Antigen Targeting of Porcine Skin DEC205⁺ Dendritic Cells

Dendritic cell (DC) targeting by DEC205⁺ cells effectively promotes the internalization of antigens that may trigger a specific immune response. In this study, we evaluated the ability of a recombinant antibody, anti-DEC205 (rAb ZH9F7), to trigger cellular endocytosis in subpopulations of DCs and targeted cells after intradermal injection and subsequent migration toward lymph nodes. Furthermore, the cellular immune response was evaluated in pigs after intradermal application of the antigenized rAb ZH9F7 combined with porcine circovirus type 2 cap antigen (rAb ZH9F7-Cap). We demonstrated that rAb ZH9F7 recognized conventional type 1 and 2 DCs from the blood and skin and monocytes. It promoted receptor-mediated endocytosis and migration of cDCs and moDCs toward regional lymph nodes. Intradermal application of rAb ZH9F7-Cap induced a higher frequency of IFN-γ-secreting CD4⁺CD8⁺ T lymphocytes and antibodies against Cap protein than that in the control group. In conclusion, the rAb ZH9F7-Cap system promoted the target of skin cDC1 and cDC2, provoking migration to the regional lymph nodes and inducing a Th1 response, as evidenced by the proliferation of double-positive CD4⁺CD8⁺ T cells, which correlates with an enhanced ability to target the cDC1 subset both in vitro and in vivo.