Proliferative and regenerative capacities of CD4(+) T cells upon TCR stimulation

Proliferation of activated CD4(+) T cells effectively amplifies the immune response. Based on a model of selective CD4(+) T cell proliferation using an anti-CD3:anti-CD8 bispecific monoclonal antibody that leads to selective proliferation of CD4(+) T cells, we demonstrated that the peripheral CD4(+) T cells of normal subjects can divide for 17 to 38 generations, expanding 1.7 x 10(5) to 3 x 10(11) fold, following a single short period of anti-TCR stimulation. The proliferating CD4(+) T cells maintained IL2R expression. A large subgroup from each subject maintained the CD45RA(hi)CD45RO(lo) phenotype, demonstrating that activation and proliferation do not automatically convert CD4(+) T cells into CD45RA(lo)CD45RO(hi) phenotype. The enormous number of cells generated demonstrated that the peripheral CD4(+) T cells have remarkable regenerative expansion capacity. The high, but substantially variable, proliferative capacities among subjects have important implications for diseases in which CD4(+) T cells play an important role, such as HIV-infection, graft rejection, and autoimmunity.