Early immune responses in skin and lymph node after skin delivery of Toll-like receptor agonists in neonatal and adult pigs

The skin is potentially an important vaccine delivery route facilitated by a high number of resident antigen presenting cells (APCs), which are known to be stimulated different Toll-like receptor agonists (TLRa). In this study, neonatal and adult pigs were vaccinated in the using dissolving microneedle patches investigate immuno-stimulatory potential TLRa possible age-dependent differences early after vaccination. These contained TLR1/2a (Pam3Cys), TLR7/8a (R848) or TLR9a (CpG ODN) combined with inactivated porcine reproductive respiratory syndrome virus (PRRSV) oil-in-water stable emulsion. Vaccinated draining lymph nodes analysed for immune response genes microfluidic high-throughput qPCR evaluate activation APCs. Skin pathology immunohistochemistry used local responses APCs skin, respectively. both pigs, vaccination induced most prominent inflammatory cell responses, particularly skin. histopathology showed comparable results vaccines. However, node more related upregulated compared pigs. We that could develop response, vaccination, regulation genes. Therefore, should considered when developing