Induction of proliferation and differentiation of murine B cells bearing surface Igλ by rat monoclonal antibody to λ chain

Rats were immunized with the purified BCL₁-IgMλ3(1) and their spleen cells were fused with Sp2/0 cells. Hybridomas secreting antibodies relative with λ1-, λ2-, and λ3-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-λ antibody, coupled to Sepharose, was mitogenic for λ-bearing normal B cells and BCL₁ cells, and in the presence of a supernatant from Concanavalin-A (Con A) stimulated these cells to secrete IgMλ.