Antigenic markers on rat lymphocytes: I. Characterization of A.R.T., an alloantigenic marker on rat thymus and thymus-derived cells

Abstract

We report here the further characterization of an alloantigen found on rat thymus and thymus-derived lymphocytes, termed A.R.T. 2 2 Abbreviations used in this paper: B.H., Black-Hooded rat strain; MEM, minimum essential medium with Hanks base supplemented with 4% fetal calf serum; PBS, phosphate buffered saline; HBSS, calcium and magnesium-free Hanks balanced salt solution; RS, unabsorbed rabbit serum; EDTA-RS, mixture of 0.1 M EDTA and rabbit serum. (for Antigen of the Rat Thymus). This antigen previously had been shown to be specific for rat T-cells and capable of abrogating various T-dependent immune responses. Data presented here have demonstrated that the antigen is absent from rat and mouse brain as well as other nonlymphoid tissues. These data, along with those showing an augmentation of serum titers by substituting absorbed rabbit serum for guinea pig serum as a complement source, points to a closer relationship of the rat antigen to the mouse Ly than to theta (Thy 1). Treatment of rats with cortisone acetate did not render the remaining thymocytes any more or less susceptible to the action of the anti-A.R.T. serum. In a survey of a variety of inbred rat strains, no relationship was found between the presence of the A.R.T. antigen and the Ag-B phenotype. Using Ag-B compatible strains, one that lacked the antigen and one that possessed it, we were able to produce antisera other than the Black-Hooded anti-Lewis. Lastly, quantitative absorption experiments supported our earlier supposition that peripheral T-cells, as represented by lymph node cells, had a higher concentration of A.R.T. than did thymus cells.