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Biomedical subjects

C S David

Publications and source records attributed to C S David.

341 records · Page 19Linked to original sources
PubMed1973

New lymphocyte antigen system (Lna) controlled by the Ir region of the mouse H-2 complex.

A new system of lymphocyte alloantigens in mice is described. This Lna (lymph-node antigen) system is associated with the Ir region of the H-2 (histocompatibility-2) gene complex. It has the following distinctive characteristics: (1) The gene or genes controlling these antigens has been mapped in the Ir (immune response) region between H-2K and Ss-Slp. (2) The antigens are most readily detectable on lymph-node cells, although they are also expressed on peripheral blood lymphocytes, splenic lymphocytes, and thymocytes. (3) Cytotoxicity against only about half of lymph-node cells is consistently observed. (4) Cytotoxic antibody titers against these antigens are strikingly high-more than 2000 by (51)Cr-release and up to 100,000 in the microcytotoxic test. (5) At least two, probably allelic, forms of the antigen(s) have been defined, one associated with the H-2(k) haplotype and one with the H-2(a) haplotype. (6) Antisera against Lna contain multiple antibody specificities that can be fractionated by absorption either with certain recombinants or with other H-2 halotypes that have crossreactive antigens. The antisera against Lna may be of value for definition and characterization of the products of the Ir and MLR (mixed lymphocyte reaction stimulatory) genes associated with the H-2 complex.

Age Factors↗
PubMed1972

Characterization of chicken b-locus (IgG) allotypes.

Chicken allotypes b1 and b2 are controlled by allelic genes and associated with the IgG class of immunoglobulins. The determinants cannot be detected on either isolated heavy and light polypeptide chains or the enzymatic fragments. The results suggest that either the intact IgG molecule is required for their expression or the conditions normally used for isolation of the subunits destroy or modify the antigenic specificities in chickens.

Animals↗
PubMedDate not supplied

Transcriptional control of MHC class II antigen expression on mouse T cell lines.

We have analysed the factors which regulate MHC class II expression in mouse T cell lines. Two such lines, BW 5147 and PLT-24.2, were used in this study. Using 5-azacytidine (5 AzaC) we have shown that hypomethylation of DNA can induce class II antigen synthesis in BW 5147. The expression of class II in PLT-24.2 cells seems to be under a different control mechanism. Southern blot analysis of I-A beta gene in PLT-24.2 suggests that the expression of class II in this cell line is probably the outcome of a gene rearrangement. We hypothesise that insertion of viral long terminal repeats (LTR) next to the class II genes in transformed T cell lines can act as a promoter for the expression of class II antigens.

Animals↗
PubMedDate not supplied

Expression of I-A alpha k and allelic restriction on A alpha/A beta pairing in transgenic mice.

Cell surface expression of class 11 major histocompatibility complex encoded (1a) molecules depends on association of the component alpha and beta chain into a stable heterodimer. Studies on cell lines transfected with MHC class II genes have revealed important limitations on the assembly of haplotype-mismatched A alpha:A beta complex. In order to study alpha:beta chain pairing restrictions in vivo a number of lines of transgenic mice carrying the A alpha k gene were generated. The transgene was studied in the context of H-2b, H-2s, H-2q, H-2u, H-2f and H-2v haplotypes. Initial FACS analysis of spleen and peripheral blood cells showed no A alpha kappa expression. Spleen cells stimulated with LPS and analysed by FACS showed A alpha k expression in three different H-2b strains as well as H-2u, but not in others. These data indicate that A alpha k can associate with A beta b and A alpha k, but not with A beta s, A beta q, A beta f, A beta v.

Alleles↗
PubMedDate not supplied

Immunogenetics of collagen induced arthritis in mice: a model for human polyarthritis.

Collagen induced arthritis is an experimental animal model of inflammatory polyarthropathy that has many features of human rheumatoid arthritis. Type II collagen is the major matrix protein of hyaline cartilage and is a sequestered protein which can be presented as an autoantigen under certain conditions. To induce CIA, type II collagen is injected intradermally with complete Freund's adjuvant. Susceptibility to CIA is dependent on the presence of the trimolecular complex: 1) the arthritogenic epitope on the type II collagen; 2) a class II MHC molecule on the accessory cell presenting the arthritogenic epitope; and 3) T cells expressing specific V beta chains in their TCRs. Complement and other non-MHC background genes also may play a role in susceptibility to CIA. Both cell mediated and humoral immunity are involved in the pathogenesis of CIA. To date immunotherapies that have modulated CIA include use of anti-class Ii antibodies, anti-lymphokines, and monoclonal antibodies directed against specific cellular markers. All of these therapies are able to modulate disease to some extent but lack the specificity and efficacy to make them practical for widespread use in human disease. Most promising, is the use of monoclonal antibodies directed against specific V beta TCR subsets. This is potentially a very specific and effective therapy because it will affect only the cells involved in disease while leaving the host otherwise immunocompetent. Therapies on the horizon include the use of synthetic peptides with sequences homologous to various regions on the TCR, immunotoxins, and superantigens to modulate the immune response and ameliorate disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗