Serological characterization of guinea pigs infected with H3N2 human influenza or immunized with hemagglutinin protein

Abstract

BackgroundRecent and previous studies have shown that guinea pigs can be infected with, and transmit, human influenza viruses. Therefore guinea pig may be a useful animal model for better understanding influenza infection and assessing vaccine strategies. To more fully characterize the model, antibody responses following either infection/re-infection with human influenza A/Wyoming/03/2003 H3N2 or immunization with its homologous recombinant hemagglutinin (HA) protein were studied.ResultsSerological samples were collected and tested for anti-HA immunoglobulin by ELISA, antiviral antibodies by hemagglutination inhibition (HI), and recognition of linear epitopes by peptide scanning (PepScan). Animals inoculated with infectious virus demonstrated pronounced viral replication and subsequent serological conversion. Animals either immunized with the homologous HA antigen or infected, showed a relatively rapid rise in antibody titers to the HA glycoprotein in ELISA assays. Antiviral antibodies, measured by HI assay, were detectable after the second inoculation. PepScan data identified both previously recognized and newly defined linear epitopes.ConclusionsInfection and/or recombinant HA immunization of guinea pigs with H3N2 Wyoming influenza virus resulted in a relatively rapid production of viral-specific antibody thus demonstrating the strong immunogenicity of the major viral structural proteins in this animal model for influenza infection. The sensitivity of the immune response supports the utility of the guinea pig as a useful animal model of influenza infection and immunization.

Animal models for influenza virus pathogenesis, transmission, and immunology

“…Currently, guinea pigs are most often inoculated intranasally with virus suspended in a total volume of 300 μl of phosphate-buffered saline (PBS), divided evenly between each nostril ( Lowen et al, 2006 , Bouvier et al, 2008 , Mubareka et al, 2009 , Van Hoeven et al, 2009 , Sun et al, 2010 , Long et al, 2011 ). However, over the years a range of inoculum volumes – 200 μl ( Wetherbee, 1973 , Azoulay-Dupuis et al, 1984 ), 500 μl ( Phair et al, 1979 ), and 1 ml ( Kwon et al, 2009 , Bushnell et al, 2010 ) – have been used to infect guinea pigs. There is less consistency among different laboratories regarding the total volume of intranasal inoculation in ferrets: 200 μl ( Matsuoka et al, 2009 , Smith et al, 2011b ), 300 μl ( van den Brand et al, 2012 ), 500 μl ( Bodewes et al, 2011 , Lakdawala et al, 2011 , Herfst et al, 2012 , Kroeze et al, 2012 ), and 1 ml ( Herlocher et al, 2001 , Duan et al, 2010 , Gustin et al, 2011 ) volumes have been recently reported.…”

Animal Models Utilized for the Development of Influenza Virus Vaccines

“…Ferrets are commonly used to assess how well a vaccine protects from morbidity and transmission. Additionally, host antibody responses can be evaluated to determine whether a vaccine induced protective HAI titers [ 113 , 116 , 156 ]. Ferrets are typically infected via direct administration of virus into each nostril [ 85 ].…”

“…Sera is also collected prior to vaccination and at various timepoints during the study. It can be used to verify seroconversion and to measure the levels of vaccine specific antibody titers [ 156 ]. One study utilized guinea pigs to determine that intranasal vaccination using recombinant NA protein was sufficient to prevent transmission from an infected to naïve animal [ 72 ].…”

Evolution of H3N2 Influenza Virus in a Guinea Pig Model

“…Several animal models have been used to study influenza infection and immunity. Although mouse, rat, and ferret models dominate the recent literature [8] , [12] , [13] , [14] , [15] , publications from Lowen et al and Bushnell et al have advanced the Guinea pig as a relevant model of human influenza virus infection, transmission, and serology [8] , [16] . Guinea pigs are susceptible to infection by unadapted human influenza virus strains and can transmit the virus to cage mates via aerosol [8] .…”