IgM and IgY CDR3 sequences from naive, vaccinated and/or infected chickens

Avian influenza viruses (AIVs) are a major economic burden to the poultry
industry, and pose serious zoonotic risk, with human infections being
reported every year. To date, the vaccination of birds remains the most
important method for the prevention and control of AIV outbreaks. Most
national vaccination strategies against AIV infection use whole-virus
inactivated vaccines, which predominantly trigger a systemic
antibody-mediated immune response. There are currently no studies that
have examined the antibody repertoire of birds that were infected with
and/or vaccinated against AIV. To this end, we evaluate the changes in the
H9N2-specific IgM and IgY repertoires in chickens subjected to
vaccination(s) and/or infectious challenge. We show that a large
proportion of the IgM and IgY clones were shared across multiple
individuals, and these public clonal responses are dependent on both the
immunisation status of the birds and the specific tissue that was
examined. Furthermore, analysis reveals specific clonal expansions which
are restricted to particular H9N2 immunisation regimes. These results
indicate that both the nature and number of immunisations are important
drivers of the antibody responses and repertoire profiles in chickens
following H9N2 antigenic stimulation. We discuss how the repertoire
biology of avian B cell responses may affect the success of AIV
vaccination in chickens, in particular the implications of public versus
private clonal selection.