Ultrastructural study of the specific granule of the human eosinophil.

: The authors have shown in one of their previous papers that incubation of human eosinophils with homologous immunocomplexes produces a lysis of specific granules and simultaneously releases a large amount of peroxidase from the granule matrix in the incubation medium. The present study has clarified that the matrix contains a membranous tubular structure, which is considered a container of enzymatic content on the basis of the experimental evidence that the peroxidase content of the matrix decreases as the tubular structure emerges both in the specific granules on incubation of eosinophils with immunocomplexes and in the allergic nasal mucous membrane. This study has also suggested that the tubular structure serves a channel to excrete the content of the matrix outside the cells.