FIGURE 2.

NK cell responses to vaccine Ag are affected by HCMV infection. PBMCs were cultured in vitro for 18 h with medium alone, LCC, killed whole-cell pertussis (Per), inactivated whole H1N1 influenza virus (H1N1), Per + LCC, H1N1 + LCC, or HCC. Donors were stratified into HCMV⁻ (−) and HCMV⁺ (+) groups. Responses were measured as the percentage of NK cells expressing CD25 (A), coexpressing CD25/IFN-γ (B) or CD107a (C). Bivariate regression of age against responses to Per + LCC was performed for the percentage of NK cells expressing CD25 (D), CD25/IFN-γ (E), and CD107a (F). Each data point represents one donor, n = 152, except for H1N1 and H1N1 + LCC where n = 52. Bar graphs denote medians. NB, all Ag stimulations induced statistically significant increases in expression of CD25, CD25/IFN-γ, and CD107a over background (medium alone for pertussis/H1N1, or LCC for pertussis+LCC/H1N1+LCC; p < 0.05 in all cases), except that H1N1 did not induce a significant increase in CD25⁺IFN-γ⁺ NK cells in HCMV⁺ donors (p = 0.416). Data were analyzed in Prism using, one-tailed Mann–Whitney U tests. ****p ≤ 0.0001, ***p < 0.001, **p < 0.01, *p < 0.05.