Evolutionary consequences of a decade of vaccination against subtype H6N2 influenza

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Authors

Rauff, Dionne
Strydom, Christine
Abolnik, Celia

Journal Title

Journal ISSN

Volume Title

Publisher

Elsevier

Abstract

The evolutionary dynamics of chicken-origin H6N2 viruses isolated in South Africa between 2002 and 2013 were investigated. Sub-lineages I and II continued to co-circulate under vaccination pressure, but sublineage I, from which the inactivated vaccine was derived, displayed a markedly higher mutation rate and a three-fold increase in the emergence of potential antigenic sites on the globular head of HA compared to sub-lineage II. Immunological pressure culminated in a critical phenotypic change as four of the five isolates from 2012-2013 had lost the ability to haemagglutinate chicken erythrocytes, correlating with a pattern of predicted O-glycosylation sites at residues 134, 137 and 141 within the critical 130 loop of the receptor binding domain site. Coassortment of the HA, NA and M genes in the respective sub-lineages contrasted reassortment of the other internal protein genes, and the vaccine seed strain itself was the probable donor of segments to sub-lineage II field strains.

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Keywords

Avian influenza, H6N2, Glycosylation, Reassortment, Coassortment, Genetic drift, Vaccines

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Citation

Rauff, D, Strydom, C & Abolnik, C 2016, 'Evolutionary consequences of a decade of vaccination against subtype H6N2 influenza', Virology, vol. 498, pp. 226-239.