Population immunity assessed by antibody landscaping as defined by the antigenic evolution of influenza A viruses (IAV) in swine and evolution of influenza A virus in swine in Brazil

Swine influenza presents a substantial disease burden for pig populations worldwide and poses a potential pandemic threat to humans. There is considerable diversity in both H1 and H3 influenza viruses circulating in swine due to the frequent introductions of viruses from humans and birds coupled with geographic segregation of global swine populations. Much of this diversity is characterized genetically but the antigenic relationships of these viruses remain poorly understood. Critically, it is the antigenic diversity that shapes the risk profile of swine influenza viruses in terms of their epizootic and pandemic potential.

Aims:

This project will build upon the foundation of previous work to antigenically characterize circulating IAV in swine with the goal of the new project to evaluate individual and population immunity to the circulating antigenic variants. The previous results established a baseline from which to measure ongoing antigenic evolution of contemporary swine isolates and quantify the distance from current human seasonal or swine vaccine strains. Antigenic cartography is a computational and mathematical tool developed at the University of Cambridge for the analysis of binding assay data, providing a quantification and visualization of antigenic data generated by hemagglutination inhibition (HI) assays. Here the student will characterize the antigenic impact of genetic changes in the hemagglutinin protein of influenza A viruses in swine and assess individual and population immunity to current antigenic variants.

This project will also utilize hemagglutination inhibition assays with the NADC reference serum panel, antigenic cartography and sequence analyisis tools to quantify swine influenza A virus evolution in Brazil.

Here the student will use advanced phylogenetic analyses, protein modeling, and antigenic cartography resources to further characterize IAV from swine in Brazil. An additional 78 isolates were collected from pigs in Brazil during 2010-2014 that have not yet been sequenced and none of the isolates have been antigenically characterized by the NADC reference panel and antigenic cartography. Using a common set of sera that includes current human seasonal viruses will allow incorporation of the Brazilian swine viruses into what is known for the USA and other reporting countries to gain a global understanding of the antigenic diversity of swine IAV.