STUDIES ON LYMPHOCYTES .12. ROLE OF IMMUNOLOGICALLY COMMITTED LYMPHOCYTES IN REJECTING SKIN ALLOGRAFTS

Extracorporeal irradiation of thoracic duct lymph was carried out in calves for up to 68 days. Extracorporeal irradiation of thoracic duct lymph prolonged the survival of skin allografts in nearly all calves studied. In certain instances, however, skin allografts placed within the drainage bed of the thoracic duct survived significantly longer than skin allografts not within the drainage bed of the thoracic duct. The results from these experiments suggested that viable, immunologically committed lymphocytes, involved in the first-set skin allograft rejection, enter the circulation via efferent lymph from the regional lymph nodes, and these cells could apparently be inactivated by extracorporeal irradiation of thoracic duct lymph. Lymphocytoxins failed to induce accelerated rejection of skin allografts in the absence of viable committed lymphocytes. © 1969 by The Williams and Wilkins Co.