<P> A lymphocyte is one of the subtypes of white blood cell in a vertebrate 's immune system . Lymphocytes include natural killer cells ( which function in cell - mediated , cytotoxic innate immunity ) , T cells ( for cell - mediated , cytotoxic adaptive immunity ) , and B cells ( for humoral , antibody - driven adaptive immunity ) . They are the main type of cell found in lymph , which prompted the name `` lymphocyte '' . </P>
where are antibodies made and by what type of lymphocyte
lymph B cells