ANTIGEN-INDUCED DEGRANULATION OF BASOPHIL LEUKOCYTES FROM ATOPIC SUBJECTS STUDIES BY ELECTRON-MICROSCOPY

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  • 1 January 1977
    • journal article
    • research article
    • Vol. 36  (2) , 173-182
Abstract
Suspensions of washed leukocytes were prepared from the blood of atopic subjects and incubated with diluent, ragweed antigen E or rye grass group I antigen. Histamine release into the suspending medium was measured and directly correlated with changes in the ultrastructure of basophil leukocytes from the same tubes. Incubation of leukocytes with either diluent or an antigen to which the donor was not hypersensitive caused no significant histamine release and the morphology of the basophils was unaltered. Incubation of leukocytes with an antigen to which the donor was hypersensitive caused substantial histamine release and characteristic morphologic changes in the basophils, many of which underwent exocytotic degranulation. Degranulated human basophils had an irregular surface, to which platelets and leukocytes were often adherent. The number of basophilic granules was reduced. Residual granular material was found both in exocytotic cavities and at the cell surface. Coated vesicles and cisternae of smooth endoplasmic reticulum, frequently related to the plasma membrane at sites of exocytosis, were observed. Thin membrane-bounded granules appeared unaltered. No consistent change was observed in centrioles, microtubules, 90 .ANG. filaments, mitochondria or multivesicular bodies and degranulated basophils appeared ultrastructurally viable. In reaction cell suspensions, nondegranulated basophils often showed a more active contour than control cells. Both reacting but nondegranulated basophils and degranulated basophils sometimes showed localized filamentous webs at their periphery.