HUMAN PARAINFLUENZA VIRUS TYPE-1 EVOLUTION COMBINES COCIRCULATION OF STRAINS AND DEVELOPMENT OF GEOGRAPHICALLY RESTRICTED LINEAGES

The hemagglutinin neuraminidase (HN) glycoprotein of human parainfluen za virus type 1 (HPIV-1) mediates attachment to the host cell and is t he target of protective antibody. Since the efficacy of a potential va ccine depends on antigenic constancy, the antigenic and genetic stabil ity of the HPIV-1 HN glycoprotein was examined for 13 isolates obtaine d between 1981 and 1989. Antigenic analysis with a panel of 11 monoclo nal antibodies demonstrated a single change among 3 isolates from 1989 that distinguished them from all other isolates. The HN genes from al l 13 isolates and 13 previously published HN gene sequences shared >95 % homology. Evolutionary analysis demonstrated cocirculation of strain s, without a dominant lineage. The 1989 isolates and the previously pr oposed subtype A isolates occupied distinct evolutionary branches, ind icating geographically limited evolution. The slow rate of evolution a nd HN homogeneity may allow development of a single vaccine formulatio n for the prevention of disease.