Linear antigenic and immunogenic regions of the respiratory syncytial virus P protein

Three linear antigenic regions on the P protein from human respiratory syncytial virus (RSV) subgroup A (strain A2) were represented by peptides that reacted with monoclonal antibodies and with sera from humans with recent or previous RSV infection. The determinants were localized within three hydrophilic regions of the P protein: Pro91 to Asp110, Ser161 to Lys180 and Glu221 to Phe241. The role of individual amino acids in the epitopes defined by monoclonal antibodies was determined. Two monoclonal antibodies reacting with the same antigenic site were found to detect epitopes that had different amino acid dependencies. Rabbit hyperimmune sera raised against selected peptides specifically precipitated different forms of the P protein from RSV-infected 35S-labelled cell extracts in a radioimmune precipitation assay. These findings have implications for forthcoming structural-functional studies of RSV capsid component interactions and also for serological diagnosis of RSV infection.