Purification and characterization of monoclonal IgG antibodies recognizing Ebola virus glycoprotein

Han, Baek-Sang; Jang, Ho-Young; Racine, Trina; Qiu, Xiangguo; Sin, Jeong-Im

In this study, we observed that vaccination with DNA vaccines encoding cell membrane-targeting viral antigens led to induction of IgG antibodies recognizing the native forms of the antigens expressed on the cell surface. For instance, immune sera, displaying reactivity to GP expressed on the cell surface, were demonstrated by flow cytometry using both FITC-conjugated IgG (Fc) and FITC-conjugated IgG (whole molecule). In this case, FITC-conjugated IgG (Fc) recognized only IgG types, as opposed to FITC-conjugated IgG (whole molecule) (data not included). Moreover, DNA vaccines coding for cell membrane-associated antigens were reported to be more effective at inducing Ag-specific immune responses, as compared to those coding for intracellular antigens [12] . These data including ours suggest that DNA vaccines encoding any viral surface membrane proteins can induce IgG responses to the native and outer-membrane forms of the viral proteins. Thus, it is possible that these IgG antibodies may be utilized to target viral surface antigens as either diagnostic or neutralizing antibodies. Previously, we reported that DNA vaccina-tion alone resulted in the preferential production of IgM-secreting hybridomas over IgG-secreting hybridomas [10] . In that study, use of recombinant proteins in the DNA vaccination platform reversed this propensity, highlighting the notion that proteins may be a useful vaccine type for increased production of IgG-specific hybridomas in DNA vaccination.