Effect of passive immunization on immunogenicity and protective efficacy of vaccination against a Mexican low-pathogenic avian H5N2 influenza virus.
Bottom Line: Booster doses of vaccine reduced the immunosuppressive effects of the administered sera.Vaccine efficacy against LP H5N2 in Mexico can be severely reduced by maternal antibodies.Source-dependent antisera effects offer the possibility of further elucidation of the immunosuppressive components involved.
Affiliation: Division of Virology, Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, USA.Show MeSH
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Mentions: In addition to virus shedding, a four‐fold increase in HI titer 14 dpc was also suggestive of infection. All birds in the naïve group met these criteria, and 2 birds from the vaccine control group increased their titers after challenge (Figure 1). Of the experimental groups, group 6 (neat, field‐derived post‐vaccination antiserum) had the most animals that showed increased titers (n = 7), and group 3 (neat, laboratory‐derived post‐infection antiserum) had the fewest animals with increases (n = 3). Some of the animals in the vaccine control group and groups 3–5 showed increased HI titers, but did not shed after challenge. Although vaccination may not have been effective in preventing infection in these specific instances, it did eliminate viral shedding. If both seroelevation and virus shedding are taken as evidence of infection, then all birds passively immunized with field‐derived post‐vaccination antisera had evidence of infection, despite vaccination with or without boost.
Affiliation: Division of Virology, Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, USA.