Intérêt des sondes ARNc (ribosondes) synthétisés in vitro dans la détection des entérovirus par hybridation moléculaire

Summary Radioactively labelled RNA transcripts made in vitro of various fragments from cDNA clones of poliovirus type 1 and of hepatitis A virus under the control of bacteriophage T7 or SP6 promoters have been evaluated for diagnostic purposes. The RNA transcripts were 2 orders of magnitude more sensitive as hybridization probes than corresponding cDNA preparations labelled by the nick translation procedure. A combination of hybridization analysis and sequence comparison showed that some regions of the genome of a number of enteroviruses are highly conserved, while others show very little homology; the general order of conservation is: 5′-non-coding>3′-terminal>central (2C)>VP3>VP1. The 350 bases of the poliovirus VP1 region were highly specific for that virus, while the 450-bases of the 5′NC region showed extensive cross-reaction with other enteroviruses. However, these probes did not hybridize with HAV, which was detected only by HAV-specific riboprobes. The transcripts have been successfully applied as hybridization probes in diagnostic tests on supernatants of infected cell culture lysates and in clinical samples, mainly in stool extracts.