| Popis: |
Harnessing dendritic cells for development of effective vaccines necessitates further understanding of the functional specialisation of distinct dendritic cell populations in vivo. We availed of polymeric dissolvable microneedle arrays laden with antigen encapsulated nanoparticles to target skin dendritic cell networks in mice and to investigate the capacity of different skin dendritic cell subsets to present antigen to antigen-specific naive T cells. Following in situ uptake, skin-resident dendritic cell subsets are able to deliver antigenen-capsulated poly-d,l-lactide-co-glycolide-acid nanoparticles to cutaneous draining lymph nodes where they subsequently induce significant expansion of antigen-specific T cells. This approach provides complete protection in vivo against both the development of antigen-expressing B16 melanoma tumours and a murine model of para-influenza, through the activation of antigen-specific cytotoxic CD8+ T cells. In addition, we demonstrate that Langerhans cells constitute the major subset capable of antigen cross-presentation to CD8+ T cells. Indeed, LCs are critical for effective immunisation using antigen-laden nanoparticles, as depletion of Langerhans cells dramatically reduces the proliferation of antigen-specific CD8+ T cells in vivo. Langerhans cells are also necessary for IFN-y and IL-17 production by antigen-specific CD4+ T cells. Moreover, we have explored the contribution of skin dendritic cell subsets for the generation of antigen-specific anti-tumour and anti-viral immune responses following microneedle immunisation in vivo and demonstrate that depletion of Langerhans cells significantly reduces protective immunity in both disease models. In addition, we show promising findings that nano-encapsulation facilitates antigen retention into skin layers and provides antigen stability in microneedles. Therefore, targeting of nano-encapsulated antigen to specific skin dendritic cell subsets, in particular to Langerhans cells, through dissolvable, biocompatible and self-disabling microneedles potentially provides a novel and promising technological platform for improved vaccination efficacy |
