mouse monoclonal IgG2b; Lymphocyte Marker Antibody (MB3) is an IgG2b mouse monoclonal Lymphocyte Marker antibody that detects Lymphocyte Marker of human origin by WB, IF and IHC(P). Lymphocyte Marker Antibody (MB3) is available as the non-conjugated anti-Lymphocyte Marker antibody form. A lymphocyte is a type of white blood cell that plays an important role in the immune system. There are two types of lymphocytes: large granular lymphocytes and the small lymphocytes. The large granular lymphocytes are more commonly known as the natural killer cells (NK cells), and the small lymphocytes include the T cells and B cells. T cells are mainly responsible for cell-mediated immunity, whereas B cells are primarily responsible for humoral immunity. When an antigen is present, B cells rapidly become metabolically active and differentiate into plasma cells, which secrete large amounts of antibodies. Antigens expressed on sets and subsets of lymphocytes may aid in the identification of these types of cells.