The traditional herbal medicines Ninjinto and Ninjin'yoeito significantly suppressed the reversion of type 1 and type 3 oral polio vaccine viruses to neurovirulent genotypes in human cell cultures.
Do traditional herbal medicines like Ninjinto suppress the reversion of polio vaccine viruses to the neurovirulent genotype in cell cultures?
Traditional herbal medicines like Ninjinto and Ninjin'yoeito suppress the neurovirulent reversion of polio vaccine viruses in vitro, suggesting a potential approach to improve oral poliovirus vaccine safety.
p-value: p=<0.05
Background The oral poliovirus vaccine (OPV) is regarded as one of the most effective and safest vaccines. However, some paralytic cases have been reported among vaccinees and individuals who have been in contact with vaccinees, because vaccine viruses undergo neurovirulent reversion during repeated replication in the alimentary tract. Moreover, the revertants are excreted with the feces into the environment, and the viruses have caused epidemics of poliomyelitis in the world. Objective We have reported that Ninjin'yoeito suppressed the reversion of polio vaccine viruses. In this study, to clarify the herbal constituent which takes part in the suppressive effect, we investigated the effect of Ninjinto, which is composed of simpler herbal constituents than Ninjin'yoeito, and of the individual herbal constituents in Ninjinto. Methods Polio vaccine viruses were serially passaged three times in the presence of herbal medicines in cells derived from the human alimentary tract. The reversion of the passaged viruses was analyzed by the MAPREC and non-RI-modified MAPREC method, designed to estimate the ratio of revertants in a virus population. Results It was shown that Ninjinto suppressed the reversion of polio vaccine viruses. Although Ginseng Radix and Glycyrrhizae Radix (common herbal constituents in Ninjinto and Ninjin'yoeito) did not show the suppressive effect, the mixture of both herbal constituents was a little inhibitory in regard to the reversion of the viruses. Conclusion It is quite likely that the suppressive effect on reversion is not a simple process. A complicated interaction of some components of the herbal constituents might take part in the effect. It is expected that traditional herbal medicines like Ninjinto and Ninjin'yoeito will contribute to solving the problems of OPV though further analyses of the herbal constituents and their components are necessary to clarify the mechanism of the suppressive effect.
Horie et al. (Tue,) conducted a other in Poliovirus vaccine reversion. Ninjinto (TJ-32) and Ninjin'yoeito (TJ-108) vs. Control (no medicine) was evaluated on Accumulation of neurovirulent revertants (480-A, 525-C in type 1; 472-C in type 3) (p=<0.05). The traditional herbal medicines Ninjinto and Ninjin'yoeito significantly suppressed the reversion of type 1 and type 3 oral polio vaccine viruses to neurovirulent genotypes in human cell cultures.