|GAUGER, PHILLIP - Iowa State University|
Submitted to: Autumn Immunology Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/14/2014
Publication Date: N/A
Technical Abstract: Vaccine associated enhanced respiratory disease (VAERD) has been described in pigs vaccinated with whole-inactivated influenza virus (WIV) following infection with heterologous influenza A virus (IAV). WIV vaccination elicits production of non-neutralizing antibody that is cross-reactive to the challenge IAV strain suggesting immune complexes or antibody dependent cell-mediated cytotoxicity could contribute to VAERD pathology. Moreover, pathological findings in VAERD lungs include significant lymphocytic infiltration and increased levels of proinflammatory cytokines. A characterization of lymphocytes in lungs following IAV challenge has not been completed and such information will contribute to understanding the mechanism of VAERD versus cross-protection. WIV vaccinated pigs had a transient increase in IAV-specific IFNgamma secreting cells (SC) in peripheral blood and numbers were heightened after challenge. Post-challenge IAV-specific IFNgamma SC in the lungs were increased in pigs with VAERD compared to non-vaccinated, challenged controls. CD8 T cells and NK cells were significantly higher in the lungs of pigs protected from homologous challenge, suggesting these cells may play a role in protection. Interestingly, pigs with VAERD had a significant increase of CD4/CD8 double-positive T cells that was not observed in pigs without VAERD. These data further describe the lymphocytic pathology seen in VAERD and suggest double-positive memory T cells may contribute to disease pathology.