Immune competence in 90Sr-exposed, adult thymectomized and antilymphocyteglobulin-treated CBA mice. II. Reticuloendothelial phagocytic function and in vitro mitogen responsiveness of spleen cells.

The hypothesis that immune system failure plays a role in the development of radiation induced tumours was recently investigated experimentally. Young adult CBA mice, intact or immunocompromised by adult thymectomy (ATx) and/or anti-lymphocyteglobulin (ALG) treatment, were exposed to single doses of 90Sr, after which tumour development was monitored. To evaluate the experimental results required knowledge about the immunological responsiveness of the mice. The present paper contributes to that knowledge by reporting on the in vitro responsiveness of lymphoid cells to mitogens (LPS, PHA, Con-A) and the in vivo phagocytic functioning of the reticuloendothelial system (RES), measured as the rate of clearance of 125I-albumin micro-aggregates in peripheral blood. 90Sr, ATx and ALG-treatments, separately and in combination, suppressed mitogenic lymphoid cell activation, whereas the RES phagocytic function remained unchanged, except in response to 90Sr + ALG treatment, which seemed to slightly inhibit phagocytic activity.