CXCR3 expression on AFCs and GC B cells by responding CD8 T cells is induced by IFN-γ. Chimeras were constructed by transfer of OTII or both OTI and OTII cells in C57Bl/6 recipients and were immunized with alumOVA in the footpads 1 day later. Neutralizing anti–IFN-γ antibody or isotype control antibody was given to 2 groups of OTI and OTII chimeras at the time of immunization and 3 days later. Seven days after immunization, the percentage of CXCR3⁺ cells in the draining LN was assessed by flow cytometry for: (A) CD138⁺B220^int AFC or (B) B220⁺GL7⁺Fas⁺ GC B cells. (C) The geometric mean ± SD of CD138⁺B220^int AFC or B220⁺GL7⁺Fas⁺ CG B cells per popliteal LN in the different types of chimeras is shown. Data are derived from 2 independent experiments with a total of 7 or 8 mice per groups. The significance of differences is assessed by 2-tailed Mann-Whitney nonparametric statistics. NS indicates not significant. (D) Numbers on dot plots indicate the percentage of AFCs expressing CXCR4 ± SD for the groups of immunized WT chimeras that had received OTII + OTI cells and were treated with anti–IFN-γ neutralizing antibody or control antibody. The significance of differences between groups is assessed by 2-tailed Mann-Whitney nonparametric statistics.