Effect of various synthetic RNA motifs on specific antibody and T cell immunity. (a) The impact of various RNA pools (see Table 1) on adaptive immunity was measured in C57BL/6 mice coimmunized with OVA via the respiratory tract. Mice were immunized intratracheally, followed by two boosts 2 weeks apart by intranasal instillation. The antibody response was expressed as mean ± SEM of IgG endpoint titers (n = 4/group). As controls, we used dose-matched OVA in sterile PBS, OVA with CTB, and PBS alone, respectively. (b) Effect of various dsRNA motifs on the induction of antibody response to OVA; results are expressed as in a. The data are representative of two independent experiments. Inset: the ratio of mean IgG2a and IgG1 titers to OVA. The order from left to right is similar to that in the larger graph: PBS OVA, CTB OVA, pC:pG OVA, pI:pC OVA, and pA:pU OVA. (c) Magnitude and profile of T cell response induced by OVA together with various dsRNA motifs in female C57BL/6 mice. The results obtained by ELISpot analysis were expressed as mean ± SEM of the number of IFN-γ and IL-4 spot-forming colonies (SFCs) per spleen (n = 4/group). The results are representative of two independent experiments.