The Lyb-3+5+ subset of B cells is not required for lupus-like autoantibody formation caused by graft-vs-host reaction.

We asked the question whether or not the Lyb-3+5+ B cell subset, which is lacking in CBA/N immune defective mice, is required for the lupus-like autoantibody formation caused by graft-vs-host reaction (GVHR). (CBA/N X DBA/2)F1 male defective mice injected with DBA/2 T cells produced IgG autoantibodies to the same extent as did nondefective F1 mice suffering from GVHR. Although a very small number of DBA/2 B cells might have contaminated the T cell inocula, it was shown that these were B cells of the defective F1 mice that produced autoantibodies during the GVHR. This was demonstrated by detecting autoantibodies carrying an immunoglobulin allotype of the F1 recipient. Furthermore, the defective F1 male mice injected with CBA/N lymphoid cells, which were lacking Lyb-3+5+ B cells, also produced autoantibodies. Isotype analysis of antinuclear antibodies revealed that some of them belonged to IgG3 isotype. It was concluded that the ontogenically late-appearing B cell subset is not required for GVH autoimmunity.