Antibody-dependent enhancement of hantavirus infection in macrophage cell lines.

Antibody-dependent enhancement (ADE) of hantavirus infections (strains Hantaan 76-118 and SR-11) was studied using macrophage-like cell lines (J774.1, P388D1, and U937). Significantly higher virus titers (1,000 to 4,000 FFU/ml) were obtained by pretreatment of the virus with immune serum as compared to normal serum (less than 20 FFU/ml). Monoclonal antibodies (MAbs) to strain Hantaan 76-118 were employed to determine the antigenic determinants responsible for the ADE activity. ADE of the infection occurred with MAbs to both G1 and G2 envelope glycoproteins, but not with MAbs to nucleocapsid protein. Antigenic determinants related to haemagglutination or virus neutralization were found to cause ADE of the infection.