B Cells (B Lymphocytes):
1. Originate in the bone marrow.
2. Also known as B lymphocytes.
3. Present inside lymph nodes.
4. Have surface antibodies.
5. Connect to the surface of invading bacteria and viruses.
6. Membrane receptor for antigen is BCR (B cell receptor).
7. Life span is short.
8. Secrete antibodies.
9. Have only one active type.
T Cells (T Lymphocytes):
1. Originate in the thymus.
2. Also known as T lymphocytes.
3. Present outside lymph nodes.
4. Do not have surface antibodies.
5. Connect to the virus antigen on the outer side.
6. Membrane receptor for antigen is TCR (T cell receptor).
7. Life span is long.
8. Secrete lymphokines.
9. Have two types: Helper and killer.