In vitro properties of heterologous anti-lizard thymocyte serum

Abstract

A potent and specific antiserum was raised in rabbits by injecting a single cell suspension of thymocytes of the lizard, Calotes versicolor. Rabbit anti-Calotes thymocyte serum (ATS) was characterizedin vitro by using cytotoxicity assay and quantitative absorption analysis. The cytolytic activity of ATS was always higher towards thymocytes than towards lymphoid cells of spleen, bone-marrow and peripheral blood. Various absorption experiments indicate the existence of two antigens among thymocytes-one distinct for thymocytes and thymus derived cells and another, common to lymphocytes. Further, thymus-brain antigenic correlation has been demonstrated in this reptilian species. The Calotes complement is less efficient than that of guinea pig in mediating the cytolysis of target cells by ATS. Further, ATS did not have cytotoxic effect on antibody producing cells. The significance of these findings has been discussed with reference to the dichotomy of lymphoid systems at this phylogenetic level.