Vaccination-and-challenge schedules with longitudinal serum antibody responses in the V+M group prechallenge. (A) Schematic representation of vaccination-and-challenge schedules. Groups: V, vaccine alone; V+M, vaccine plus microbicide; M, microbicide alone; C, control. Green vertical arrows indicate i.n. vaccinations with R848 at weeks 0, 4 and 8; red vertical arrows indicate i.m. vaccinations with MF59 at weeks (w) 16 and 28; blue vertical arrows indicate 12 challenges in the absence of microbicide (weeks 39 to 59 and 60 to 80); and black vertical arrows indicate 12 challenges in the presence of microbicide (weeks 39 to 60). (B to E) SF162 serum IgG responses (B), SF162 serum IgA responses (C), TV-1 serum IgG responses (D), and serum IgA TV-1 responses (E) in the V+M group, all prechallenge.