IMMUNE RESPONSIVENESS OF LYMPHOTOXIN-ALPHA-DEFICIENT MICE - 2 RECONSTITUTION MODELS

The effects of lymphotoxin-alpha (LT-alpha) deficiency on mucosal immu ne status has not been defined. We utilized severe combined immunodefi ciency (scid) mice as recipients of both mutant and wild-type whole sp lenocytes to determine whether lymphocytes from mutant mice had impair ed homing ability. We also utilized irradiated mutant mice as recipien ts of wildtype whole splenocytes to determine whether lymphoid tissue anlages had, indeed, failed to develop as a consequence of LT-alpha de ficiency. Subsequently, all mice were immunized orally with an attenua ted strain of Salmonella typhimurium and mucosal IgA responses were mo nitored. The data presented here demonstrate that acid recipients gene rate mucosal responses equally well when reconstituted with mutant or wild-type lymphocytes. In contrast, reconstitution of mutant mice with wild-type cells failed to affect the efficiency of their mucosal immu nity. The mutant phenotype, therefore, appears to involve neither impa ired lymphocyte homing nor function in the generation of mucosal immun ity. However, the mutant phenotype and immune responsiveness cannot be transformed merely by the provision of LT-alpha-expressing donor cell populations. The consequence of LT-alpha deficiency on mucosal immune responsiveness appears to be due to the lack of gut-associated lympho id tissues, which may include the spleen, in mutant mice, (C) 1998 Aca demic Press.