Fig. 6: MVA-induced innate response and its effect on shaping the adaptive immune response.

MVA immunization-induced inflammasome-mediated innate activation was higher in the MVA-IM group and lower in the MVA-ID group. The higher innate activation leads to high Th1, low Tfh and a high Th1/Tfh ratio. The migration of these higher numbers of Th1 cells to mucosal tissues could potentially lead to more number of target cells for SHIV infection. Lower innate activation leads to high Tfh, low Th1 and low Th1/Tfh. These higher Tfh cells provide greater B cell help. Low Th1 and low Th1/Tfh were associated with higher vaginal IgA and higher serum ADP activity, which, in turn, were associated with better protection. Solid arrows represent observed associations and dotted arrows represent predicted associations.