Fitness costs limit influenza A virus hemagglutinin glycosylation as an immune evasion strategy




Das SR, Hensley SE, David A, Schmidt L, Gibbs JS, Puigbo P, Ince WL, Bennink JR, Yewdell JW

PublisherNATL ACAD SCIENCES

2011

Proceedings of the National Academy of Sciences of the United States of America

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

P NATL ACAD SCI USA

108

51

E1417

E1422

6

0027-8424

DOIhttps://doi.org/10.1073/pnas.1108754108



Here, we address the question of why the influenza A virus hemagglutinin (HA) does not escape immunity by hyperglycosylation. Uniquely among dozens of monoclonal antibodies specific for A/Puerto Rico/8/34, escape from H28-A2 neutralization requires substitutions introducing N-linked glycosylation at residue 131 or 144 in the globular domain. This escape decreases viral binding to cellular receptors, which must be compensated for by additional substitutions in HA or neuraminidase that enable viral replication. Sequence analysis of circulating H1 influenza viruses confirms the in vivo relevance of our findings: natural occurrence of glycosylation at residue 131 is always accompanied by a compensatory mutation known to increase HA receptor avidity. In vaccinated mice challenged with WT vs. H28-A2 escape mutants, the selective advantage conferred by glycan-mediated global reduction in antigenicity is trumped by the costs of diminished receptor avidity. These findings show that, although N-linked glycosylation can broadly diminish HA antigenicity, fitness costs restrict its deployment in immune evasion.



Last updated on 2024-26-11 at 15:11