Ontogeny of cell-mediated immunity. I. Early development of alloantigen-specific cytotoxic T-cell precursors in postnatal mice.

Cytotoxic T-cell precursors have been shown to occur in spleens of 2-3-day-old mice. By 12 days after birth, the cytotoxic T-cell response of spleen cells to alloantigens has reached 23-32% of adult levels. Addition of extra T-helper cells did not permit cytotoxic T-cell development in spleen cells from newborn to 2-day-old mice suggesting either a lack of precursors or suppression of precursors. The ontogeny of cell-mediated immune functions has thus been shown to correlate well with other work on the development of humoral immunity, accessory cells, and graft versus host reactivity.