TY - JOUR

T1 - Hepatitis C virus escape studies of human antibody AR3a reveal a high barrier to resistance and novel insights on viral antibody evasion mechanisms

AU - Velázquez-Moctezuma, Rodrigo

AU - Galli, Andrea

AU - Law, Mansun

AU - Bukh, Jens

AU - Prentoe, Jannick

PY - 2019

Y1 - 2019

N2 - Yearly, 2 million people become hepatitis C virus (HCV) infected, resulting in an elevated lifetime risk for severe liver-related chronic illnesses. Characterizing epitopes of broadly neutralizing antibodies (NAbs), such as AR3A, is critical to guide vaccine development. Previously identified alanine substitutions that can reduce AR3A binding to expressed H77 envelope were introduced into chimeric cell culture-infectious HCV recombinants (HCVcc) H77(core-NS2)/JFH1. Substitutions G523A, G530A, and D535A greatly reduced fitness, and S424A, P525A, and N540A, although viable, conferred only low-level AR3A resistance. Using highly NAb-sensitive hypervariable region 1 (HVR1)-deleted HCVcc, H77/JFH1 ΔHVR1 and J6(core-NS2)/JFH1 ΔHVR1 , we previously reported a low barrier to developing AR5A NAb resistance substitutions. Here, we cultured Huh7.5 cells infected with H77/JFH1, H77/JFH1 ΔHVR1 , or J6/ JFH1 ΔHVR1 with AR3A. We identified the resistance envelope substitutions M345T in H77/JFH1, L438S and F442Y in H77/JFH1 ΔHVR1 , and D431G in J6/JFH1 ΔHVR1 . M345T increased infectivity and conferred low-level AR3A resistance to H77/JFH1 but not H77/JFH1 ΔHVR1 . L438S and F442Y conferred high-level AR3A resistance to H77/ JFH1 ΔHVR1 but abrogated the infectivity of H77/JFH1. D431G conferred AR3A resistance to J6/JFH1 ΔHVR1 but not J6/JFH1. This was possibly because D431G conferred broadly increased neutralization sensitivity to J6/JFH1 D431G but not J6/JFH1 ΔHVR1/D431G while decreasing scavenger receptor class B type I coreceptor dependency. Common substitutions at positions 431 and 442 did not confer high-level resistance in other genotype 2a recombinants [JFH1 or T9(core-NS2)/JFH1]. Although the data indicate that AR3A has a high barrier to resistance, our approach permitted identification of low-level resistance substitutions. Also, the HVR1-dependent effects on AR3A resistance substitutions suggest a complex role of HVR1 in virus escape and receptor usage, with important implications for HCV vaccine development.

AB - Yearly, 2 million people become hepatitis C virus (HCV) infected, resulting in an elevated lifetime risk for severe liver-related chronic illnesses. Characterizing epitopes of broadly neutralizing antibodies (NAbs), such as AR3A, is critical to guide vaccine development. Previously identified alanine substitutions that can reduce AR3A binding to expressed H77 envelope were introduced into chimeric cell culture-infectious HCV recombinants (HCVcc) H77(core-NS2)/JFH1. Substitutions G523A, G530A, and D535A greatly reduced fitness, and S424A, P525A, and N540A, although viable, conferred only low-level AR3A resistance. Using highly NAb-sensitive hypervariable region 1 (HVR1)-deleted HCVcc, H77/JFH1 ΔHVR1 and J6(core-NS2)/JFH1 ΔHVR1 , we previously reported a low barrier to developing AR5A NAb resistance substitutions. Here, we cultured Huh7.5 cells infected with H77/JFH1, H77/JFH1 ΔHVR1 , or J6/ JFH1 ΔHVR1 with AR3A. We identified the resistance envelope substitutions M345T in H77/JFH1, L438S and F442Y in H77/JFH1 ΔHVR1 , and D431G in J6/JFH1 ΔHVR1 . M345T increased infectivity and conferred low-level AR3A resistance to H77/JFH1 but not H77/JFH1 ΔHVR1 . L438S and F442Y conferred high-level AR3A resistance to H77/ JFH1 ΔHVR1 but abrogated the infectivity of H77/JFH1. D431G conferred AR3A resistance to J6/JFH1 ΔHVR1 but not J6/JFH1. This was possibly because D431G conferred broadly increased neutralization sensitivity to J6/JFH1 D431G but not J6/JFH1 ΔHVR1/D431G while decreasing scavenger receptor class B type I coreceptor dependency. Common substitutions at positions 431 and 442 did not confer high-level resistance in other genotype 2a recombinants [JFH1 or T9(core-NS2)/JFH1]. Although the data indicate that AR3A has a high barrier to resistance, our approach permitted identification of low-level resistance substitutions. Also, the HVR1-dependent effects on AR3A resistance substitutions suggest a complex role of HVR1 in virus escape and receptor usage, with important implications for HCV vaccine development.

KW - Antibody escape

KW - Hepatitis C virus

KW - HVR1

KW - Immune evasion

KW - Liver disease

KW - Vaccine

U2 - 10.1128/JVI.01909-18

DO - 10.1128/JVI.01909-18

M3 - Journal article

C2 - 30487284

AN - SCOPUS:85061133212

VL - 93

JO - Journal of Virology

JF - Journal of Virology

SN - 0022-538X

IS - 4

M1 - e0190918

ER -