| Abstract: | The grafting of a single spleen colony obtained from irradiated mice protected with 12-day fetal liver will reconstitute the lymphopoietic and erythropoietic system of irradiation-deprived syngeneic recipients. Using this experimental model, the early events during the ontogenic development of the immune system were studied in CBA mice. Cells capable of binding radio-iodine labeled S. adelaide polymerized flagellin were first detectable after 18 to 20 days of lymphopoiesis starting from presumably a single stem cell. However, antibody-forming cell production after immunization against the same antigen was not demonstrable until days 19 to 26. The same sequential development of antigen recognition (by rosette formation) followed by immune reactivity was observed for sheep red cell antigens, both events occurring later than those for POL. Our observed requirement for the ontogeny of an antigen-recognition spectrum is compatible with Jerne's theory on the generation of antibody diversity. |
