Influence of ⁹⁰Sr, Adult Thymectomy and Antilymphocyteglobuline on T-Cells in Mouse Peripheral Blood

Abstract

Three groups of male CBA mice were treated by (1) ⁹⁰Sr injection (14.8 kBq/g body weight i.p.), (2) adult thymectomy (ATx) + antilymphocyteglobuline (ALG), and (3) ⁹⁰Sr + ATx + ALG, respectively, and one untreated group served as a control. The relative number of T-lymphocytes was determined in peripheral blood mononuclear cells of individual animals using a dye exclusion cytotoxicity assay with antisera against the T-cell surface membrane marker Thy 1.2 and complement. Total and differential leucocyte counts were also performed. ⁹⁰Sr irradiation decreased the total number of leucocytes irrespective of type, and the combined treatment of ATx and ALG decreased mainly mononuclear cells and particularly T-cells. The most advanced T-cell depletion in peripheral blood was found in the ⁹⁰Sr + ATx + ALG treated group with a 97 per cent reduction as compared with untreated controls. ATx + ALG thus proved to be useful for blood T-cell depletion in mice treated simultaneously with ⁹⁰Sr, and might provide a valuable tool in investigations on the possible role of cell-mediated immune response in radiation-induced oncogenesis, with particular emphasis on selective depletion within the monomorphonuclear compartment.