Distribution of cross-reacting antigen common to epithelium and group A streptococci in human and animal tissues

The location of a cross-reacting antigen common to streptococci and human and animal tissues was studied by the indirect immunofluorescence method, using pure antibodies against the polysaccharide of group A streptococci and pure antibodies against rabbit immunoglobulins, labeled with fluorescein isothiocyanate, in epithelial cells of ectodermal origin, namely the skin, salivary ducts, mucous membrane of the mouth, esophagus, lower part of the rectum, and cervic uteri, and in elements of the epithelium of the thymus. The discovery of the cross-reacting antigen is interesting in connection with the study of mechanisms of development of immunopathological processes in man connected with streptococcal infection and with the investigation of the structure, function, and pathology of the thymus.