Analysis of mutations in oral poliovirus vaccine by hybridization with generic oligonucleotide microchips

This paper describes use of a new technology of hybridization with a micro- array of immobilized oligonucleotides for detection and quantification of n eurovirulent mutants in Oral Poliovirus Vaccine (OPV). We used a micro-arra y consisting of three-dimensional gel-elements containing all possible hexa mers (total of 4096 probes). Hybridization of fluorescently labelled viral cDNA samples with such microchips resulted in a pattern of spots that was r egistered and quantified by a computer-linked CCD camera, so that the seque nce of the original cDNA could be deduced. The method could reliably identi fy single point mutations, since each of them affected fluorescence intensi ty of 12 micro-array elements. Micro-array hybridization of DNA mixtures wi th varying contents of point mutants demonstrated that the method can detec t as little as 10% of revertants in a population of vaccine virus. This new technology should be useful for quality control of live viral vaccines, as well as for other applications requiring identification and quantification of point mutations.