The mapping out of the histologic distribution of blood group antigens A and B in human tissues was performed by means of the fluorescent antibody technique. Human hyperimmune sera were conjugated with fluorescein isocyanate and applied to frozen sections of human material obtained at autopsy or after surgical removal. The material examined encompassed A, B, and AB subjects. In the latter the anti-A and the anti-B conjugate elicited the same picture. Group O tissues were used for controls and were uniformly negative. The secretor status of subjects was determined from the saliva or by the Lewis typing of erythrocytes.
The results fall into the following main divisions:
Endothelia of Vessels.—Widespread localization was demonstrated in the cell walls of endothelium of capillaries, veins, arteries, and of sinusoidal cells of spleen.
Stratified Epithelia.—These showed good outlining of cells of the Malpighian (and the granular, when present) layers. In transitional epithelia, cells of the basal and contiguous layers gave specific staining.
Mucus-Secreting Apparatus.—Positive staining was obtained in glands, goblet cells, and secreting surface epithelia. In non-secretors there was no identifiable antigen with the important exception of the deeper parts of gastric foveolae, deeper parts of crypts of Lieberkühn of bowel mucosa and Brunner's glands of the duodenum.
Various Organs of Secretion and Excretion.—The pancreas (exocrine portion) and the sweat glands were found to produce the antigen irrespectively of secretor status. Breast, prostate, and endometrial glands on the other hand apparently secrete the antigen in conformity with the subject's secretor:non-secretor make-up.
Thus the secretor:non-secretor status governs principally the antigens associated with mucous secretions and this in most but not all locations. The possible nature of this control is briefly discussed.
An enzymatic basis for secretor status and blood group substance specificity in humans.