Figure 3.

Allogeneic thymic epithelium positively selects 2C cells in vivo. Lymph nodes were collected and analyzed (see Materials and Methods) from animals having received either TAP1^−/− H-2^b (A), TAP1^+/+ H-2^b (B), or TAP1^+/+ H-2^d (C) thymic transplants. The high proportion of CD4⁺ cells observed may be because of either the expansion of some mature CD4 cells present in the transplanted bone marrow or of cells that arose from some surviving host bone marrow. For each type of transplant two mice were studied with similar results.