Studies on the Development of the Isoantigens of the H-2 System in Newborn Mice

Summary Erythrocytes and spleen cells from C3H mice were insensitive to humoral H-2-isoantibodies until 2–3 days after birth. Adult reactivity was reached after 6–10 days. Newborn, less than 1 ½-day-old C3H mice were able to absorb intravenously injected antiserum. Erythrocytes of less than 1 ½-day-old C3H mice could not absorb H-2-isoantibodies in vitro. Spleen, liver and kidney cells of less than 1 ½-day-old C3H mice were able to absorb isoantibodies in vitro. Erythrocytes and spleen cells of newborn CBA and A mice were insensitive to humoral isoantibodies at 1 ½ days after birth. Erythrocytes and spleen cells of newborn C57B1 and C57L mice were sensitive to humoral isoantibodies from the day of birth. Immunization of adult C57L mice with x-irradiated spleen cells of less than 1 ½ day old C3H mice gave rise to humoral antibodies. The possible significance of these findings is discussed.