Biomedical subjects

A Marshak-Rothstein

Publications and source records attributed to A Marshak-Rothstein.

76 records · Page 5Linked to original sources

PubMed1980

Hybridoma proteins expressing the predominant idiotype of the antiazophenylarsonate response of A/J mice.

Hybridoma cell lines that secrete monoclonal antiazophenylarsonate antibodies were isolated from the fusion of A/J splenic lymphocytes with a myeloma cell line. A small percentage of these hybridoma proteins were recognized by rabbit antisera that detect the crossreactive idiotype characteristics of the antiazophenylarsonate response of A/J mice. The isotype, pI value, and amino-terminal sequences of four independently derived idiotype-positive hybridoma proteins were determined. These proteins were either of the IgG1 or IgG2a heavy chain class. For two mice tested, the majority of the idiotype in the immune serum was shown to be of the same isotype as the fusion-derived monoclonal antibodies. The pI values of the hybridoma proteins differed from one another and ranged from 6.9 to 7.6. Amino acid sequences of the heavy chains showed a significant degree of homology with each other, but each chain was unique in the framework or the first complementarity determining region (or both). A comparable pattern of sequence variation was evident for the light chains. The azophenylarsonate idiotype, therefore, appears to consist of a family of nonidentical but closely related molecules that are the product of more than one germline gene or the result of somatic mutation of a single germline gene.

Amino Acid Sequence↗

PubMed1980

Unique determinants associated with hybridoma proteins expressing a cross-reactive idiotype: frequency among individual immune sera.

It is possible to prepare antisera that recognize individual members of a family of hybridoma proteins in which all members of the family express the cross-reactive idiotype (IdCR) characteristic of the A/J anti-Ars response. These hybridoma-specific reagents also recognize a small percentage of the IdCR+ anti-Ars antibodies, which constitute the normal A/J anti-Ars response. Thus, the previously reported sequence heterogeneity of our IdCR+ hybridoma proteins actually represents components of the normal A/J anti-Ars response. Determinants associated with one particular IdCR+ hybridoma protein, 36-71 (Id36-71), were found on approximately 0.01 to 5.0% of the IdCR+ antibodies in all of the A/J hyperimmune sera that were examined. Determinants associated with 2 other IdCR+ hybridoma proteins, 16-46-4-8 (Id16-46) and 44-10 (Id44-10) were also found in almost all A/J immune sera, again at various concentrations. These results indicate that the heritable trait (IdCR) is expressed as a large number of antibody sequences that probably arise from the somatic diversification of a limited number of germ line genes. The pattern of diversification is qualitatively similar among individual mice but varies with regard to the relative proportions of the individual antibody components.

Animals↗

PubMed1979

Properties and applications of monoclonal antibodies directed against determinants of the Thy-1 locus.

Fusion of cells of the mouse myeloma line, P3/X63-Ag8 with spleen cells from AKR/J mice immunized against C3H thymocytes or from (BALB/c x BALB.K)F1 mice immunized against AKR/J thymocytes gave rise to hybrid cell lines that continuously secrete antibodies specific for the Thy-1.2 and Thy-1.1 antigens, respectively. Monoclonal antibodies from four such cell lines were analyzed in detail. All were 19S IgM, and, in the presence of complement (C), had high lytic titers on T cells of the appropriate antigenicity. Their specificity was shown by lysis of thymocytes from Thy-1 congenic mouse strains, A/J(Thy-1.2) and A. Thy 1.1. Furthermore, they lyse only 60 to 70% of lymph node cells, suggesting cytotoxicity for mature T cells and not B cells. Treatment of peripheral lymphocyte populations with monoclonal antibody plus C eliminated effector cytotoxic T lymphocytes, their precursors, and the mitogenic response to Con A, but did not affect the response to LPS. Purified, fluorescein-labeled monoclonal anti-Thy-1 antibody could be used to distinguish T and B cells. Purified antibody coupled to Sepharose 6MB was used to separate viable T and B cells. Two independently isolated anti-Thy-1.2 hybridomas are indistinguishable and bind the same determinant whereas a third is unique and may bind a separate site.

Animals↗

PubMedDate not supplied

The role of clonal selection and somatic mutation in autoimmunity.

Polyclonal activation has been proposed as the reason that autoantibodies are produced during autoimmune disease. This model denies a role for specific antigen selection of B cells and predicts instead a multiclonal population of unmutated or randomly mutated autoantibodies. We have found that the genetic features and clonal composition of spontaneously derived immunoglobulin G (IgG) antiself-IgG (rheumatoid factor (RF] autoantibodies derived from the autoimmune MRL/lpr mouse strain are inconsistent with both the predictions of this model and the actual outcome of experimental polyclonal activation. Instead we have found that MRL/lpr RFs are oligoclonal or even monoclonal in origin. They harbour numerous somatic mutations which are distributed in a way that suggests immunoglobulin-receptor-dependent selection of these mutations. In this sense, the MRL/lpr RFs resemble antibodies elicited by exogenous antigens after secondary immunization. The parallels suggest that, like secondary immune responses, antigen stimulation is important in the generation of MRL/lpr RFs.

Amino Acid Sequence↗