実験的アレルギー性脳脊髄炎における胸腺および脾臓の形態変化の意義

MORPHOLOGICAL CHANGES OF THE THYMUS AND SPLEEN WITH ACUTE EXPERIMENTAL ALLERGIC ENCEPHALOMYELITIS (EAE) IN LEWIS RATS

　抄録　個体を生体防御機構という視点からみると，神経系と免疫系は2大システムと考えられる。最近，この両システムに共通抗原の存在することが明らかにされ，その関連性が注目されている。我々は実験的アレルギー性脳脊髄炎（EAE）のモデルを用いてその関連性を検索した。

　Lewisラット17匹に脳組織で免疫し，10匹にacute EAEが発症した。acute EAEラットでは胸腺は著明に萎縮し，著しいリンパ球の脱落，線維化，多数のmacrophageの小葉周辺よりの浸潤を認めた。脾臓も重量を減ずるものの，光顕所見に著明な変化はなかった。この胸腺の崩壊は，リンパ球とoligodendro-gliaに共通抗原が存在するため，同一targetとみなされた結果と考えられる。脳組織で免疫すると胸腺が崩壊するという事実は，神経系と免疫系の2大システムに相互作用の存在する可能性を示唆しているものと思われる。

Nervous and immune systems are thought to have an important role in host defence mechanism. Re-cent reports have suggested the presence of com-mon antigens between nervous and immune sys-tems. In this paper, we described the interactions between nervous and immune systems observed in an acute EAE model of Lewis rats.

Seventeen Lewis rats were immunized by homo-genized brain tissue in complete Freund adjuvant. Acute EAE rats were developed in 10 rats, all of which died within 25 days after the immunization. The thymus of these rats showed marked atrophy and histological examination revealed severe de-generation of the lymphocytes and infiltration of macrophage showing phagocytosis in the thymus.

The weight of spleen was also decreased, but no remarkable changes were observed microscopically except slight reduction of the white pulp.

The fact that the immune reactions was induced not only in the nervous sysetem but also in the thymus of EAE animals may suggest the possibility of common antigen between oligodendroglia and lymphocytes.

This also suggest the close interaction between nervous system and immune system. However, the reactions of the thymus and spleen were different in this experiment, and further studies are neces-sary to evaluate the mechanism of these immune reactions.