Early dominance of irradiated host cells in the responder profiles of thymocytes from P→F1 radiation chimeras

Abstract

The number of cells in the thymus of {k→(b x k)F1} radiation (1000 rad) chimeras increases approximately 10-fold between 7 and 14 days after reconstitution with bone marrow. At least 50% of the cells in thymus on day 14 are of host origin and respond to virus presented in the context of both H-2(k) and H-2(b) when primed in irradiated, virus-infected (b x k)F1 recipients. Strong CTL responses can be generated from thymocytes of donor origin on day 21. All evidence of a significant host thymocyte component has disappeared by day 28. The responsiveness of 14-day thymocytes is not abrogated by pretreatment of the mice used to make the chimeras with anti-thymocyte serum or by using doses of irra..