[The effect of hypothalamic lesions on the immune response in rats]

The nervous and immune systems are thought to have important roles in the host defence mechanism. Recent reports have suggested that presence of common antigens between the nervous and immune systems. It would be of interest to know the possibility of mutual relations between both systems. For the purpose of examining the relations, the author investigated peripheral blood lymphocyte blastogenesis, growth curves of inoculated subcutaneous tumor and serum levels of catecholamine and corticosterone, 2 weeks after the bilateral stereotaxic destruction of WKA rat medial hypothalamic nuclei. As a result of hypothalamic destruction, lower stimulation indices to PHA of the lymphocytes in the peripheral blood were obtained in rats with anterior hypothalamic lesions, premamillary lesions and mamillary lesions, and higher stimulation indices in those with dorsomedial hypothalamic lesions. On the other hand, lower stimulation indices to PWM were obtained in rats with dorsomedial hypothalamic lesions and higher ones in those with mamillary lesions. These results may suggest the existence of reciprocal function between the dorsomedial hypothalamic nucleus and mamillary nucleus. To examine the effect of hypothalamic lesions on tumor immunity, subcutaneous tumor inoculation and its growth curves were studied. As the tumor cells of KMT-17 are allogeneic in WKA rats, inoculated subcutaneous tumors grew temporarily and disappeared within 15 days. The peak of the growth curves was raised in rats with anterior hypothalamic lesions. Rats with other hypothalamic lesions and controls showed almost the same growth curves. From the results, it is suggested that the anterior hypothalamic nucleus may have some effect on tumor immunity.(ABSTRACT TRUNCATED AT 250 WORDS)