<正> Leu 7（HNK-1）

a glycoprotein

is a specific antigen presented on the surfaceof human natural killer cells and killer cells.In this study ABC immunostaining with spe-cific monoclonal antibody to Leu 7 was used to detect the expression of Leu 7 in humanlung.The results demonstrated that the Leu 7 immunoreactivity was localized in theneuroepithelial bodies（NEB）and neuroendocrine cells（NEC）of the human lung.In addi-tion

the anti-Leu 7 monoclonal antibody stained the nerve fibers in the wall of theintrapulmonary bronchi.Adjacent sections immunostained with antibodies to Leu 7 and5-hydroxytryptamin（5-HT）or calcitonin gene-related peptide（CGRP）proved thecoexistence of Leu 7 and CGRP or 5-HT in endocrine cells.The CGRP immunoreactivenerve fibers also showed positive staining with the monoclonal antibody to Leu 7.Ourfindings support the hypothesis that the nervous and endocrine systems share some com-mon antigenic determinants with the immune system.