FIGURE 2.

In vitro EBV-induced activation and expansion of B cells differs with age and serostatus to CMV. CBMC or PBMC derived from 2- or 5-y-old children were subjected to in vitro EBV infection and cultured for 14 d when the characteristics of the CD19⁺ B cell population were assessed by flow cytometry. (A) Frequencies of CD19⁺ cells on days 7 and 14 postinfection. (B and E) One representative example for each group of CD19⁺ cell subset proportions based on IgD and CD27 expression. (C, D, and F) Comparison of EBV-induced changes in the CD19⁺ IgD⁺CD27⁺ and IgD⁻CD27⁺ cell subsets between groups. In (E) and (F), data from the 2-y-old children are divided into CMV-seronegative (CMV⁻) or -seropositive (CMV⁺) groups. Open circles depict outlier values. CB (n = 5), 2-y-olds (n = 15, CMV⁻, n = 9, and CMV⁺, n = 6) and 5-y-olds (n = 8). **p < 0.01, ***p < 0.001.