Different HIV pox viral vector-based vaccines and adjuvants can induce unique antigen presenting cells that modulate CD8 T cell avidity

The lung-derived dendritic cell (LDC) recruitment following intranasal (i.n.) vaccination of different poxviral vector-based vaccines/adjuvants were evaluated to decipher how these factors influenced CD8⁺ T cell avidity. Compared to the standard i.n. recombinant fowlpox virus (FPV)-HIV vaccination, the FPV-HIV IL-13Rα2 or IL-4Rα antagonist adjuvanted vaccines that induced higher avidity CD8⁺ T cells, also recruited significantly elevated MHCII⁺ CD11c⁺ CD11b⁺ CD103^- CD64^- MAR-1^- conventional DC (cDCs) to the lung mucosae (hierarchy: IL-4R antagonist>IL-13Rα2>unadjuvanted). In contrast, elevated CD11b^- CD103⁺ LDCs were detected in animals that received recombinant HIV vaccinia virus (rVV) or Modified Vaccinia Ankara virus (MVA) vector-based vaccines. Adoptive transfer studies indicated that CD11b^- CD103⁺ LDCs significantly dampened HIV-specific CD8⁺ T cell avidity compared to CD11b⁺ CD103^- LDCs. Collectively; our observations revealed that rFPV vector prime and transient inhibition of IL-4/IL-13 at the vaccination site favoured the recruitment of unique LDCs, associated with the induction of high quality immunity.