Redeveloping antigen detection kits for the diagnosis of rat hepatitis E virus

Abstract

The emergence of Rocahepevirus ratti [species HEV ratti ( r HEV)] as a causative agent of hepatitis E in humans presents a new potential threat to global public health. The R. ratti genotype 1 ( r -1 HEV) variant only shares 50%–60% genomic identity with Paslahepevirus balayani [species HEV balayani ( b HEV)] variants, which are the main causes of hepatitis E infection in humans. Here, we report antigen diagnoses for r -1 HEV and b HEV using an enzymatic immunoassay (EIA) method. We detected recombinant virus-like particles protein (HEV 239) of r HEV and b HEV using a collection of hepatitis E virus (HEV)-specific monoclonal antibodies. Two optimal candidates, the capture antibody P#1-H4 and the detection antibodies C145 (P#1-H4*/C145 # ) and C158 (P#1-H4*/C158 # ), were selected to detect antigen in infected rat samples and r -1 HEV- or b HEV-infected human clinical samples. The two candidates showed similar diagnostic efficacy to the Wantai HEV antigen kit in b HEV-infected clinical samples. Genomic divergence resulted in low diagnostic efficacy of the Wantai HEV antigen kit (0%, 0 of 10) for detecting r -1 HEV infection. Compared with the P#1-H4*/C145 # candidate (80%, 8 of 10), the P#1-H4*/C158 # candidate had excellent diagnostic efficacy in r -1 HEV-infected clinical samples (100%, 10 of 10). The two candidates bind to a discrete antigenic site that is highly conserved across r HEV and b HEV. P#1-H4*/C145 # and P#1-H4*/C158 # are efficacious candidate antibody combinations for rat HEV antigen detection.

Transmission and Surveillance of Rat Hepatitis E Virus in Swine

“…One relevant aspect highlighted by the authors is that limited prior evidence of rat HEV infection in swine might be partially explained by the lack of rat HEV serology tests for pigs. The low genomic homology between rat HEV and other HEV (<60%) makes most of the commercially available HEV-based tests ineffective in detecting rat HEV ( 2 , 3 ).…”