| Abstract: | MAPREC test (mutant analysis by polymerase chain reaction and restriction enzyme cleavage), evaluating the content of neurovirulent mutants with nucleotide substitution of U for C in position 472 in the 5'-nontranslated RNA region, in a virus population was used for a retrospective analysis of 3 specimens of inoculated viruses and 55 lots of type 3 oral poliovirus vaccine (OPV) prepared at M. P. Chumakov Institute of Poliomyelitis, Russian Academy of Medical Sciences, during recent 6 years. The mean content of neurovirulent mutants in inoculated viruses was 0.26 +/- 0.06%, in monovaccines 0.34 +/- 0.04% (the maximum allowable content is 1%). The method is well reproducible and detects about 0.1% mutants in the population. MAPREC test can be used instead of currently used residual virulence control on monkeys, as it detects viral preparations which were not tested on monkeys and does not reject high-quality vaccines. The protocol of using this method in combination with other methods for neurovirulence and genetic stability control of type 3 OPV is discussed. |
