Abstract: | Since the central area is an integral part of the guinea pig thymus, the cells in this area were compared with those in the thymic cortex and medulla in cryostat-sections by using methods for demonstration of E-, EA-, EAC-adherence and surface membrane immunoglobulins. In the extra cortical central area (ECCA) 15 to 25% of the lymphocytes showed EAC-adherence and 5 to 10% appeared to bear surface membrane immunoglobulins (SIg). In the lymph sinuses up to 70% of the lymphocytes were EAC- and SIg-positive. A small amount of EAC-adhering cells was present in the medulla of the central area. Cortical lymphocytes were EAC- and SIg-negative. From these results we conclude that in the guinea pig thymus B lymphocytes are specifically localized in the central area. |