Maturation of human B lymphocytes--studies with a panel of monoclonal antibodies against membrane antigens.

The expression of six different membrane markers by cells of the human B lymphocyte lineage has been studied, using monoclonal antibodies. B cells representing various stages of differentiation/maturation have been examined, using normal cells, leukaemia cells, and continuous cell lines. The expression of the six markers has been compared with maturation stages defined by immunoglobulin expression. The HLA/beta 2-microglobulin complex is present throughout the B cell lineage, whilst the Ia (p28,33) marker is present from the earliest stage that can be attributed to the B lineage, but is lost during plasma cell differentiation. A marker detected by monoclonal antibody FMC 1 is present only on mature B lymphocytes, being absent from pre-B cells or plasma cells. FMC 7 detects an antigen found on a relatively mature subpopulation, whereas FMC 8 detects early as well as mature B cells. FMC 3 expression is found on a proportion of cells at any maturation stage, suggesting that expression of this marker is controlled by factors unrelated to maturation.