Immunosuppression inhibits switch from naive to memory phenotype in human T lymphocytes.

Recently, human T cells have been divided into memory (antigen-primed) and naive (unprimed) subsets, which vary in phenotype and function. Immunosuppressive drugs and heparin have been found to inhibit PHA-induced in vitro switching from naive to memory cell phenotype in a process that is at least partly independent of cell proliferation. Furthermore, T cells isolated from immunosuppressed renal allograft recipients were deficient in their in vitro PHA-induced transition from naive to memory phenotype.