Fig. 7

Sustained proliferation of B cells within the CNS following MCMV infection. a B cell proliferation within the infected brains was detected by gating on the CD45^hiCD11b^loCD19⁺ population of infiltrating leukocytes followed by analysis of Ki67 (anti-Ki67-APC) expression at 7, 14, 30, and 60 increasing proportion of B cells as time. Histograms presented are representative of two independent experiments. b Expression of transcripts for the B cell activating factor BAFF was assessed in RNA extracted from the brains of the infected animals at the indicated time points p.i. Data presented are mean ± SEM of two separate experiments. c Immunohistochemical staining showing expression of BAFF protein (CD257) within the brain co-localized to GFAP-expressing astrocytes. Twenty-five-micrometer sections of the infected brain shown were obtained at 30 increasing proportion of B cells as time d BAFFR expression on CD19⁺ B cells within infected brains was detected by gating on the CD45^hiCD11b^loCD19⁺ population of infiltrating leukocytes followed by analysis of BAFFR expression at 7, 14, 30, and 60 increasing proportion of B cells as time. Histograms presented are representative of two independent experiments. e Anti-BAFFR staining was used to determine the total number of B cells expressing BAFFR at the indicated time points p.i. Data (mean ± SD) are presented as absolute number of cells. f Anti-TACI and anti-BCMA staining was used to analyze expression of these receptors on brain-infiltrating B cells using flow cytometry at the early (7 d) and late (60 day) time points p.i. Histograms presented are representative of two independent experiments, and data presented are mean percentages from two animals per time point