Role of long-persisting XXXX hepatitis E virus antibodies in protection.

@entity1 @entity2608 @entity4973
The role of long-persisting HEV antibodies in @entity1 was investigated. A well-characterized human volunteer anti-HEV (IgG) after 4 years of the recovery of the disease was passively immunized (200 mg kg-1 body wt) intramuscularly into three @entity2608 (nos 7, 8 and 9), while two monkeys (nos 5 and 6) were injected with normal immunoglobulin preparation (negative for anti-HEV IgG). At 16 h later all the animals were challenged intravenously with live @entity4973 , as 10% stool extract prepared from the volunteer (positive for @entity4973 by solid-phase immune electron microscopy). It was seen that transaminases (ALT/AST) were elevated in immunized monkeys on day 49 (no. 8), 60 (no. 7) and 86 (no. 9) after the virus challenge. On serological examination, all immunized (nos 7, 8 and 9) and one unimmunized (no. 6) monkeys were found positive for @entity4973 IgM on day 10 post-challenge, while monkey no. 5 was negative. Further, all the animals from the immunized and unimmunized group seroconverted to HEV-IgG when tested on days 25 and 55 post-challenge. This has clearly shown that there is no protection. Therefore, these long-persisting HEV antibodies alone in @entity1 , may not be protective in passive immunization.
