Effect of Internal Irradiation from Colloidal Chromic Phosphate (P-32) on the Primary Immune Response in Rabbits

[摘要] Effects of internal irradiation from intravenously administered radioactive colloidal CrP32O4 on the primary immune response of rabbits to sheep erythrocytes and typhoid H-antigen were described. Test rabbits were given various µc amounts of CrP32O4. Immunization, either a single antigen injection or a series of three or four injections, was begun either 24 hr, 14 days or 36 days later. Radiation for 24 hr from 31, 60, 105, 120 or 488 µc of CrP32O4 did not alter the immune responses of rabbits given three or four intravenous antigen injections over a 9- to 14-day period. However, when 14 days of internal radiation from 520, 624 and 780 µc preceded a single immunizing injection, antibody responses to both antigens were significantly depressed. These effects included delayed appearance of antibody, decreased antibody synthesis rates, and lowered maximum antibody titers. When similar amounts of radiation, 488, 624 and 780 µc for 14 days, preceded a series of three antigenic stimuli given within 11 to 14 days, prolonged antibody induction periods were the only apparent evidences of radiation injury. The depressive effects observed herein paralleled those obtained by others with certain regimens of external x- and γ-radiation and internal β-irradiation.The nearly complete reversal of immunologic impairement by additional antigen stimulus was discussed and attributed to compensatory hyperactivity of nonsplenic antibody synthesis sites. Splenic participation in the immune response of rabbits given 488 µc or more was judged non-operative. The spleens of these rabbits were estimated to have adsorbed 7000 to 14000 rep during the 14 days preceding immunization. The resultant immunologic impairement and its reversal with multiple antigen injections paralleled results obtained by other investigators studying surgically splenectomized rabbits. Cognizance of these immunologic-radiation relationships in clinical use was emphasized.The exact interval of immunologic impairement was not established. Rabbits which received 650 µc of CrP32O4 36 days prior to three antigen injections, responded essentially normally even though lymphopenic during immunization. Lymphopenias were found to increase in intensity and duration with increased CrP32O4 dose.

[学科分类] 生物科学（综合）