Mucosal Application of gp140 Encoding DNA Polyplexes to Different Tissues Results in Altered Immunological Outcomes in Mice

Abstract

Increasing evidence suggests that mucosally targeted vaccines will enhance local humoral and cellular responses whilst still eliciting systemic immunity. We therefore investigated the capacity of nasal, sublingual or vaginal delivery of DNA-PEI polyplexes to prime immune responses prior to mucosal protein boost vaccination. Using a plasmid expressing the model antigen HIV CN54gp140 we show that each of these mucosal surfaces were permissive for DNA priming and production of antigen-specific antibody responses. The elicitation of systemic immune responses using nasally delivered polyplexed DNA followed by recombinant protein boost vaccination was equivalent to a systemic prime-boost regimen, but the mucosally applied modality had the advantage in that significant levels of antigen-specific IgA were detected in vaginal mucosal secretions. Moreover, mucosal vaccination elicited both local and systemic antigen-specific IgG+ and IgA+ antibody secreting cells. Finally, using an Influenza challenge model we found that a nasal or sublingual, but not vaginal, DNA prime/protein boost regimen protected against infectious challenge. These data demonstrate that mucosally applied plasmid DNA complexed to PEI followed by a mucosal protein boost generates sufficient antigen-specific humoral antibody production to protect from mucosal viral challenge.

Enhanced Immunogenicity of an HIV-1 DNA Vaccine Delivered with Electroporation via Combined Intramuscular and Intradermal Routes

“…To assess gamma interferon (IFN-␥) T cell responses, cultures of lymphocytes from spleens were prepared as described previously (18,19 Immunoglobulin ELISA and avidity assay. A quantitative immunoglobulin enzyme-linked immunosorbent assay (ELISA) protocol described previously (18,19) was followed. Briefly, 5 g/ml gp140-coated ELISA plates were blocked with 200 l/well 1% bovine serum albumin and 0.05% phosphate-buffered saline (PBS)-Tween 20 (PBST).…”

“…IFN-␥ enzyme-linked immunosorbent spot (ELISpot) assays (Mabtech, United Kingdom) were carried out on splenocytes per the manufacturer's instructions and as described previously (18,19). Plates were blocked for 30 min using complete RPMI before addition of 5 ϫ 10 6 cells/ml.…”

DNA Vaccines for the Induction of Immune Responses in Mucosal Tissues

“…In subsequent i.n. challenge with live murine-adapted X-31 (H3N2) influenza virus, statistically significant protection was confirmed (Mann et al, 2013). …”

CD71 targeting boosts immunogenicity of sublingually delivered influenza haemagglutinin antigen and protects against viral challenge in mice

“…To test this, we evaluated whether Tf-HA could boost responses after sublingual priming with a DNA vaccine expressing HA. In previous studies, we have demonstrated that HA delivered as DNA can induce a potent immune response [14] and have demonstrated that mucosal DNA delivery can be potentiated by PEI [10]. Mice were immunized three times with DNA sublingually and subsequently boosted with HA alone or Tf-HA.…”

“…The sublingual route of oral vaccine delivery has long been investigated due to its numerous antigen sampling points and organized lymphoid structures [7][8][9][10]. However, it has had limited success in larger animals [11] and therefore strategies to boost efficacy are required.…”