On the role of MHC class II molecules in the survival and lymphopenia-induced proliferation of peripheral CD4+ T cells
AbstractCD4+ T cells expand after transfer into lymphopenic H-2b Aβ −/− mice (I-Aβ-, I-Eα-deficient mice) but not after transfer into lymphopenic MHC IIΔ/Δ mice (I-Aα-, I-Aβ-, I-Eα-, and I-Eβ-deficient mice), implying that in H-2b Aβ −/− mice, Aα chain and Eβ chain associate to form a hybrid AαEβ MHC class II molecule. In light of this unexpected result, we reexamined the MHC class II requirement in the survival and lymphopenia-induced proliferation of CD4+ T cells. Here we show that expansion, but not short-term survival, of CD4+ T cells depends on interactions with MHC class II molecules in lymphopenic mice. Nevertheless, interactions with classical MHC class II molecules are required for CD4+ T cells to survive in CD8+ T-cell-containing mice.