Antibody dependent enhancement of frog virus 3 infection | Eaton et al. Virology Journal 2010 7 41 http content 7 1 41 VIROLOGY JOURNAL RESEARCH Open Access Antibody dependent enhancement of frog virus 3 infection Heather E Eaton Emily Penny Craig R Brunetti Abstract Background Viruses included in the family Iridoviridae are large icosahedral dsDNA viruses that are subdivided into 5 genera. Frog virus 3 FV3 is the type species of the genus Ranavirus and the best studied iridovirus at the molecular level. Typically antibodies directed against a virus act to neutralize the virus and limit infection. Antibody dependent enhancement occurs when viral antibodies enhance infectivity of the virus rather than neutralize it. Results Here we show that anti-FV3 serum present at the time of FV3 infection enhances infectivity of the virus in two non-immune teleost cell lines. We found that antibody dependent enhancement of FV3 was dependent on the Fc portion of anti-FV3 antibodies but not related to complement. Furthermore the presence of anti-FV3 serum during an FV3 infection in a non-immune mammalian cell line resulted in neutralization of the virus. Our results suggest that a cell surface receptor specific to teleost cell lines is responsible for the enhancement. Conclusions This report represents the first evidence of antibody dependent enhancement in iridoviruses. The data suggests that anti-FV3 serum can either neutralize or enhance viral infection and that enhancement is related to a novel antibody dependent enhancement pathway found in teleosts that is Fc dependent. Background Following a viral infection an immune response is elicited by the host which includes both an innate and adaptive response. During the adaptive immune response antibodies are produced that are designed to recognize and neutralize a pathogen. Typically viral antibodies neutralize a virus by preventing the attachment of specific cell surface receptors with viral glycoproteins while also activating the complement system. However not all .
