A bacterially expressed peptide prevents experimental infection of primates by the hepatitis E virus

A 23 kDa peptide of the major structural protein of the hepatitis E virus ( HEV) expressed in E. coli was found to naturally interact with one another to form homodimers and the peptide was recognized strongly in its dimeric f orm by HEV reactive human sera. To determine if the peptide may confer prot ection against HEV infection, three monkeys were immunized with the purifie d peptide and three were given placebo. Both groups of animals were challen ged with 10(5) genome equivalent dose of the homologous strain of HEV. All control animals excreted the virus for 10-12 days beginning 5 days after th e infection. The viral genome was also present in the peripheral blood mono cyte (PBMC) samples from two animals, but it was not detected in the plasma samples from any of the animals. The infection in two control animals was accompanied by HEV seroconversion. Immunization was found to abrogate HEV s tool excretion in two animals and reduced the viral excretion to one day in the third. None of the immunized animals showed detectable HEV in plasma o r PBMC samples nor did the animals showed evidence of HEV seroconversion. T hese results suggested that immunization with the bacterially expressed pep tide may prevent experimental infection of primates with the homologous str ain of HEV. (C) 2001 Elsevier Science Ltd. All rights reserved.