences of bovine origin inEscherichia coli

      Pramod Khandekar G P Talwar Renu Chaudhury

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      We have constructed a partial library of Y chromosome derived DNA sequences of bovine origin inEscherichia coli. That, the recombinants arc Y derived and Y specific was ascertained by differential colony hybridization using male and female DNA probes. Out of 1000 recombinants analysed, 17 were found to be Y derived as well as Y specific and were of repetitive nature. Restriction analysis revealed that most of them had short DNA inserts.

    • Isolation and characterization of cDNA clones for α- and β-subunits of ovine luteinizing hormone

      Swatantra K Jain William W Chin G P Talwar

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      A cDNA library of ovine pituitary DNA in plasmid pBR322 has been constructed by conventional methods with certain modifications. The library was screened using partial cDNAs for ratα-subunit and LHβ. We have isolated cDNA clones for ovineα-subunit and LHβ. The identification of these clones was confirmed by partial sequencing. The clones bear about 80% sequence homology with the respective rat cDNAs in the sequenced regions and hybridize with the rat clones in 5 X SSC at 55°C. The ovine LHβ clone has an insert of about 650 bp and selects an RNA of about 750 bases in a northern blot. The α-subunit cDNA clone has an insert of about 550 bp; it has two internalPst I sites and thus shows restriction-based differences from ratα-subunit cDNA, which does not have anyPst I site.

    • A destiny to fulfill

      G P Talwar

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    • A partner monoclonal antibody to Moab 730 kills 100% of DU145 and PC3 androgen-independent cancer cells

      Hemant Kumar Vyas Rahul Pal Nirmal K Lohiya G P Talwar

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      A number of therapeutic options are available for patients with prostate carcinoma till the time that the tumour is hormone dependent. However, no fully effective therapy is available for the treatment of androgen-independent prostate carcinomas. Antibodies directed at epitopes unique to or overexpressed on the cancer cells could be of therapeutic utility. A monoclonal antibody (Moab) 2C4 has been generated, which binds with cells of two androgenindependent prostate cancers, DU145 and PC3, and does not bind to peripheral blood leukocytes (PBLs) of healthy donors. This antibody, along with the previously developed Moab 730, kills 100% of both DU145 and PC3 cells in the presence of complement and does not have a deleterious effect on PBLs of healthy males. The anti-tumour action of the two antibodies prevents the establishment of DU145 cell tumour in nude mice in vivo. Moab 2C4 in combination with 730 has potential for use as therapy for androgen-independent cancers.

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