Monoclonal antibodies to the large glycoproteins of respiratory syncytial virus: possible evidence for several functional antigenic sites

Abstract

Employing different routes of immunization and different adjuvants, a large number of hybridomas were produced that secreted monoclonal antibodies (MAbs) against the large envelope glycoprotein (GP90) and the fusion glycoprotein (GP70) of respiratory syncytial virus (RSV). The antigenic specificity of the MAbs was established by immunoblot analysis and radioimmunoprecipitation. Three hybridomas secreting anti-GP90 MAbs were established from mice immunized by intraperitoneal injection of purified RSV in Freund's complete adjuvant. MAbs from these hybridomas did not neutralize viral infectivity. Three other hybridomas established from mice immunized by intraperitoneal inoculation of purified RSV with Bordetella pertussis produced anti-GP90 MAbs that neutralized the virus with or without complement. Similarly three other hybridomas established from mice immunized by infection with RSV via intranasal instillation of the virus produced anti-GP90 MAb that neutralized the virus in the presence and absence of complement. On the other hand, most anti-GP70 MAbs exhibited no neutralizing activity in the absence of complement, although many had low levels of neutralizing activity in the presence of complement, regardless of the type of immunization or the isotype of immunoglobulin. These observations suggest that there may be multiple antigenic sites on GP90, some of which involve a region of the molecule that functions in viral neutralization.