Immune Competence in ⁹⁰Sr-Exposed, Adult Thymectomized and Antilymphocyteglobulin-Treated Cba Mice I. Allogenic Skin Graft Reaction

Abstract

CBA mice subjected to either adult thymectomy, internal exposure to ⁹⁰Sr or antilymphocyteglobulin treatment separately, or to combinations of the three were tested for cellular immune competence using their reaction to allogenic skin grafts. Peripheral blood white cell counts did not reveal any obvious correlation between the degree of mononuclear cell depletion and the ability to accept grafts, suggesting that the particular treatments depleted specific fractions of mononuclear cells, differing in their extent of involvement in the rejection process. No single treatment alone induced a significant prolongation in the time elapsed before graft rejection. Adult thymectomy followed by appropriate antilymphocyteglobulin treatment induced severe lymphocytopenia and a profound suppression of the cell-mediated immune system, as evidenced by the acceptance of allogenic skin grafts. When applied to ⁹⁰Sr-preexposed mice the same treatment induced lifelong acceptance of grafts, indicating a similar, though weaker immunosuppressive impact of ⁹⁰Sr. Hence it was possible to significantly enhance immunosuppression in ⁹⁰Sr-exposed mice. This in vivo model should be useful when investigating the role of immunological responsiveness in radiation carcinogenesis.

Key Words:

• Radiation biology
• mice
• immunology
• strontium-90
• thymectomy
• antilymphocyteglobulin
• skin-grafting