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Biomedical subjects

K Hariharan

Publications and source records attributed to K Hariharan.

31 records · Page 2Linked to original sources
PubMed1993

Analysis of the cross-reactive anti-gp120 antibody population in human immunodeficiency virus-infected asymptomatic individuals.

This study was undertaken to analyze the specificity and neutralizing properties of cross-reactive anti-gp120 antibodies (Abs) in the sera of two human immunodeficiency virus (HIV)-infected asymptomatic individuals. Two panels of murine monoclonal anti-idiotype Abs (anti-id MAbs) were established against cross-reactive polyclonal anti-gp120 Abs purified from HIV+ sera by sequential affinity chromatography using gp120SF2- and gp120IIIB-Sepharose columns. These panels of anti-id MAbs were then used to affinity purify idiotype-positive (Id+) anti-gp120 Abs from HIV+ sera. The recovery of each of these Id+ Abs by purification indicated that several idiotypically distinct cross-reactive anti-gp120 Abs are present in sera over a wide range of concentrations. Immunological and biological studies showed that although all of the Id+ Abs were reactive against gp120SF2 and gp120IIIB, they exhibited unique epitope specificities and distinct neutralizing activities. Most of the Id+ Abs were directed against epitopes in the CD4 attachment site (CD4 site epitopes) of gp120 and exhibited a spectrum of broadly neutralizing activities. On the other hand, a minor population of Id+ Abs showed specificity for the V3 region of gp120 and exhibited limited cross-neutralizing activities. Together, these studies indicate that the CD4 site epitope-specific Abs are heterogeneous with respect to their clonality, neutralizing activity, and concentration in sera. This heterogeneity suggests that anti-gp120 Abs to the CD4 attachment site are developed in response to multiple overlapping epitopes present on the original virus isolate and/or epitopes on mutated variants which emerged over time.

Amino Acid Sequence↗
PubMed1991

Bovine monoclonal anti-idiotypes induce antibodies specific for a synthetic peptide bearing a neutralizing epitope of bovine herpesvirus 1 glycoprotein gI (gB).

Bovine monoclonal anti-Id mimicking a neutralizing epitope of bovine herpesvirus-1 (BHV-1) glycoprotein gI were developed. An epitope present on the 74K subunit of gI identified by a murine mAb 1E11 was selected for this study. Bovine lymphocytes from the prefemoral lymph node of a heifer immunized with mAb 1E11 were fused with SP-2/0, a nonsecreting murine cell-line. Two bovine x murine hybridomas secreting bovine monoclonal anti-Id specific for the Id of 1E11 were stabilized. These anti-Id inhibited the binding of 1E11 to purified glycoprotein gI in a dose-dependent fashion. Naive mice immunized with the anti-Id produced anti-anti-Id (Ab3) that reacted with BHV-1 glycoprotein gI in a RIA, and neutralized BHV-1 infection in vitro. The Ab3 also showed reactivity to the 74K subunit of authentic gI glycoprotein in a Western blot analysis, and to the synthetic peptide bearing the 1E11 epitope in a RIA. These results substantiate the presence of the population of anti-Ab2 that functionally resemble antibodies specific for the immunizing Ag BHV-1 in Ab3, and demonstrate the ability of these anti-Id to elicit BHV-1-specific antibody response.

Animals↗
PubMed1991

Quantitation of bovine immunoglobulins in culture fluids by use of sandwich radioimmunoassay with monoclonal antibodies.

Bovine immunoglobulin isotype-specific murine monoclonal antibodies were used in sandwich radioimmunoassays to detect and quantitate bovine IgG1, IgG2, IgM, and IgA in culture fluids. The concentrations of bovine immunoglobulins in unknown samples were extrapolated from standard curves generated with bovine monoclonal immunoglobulins. The lowest detection limits for the bovine immunoglobulin isotypes ranged from 65 to 270 ng/ml.

Animals↗
PubMed1989

Induction of neutralizing antibodies to transmissible gastroenteritis virus by anti-idiotypic antibodies.

The potential of anti-idiotypic antibodies (anti-ids) as immunogens against transmissible gastroenteritis virus (TGEV) was tested in a heterologous system. A month-old pig was immunized with a neutralizing murine monoclonal antibody (MAb, 5A5) of the IgG2a isotype, specific for the E2 glycoprotein of TGEV. The anti-ids were isolated from the serum of the immunized pig by affinity chromatography, initially on a 5A5-Sepharose column, followed by repeated adsorption on a mouse IgG2a column. The swine anti-ids thus obtained bound to the MAb 5A5 (the idiotype), but not to MAbs of the same isotype IgG2a but of different idiotypes. The anti-ids also inhibited the binding of 5A5 to TGEV in a concentration-dependent manner. Mice immunized with the anti-ids produced antibodies to TGEV. These antibodies, neutralized TGEV in vitro and inhibited the binding of 5A5 to TGEV.

Animals↗
PubMed1984

Occurrence of a Lysogenic Streptomyces sp. on the Nodule Surface of Black Gram (Vigna mungo (L.) Hepper).

A lysogenic Streptomyces sp., strain NS.A4, which was isolated from the nodule surface of black gram (Vigna mungo (L.) Hepper), was found to inhibit rhizobia of fast-and slow-growing strains of cowpeas and soybeans. It exhibited plaques when there was a change in cultural conditions. Repeated culturing of the organism in nutrient agar and broth confirmed the infection of Streptomyces sp. strain NS.A4 by an actinophage. Addition of the culture filtrate of Streptomyces sp. strain NS.A4 to shaken broth cultures of three other Streptomyces spp. resulted in phage infection.

Journal Article↗
PubMed1969

A study of the metabolism of L-alpha gamma-diaminobutyric acid in a Xanthomonas species.

1. l-alphagamma-Diaminobutyric acid is metabolized in Xanthomonas sp. to aspartic beta-semialdehyde, aspartic acid and oxaloacetic acid. 2. Aspartic beta-semialdehyde is formed from diaminobutyric acid by a pyruvate-dependent gamma-transamination. 3. The transaminase has a pH optimum of 9 and exhibits a high degree of substrate specificity, as analogues of diaminobutyric acid and pyruvate are inert in the system. The transaminase is inhibited by carbonyl-binding agents such as hydroxylamine. 4. Aspartic acid is formed from aspartic beta-semialdehyde by an NAD(+)-dependent dehydrogenation. 5. The dehydrogenase has a pH optimum of 8.5 and is a thiol enzyme. It is specific for aspartic beta-semialdehyde but analogues of NAD(+) such as 3-acetylpyridine-adenine dinucleotide and deamino-NAD are partly active in the system. 6. The significance of these reactions is discussed in relation to diaminobutyric acid metabolism in plants and mammalian systems.

Aminobutyrates↗
PubMed1965

Histidine metabolism in experimental protein malnutrition in rats.

1. The activities of the enzymes histidase, urocanase and histidine-pyruvate transaminase were studied in rats under conditions of protein malnutrition. Urocanase and histidase activities in liver were markedly lowered in experimental protein malnutrition, but the activity of histidine-pyruvate transaminase was unaffected. There is a metabolic control in vivo of the enzymes involved in the catabolism of histidine. 2. Significant changes in the urinary excretion of histidine, composition of liver and serum were apparent in the protein-malnourished rat. 3. The changes in the activities of the enzymes and other parameters were of a reversible nature and dependent on the nature of the dietary protein. 4. The significance of these findings is discussed in relation to abnormal histidine metabolism in kwashiorkor.

Journal Article↗