Abstract
Contemporary isolates of measles virus, characterized by their inability to hemagglutinate, have been shown to possess a hemagglutinin type distinct from that of classical strains such as the Edmonston strain in that there is a new glycosylation site at amino acid residue 416. This change abolishes a Sau3Al site that is found in the corresponding position of the hemagglutination-positive classical strains. This molecular information prompted us to develop a restriction fragment length polymorphism (RFLP) assay that is capable of distinguishing these two distinct hemagglutinin types. The assay consists of the amplification of a 349-bp segment of the hemagglutinin gene by reverse transcription followed by the polymerase chain reaction and Sau3Al digestion of this amplification product. The resulting two distinct RFLP patterns identified the hemagglutinin types with regard to the presence or absence of the potential new glycosylation site. This assay was applied to determine the relative frequencies over a 28-year period of these two hemagglutinin types present in the archival acute serum specimens taken from patients with measles. This study revealed that strains carrying the classical hemagglutinin type predominated until the early 1980s when it became completely replaced with strains possessing the contemporary hemagglutinin type. Because of its direct applicability to the clinical specimens avoiding selection bias during cell-culture adaptation, this assay provides a valuable asset in both clinical laboratory and epidemiological settings.
Published Version
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