A simple method for genetic differentiation of the AIK-C vaccine strain from wild strains of measles virus.

Restriction fragment length polymorphism (RFLP) analysis was used to differentiate the AIK-C vaccine strain from the wild circulating measles viruses. Virus genomes were amplified by using reverse transcriptase-polymerase chain reaction (RT-PCR) in the part of the H-gene. The PCR product of the AIK-C strain was cut into 2 fragments after digestions with Hpall, BstPl and Avall, respectively. Otherwise, those of 17 wild-type strains isolated during 1950s-1991 were cleaved into 3 fragments only when digested with Avall. Comparison with wild strain sequences suggest that the above Hpall site and BstPl site are characteristic of the AIK-C strain. This molecular approach is also applied for the discrimination whether some symptoms after vaccination were related to the vaccine strain or not.