Reactive and non-reactive lymphocytes in experimental allergic encephalomyelitis.

Myelin basic protein (BP),induces an increased in vitro proliferative response of peritoneal exudate cells (PEC), compared with that given by pheripheral blood lymphocytes (PBL), in guinea-pigs with experimental allergic encephaloMYELITIS (EAE). This response is determined by the nature of the lymphocytes in such exudates. We have also found that: (a) the majority of peritoneal lymphocytes from non-sensitized animals are E-rosetting (T cells) (59 percent) or null cells (greater than 40 percent) with EAC-rosetting (B cells) comprising 1 percent or less of cells; (b) both T cells and null cells respond equally to BP as determined by a technique combining rosette-formation and autoradiography; (c) the increased in vitro peritoneal lymphocyte response in animals with EAE cannot be explained solely by the number of null cells since peripheral blood and lymph nodes also contain appreciable numbers of null cells.