IgE-secreting cells in the thymus: correlation with induction of tolerance to IgE.

We have shown previously that normal mice become tolerant to endogenous IgE when they are approximately 2 weeks old and that this corresponds closely with the initial appearance of IgE in serum. Tolerance evidently is restricted to T cells, since B cells responsive to IgE are present in neonatal and adult mice. The present report shows that IgE-secreting cells can be detected in the thymus between days 7 and 11 after birth and that the onset of tolerance to IgE occurs at the age of 11 days. Similar results were obtained in A/J and (BALB/c x A/J)F1 mice. This suggests that tolerance is induced in the thymus, probably by cells bearing peptide fragments of IgE. The order of appearance of IgE-secreting cells is thymus, spleen, and mesenteric lymph nodes.