FIG. 2.

Expression of CD69 on OT-I CD8⁺ and OT-II CD4⁺ T cells after in vitro interaction with recombinant S. gordonii. CD69 expression was assessed in OT-I and OT-II cells incubated for 24 h with control strain GP1295 (open histogram bars) or recombinant vaccine strain GP1456 (filled histogram bars) at different doses (0.1, 1, and 10 bacteria per cell). The percentage of CD69-positive OT-I CD8⁺ or OT-II CD4⁺ T cells is reported as the mean ± the standard error of the means of two individual experiments, performed in triplicate. *, P ≤ 0.05; **, P ≤ 0.01 versus GP1295.