Respiratory syncytial virus(RSV) is the major cause of lower respiratory tract infection in infants and young children. This study was performed to analyze antigenic and genetic variation of G protein of subgroup A RSV.

One hundred seventy-nine strains isolated at the Seoul National University Children's Hospital over 8 year-period from 1990 through 1998 were analysed for antigenic and genetic variability. Analysis was made by reactivity wish monoclonal antibodies raised against RSV, and by restriction mapping and, for selected strains, nucleotide sequencing following amplification of full sequence of G gene by reverse transcription-polymerase chain reaction.

Restriction fragment analysis of the amplified G protein gene revealed 23 restriction patters, 12 of which included more than 2 isolate, and the most frequent genetic type comprised 30% of the strains. Indirect immunofluorescent staining with monoclonal antibodies revealed 6 antigenic types with one predominant pattern accounting for 91% of the total strains. The most frequent antigenic type had 21 restriction patterns, and some viruses with same restiction pattern had different monoclonal antibody reaction pattern. Nucleotide sequence homology of subgroup A was 91-93% between reference(A2, Long) and Korean isolates, 93~99% among Korean isolates. Maximum-parsimony analysis demonstrated that Korean isolates were distinct from reference strains and subgroup A strains were clustered in 4 groups.

The restriction analysis pattern of G protein gene identified greater diversity within subgroup A than was seen with the monoclonal analysis and a variety of antigenic and genetic types of RSV are circulating in Korea which are different from reference strains or strains isolated from other countries.