Expression of interleukin-2 receptor α and CD45RO antigen on T lymphocytes cultured with rubella virus antigen, compared with humoral immunity in rubella vaccinees

Abstract

We studied the expression of interleukin-2 receptor α (CD25) +CD45RO +CD4 + T lymphocytes (T-cell activation) in response to the rubella virus (RV) antigen (Matsuura strain, Biken, Osaka, Japan) using three-color-staining flow cytometry. The subjects were 48 healthy children (3–14 years old, 31 boys and 17 girls), who had received either monovalent vaccine ( n=5; mean age, 13.2 years) or measles–mumps–rubella (MMR) vaccine ( n=21; mean age, 10.5 years), had been naturally infected ( n=5; mean age, 11.4 years), or had been neither vaccinated nor naturally infected ( n=17; mean age, 10.0 years) and 62 healthy adolescents and adults (15–37 years old; 19 males and 43 females), who had received monovalent vaccine ( n=26, mean age, 27.4 years), had been naturally infected ( n=8; mean age, 24.0 years), or had been neither vaccinated nor naturally infected ( n=8; mean age, 16.5 years). Ninety-four of 110 subjects had HI titers≥1:16. T-cell activation in these subjects was significantly higher than that in 6 seronegative (HI titers<1:8) subjects ( p<0.05). T-cell activation did not differ significantly with the history of exposure to RV. HI antibody titers≥1:16 and T-cell activation persisted in vaccinated subjects for ≥20 years and was similar to those in naturally infected subjects. Our results suggest that cell-mediated immunity and humoral immunity persist for at least 20 years after vaccination.