INDUCTION OF RUNT DISEASE IN RATS BY INJECTION OF THORACIC DUCT LYMPHOCYTES AT BIRTH

Abstract

It is apparent that injection of living homologous thoracic duct lymphocytes causes runt disease in newborn rats, whereas injection of isologous cells does not. The failure to obtain runt disease in 5 of the 30 animals which received homologous cells cannot be accounted for with certainty, but may well have been due to failure to inject all the cells intravenously. The general conclusion is that thoracic duct lymphocytes are capable either of reacting immunologically in the presence of homologous tissue antigens, or of quickly giving rise to cells with this capacity. Gowans has reported that about 95% of the cells in rat thoracic duct lymph are typical small lymphocytes, and that these do not divide in tissue culture. The other 5% of cells are medium or large lymphocytes, and these do divide in culture, specially during the first 6 hours of incubation. It seems likely that the large lymphocytes are the immunologically active cells, and that the plasma cells observed in the runts'' spleens were derived from them, but further investigation is needed to prove or refute this hypothesis.