A neutralizing monoclonal antibody to respiratory syncytial virus which binds to both F1 and F2 components of the fusion protein.

A virus-neutralizing monoclonal antibody (1E3) specifically immunoprecipitated the 70000 mol. wt. (70K) fusion (F) protein from respiratory syncytial (RS) virus-infected HeLa cells. Western blotting analysis of polypeptides from such cells separated by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing conditions revealed that 1E3 was peculiar in that it bound to both F1 (50K) and F2 (20K) components of the F protein. Antibody subsequently eluted from either the F1 or the F2 regions of immunoblots re-bound to both F1 and F2 regions of the SDS-PAGE blot. These results show that monoclonal antibody 1E3 reacts with an epitope which is found on both F1 and F2 subunits of RS virus fusion protein.