The origin, kinetics and distribution of large lymphocytes from the thoracic duct of rats with trichinosis.

Studies were done on the distribution and recirculation of thoracic duct lymphocytes from rats infected with larvae. Previously it had been found that in rats with trichinosis, when large lymphocytes were transferred into normal rats, eosinophil leucocyte production was increased. These lymphocytes, which constituted up to 30 per cent of the cells in thoracic duct lymph, were specifically labelled with tritiated thymidine and they were followed in tissues and lymph. As some of the labelled large lymphocytes were found in bone marrow, it was postulated that eosinophil production could be increased by local interaction between lymphocyte, and eosinophil precursors. Large lymphocytes either divided to form small lymphocytes within 24 hours of injection, or persisted as large pyroninophilic cells in intestinal villi. Labelled lymphocytes did not accumulate around larvae in inflammatory sites where eosinophils were found, but these two cell types were commonly found together in intestinal villi. The recirculation kinetics of thoracic duct lymphocytes was not altered from normal in rats with trichinosis, and 10–30 per cent of the progeny of large lymphocytes recirculated into the thoracic duct lymph within 36 hours of injection.