Abstract

Changes of Antibody Associated with Cell-Mediated Immunity in College Students During Two Years after Rubella Vaccination

Kihei Terada, Kimiko Hagihara, Yuhei Tanaka, Hideto Teranishi, Tomohiro Oishi, Ippei Miyata, Satoko Ogita, Naoki Ohno and Kazunobu Ouchi

Objective: This study measured cell-mediated immunity (CMI) and serum antibody levels against rubella to clarify antibody changes associated with CMI during 2 years after vaccination.
Methods: The study subjects were 64 college students in two groups: 38 subjects who (having exhibited hemagglutination-inhibition (HI) anti-rubella antibody titers of ≤ 1:16) had been vaccinated with a rubella vaccine 2 years previously (Group 1); and 26 subjects who (having exhibited HI titers ≥ 1:32) had not been vaccinated 2 years previously (Group 2). All students were tested for IgG antibody levels (by enzyme-linked immunosorbent assay) and CMI (by interferon-γ (IFN-γ release assay).
Results: The IgG antibody and IFN-γ values decreased significantly in Group 1 during the 2 years postvaccination, while antibody titers in Group 2 did not decrease over this interval. The proportion of Group-1 individuals with HI antibody titers ≤ 1:16 increased to 27/38 (71.1%) at two years following vaccination, compared with 6/26 (23.1%) in Group 2. No correlation of IgG antibody titers was observed in Group 1 between one month and two years after vaccination. However, a strong correlation (r=0.85, p<0.00001) was detected in Group 2 between two years ago and the present. The correlation of IFN-γ values in Group 1 between one month and two years after vaccination was 0.614 (p<0.00005). When the subjects were classified by CMI status, the numbers of individuals who were intermediate and negative for IgG antibody at two years after vaccination were 1 and 0 of 13 subjects, 3 and 1 of 9 subjects, and 3 and 2 of 16 subjects in Group 1, respectively, while the antibody-positive status was maintained in all subjects in Group 2.
Conclusion: The IgG antibody and IFN-γ values decreased in distinct ways during the 2 years of the study; the persistence of the seropositivity was associated with CMI status.