The lymphocytes are of two types: B and T cells. The B cells synthesize antibodies causing agglutination of unwanted antigens, while T cells carry out cellular immune responses, where cells having unwanted antigens on their surface are attacked without any medication by antibodies. The former response is called humoral immunity and the latter the cellular immunity. The T cells interact with antigen through cell surface proteins called T cell receptors, which are specially attached to the cell membrane.B cells and T cells, both originate in bone marrow.
When an animal first encounters an antigen, it produces a low primary response. Due to first exposure to antigen, not only mature antibody producing B cells are produced, but immature B and T memory cells are also produced.
Lymphocytes are one of the 5 types of white blood cells in the human body. All lymphocytes deveop in the bone marrow. T Lymphocytes mature in the thymus, while B lymphocytes remain in the bone marrow until they mature. T lymphocytes are responsible for cell mediated immunity.
T lymphocytes can destroy the pathogen in several ways, including destroying the microorganism and stimulating other immune defenses.
B lymphocytes create antibodies that destroy the pathogen. Memory T cells "remember" how to make specific antibodies for a quick response to a second exposure to a pathogen.