Seven complementation groups of respiratory syncytial virus temperature-sensitive mutants

Abstract

Fifteen temperature-sensitive mutants of the RSN-2 strain of respiratory syncytial virus were classified into 6 complementation groups, 2 of which appeared to be homologous with 2 of the 3 complementation groups of the A2 strain described by Wright et al. Thus, 7 complementation groups of respiratory syncytial virus, designated A, B, C, D, E, F and G, were defined. The frequency and type of mutant isolated varied according to strain; group C was unique to the A2 strain, and groups D, E, F and G were unique to the RSN-2 strain. The highest complementation indexes were obtained by preincubation for 7 h at permissive temperature, followed by incubation at restrictive temperature for 40-50 h in the case of A2 strain mutants or 80-90 h for RSN-2 strain mutants. Genetic recombination was not detected.