Monoclonal antibodies demonstrate heterogeneity in the G glycoprotein of prototype strains and clinical isolates of respiratory syncytial virus

In order to study variation among prototype strains and clinical isolates of respiratory syncytial (RS) virus. four prototype strains (Long, A2, CH 18537. 9320) were used to produce monoclonal antibodies to this virus. The majority of monoclonals reacted with all four prototype strains by fluorescent antibody staining. Among the non‐cross‐reacting monoclonals, five additional patterns of reactivity with the prototype strains were recognised. Fourteen monoclonals, including ones representative of each of the patterns of reactivity with the prototype strains. were selected to use for typing prototype strains and community isolates. All 14 were found by immunoprecipitation to recognise the RS virus G glycoprotein. These monoclonals could uniquely identify each of the prototype strains. In addition to the antigenic differences among the prototype strains detected by the monoclonals. differences were also detected in the migration of the G glycoprotein of the prototype strains in polyacrylamide gel electrophoresis. Fluorescent antibody staining with panels of monoclonals distinguished two antigenic types among 114 isolates of RS virus recovered from children in St. Louis during the period 1981 86. The predominant type (80% of isolates) had a pattern of reactivity that resembled but differed from that of either the Long or A2 strains. The second type had a pattern of reactivity identical with that of 9320. The possible significance of this heterogeneity must be considered in developing diagnostic tests as well as active or passive immunotherapy for infections caused by RS virus.