Tolerance to allotypic determinants induced by lymphoid cells from congenic mice bearing the allotype.

Mice of one allotype (Igb) were immunized against immunoglobulin from a congenic strain of mice bearing another allotype (Iga). This Igb anti-Iga response was profoundly suppressed by injecting lymphoid cells from congenic Iga mice but not by serum Iga. Suppression was specific, could be induced by congenic B cells but not histoincompatible lymphoid cells and depended both on the time of administration of cells relative to immunogenic challenge and to the number of cells injected. Unresponsiveness was more easily induced in neonates than adults. It is considered that tolerance to the allotype depends on the properties of the cells to which they are bound.