A Nanoparticle-Poly(I:C) Combination Adjuvant Enhances the Breadth of the Immune Response to Inactivated Influenza Virus Vaccine in Pigs

Abstract

Intranasal vaccination elicits secretory IgA (SIgA) antibodies in the airways, which is required for cross-protection against influenza. To enhance the breadth of immunity induced by a killed swine influenza virus antigen (KAg) or conserved T cell and B cell peptides, we adsorbed the antigens together with the TLR3 agonist poly(I:C) electrostatically onto cationic alpha-D-glucan nanoparticles (Nano-11) resulting in Nano-11-KAg-poly(I:C) and Nano-11-peptides-poly(I:C) vaccines. In vitro, increased TNF-α and IL-1ß cytokine mRNA expression was observed in Nano-11-KAg-poly(I:C)-treated porcine monocyte-derived dendritic cells. Nano-11-KAg-poly(I:C), but not Nano-11-peptides-poly(I:C), delivered intranasally in pigs induced high levels of cross-reactive virus-specific SIgA antibodies secretion in the nasal passage and lungs compared to a multivalent commercial influenza virus vaccine administered intramuscularly. The commercial and Nano-11-KAg-poly(I:C) vaccinations increased the frequency of IFNγ secreting T cells. The poly(I:C) adjuvanted Nano-11-based vaccines increased various cytokine mRNA expressions in lymph nodes compared to the commercial vaccine. In addition, Nano-11-KAg-poly(I:C) vaccine elicited high levels of virus neutralizing antibodies in bronchoalveolar lavage fluid. Microscopic lung lesions and challenge virus load were partially reduced in poly(I:C) adjuvanted Nano-11 and commercial influenza vaccinates. In conclusion, compared to our earlier study with Nano-11-KAg vaccine, addition of poly(I:C) to the formulation improved cross-protective antibody and cytokine response.

Intranasal Delivery of Inactivated Influenza Virus and Poly(I:C) Adsorbed Corn-Based Nanoparticle Vaccine Elicited Robust Antigen-Specific Cell-Mediated Immune Responses in Maternal Antibody Positive Nursery Pigs

“…The Nano-11 based vaccine formulation was prepared using KAg adsorbed with or without the TLR-3 agonist Poly(I:C) electrostatically on Nano-11 leading to two vaccine formulations, Nano-11-KAg+Poly(I:C) or Nano-11-KAg, respectively. Furthermore, one more formulation KAg+Poly(I:C) was prepared and used as a control ( 17 ). Poly(I:C) was procured (Invivogen, CA, USA) and dissolved as per the manufacturer’s instructions and aliquots were stored frozen.…”

“…PBMCs isolated at day 34 post-prime vaccination (prechallenge) and DPC6 and TBLN mononuclear cells (MNCs) isolated at DPC6 were restimulated with H1N2-OH10 and H1N1-OH7 SwIAV KAg [10 ug/ml] for 72 hours (hr) in vitro . The cells were labeled and analyzed by flow cytometry for frequencies of cytotoxic T-lymphocyte (CTL) [CD3 + CD4 - CD8α + β + ], T-helper/Memory cells [CD3 + CD4 + CD8α + β - ], T-helper cells [CD3 + CD4 + CD8α - β - ], and naïve T-helper cells [CD3 + CD4 + CD8α - β - CD27 + ] as described previously ( 17 , 30 ).…”

Nano-based approaches in the development of antiviral agents and vaccines

“…Successful nasal immunization was achieved in rabbits immunized with whole influenza virus incorporated into a mucoadhesive carrier chitosan; significant levels of anti-hemagglutinin antibody, local anti-influenza virus IgA, systemic IL-2, and IFN-γ were detected in the serum [ 131 ]. Another successful nanovaccine was established by adsorbing both inactivated swine influenza virus antigens and TLR3 agonist poly(I:C) onto cationic alpha- d -glucan NPs [ 132 ]. The poly(I:C) adjuvant promoted cytokine production; thus, the nanovaccine induced high levels of virus-neutralizing antibodies in bronchoalveolar lavage fluid and IgA antibodies in the nasal passage and lungs of immunized pigs [ 132 ].…”

“…Another successful nanovaccine was established by adsorbing both inactivated swine influenza virus antigens and TLR3 agonist poly(I:C) onto cationic alpha- d -glucan NPs [ 132 ]. The poly(I:C) adjuvant promoted cytokine production; thus, the nanovaccine induced high levels of virus-neutralizing antibodies in bronchoalveolar lavage fluid and IgA antibodies in the nasal passage and lungs of immunized pigs [ 132 ]. Beneficial effects of mucosal immunization with NPs were also observed in chickens immunized via the aerosol route.…”

Image_3.tif

“…, a n d n a ï v e T -h e l p e r c e l l s [CD3 + CD4 + CD8ab -CD27 + ] as described previously (17,30).…”