Developmental Changes and Functional Properties of Human Memory T Cell Subpopulations Defined by CD60 Expression

The present study was undertaken to examine developmental changes of T cells expressing CD60 and their functional properties. Three-color immunofluorescence analysis revealed that the CD60 antigen was preferentially expressed on a proportion of memory (CD45RO+) CD4+T cells, but less on memory CD8+T cells, while this antigen is undetectable in naive (CD45RO−) T cells. A frequency of memory CD4+T cells expressing CD60 in the peripheral blood was negligible in newborns and gradually increased with advancing age. CD60+memory CD4+T cells showed stronger proliferative responses to PPD and produced higher levels of IL-4 and IL-10 than CD60−ones, whereas production of IL-2 and IFN-γ was similarly found in both cell subpopulations. In addition, it was shown that efficient helper activity for Ig production by B cells was predominated in CD60+memory CD4+T cells. These results suggest that CD60 may be primarily expressed on the functionally differentiated memory effector cells among circulating CD45RO+CD4+T cells.