Induction of proliferation and differentiation of murine B cells bearing surface Ig lambda by rat monoclonal antibody to lambda chain.

Rats were immunized with the purified BCL1-IgM lambda 3(1) and their spleen cells were fused with Sp2/0 cells. Hybridomas secreting antibodies reactive with lambda 1-, lambda 2-, and lambda 3-containing myeloma proteins were subcloned and propagated in spinner culture. The antibodies were tested in a solid-phase radioimmunoassay and by indirect immunofluorescence using either BCL1 cells or normal mouse spleen cells. One of the monoclonal antibodies was purified to 95% homogeneity on DEAE-Sephadex. The purified anti-lambda anti-body, coupled to Sepharose, was mitogenic for lambda-bearing normal B cells and BCL1 cells, and in the presence of a supernatant from Concanavalin-A (Con A) stimulated these cells to secrete IgM lambda.