~Lymphocytes~ are a type of white ~blood~ cell produced in the lymphoid tissue of the lymphatic system. They are colorless and slightly larger than red |blood cells|. The number of ~lymphocytes~ in the body remains fairly constant, but may rise or fall under certain conditions. ~Lymphocytes~ are concerned with immunity. They multiply to produce antibodies to neutralize infectious substances such as invading bacteria. There are two main groups, B and T ~lymphocytes~. The B cells are ordinarily concerned with making antibodies, while T cells have a dual role: they control immune mechanisms and fight foreign cells.
