Antigen-antibody reactions in allergic human tissues. I. Preparation and use of fluorescein-conjugated reagins for staining the reaction sites.

Skin sensitizing human antibodies were conjugated with various fluorescent dyes without significant loss in their ability to combine with specific antigen in vitro. A biopsy of the skin site challenged with egg albumin in a patient sensitive to this antigen could be stained specifically by the fluorescent reagins. The epithelial cells of the epidermis, sweat glands, hair follicles, and sebaceous glands in such a challenged site showed specific staining. In addition to the epithelial cells, the most intense staining was in macrophages and in pericapillary cells. The endothelium of the small blood vessels stained less intensely. Fibrous tissue bundles were specifically stained. The immunologic staining with the conjugated reagins was similar to but more intense than that obtained with conjugated rabbit anti-egg albumin globulins.