Distribution of lymphocytes identified by surface markers in murine strains with systemic lupus erythematosus-like syndromes

The frequencies and absolute numbers of B and T cells in the lymphoid organs of five murine strains (NZB, (NZB X NZW)F1, BXSB, MRL/l, and MRL/n) with SLE-like syndromes were examined. We assessed the frequencies of cells bearing surface Ig, C3d and IgG Fc receptors, and theta-antigen. The sequential expression of Ig isotopes on developing B cells and the Ig isotypes expressed on adult B cells were ascertained. In addition, the Ly subsets and the expression of Ia antigens coded for by the I-J subregion of the mouse H-2 complex were examined. Compared to normal, older mice, New Zealand mice had low frequencies and absolute numbers of B cells, BXSB mice had a moderate B-cell proliferation, and MRL/l mice had normal absolute numbers of B cells but a reduced frequency concomitant with a massive T-cell proliferation. Old New Zealand mice and BXSB mice had reduced frequencies and absolute numbers of T cells compared to old controls. The developmental Ig-isotype diversity during the 1st wk of age was similar in normal mice and those with autoimmune manifestations. Mature B cells were present in lymphoid organs of New Zealand mice and BXSB mice as evidenced by the high frequency of C3d receptor-bearing cells and Ig-isotype expression (high ratio of IgM- to IgD-bearing cells) in adult spleen cells. Numbers of IgG Fc receptor-bearing cells were reduced in autoimmune mice with advanced age and disease. The proliferating T cells in MRL/l mice were found to be theta-antigen positive but Ly null. These theta+-, Ly null cells may have arisen from Ly123+ T cells. MRL/l and BXSB mice seemed normal in their content of T cells bearing Ia antigens coded for by the I-J subregion of H-2. Overall, mice with autoimmune manifestations appear to express perturbations in T and B cells with development of disease, and their patterns of change vary from one strain to another.