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

The ontogeny of I-A^k 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-A^k 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-A^k antigens as detected in adult mice is reached only at I month of age.