Retrospective study of Western blot profiles in immune sera of natural dengue virus infections

The Western blot (WB) assay was used to determine dengue virus antibodies p resent in human immune sera arising from recent primary and secondary dengu e virus infections in Singapore. Cell lysates of dengue-2 virus-infected C6 /36 and Vero cells were used. Antibodies directed against structural protei ns of dengue-2 virus including envelope (E, gp60/50), capsid-premembrane (C -PrM, gp35), and premembrane (PrM, gp20) were detected, with antibody again st envelope protein being most dominant. Similar WB profiles were detected in both primary and secondary dengue virus infections. The reactivity rate of antibodies to dengue-2 virus proteins was higher in infected Vero cell l ysate than in infected C6/36 cell lysate, with the exception of antibodies to nonstructural proteins of NS1 and NS3, which were detected predominantly in infected C6/36 cell lysate. More than 75% of "normal" individuals (with no complaint of recent dengue virus infection) examined had low levels of dengue virus antibodies, but all presented with similar WB profiles as pati ents with recent dengue virus infections. This finding reflects a high sero prevalence of dengue virus infections and the long lasting nature of E, C-P rM, and PrM antibodies. Results from this study indicate that in natural de ngue virus infections, native E, C-PrM, and PrM antigens of dengue virus ar e immunogenic and elicit long-lasting antibodies. J. Med. Virol. 57:322-330 , 1999. (C) 1999 Wiley-Liss, Inc.