Frequencies of memory T cells specific for varicella-zoster virus, herpes simplex virus, and cytomegalovirus by intracellular detection of cytokine expression

Memory T cells specific for varicella-zoster virus (VZV), herpes simplex virus (HSV), and human cytomegalovirus (HCMV) were compared in immune adults by intracellular cytokine (ICC) detection. The mean percentages of CD4(+) T cells were 0.11% for VZV and 0.22% for HSV by interferon (IFN)-gamma production; the frequency for HCMV was significantly higher at 1.21%, Percentages of VZV-, HSV-, and HCMV-specific CD4(+) T cells were similar by use of tumor necrosis factor (TNF)-alpha. HCMV-stimulated CD8(+) T cells produced IFN-gamma (1.11%) and TNF-alpha (1.71%); VZV- and HSV-specific CD8(+) T cells were not detectable. VZV CD4(+) T cell numbers were similar in young adults with natural or vaccine-induced immunity. VZV CD4(+) T cells were significantly less frequent in older adults. Secondary varicella immunization did not increase VZV-specific CD4(+) T cell frequencies by ICC assay, Numbers of memory T cells specific for herpesviruses may vary with sites of viral latency and with hose age.