ANALYSIS OF CELL-SURFACE ANTIGENS ON GLUCOCORTICOID-TREATED RAT THYMOCYTES WITH MONOCLONAL-ANTIBODIES

The effects of glucocorticoid (GC) on thymocytes have been utilized to investigate the maturation and differentiation of thymocytes, but the se experiments have mainly been performed on mouse thymocytes. We inve stigated the cell surface antigens expressed by LEW rat thymocytes dur ing thymic reconstitution after GC treatment. Three-color flow cytoflu orometric analysis of CD4, CD8 and the T cell antigen receptor (TCR al pha beta) dearly demonstrated that normal rat thymocytes contain CD4(- )8(+) TCR alpha beta(-) and CD4(+)8(-) TCR alpha beta(-) cells. After GC treatment, we observed significant increases in the percentages of CD4(-)8(+) TCR alpha beta(-) and CD4(+)8(-) TCR alpha beta(-) cells. T he extent of the increase in the percentage of CD4(-)8(+) TCR alpha be ta(-) cells was greater than that of CD4(+)8(-) TCR alpha beta(-) thym ocytes. Two-color analysis of TCR alpha beta and major histocompatibil ity complex (MHC) class I antigen showed that GC treatment significant ly increased the percentage of TCR alpha beta(-) MHC class I-hi cells. Three-color analysis of CD4, CD8 and MHC class I demonstrated that no rmal rat thymocytes contain CD4(-)8(-) MHC class I-hi cells, which inc reased in number after GC treatment. These results indicate that rat t hymocytes contain no fewer CD4(-)8(+) TCR alpha beta(-) and CD4(divide d by) 8(-) TCR alpha beta(-) cells than do mouse thymocytes, and that CD4(-)8(+) TCR alpha beta(-) cells predominate over CD4(+)8(-) TCR alp ha beta(-) cells. in LEW rat thymus. Rat CD4(-)8(-) cells seemed to be divided into two subsets of TCR alpha beta(-) MHC class I-hi and TCR alpha beta(-) MHC class I- cells.