| Abstract: | The distribution and amount of Thy-1.1 antigen expressed in rat and mouse tissues have been studied. When anti-Thy-1.1 antisera were absorbed with various tissues and assayed by cytotoxicity or radioactive binding assays, it was found that antigen was expressed in similar amounts on thymocytes and brain of both species. Lymphocytic leukemia cells from PVG/c rats also expressed as much Thy-1.1 as rat thymocytes. In contrast, Thy-1.1 was only detected in very small amounts on rat lymph node cells or thoracic duct lymphocytes; the level was 20-fold less than the AKR mouse equivalent. Rat spleen cells had larger amounts than other peripheral rat lymphocytes, and had only 2–3 times less antigen than AKR spleen cells. These results were confirmed by direct binding assays which showed that AKR mouse and PVG/c rat thymocytes bound more than 500000 molecules of anti-Thy-1.1 antibody per cell. Autoradiographic analysis showed 90 % of thymocytes, 12 % of spleen cells, and 2 % of lymph node or thoracic duct lymphocytes of the rat to be specifically labeled. |
