The Fcγ receptor expression profile on porcine dendritic cells depends on the nature of the stimulus

Nowadays, vaccine research focuses on the development and implementation of subunit vaccines into existing or future vaccination platforms. However, recombinant proteins are often poor immunogens, necessitating adjuvants to activate and direct the immune response. Alternatively, the immunogenicity of antigens can be enhanced by targeting antigens to Fcγ receptors on antigen-presenting cells and as dendritic cells (DCs) are the most potent antigen-presenting cells, orchestrating innate and adaptive immune responses, they are attractive for this selective targeting of vaccine antigens. However, DCs express both inhibitory and activating Fcγ receptors and regulating DC function is pivotal to ensure the induction of effective immune responses and to prevent exaggerated immune responses causing inflammation. Previously, we demonstrated that immature porcine MoDC express FcγRII and FcγRIII on their cell surface, which mediate a functional DC maturation upon activation through immune complexes. In the present study, we clearly demonstrate that immune complexes are primarily internalised via FcγRIII, resulting in DC maturation and that depending on the DC maturation stimulus the FcγR expression profile is differentially regulated. These results could not only expedite the development of FcγR-targeting based vaccines, but also provide insights into FcγR-mediated autoimmune diseases.