ANALYSIS OF ANTIGENIC AND GENETIC VARIABILITY OF RESPIRATORY SYNCITIAL VIRUS

Kong XH, Liu ChY, Wang ShX, Jiang ZF

Beijing Children’s Hospital, Beijing, China

 

Objective: To analysis antigenic and genetic variability of respiratory cyncitial virus (RSV) in Beijing. 

Methods: Each of 20 RSV isolates was reacted with 8 anti-NP, or anti-G antibodies respectively, and then typed into subgroup A or B by IIF. These isolates were classified into patterns NP and lineages SHL by restriction mapping of N gene fragments and sequencing of SH gene. cDNA of the entire G protein gene of one subgroup A isolate was also sequenced.

Results:  Compared with reference isolates, 2 subgroup A isolates from 1990 to 1991 were unreactive with anti-NP antibody B90 (epitype NP1), 1 subgroup B isolate reacted with B90. Whereas 2 subgroup A isolates from 1997 to 1998 failed to react with anti-NP antibody C797 (epitype NP1), anti-NP6 antibody B63 (epitype NP6), and anti-G2-G6 antibody B25 (epitype G2-G6), 2 subgroup B isolates were positive with B90 and anti-G2-G6 antibody B14 (epitype G2-G6).  
Of 10 isolates from 1990 to 1991, 8 subgroup A isolates gave pattern NP3 (SHL2), 2 subgroup B isolates NP4. With 10 isolates from 1997 to 1998, 2 subgroup A isolates fell into NP3 (SHL2), 8 subgroup B NP4, but the ratio of subgroup A to B was reverse (4:1 v1:4).   

Comparison of the sequences of the G genes of one subgroup A isolate in 1998 and prototype A2 showed that there was 6.7% nucleotide sequence variability and 11.4% amino acid sequence variability overall. Moreover, the variability was concentrated in the ectodomain of the G protein.

Conclusion   There was extensively antigenic and genetic variability between subgroup A and B, even within subgroups.

 
0748