Live-Animal Assay for Identifying Correlates of Cross-Protection for Swine Influenza Virus Vaccines When Vaccinated in Presence of Maternal Antibody
Project Number: 3625-32000-109-10
Start Date: Aug 01, 2014
End Date: Aug 01, 2015
Current vaccines used to control swine influenza A virus (SIV) include inactivated products delivered by intramuscular administration. While these types of vaccines induce a peripheral antibody response that allows serum antibody to be used in a hemagglutination inhibition (HI) assay to evaluate functional antibody to SIV antigen, next generation IAV vaccines, particularly intranasally delivered live-attenuated influenza virus (LAIV), typically do not induce a robust serum antibody response. However, LAIV platforms have been shown to be highly efficacious, even when delivered in the face of maternal antibody. But, assays that have recently been developed in our lab to evaluate immunogenicity and predict cross-protection with LAIV do not apply to studies in which LAIV is administered in the presence of maternally-derived antibody (MDA). Thus, if these newer vaccine platforms are going to be used, particularly in the current climate of vaccinating sows with WIV, better antemortem assays are needed for evaluating vaccination status, evaluating cross-reactivity to drifted viruses, and ultimately, predicting cross-protection when LAIV is given to piglets with MDA. The purpose of this proposal is to utilize different assays to identify at least one that could be used at the diagnostic level to predict protection/cross-protection to field viruses following intranasal vaccination with different next generation swine IAV vaccines when given in presence of MDA
Preliminary data suggests that evaluating mucosal antibody (nasal wash or oral fluids) will be a useful sample for predicting cross-reactive and protection immunity following LAIV vaccination in naïve piglets. Additional data indicates this approach may not work when LAIV is given to MDA-positive piglets; instead, measures of cell-mediated immunity may be more valuable. These two approaches will be evaluated in MDA- and MDA+ piglets to identify the best assay.