CXCR5 and infection: By 4-weeks post-infection and treatment, PbTII cells and polyclonal CD4+ T cells exhibit GC Tfh (PD1hi CXCR5hi), Tfh/TCM-like (CXCR5+ PD1lo) or Th1-TEM (CXCR5lo CXCR6+) memory phenotypes in the spleen (Fig 1A) [11,15].