Naive CD4(+) lymphocytes convert to anergic or memory-like cells in T cell-deprived recipients

Recent demonstrations that naive T cells proliferate after transfer to lymp hopenic hosts have led to the theory that active homeostatic mechanisms fil l the peripheral pool of naive T cells. To extend these data, we injected n aive CD4(+) T cells from AND TCR transgenic mice (H-2(b/b) or H-2(k/k)) int o CD3(epsilon)-deficient mice, and studied the absolute number, phenotype a nd functional capacities of the transferred lymphocytes, from the first day s to a few months after transfer. Proliferation of naive CD4(+) T cells did not fill the peripheral naive T cell pool. Injected naive T cells acquired a memory-like phenotype that was stable with time, despite the absence of foreign antigenic stimulation. Their functional capacities were modified, e nhanced or abolished depending on the MHC haplotype. Thus, "homeostatic" pr oliferation of naive CD4(+) T cells in T cell-deprived recipients does not regenerate the naive CD4(+) T cell pool.