Immune Responses to Pandemic H1N1 Influenza Virus Infection in Pigs Vaccinated with a Conserved Hemagglutinin HA1 Peptide Adjuvanted with CAF®01 or CDA/αGalCerMPEG

Abstract

This study aimed to evaluate the immune response and protection correlates against influenza virus (IV) infection in pigs vaccinated with the novel NG34 HA1 vaccine candidate adjuvanted with either CAF®01 or CDA/αGalCerMPEG (αGCM). Two groups of six pigs each were vaccinated intramuscularly twice with either NG34 + CAF®01 or NG34 + CDA/αGCM. As controls, groups of animals (n = 6 or 4) either non-vaccinated or vaccinated with human seasonal trivalent influenza vaccine or NG34 + Freund’s adjuvant were included in the study. All animal groups were challenged with the 2009 pandemic (pdm09) strain of H1N1 (total amount of 7 × 106 TCID50/mL) via intranasal and endotracheal routes 21 days after second vaccination. Reduced consolidated lung lesions were observed both on days three and seven post-challenge in the animals vaccinated with NG34 + CAF®01, whereas higher variability with relatively more severe lesions in pigs of the NG34 + CDA/αGCM group on day three post-infection. Among groups, animals vaccinated with NG34 + CDA/αGCM showed higher viral loads in the lung at seven days post infection whereas animals from NG34 + CAF®01 completely abolished virus from the lower respiratory tract. Similarly, higher IFNγ secretion and stronger IgG responses against the NG34 peptide in sera was observed in animals from the NG34 + CAF®01 group as compared to the NG34 + CDA/αGCM. NG34-vaccinated pigs with adjuvanted CAF®01 or CDA/αGCM combinations resulted in different immune responses as well as outcomes in pathology and viral shedding.

Vaccination against swine influenza in pigs causes different drift evolutionary patterns upon swine influenza virus experimental infection and reduces the likelihood of genomic reassortments

“…Furthermore, the hemagglutination inhibition (HI) assay was performed in samples collected at day of seeders challenge and each pig euthanasia day as previously described ( López-Serrano et al., 2021 ). All tested serum samples were first treated with RDE II Seiken (Denka Chemicals, Tokyo, Japan) at 37°C during 18 h and later inactivated at 56°C for 1 h. Unspecific hemadsorption inhibitors were removed by adding a volume of 50% chicken red blood cells (RBCs) and later diluted in PBS (1:10).…”

Identification and Characterization of Swine Influenza Virus H1N1 Variants Generated in Vaccinated and Nonvaccinated, Challenged Pigs

“…Three weeks after the second immunization (42 dpv), animals from both groups were challenged using two administration routes: intranasal (1 mL per nostril) with a diffuser device (MAD Nasal, Teleflex, Morrisville, NC, USA) and endotracheal (5 mL), by intubation of the animal restrained with an immobilizing pig lasso, both with 10 6 TCID 50 of the A/Swine/Spain/01/2010 (H1N1) [ 24 ]. After challenge, pigs were monitored daily for clinical signs and animal behavior in a blind manner by trained veterinarians.…”

Immune responses following neonatal vaccination with conserved F4 fragment of VtaA proteins from virulent Glaesserella parasuis adjuvanted with CAF®01 or CDA

“…In agreement with this idea and previous observations with CAF®01, F4+CAF®01 vaccination significatively reduced the nasal colonization by G . parasuis [28] , [44] , [45] . A reduction of G. parasuis nasal colonization after vaccination has been also shown with another subunit vaccine, TbpB, using different adjuvants and administration routes [46] .…”

“…Concentration of PBMCs was adjusted and 5 × 10 5 cells/well were plated in flat-bottomed 96-well tissue culture plates with RPMI 1640 medium (Lonza, Basel, Switzerland) supplemented with 10% fetal bovine serum (FBS) (Euroclone, Milan, Italy), 1% glutamine (Gibco Life Technologies, Madrid, Spain), 1% penicillin-streptomycin (Gibco Life Technologies, Madrid, Spain) and 0.05 mM of β-mercaptoethanol (Sigma-Aldrich, Madrid, Spain). PBMCs were freshly used to perform an IFN-γ Enzyme-Linked ImmunoSpot Assay (ELISPOT), following a protocol described before [28] , with minor modifications. Briefly, high binding 96-well plates (Costar Corning Incorporated, New York, NY, USA) pre-coated with 250 ng of porcine anti-IFN-γ per well (Clone P2G10 Mouse IgG1, BD Pharmingen™, San José, CA USA) were used to plate PBMCs.…”