INDUCTION OF CD80 EXPRESSION IN LOW-GRADE B-CELL LYMPHOMA - A POTENTIAL IMMUNOTHERAPEUTIC TARGET

The CD80 antigen (B7) is expressed on activated B lymphocytes. It is t hought to be important in eliciting a T cell response via its ligands CD28 and CTLA-4 when antigen is presented in the presence of the MHC-1 peptide. Low-grade B cell lymphomas analysed by flow cytometry expres s CD80 very poorly. However, when grown in vitro using the IL-4/anti-C D40 stromal cell culture system, following depletion of T and IgD-bear ing cells, a monoclonal B cell expansion occurs. Cells harvested at da ys 10-13 express the antigen strongly, regardless of the histological subtype of lymphoma. Further investigation of CD80-mediated immune fun ctions may be possible using this system as a basis for testing immuno therapy.