Figure 1

HSV-1 0∆NLS vaccination induces more CD4⁺ T_FH cells along with germinal center B cells. C57BL/6 mice (n = 6–7/group) were injected in the footpad with the HSV-1 parental (GFP105) or live-attenuated HSV-1 0ΔNLS at 10⁵ plaque forming units in 10 µl PBS. At day 7 or day 21 post immunization, the PLN and spleen were harvested and CD4⁺ T_FH cell and GC B cell numbers were assessed by flow cytometry. Panel A and B present gating strategy for discrimination of CD4⁺ T_FH cells and GC B cells, respectively. Panel C shows the CD4⁺ T_FH cell numbers found in the PLN at day 7 post-vaccination whereas panel D shows the CD4 + TFH cell numbers found in the spleen at day 21 post-vaccination. Panels E and F present the GC B cell numbers in the PLN at day 7 and in the spleen at day 21 post-vaccination, respectively. Panel G shows a representative flow cytometry profile of intracellular IL-21 cytokine staining in CD4⁺ T_FH cells after stimulation with PMA and ionomycin. Panel H summarizes the results showing frequency of CD4⁺ T_FH cells expressing IL-21. Panel I includes ELISA results quantifying the amount of IL-21 recovered in the PLN at day 7 post-vaccination normalized to tissue weight. The values are presented as mean ± SEM, **p < 0.01 and *p < .05 as determined by Student’s t-test.