ANTIGENIC STRUCTURE, FUNCTION, AND EVOLUTION OF THE HEMAGGLUTININ-NEURAMINIDASE PROTEIN OF HUMAN PARAINFLUENZA VIRUS TYPE-1

Twenty-two monoclonal antibodies directed to the hemagglutinin-neurami nidase protein of human parainfluenza virus type 1 (HPIV-1) were used in competition assays to create an antigenic map of neutralization sit es. Eighty-seven clinical strains isolated over 35 years from multiple geographic regions were reacted in ELISA, hemagglutinin-inhibition, a nd microneutralization assays with these monoclonal antibodies. Togeth er these assays revealed 21 epitopes on five nonoverlapping antigenic sites (I, III-VI) with a sixth (II) bridging site connecting sites I, III, and IV. Only 7 (33%) of these epitopes were conserved among all i solates. Previously described HPIV-1 genotypes were associated with th e presence or absence of specific antigenic sites and evidence of prob able immune selection within genotypes. Two sites were present on all isolates tested (III, V), and one (VI, genotype A) has not been found for 15 years. Forty hemagglutinin-neuraminidase nucleotide sequences w ere analyzed in terms of homology, structure, and evolution. These dat a may be useful in future epidemiologic, therapeutic, or vaccine-relat ed work.