scholarly journals In vitro adaptation and characterization of attenuated hypervariable region 1 swap chimeras of hepatitis C virus

2021 ◽  
Vol 17 (7) ◽  
pp. e1009720
Author(s):  
Christina Holmboe Olesen ◽  
Elias H. Augestad ◽  
Fulvia Troise ◽  
Jens Bukh ◽  
Jannick Prentoe
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Hypervariable Region ◽  
Neutralizing Antibody ◽  
Virus Envelope ◽  
E2 Protein ◽  
Hypervariable Region 1 ◽  
Increased Sensitivity ◽  
Viral Attenuation

Hepatitis C virus (HCV) chronically infects 70 million people worldwide with an estimated annual disease-related mortality of 400,000. A vaccine could prevent spread of this pervasive human pathogen, but has proven difficult to develop, partly due to neutralizing antibody evasion mechanisms that are inherent features of the virus envelope glycoproteins, E1 and E2. A central actor is the E2 motif, hypervariable region 1 (HVR1), which protects several non-overlapping neutralization epitopes through an incompletely understood mechanism. Here, we show that introducing different HVR1-isolate sequences into cell-culture infectious JFH1-based H77 (genotype 1a) and J4 (genotype 1b) Core-NS2 recombinants can lead to severe viral attenuation. Culture adaptation of attenuated HVR1-swapped recombinants permitted us to identify E1/E2 substitutions at conserved positions both within and outside HVR1 that increased the infectivity of attenuated HVR1-swapped recombinants but were not adaptive for original recombinants. H77 recombinants with HVR1 from multiple other isolates consistently acquired substitutions at position 348 in E1 and position 385 in HVR1 of E2. Interestingly, HVR1-swapped J4 recombinants primarily acquired other substitutions: F291I (E1), F438V (E2), F447L/V/I (E2) and V710L (E2), indicating a different adaptation pathway. For H77 recombinants, the adaptive E1/E2 substitutions increased sensitivity to the neutralizing monoclonal antibodies AR3A and AR4A, whereas for J4 recombinants, they increased sensitivity to AR3A, while having no effect on sensitivity to AR4A. To evaluate effects of the substitutions on AR3A and AR4A binding, we performed ELISAs on extracted E1/E2 protein and performed immunoprecipitation of relevant viruses. However, extracted E1/E2 protein and immunoprecipitation of HCV particles only reproduced the neutralization phenotypes of the J4 recombinants. Finally, we found that the HVR1-swap E1/E2 substitutions decrease virus entry dependency on co-receptor SR-BI. Our study identifies E1/E2 positions that could be critical for intra-complex HVR1 interactions while emphasizing the need for developing novel tools for molecular studies of E1/E2 interactions.

scholarly journals Expression of Noncovalent Hepatitis C Virus Envelope E1-E2 Complexes Is Not Required for the Induction of Antibodies with Neutralizing Properties following DNA Immunization

1999 ◽  
Vol 73 (9) ◽  
pp. 7497-7504 ◽  
Author(s):  
A. Fournillier ◽  
E. Depla ◽  
P. Karayiannis ◽  
O. Vidalin ◽  
G. Maertens ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Hypervariable Region ◽  
Virus Envelope ◽  
Hypervariable Region 1 ◽  
Viral Particles ◽  
Expression Plasmids

ABSTRACT Interactive glycoproteins present on the surface of viral particles represent the main target of neutralizing antibodies. The ability of DNA vaccination to induce antibodies directed at such structures was investigated by using eight different expression plasmids engineered either to favor or to prevent interaction between the hepatitis C virus (HCV) envelope glycoproteins E1 and E2. Independently of the injection route (intramuscular or intraepidermal), plasmids expressing antigens capable of forming heterodimers presumed to be the prebudding form of the HCV envelope protein complex failed to induce any significant, stable antibodies following injection in mice. In sharp contrast, high titers of antibodies directed at both conformational and linear determinants were induced by using plasmids expressing severely truncated antigens that have lost the ability to form native complexes. In addition, only a truncated form of E2 induced antibodies reacting against the hypervariable region 1 of E2 (specifically with the C-terminal part of it) known to contain a neutralization site. When injected intraepidermally into small primates, the truncated E2-encoding plasmid induced antibodies able to neutralize in vitro the binding of a purified E2 protein onto susceptible cells. Because such antibodies have been associated with viral clearance in both humans and chimpanzees, these findings may have important implications for the development of protective immunity against HCV.

scholarly journals Antigenic and immunogenic evaluation of permutations of soluble hepatitis C virus envelope protein E2 and E1 antigens

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0255336
Author(s):  
Jannick Prentoe ◽  
Christoph M. Janitzek ◽  
Rodrigo Velázquez-Moctezuma ◽  
Louise Goksøyr ◽  
Rebecca W. Olsen ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Envelope Protein ◽  
Neutralizing Antibodies ◽  
Hypervariable Region ◽  
Protein Antigens ◽  
Virus Envelope ◽  
Transmembrane Glycoprotein ◽  
Chronic Hcv

Yearly, about 1.5 million people become chronically infected with hepatitis C virus (HCV) and for the 71 million with chronic HCV infection about 400,000 die from related morbidities, including liver cirrhosis and cancer. Effective treatments exist, but challenges including cost-of-treatment and wide-spread undiagnosed infection, necessitates the development of vaccines. Vaccines should induce neutralizing antibodies (NAbs) against the HCV envelope (E) transmembrane glycoprotein 2, E2, which partly depends on its interaction partner, E1, for folding. Here, we generated three soluble HCV envelope protein antigens with the transmembrane regions deleted (i.e., fused peptide backbones), termed sE1E2 (E1 followed by E2), sE2E1 (E2 followed by E1), and sE21E (E2 followed by inverted E1). The E1 inversion for sE21E positions C-terminal residues of E1 near C-terminal residues of E2, which is in analogy to how they likely interact in native E1/E2 complexes. Probing conformational E2 epitope binding using HCV patient-derived human monoclonal antibodies, we show that sE21E was superior to sE2E1, which was consistently superior to sE1E2. This correlated with improved induction of NAbs by sE21E compared with sE2E1 and especially compared with sE1E2 in female BALB/c mouse immunizations. The deletion of the 27 N-terminal amino acids of E2, termed hypervariable region 1 (HVR1), conferred slight increases in antigenicity for sE2E1 and sE21E, but severely impaired induction of antibodies able to neutralize in vitro viruses retaining HVR1. Finally, comparing sE21E with sE2 in mouse immunizations, we show similar induction of heterologous NAbs. In summary, we find that C-terminal E2 fusion of E1 or 1E is superior to N-terminal fusion, both in terms of antigenicity and the induction of heterologous NAbs. This has relevance when designing HCV E1E2 vaccine antigens.

scholarly journals A chimeric GB virus B encoding the hepatitis C virus hypervariable region 1 is infectious in vivo

2007 ◽  
Vol 88 (3) ◽  
pp. 895-902 ◽  
Author(s):  
G. Haqshenas ◽  
X. Dong ◽  
H. Netter ◽  
J. Torresi ◽  
E. J. Gowans
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Hypervariable Region ◽  
Immunoblot Analysis ◽  
Post Inoculation ◽  
Sequencing Analysis ◽  
Coding Region ◽  
Hypervariable Region 1

Two GB virus B (GBV-B) chimeric genomes, GBV-HVR and GBV-HVRh (with a hinge), containing the coding region of the immunodominant hypervariable region 1 (HVR1) of the E2 envelope protein of Hepatitis C virus (HCV) were constructed. Immunoblot analysis confirmed that HVR1 was anchored to the GBV-B E2 protein. To investigate the replication competence and in vivo stability of in vitro-generated chimeric RNA transcripts, two naïve marmosets were inoculated intrahepatically with the transcripts. The GBV-HVR chimeric genome was detectable for 2 weeks post-inoculation (p.i.), whereas GBV-HVRh reverted to wild type 1 week p.i. Sequencing analysis of the HVR1 and flanking regions from GBV-HVR RNA isolated from marmoset serum demonstrated that the HVR1 insert remained unaltered in the GBV-HVR chimera for 2 weeks. Inoculation of a naïve marmoset with serum collected at 1 week p.i. also resulted in viraemia and confirmed that the serum contained infectious particles. All animals cleared the infection by 3 weeks p.i. and remained negative for the remaining weeks. The chimera may prove useful for the in vivo examination of any HCV HVR1-based vaccine candidates.

scholarly journals Hypervariable region 1 variant acting as TCR antagonist affects hepatitis C virus-specific CD4+T cell repertoire by favoring CD95-mediated apoptosis

2005 ◽  
Vol 78 (2) ◽  
pp. 372-382 ◽  
Author(s):  
Cristiano Scottà ◽  
Loretta Tuosto ◽  
Anna Maria Masci ◽  
Luigi Racioppi ◽  
Enza Piccolella ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
T Cell ◽  
Hypervariable Region ◽  
Cd4 T Cell ◽  
T Cell Repertoire ◽  
Cell Repertoire ◽  
Hypervariable Region 1
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