B cells developed from hematopoietic stem cells that originate
from bone marrow. B cells recognize viral antigens outside infected
cells. They secrete antibodies and have surface antigens. B cells
involved in humoral mediated immunity. 20 percent of lymphocytes
are b cells. Have two types plasma cells and memory cells
T cells originate in the bone marrow and mature in thymus . In
the thymus t cells divides in helper , cytotoxic, and suppressor t
cells. T cells recognize the surface antigens of bacteria and
virus. T cells have lack of surface antigens. Involved in cell
mediated immunity . 80 percent lymphocytes are t cells. T cells
secrete lymphokines.