"Original antigenic sin" phenomenon in experimental flavivirus infections of guinea pigs: studies by enzyme-linked immunosorbent assay.

Guinea pigs were sequentially infected with two closely related flavivituses (Japanese encephalitis and West Nile viruses), and their antibody responses were studied both by enzyme-linked immunosorbent assay (ELISA) and hemagglutination-inhibition (HI). The results by ELISA always showed "original antigenic sin" responses: antibody activity of sera after the second infection was higher to the first infecting virus than to the second infecting virus. However, the results obtained by HI were variable.