セログループと遺伝子型の乖離例より検出した新規の2b/1b recombinant HCV

A convenient ELISA method to classify hepatitis C virus (HCV) serologically by detecting antibodies against type-specific antigens on NS3-NS4 proteins has been widely used in Japan, but sometimes it produces results that disagree with what would be obtained by nucleotide analyses. In our present study, indeed, 3 out of 103 HCV-patients showed such "serotype/genotype discrepancy", one of which (designated M2123) was subjected to further analyses. PCR/sequencing at HCV core and NS5A regions and serological typing at NS3-NS4 region suggested that M2123 contains HCV with a core gene of genotype 2b while NS3-NS4-NS5 genes of genotype 1b. To see if this result is due to inter-genotypic recombination, we searched for a PCR fragment that should contain a crossover point from 2b to 1b, and found one. Nucleotide sequence of a 1,011-nt fragment (AB558135) amplified from NS2/NS3 region possessed the crossover point within NS2. HCV recombinants, probably underestimated to date, should be called into account particularly in cases with serotype/genotype discrepancy.