U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

PubAg

Main content area

Selection and antigenic characterization of immune-escape mutants of H7N2 low pathogenic avian influenza virus using homologous polyclonal sera

Author:
Ioannis Sitaras, Erica Spackman, Mart C.M. de Jong, D. Joshua Parris
Source:
Virus research 2020 v.290 pp. 198188
ISSN:
0168-1702
Subject:
Influenza A virus, amino acid substitution, antigenic variation, chickens, hemagglutinins, high-throughput nucleotide sequencing, mutants, polyclonal antibodies, vaccination, viral antibodies, viral antigens, viral load
Abstract:
Understanding the dynamics of the selection of influenza A immune escape variants by serum antibody is critical for designing effective vaccination programs for animals, especially poultry where large populations have a short generation time and may be vaccinated with high frequency. In this report, immune-escape mutants of A/turkey/New York/4450/1994 H7N2 low pathogenic avian influenza virus, were selected by serially passaging the virus in the presence of continuously increasing concentrations of homologous chicken polyclonal sera. Amino acid mutations were identified by sequencing the parental hemagglutinin (HA) gene and every 10 passages by both Sanger and deep sequencing, and the antigenic distance of the mutants to the parent strain was determined. Progressively, a total of five amino acid mutations were observed over the course of 30 passages. Based on their absence from the parental virus with deep sequencing, the mutations appear to have developed de novo. The antigenic distance between the selected mutants and the parent strain increased as the number of amino acid mutations accumulated and the concentration of antibodies had to be periodically increased to maintain the same reduction in virus titer during selection. This selection system demonstrates how H7 avian influenza viruses behave under selection with homologous sera, and provides a glimpse of their evolutionary dynamics, which can be applied to developing vaccination programs that maximize the effectiveness of a vaccine over time.
Agid:
7133649
Handle:
10113/7133649