Normal and neoplastic lymphocyte maturation

Lymphocytes are cells that are responsible for processes of specific antigen recognition and for those aspects of the immune response that characterize adaptive immunity. In this respect adaptive immunity can be characterized as antigen-induced immune memory and effector functions as compared to native immunity - the nonspecific phagocytic and humoral protective elements in lower vertebrates. In vertebrates both B and T lymphocytes apparently express self-synthesized receptors that are involved in the recognition of antigens, and mediate the interactions between various important cells in the hematolymphoid system. There are three major subclasses of T lymphocytes - those involved with helper-inducer functions, those involved with suppressor functions, and those involved in direct cytotoxicity of antigenic target cells.