Increase of Interleukin 2 Receptor and CD45RO Antigen on Lymphocytes Cultured with Human Cytomegalovirus

To determine the expression of interleukin 2 receptor (IL-2R) and the change of CD45RA and CD45RO antigen on lymphocytes in response to human cytomegalovirus (HCMV), peripheral blood mononuclear cells (PBMC) were cultured with HCMV antigen, and the expression of IL-2R and of CD45RA and CD45RO antigens on lymphocytes was analyzed by flow cytometry. The expression of IL-2Rα (p55) and -β (p75) was significantly increased on T cells obtained from CMV-seropositive donors following culture with the CMV antigen. An increased expression of IL-2Rα and -β was observed on both CD4+ and CD8+ cells, but the percentage of cells that expressed IL-2R was higher in CD4+ cells. The percentage of CD45RA+ cells was decreased and the percentage of CD45RO+ cells, especially of CD4+CD45RO+ cells, was increased when cultured with the CMV antigen. These observations suggest that switching of CD45RA+ cells to CD45RO+ cells occurred following stimulation with the CMV antigen. The expression of IL-2R and the activation of memory T cells are important to the recovery from and the protection against CMV infection.