Ontogeny of murine I-Ak antigens in tissue of nonlymphoid origin.

The ontogeny of I-Ak antigens in murine tissues of nonlymphoid origin has been evaluated by reacting acetone-fixed cryostat sections of embryonic, neonate, and adult tissues with the MOAb 10-2.16 in indirect immunofluorescence. Thymus dendritic cells appear to be the first to express I-Ak antigens which become detectable only after birth in skin Langerhans cells, gastrointestinal epithelium, septal cells in lung alveoli, and some endothelia. The full expression of I-Ak antigens as detected in adult mice is reached only at 1 month of age.