Relationship between the skin and innert defense mechanisms in fish

研究了日本鳗鲡（Anguilla japonica）皮肤黏液凝集素对中性粒细胞的抑音活性，以阐明当感染通过被膜发生时，皮肤黏液中的防御机制是否对白细胞等防御机制有一定意义。从上皮组织中提取亮素，凝胶过滤分离。这种凝集素能凝集兔红细胞（rRBC），对乳糖具有特异性。将经Percoll密度梯度分离的鳗鱼中性粒细胞与经凝集素预处理的rRBC孵育，在显微镜下观察其吞噬活性。凝集素增强了中性粒细胞的吞噬作用，对凝集素结合的rRBC的吞噬指数明显高于对正常rRBC的吞噬指数，被吞噬的rRBC数量增加。在凝集素处理rRBC的过程中，添加性凝集素抑制剂（即乳糖）抑制了吞噬活性。因此，鳗鱼皮肤黏液凝集素对鳗鱼中性粒细胞表现出拮抗活性。同时存在的淋巴细胞会对吞噬作用产生影响，如增强或减弱，显示淋巴细胞的调节功能。这些发现表明，皮肤表面的防御机制与内部机制有相互关系。

Opsonic activity of the skin mucus lectin against neutrophils was examined in the Japanese eel, Anguilla japonica, to elucidate if the defense mechanisms in the skin mucus has some meaning for the defense mechansms, e.g.leucocytes, when the infection occur via integument. Leuctin was extracted from the epithelial tissue and separated by gel filtration. This lectin agglutinated rabbit red blood cells (rRBC) with specificity to lactose. Eel neutrophils separated by Percoll density gradients were incubated with rRBC pretreated with the lectin, and phagocytic activity was estimated under microscopy. The lectin was found to enhance the phagocytosis of neutrophils, phagocytic index against lectin-bound rRBC was significantly higher than against normal rRBC with an increase in numbers of phagocytized rRBC.The activation of phagocytosis was inhibited by additive lectin inhibitor, i.e., lactose in the process of lectin treatment of rRBC.The skin mucus lectin in eel thus exhibited opsonic activity against eel neutrophils. Phagocytosis was influenced, e.g., enhanced or reduced accordingly by coexistent lymphocytes, showing modulational function of the lymphocytes. These findings show that the defense mechanisms of the skin surface have interrelationship with internal mechanisms.