| dc.description.abstract | Immunology is the study of the host's resistance to disease. This resistance has been traditionally divided into two branches: humoral and cell mediated. Humoral resistance involves the inactivation of invading organisms by soluable antibodies which are produced by B lymphocytes. Another type of lymphocyte, known as T lymphocytes, are derived from the thymus and are responsible for cell mediated immunity. When a lymphocyte binds with a certain foreign antigen, the lymphocyte becomes sensitized, and its mode of action is then directed only against the specific sensitizing antigen. Lately resistance has been shown to also be dependent on macrophages, a type of phagocytic cell which engulfs invading organisms (1). T lymphocytes interact with macrophages in providing resistance against intracellular parasites, such as tuberculosis bacteria and Listeria monocytogenes. Much of the nature of this interaction has now been deciphered. Sensitized T lymphocytes, upon stimulation with the sensitizing antigen, release a number of soluable factors known as lymphokines. Some lymphokines such as blastogen are directed towards lymphocytes, causing rapid cellular division and thus an increased production of lymphokines. Other lymphokines act directly on macrophages; it is these lymphokines and their action on macrophages with which this study is concerned. | en |
