B cells have B cell receptors (BCRs), or antigen binding sites which combine as the antibody [[IgM]] when the B cell is immature, changing to [[IgD]] when the cell is mature. IgM has a large molecular mass and can bind up to 10 antigens simultaneously. B cells also express MHC II, CD9, CD,19, CD20 and CD24.</p> | B cells have B cell receptors (BCRs), or antigen binding sites which combine as the antibody [[IgM]] when the B cell is immature, changing to [[IgD]] when the cell is mature. IgM has a large molecular mass and can bind up to 10 antigens simultaneously. B cells also express MHC II, CD9, CD,19, CD20 and CD24.</p> |