ABSTRACT
Studies of superantigens (SAg) have focused primarily on their impact on CD4+ T cells, largely bypassing the impact of the sequelae of this interaction upon the antigen-presenting cell (APC). Sequelae of SAg-induced CD4+ T-cell activation include the 'bathing' of the SAg-presenting cell with cytokines that promote the differentiation of the APC. In this report, the SAg-induced differentiation of Mls+ DBA/2J B cells was studied in vivo by their transplantation into B-cell-defective BALB.xid recipients. Rapid, high-level serum immunoglobulin M (IgM) production was noted shortly after transfer, disappearing by 3 weeks. Donor B cells, as evidenced after their chemical and genetic impairment and by the use of an IgM allotype-disparate donor-recipient combination, contributed to this transient IgM production. These results clarify a discrepancy in the literature regarding donor B-cell contribution to IgM production and illustrate a model system to utilize SAg to study B-lymphocyte diversity.
Subject(s)
Adoptive Transfer , B-Lymphocytes/immunology , Immunoglobulin M/blood , Animals , B-Lymphocytes/drug effects , Enzyme-Linked Immunosorbent Assay , Female , Flow Cytometry , Lymphocyte Culture Test, Mixed , Male , Mice , Mice, Inbred BALB C , Mice, Inbred DBA , Mice, SCID , Mitomycin/pharmacology , Superantigens/pharmacologyABSTRACT
B-cell heterogeneity studies have historically focused upon BALB/c mice and their derivatives. In contrast, the B cells of DBA/2J mice, a prototype strain for the study of the endogenous minor lymphocyte stimulatory (Mls) viral superantigen Mls-1a, have not been extensively investigated. DBA/2J B cells, by functioning as Mls-1a antigen-presenting cells, influence their own differentiation and diversity by inducing the proliferation and differentiation of specific CD4 T-cell subsets. In this report, the B cells of DBA/2J and BALB/c mice were compared for their ability to restore B-cell function in severe combined immunodeficient (SCID) recipients. Although spleen and bone marrow cells from these strains exhibited similar restoration of serum IgM production, the transfer of DBA/2J B cells into SCID mice led to greater IgG1 production. The peritoneal cells of DBA/2J mice consisted of a lower percentage of B-1 B cells and were less capable of restoring B-cell function after transfer into SCID recipients. These differences are discussed with respect to the possible role of viral superantigens in influencing B-lymphocyte diversity.
