abstract–All normal human sera examined have been shown to contain complement‐fixing antibody to an antigen present in stratum corneum of human skin. By immune adherence with human sera and sections of frozen biopsy specimens, the antigen was found to be present in sections of keratotic and parakeratotic areas of human gingiva, tongue, alveolar, buccal, and palatal mucosa. Serum from biopsy donors mediated the adherence reaction. Absorption with a phenol‐water extract (water phase) of stratum corneum of skin removed the antibodies. The antigen was not detected in non‐keratinized areas of human oral mucosa, including gingival crevice and cuff epithelium. Erythrocytes also adhered to keratinized epithelium in gingival biopsy specimens fixed in ethanol and cleared in xylene at 4° C prior to sectioning and incubation with hum