The quantitative analysis showed that infected CD4+ T cells were detected in only some of the FV-mWasabi-infected mice, which corresponds with the findings from the target cell analysis described above (Fig. 2C and D), but they already appeared in early acute infection and increased in frequency toward the late phase when the infected CD4+ T cell population was clearly dominated by lymph node Tfh and Tfr (exhibiting significantly higher levels than two other subsets; P < 0.05; Fig. 5D). Here, TFRC is linked to infection.