On the mechanism of inactivation of Chikungunya virus by tannic acid.

The mechanism of the action of tannic acid (TA) Chikungunya virus (CHIKV) was investigated. Both infectivity and hemagglutination (HA) activity of CHIKV were reduced by treatment with TA in vitro. Aggregation of the TA-treated virus particles was observed by electron microscopy. The reaction was reversible, depending on the pH of the mixture. However, mere dilution of the TA-virus mixture or addition of other protein, such as bovine serum albumin, did not restore the lost infectivity. TA also suppressed the infectivity of RNA extracted from the virus and the HA activity of the viral membrane. The affinity between TA and CHIKV structural proteins (E1, E2, and C) was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in a discontinuous buffer system and the order of affinity was found to be C greater than E1 greater than E2. Specific conditions for binding of TA to each of the virus proteins were investigated.