Athymic mice are severely depleted in thymic derived lymphocytes. There is strong evidence, nevertheless, indicating that they are well endowed with T cell precursors. Indeed, a small percentage (around 4-7 per cent) of theta bearing cells can occasionally be demonstrated in the spleens of nude mice. There is also evidence suggesting that the T cell precursors of nude mice are subject to the action of thymic extracts and that they undergo maturation processes in vitro which lead to the acquisition of surface antigens usually encountered on mature T cells. Further, in many instances, polymeric substances such as polyadenylic polyuridylic acid (Poly A, Poly U), single stranded DNA (ss DNA) and lipopolysaccharide (LPS) can effectively substitute for thymic extracts in this regard. The influence of synthetic polymeric agents on the immune responsiveness of congenitally athymic (nude) mice was investigated by determining the effects of in vivo treatment with polynucleotides and polymeric haptenated antigens on splenic theta bearing cells, on mitogen stimulation and on plaque forming cell responses to thymic dependent and thymic independent antigens. Contrary to in vitro data, no evidence was obtained to demonstrate in vivo restoration of these immune parameters by the use of non specific immune enhancers. Further, despite the continued release of lipopolysaccharide from the bowel, older nude mice (10 mth old) demonstrated no acquisition of improved T cell function. Nude mice responded well to the thymic independent antigen p azobenzenearsonate N acetyltyrosylglycylglycine (A-TGG) Ficoll. Finally, the class specific responses to the thymic independent antigen dinitrophenyl (DNP) Ficoll were significantly different from those of nu/+ littermate controls, indicating the importance of thymic influences upon the class switching of immunoglobulin responses.
|Original language||English (US)|
|Number of pages||10|
|State||Published - 1977|
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