Responses to human rhinovirus in CD45 T cell subsets isolated from tonsil

Isotypes of CD45 have been used extensively as markers of memory and naive populations of T cells in peripheral blood. in this study, T cells were iso lated from human tonsil and their proliferative response against human rhin ovirus was measured. Unexpectedly, equivalent responses were found among th e CD4(+)CD45RA(+) and CD4(+)CD45RO(+) populations of T cells. This response requires MHC class II-positive antigen-presenting cells. The time course o f the T cell response in vitro was that of a classical recall response, and no proliferative response to the virus could be detected in human cord bro od. These results suggest that tonsils contain a significant population of CD45RA(+) memory cells. The presence of this population may reflect ongoing stimulation with this common infectious agent, and the anatomical location of the T cells within the major lymphoid organ draining the naso-pharyngea l epithelial surface.