ラット視床下部内側核破壊による免疫反応の変化

THE EFFECT OF HYPOTHALAMIC LESIONS ON IMMUNE RESPONSE IN RATS

　抄録　神経系と免疫系は生体の防御機構という面からみると，networkを形成した重大なsystemと考えられる。最近，この両systemに共通抗原がいくつか存在することが明らかとなり，両者の関連性が注目されている。今回，神経系，ことに視床下部と免疫の関連を検索するため，ラットの視床下部内側核を各核ごとに両側破壊し，2週後の末梢血リンパ球幼若化能，皮下腫瘍生長曲線の変化，catecholamineおよびcor-ticosteroneの変動を検索した。その結果，PHAに対する反応は前視床下部，前乳頭核，乳頭核の破壊で低下し，視床下部背内側核破壊で上昇した。PWMによる反応は乳頭核破壊で上昇し，視床下部背内側核破壊で低下した。皮下腫瘍生長曲線への影響は前視床下部破壊においてのみ生長促進を認めた。これらの現象にcatecholamineおよびcorticosteroneの介在する可能性を検索したが否定された。このように視床下部内側核を破壊することにより，視床下部背内側核と乳頭核で相反作用を有し，さらに，前視床下部は免疫現象と強く拘りを有していることが示唆された。しかし，そのmechanismに関しては不明であり，さらに他のfactorの介在を検討する必要がある。

The nervous and immune systems are thought to have important roles in the host defence nechanism. Recent reports have suggested thepresence 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 lympho-cyte blastogenesis, growth curves of inoculated subcutaneous tumor and serum levels of catechol-amine and corticosterone, 2weeks after the bila-teral 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 stimu-lation indices in those with dorsomedial hypotha-lamic 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 be-tween 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 hypothala-mic 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. In order to investigate the relations to sympathetic nerve and steroid hormones, serum levels of catecholamine and corticosterone were analized after hypothala-mic destruction, but there were no evidence found to support the relation to these phenomena.

In these experiments, it is clarified that the dorsomedial hypothalamic nucleus and mamillary nucleus have reciprocal functions and the ante-rior hypothalamic nucleus has some association with immune response.