TY - JOUR

T1 - Neutralization and receptor use of infectious culture–derived rat hepacivirus as a model for HCV

AU - Wolfisberg, Raphael

AU - Thorselius, Caroline E.

AU - Salinas, Eduardo

AU - Elrod, Elizabeth

AU - Trivedi, Sheetal

AU - Nielsen, Louise

AU - Fahnøe, Ulrik

AU - Kapoor, Amit

AU - Grakoui, Arash

AU - Rice, Charles M.

AU - Bukh, Jens

AU - Holmbeck, Kenn

AU - Scheel, Troels K.H.

N1 - Funding Information: Supported by the European Research Council (Grant No. 802899 to T.K.H.S), the Independent Research Fund Denmark (Grant No. 4004‐00598 to J.B. and 1030‐00426 to T.K.H.S), the Danish Cancer Society (R204‐A12639 to J.B. and T.K.H.S.), the Novo Nordisk Foundation (Grant Nos. NNF19OC0054518 and NNF19OC0055462 to J.B.), and U.S. Public Health Service/National Institutes of Health awards (R01AI137567 and R01AI151175 to A.K.; R01AI131688 to C.M.R.; and R01AI124680, R01AI126890, R01AI136533, and U19AI159819 to A.G. and ORIP/OD P51OD011132 [formerly NCRR P51RR000165] to the Yerkes National Primate Research Center [A.G.]). R.W. was supported by an Early Postdoc.Mobility Fellowship (P2BEP3_178527) and a Postdoc.Mobility Fellowship (P400PB‐183952) from the Swiss National Science Foundation. Rattus norvegicus Publisher Copyright: © 2022 The Authors. Hepatology published by Wiley Periodicals LLC on behalf of American Association for the Study of Liver Diseases.

PY - 2022

Y1 - 2022

N2 - Background and Aims: Lack of tractable immunocompetent animal models amenable to robust experimental challenge impedes vaccine efforts for HCV. Infection with rodent hepacivirus from Rattus norvegicus (RHV-rn1) in rats shares HCV-defining characteristics, including liver tropism, chronicity, and pathology. RHV in vitro cultivation would facilitate genetic studies on particle production, host factor interactions, and evaluation of antibody neutralization guiding HCV vaccine approaches. Approach and Results: We report an infectious reverse genetic cell culture system for RHV-rn1 using highly permissive rat hepatoma cells and adaptive mutations in the E2, NS4B, and NS5A viral proteins. Cell culture–derived RHV-rn1 particles (RHVcc) share hallmark biophysical characteristics of HCV and are infectious in mice and rats. Culture adaptive mutations attenuated RHVcc in immunocompetent rats, and the mutations reverted following prolonged infection, but not in severe combined immunodeficiency (SCID) mice, suggesting that adaptive immune pressure is a primary driver of reversion. Accordingly, sera from RHVcc-infected SCID mice or the early acute phase of immunocompetent mice and rats were infectious in culture. We further established an in vitro RHVcc neutralization assay, and observed neutralizing activity of rat sera specifically from the chronic phase of infection. Finally, we found that scavenger receptor class B type I promoted RHV-rn1 entry in vitro and in vivo. Conclusions: The RHV-rn1 infectious cell culture system enables studies of humoral immune responses against hepacivirus infection. Moreover, recapitulation of the entire RHV-rn1 infectious cycle in cell culture will facilitate reverse genetic studies and the exploration of tropism and virus–host interactions.

AB - Background and Aims: Lack of tractable immunocompetent animal models amenable to robust experimental challenge impedes vaccine efforts for HCV. Infection with rodent hepacivirus from Rattus norvegicus (RHV-rn1) in rats shares HCV-defining characteristics, including liver tropism, chronicity, and pathology. RHV in vitro cultivation would facilitate genetic studies on particle production, host factor interactions, and evaluation of antibody neutralization guiding HCV vaccine approaches. Approach and Results: We report an infectious reverse genetic cell culture system for RHV-rn1 using highly permissive rat hepatoma cells and adaptive mutations in the E2, NS4B, and NS5A viral proteins. Cell culture–derived RHV-rn1 particles (RHVcc) share hallmark biophysical characteristics of HCV and are infectious in mice and rats. Culture adaptive mutations attenuated RHVcc in immunocompetent rats, and the mutations reverted following prolonged infection, but not in severe combined immunodeficiency (SCID) mice, suggesting that adaptive immune pressure is a primary driver of reversion. Accordingly, sera from RHVcc-infected SCID mice or the early acute phase of immunocompetent mice and rats were infectious in culture. We further established an in vitro RHVcc neutralization assay, and observed neutralizing activity of rat sera specifically from the chronic phase of infection. Finally, we found that scavenger receptor class B type I promoted RHV-rn1 entry in vitro and in vivo. Conclusions: The RHV-rn1 infectious cell culture system enables studies of humoral immune responses against hepacivirus infection. Moreover, recapitulation of the entire RHV-rn1 infectious cycle in cell culture will facilitate reverse genetic studies and the exploration of tropism and virus–host interactions.

U2 - 10.1002/hep.32535

DO - 10.1002/hep.32535

M3 - Journal article

C2 - 35445423

AN - SCOPUS:85129893236

VL - 76

SP - 1506

EP - 1519

JO - Hepatology

JF - Hepatology

SN - 0270-9139

IS - 5

ER -