hDEC205 targeting with adjuvant induces Gag-specific CD4⁺ T-cell responses. (A) hDEC205 Tg mice were injected intraperitonally with 10 μg of purified 3G9-HIV Gag p24, 3D6-p24, or control Ig-p24 fusion mAbs along with 50 μg of poly IC and 25 μg of anti-CD40 mAb. After 2 weeks, splenic T-cell responses to pools of p24 peptides were analyzed. FACS plots from a representative experiment and histograms from 3 independent experiments are shown in percentiles of CD3⁺, IFN-γ–producing CD4⁺ T cells; similar results were obtained for IL-2–producing cells (not shown). Asterisks for statistically significant changes (*P ≤ .05, **P ≤ .01). (B) As in panel A, but prime-boost immunizations with 3G9-HIV Gag p24 (left, in blue) or 3G9-SIV Gag p27 (right, in red), plus only poly ICLC as an adjuvant. (C) SIV Gag p41 was the immunizing antigen to test responses to p17 and p27 regions of Gag. (D) As in panel A, showing IFN-γ–producing T cells after immunization with 3G9-HIV Gag p24, but not control anti-human DC-SIGN-p24 (left), and also specific proliferation (CFSE dilution) to HIV Gag p24, not HIV Gag p17 peptides (right). hDEC205 Tg in C57BL/6 background (A-C) and crossed with B10.BR (D).