Hyper-reactivity of mouse CD45RA- T cells

Mouse CD4 T cells have been partitioned into CD45RA and CD45RA- subpopulations by means of the monoclonal antibody 14.8. The CD45RA- subpopulation proliferated more actively and generated more interleukin-4 (IL-4) in response to stimulation with anti-CD3 antibody and phytohemagglutinin, and more IL-2 in response to anti-CD3. This subpopulation is therefore hyper-reactive to these polyclonal stimulators, but does not show the bias towards T helper type 2 activity that has been found in studies with other related CD45 isoforms. No evidence of suppression was obtained by comparing proliferation of CD45RA- cells in the presence and absence of CD45RA cells. Thus mouse CD4 T cells behave in these respects similarly to those of man, as is evident in a brief review of the quiescence-activation-quiescence cycle in the two species.