• CTL
• HCV
• adaptive immune system
• genotype
• polymorphism
• subtype

• G×G interactions
• host–pathogen coevolution
• linkage disequilibrium
• population genomics
• single nucleotide polymorphism

• Humans
• Host-Pathogen Interactions/genetics
• Polymorphism, Single Nucleotide
• Hepacivirus/genetics
• Genome-Wide Association Study
• Hepatitis C/genetics
• Hepatitis C/virology
• Bayes Theorem
• Genotype

• 274542535 (TE809/3) and 221691301 (TE809/6) Deutsche Forschungsgemeinschaft
• 220171/Z/20/Z Sir Henry Dale Fellowship jointly
• MR/K01532X/1 Medical Research Council

• Binding
• Competition
• E1E2 glycoprotein
• HCV
• HCV pseudoparticle
• Monoclonal antibody
• Neutralization
• Virus panel

• Humans
• Hepacivirus
• Antibodies, Neutralizing
• Antibody Formation
• Neutralization Tests
• Viral Envelope Proteins
• Hepatitis C
• Glycoproteins
• Epitopes
• Hepatitis C Antibodies
• Antibodies, Monoclonal
• Vaccines

• SARS-CoV-2
• competitive fitness
• homologous recombination

• Animals
• Humans
• SARS-CoV-2/genetics
• Caco-2 Cells
• COVID-19
• Homologous Recombination
• Spike Glycoprotein, Coronavirus

• 2021YFC2301300 National Key Research and Development Projects of the Ministry of Science and Technology of China
• 2022YFC2303700 National Key Research and Development Projects of the Ministry of Science and Technology of China
• 32130005 National Natural Science Foundation of China (NSFC)
• 92269117 National Natural Science Foundation of China (NSFC)
• 81925025 the National Science Fund for Distinguished Young Scholars
• 81621005 the Innovative Research Group
• 2019-I2M-5-049 the Innovation Fund for Medical Sciences
• Z201100006820029 the Beijing Nova Project

• antiviral protein
• endogenous viral elements
• host-virus interaction
• virome
• virus symbiosis

• lymphocyte differentiation
• hepatitis c virus
• immune evasion
• cytotoxic t cells

During chronic hepatitis C virus (HCV) infection, CD8⁺ T-cells become functionally exhausted, undergoing progressive phenotypic changes, i.e., overexpression of “inhibitory” molecules such as PD-1 (programmed cell death protein 1) and/or Tim-3 (T-cell immunoglobulin and mucin domain-containing molecule-3). The extreme intrahost genetic diversity of HCV is a major mechanism of immune system evasion, facilitating epitope escape. The aim of the present study was to determine whether T-cell exhaustion phenotype in chronic HCV infection is related to the sequence repertoire of NS3 viral immunodominant epitopes.

The study population was ninety prospective patients with chronic HCV genotype 1b infection. Populations of peripheral blood CD8⁺ T-cells expressing PD-1/Tim-3 were assessed by multiparametric flow cytometry, including HCV-specific T-cells after magnetic-based enrichment using MHC-pentamer. Autologous epitope sequences were inferred from next-generation sequencing. The correction of sequencing errors and genetic variants reconstruction was performed using Quasirecomb.

There was an interplay between the analyzed epitopes sequences and exhaustion phenotype of CD8⁺ T-cells. A predominance of NS3₁₄₀₆ epitope sequence, representing neither prototype KLSGLGLNAV nor cross-reactive variants (KLSSLGLNAV, KLSGLGINAV or KLSALGLNAV), was associated with higher percentage of HCV-specific CD8⁺PD-1⁺Tim-3⁺ T-cells, P=0.0102. Variability (at least two variants) of NS3₁₄₀₆ epitope sequence was associated with increased frequencies of global CD8⁺PD-1⁺Tim-3⁺ T-cells (P=0.0197) and lower frequencies of CD8⁺PD-1⁻Tim-3⁻ T-cells (P=0.0079). In contrast, infection with NS3₁₀₇₃ dominant variant epitope (other than prototype CVNGVCWTV) was associated with lower frequency of global CD8⁺PD-1⁺Tim-3⁺ T-cells (P=0.0054).

Our results indicate that PD-1/Tim-3 receptor expression is largely determined by viral epitope sequence and is evident for both HCV-specific and global CD8⁺ T-cells, pointing to the importance of evaluating autologous viral epitope sequences in the investigation of CD8⁺ T-cell exhaustion in HCV infection.

• PD-1
• T-cell exhaustion
• Tim-3
• epitope sequence
• hepatitis C virus

• COVID19
• Electron microscopy
• SARS-CoV-2
• acute respiratory distress syndrome (ARDS)
• coronavirus
• cryo-electron microscopy
• spike S protein structure

A functional adaptive immune response is the major determinant for clearance of hepatitis C virus (HCV) infection. However, in the majority of patients, this response fails and persistent infection evolves. Here, we dissect the HCV-specific key players of adaptive immunity, namely B cells and T cells, and describe factors that affect infection outcome. Once chronic infection is established, continuous exposure to HCV antigens affects functionality, phenotype, transcriptional program, metabolism, and the epigenetics of the adaptive immune cells. In addition, viral escape mutations contribute to the failure of adaptive antiviral immunity. Direct-acting antivirals (DAA) can mediate HCV clearance in almost all patients with chronic HCV infection, however, defects in adaptive immune cell populations remain, only limited functional memory is obtained and reinfection of cured individuals is possible. Thus, to avoid potential reinfection and achieve global elimination of HCV infections, a prophylactic vaccine is needed. Recent vaccine trials could induce HCV-specific immunity but failed to protect from persistent infection. Thus, lessons from natural protection from persistent infection, DAA-mediated cure, and non-protective vaccination trials might lead the way to successful vaccination strategies in the future.

• B cell
• T cell
• T cell exhaustion
• hepatitis C virus
• neutralizing antibody
• viral escape

• Adaptive Immunity
• Animals
• Antibody Formation/immunology
• Clinical Trials as Topic
• Hepacivirus/immunology
• Humans
• T-Lymphocytes/immunology
• Viral Vaccines/immunology

Direct-acting antivirals (DAAs) revolutionized treatment of hepatitis C virus (HCV) infection. Resistance-associated substitutions (RASs) present at the baseline impair response to DAA due to rapid selection of resistant HCV strains. NS5A is indispensable target of the current DAA treatment regimens. We evaluated prevalence of RASs in NS5A in DAA-naïve patients infected with HCV 1a (n = 19), 1b (n = 93), and 3a (n = 90) before systematic DAA application in the territory of the Russian Federation. Total proportion of strains carrying at least one RAS constituted 35.1% (71/202). In HCV 1a we detected only M28V (57.9%) attributed to a founder effect. Common RASs in HCV 1b were R30Q (7.5%), L31M (5.4%), P58S (4.4%), and Y93H (5.4%); in HCV 3a, A30S (31.0%), A30K (5.7%), S62L (8.9%), and Y93H (2.2%). Prevalence of RASs in NS5A of HCV 1b and 3a was similar to that worldwide, including countries practicing massive DAA application, i.e., it was not related to treatment. NS5A with and without RASs exhibited different co-variance networks, which could be attributed to the necessity to preserve viral fitness. Majority of RASs were localized in polymorphic regions subjected to immune pressure, with selected substitutions allowing immune escape. Altogether, this explains high prevalence of RAS in NS5A and low barrier for their appearance in DAA-inexperienced population.

• NS5A
• amino acid covariance
• direct-acting antivirals
• hepatitis C virus (HCV)
• immune escape
• resistance-associated substitutions

• Hepatitis C
• genetics
• genome to genome analysis
• genomics
• human
• infectious disease
• integration analysis
• interferon lambda polymorphism
• microbiology

• Adaptation, Biological
• Africa
• Asia
• Europe
• Genotype
• Hepacivirus/genetics
• Hepatitis C/immunology
• Hepatitis C/virology
• Humans
• Immunologic Factors/genetics
• Interferons/genetics
• Viral Load
• Viral Nonstructural Proteins/genetics

• PP00P3_157529 Swiss National Science Foundation
• Gilead Sciences

• HCV
• NGS
• drug resistance
• full-genome
• genotyping

• HIV-1 Nef
• PSMs
• evolution
• mutations
• positive selection
• subtype.

• Between-host
• Next generation sequencing
• RNA viruses
• Transmitted founder viruses
• Within-host

Hepatitis C virus (HCV)-specific T cell responses are critical for immune control of infection. Viral adaptation to these responses, via mutations within regions of the virus targeted by CD8⁺ T cells, is associated with viral persistence. However, identifying viral adaptation to HCV-specific CD4⁺ T cell responses has been difficult although key to understanding anti-HCV immunity. In this context, HCV sequence and host genotype from a single source HCV genotype 1B cohort (n = 63) were analyzed to identify viral changes associated with specific human leucocyte antigen (HLA) class II alleles, as these variable host molecules determine the set of viral peptides presented to CD4⁺ T cells. Eight sites across the HCV genome were associated with HLA class II alleles implicated in infection outcome in this cohort (p ≤ 0.01; Fisher’s exact test). We extended this analysis to chronic HCV infection (n = 351) for the common genotypes 1A and 3A. Variation at 38 sites across the HCV genome were associated with specific HLA class II alleles with no overlap between genotypes, suggestive of genotype-specific T cell targets, which has important implications for vaccine design. Here we show evidence of HCV adaptation to HLA class II-restricted CD4⁺ T cell pressure across the HCV genome in chronic HCV infection without a priori knowledge of CD4⁺ T cell epitopes.

• Hepatitis C virus
• T cell exhaustion
• immune response
• innate immunity
• interferon lambda
• neutralizing antibodies

• classical human leukocyte antigens
• hepatitis C virus and immune regulation
• human immunodeficiency virus
• human leukocyte antigen
• major histocompatibility complex
• non-classical human leukocyte antigens

• anti-HCV T cell response
• hepatitis C virus
• transmission
• viral adaptation

Outcomes of hepatitis C virus (HCV) infection and treatment depend on viral and host genetic factors. We use human genome-wide genotyping arrays and new whole-genome HCV viral sequencing technologies to perform a systematic genome-to-genome study of 542 individuals chronically infected with HCV, predominately genotype 3. We show that both HLA alleles and interferon lambda innate immune system genes drive viral genome polymorphism, and that IFNL4 genotypes determine HCV viral load through a mechanism that is dependent on a specific polymorphism in the HCV polyprotein. We highlight the interplay between innate immune responses and the viral genome in HCV control.

Hepatitis C virus (HCV) readily establishes chronic infection, which is characterized by failure of virus-specific CD8⁺ T cells. HCV uses epitope mutation and T-cell exhaustion to escape from the host immune response. Previously, we engineered high-affinity T-cell receptors (HATs) targeting human immunodeficiency virus escape mutants. In this study, the affinity of a T-cell receptor specific for the HLA-A2-restricted HCV immunodominant epitope NS3 1406–1415 (KLVALGINAV) was improved from a K_D of 6.6 µM to 40 pM. These HATs could also target HCV NS3 naturally occurring variants, including an escape variant vrt1 (KLVVLGINAV), with high affinities. The HATs can be used as high-affinity targeting molecules at the centre of the immune synapse for the HLA-restricted NS3 antigen. By fusing the HAT with a T-cell activation molecule, an anti-CD3 single-chain variable fragment, we constructed a molecule called high-affinity T-cell activation core (HATac), which can redirect functional CTLs possessing any specificity to recognize and kill cells presenting HCV NS3 antigens. This capability was verified with T2 cells loaded with prototype or variant peptides and HepG2 cells expressing the truncated NS3 prototype or variant proteins. The results indicate that HATac targeting the HLA-restricted NS3 antigen may provide a useful tool for circumventing immune escape mutants and T-cell exhaustion caused by HCV infection.

• Pakistan
• genotyping
• hepatitis C
• untypeable subtypes

• Genotype
• Hepacivirus/classification
• Hepacivirus/genetics
• Hepacivirus/isolation & purification
• Hepatitis C/virology
• Humans
• Pakistan
• RNA, Viral/genetics

• Genetic relatedness
• Hepatitis C virus
• Multiregion
• Next generation sequencing
• Outbreak

• Adult
• Evolution, Molecular
• Female
• Genotype
• Hepacivirus/classification
• Hepacivirus/genetics
• Hepatitis C/epidemiology
• Hepatitis C/virology
• High-Throughput Nucleotide Sequencing
• Humans
• Male
• Middle Aged
• Multilocus Sequence Typing
• Phylogeny
• Viral Load
• Viral Nonstructural Proteins/genetics

Characterisation of Hepatitis C virus (HCV)-specific CD8⁺ T-cell responses in the context of multiple HCV exposures is critical to identify broadly protective immune responses necessary for an effective HCV vaccine against the different HCV genotypes. However, host and viral genetic diversity complicates vaccine development. To compensate for the observed variation in circulating autologous viruses and host molecules that restrict antigen presentation (human leucocyte antigens; HLA), this study used a reverse genomics approach that identified sites of viral adaptation to HLA-restricted T-cell immune pressure to predict genotype-specific HCV CD8⁺ T-cell targets. Peptides representing these putative HCV CD8⁺ T-cell targets, and their adapted form, were used in individualised IFN-γ ELISpot assays to screen for HCV-specific T-cell responses in 133 HCV-seropositive subjects with high-risk of multiple HCV exposures. The data obtained from this study i) confirmed that genetic studies of viral evolution is an effective approach to detect novel in vivo HCV T-cell targets, ii) showed that HCV-specific T-cell epitopes can be recognised in their adapted form and would not have been detected using wild-type peptides and iii) showed that HCV-specific T-cell (but not antibody) responses against alternate genotypes in chronic HCV-infected subjects are readily found, implying clearance of previous alternate genotype infection. In summary, HCV adaptation to HLA Class I-restricted T-cell responses plays a central role in anti-HCV immunity and multiple HCV genotype exposure is highly prevalent in at-risk exposure populations, which are important considerations for future vaccine design.

• Alleles
• CD8-Positive T-Lymphocytes/immunology
• CD8-Positive T-Lymphocytes/virology
• Cohort Studies
• Enzyme-Linked Immunospot Assay
• Epitopes, T-Lymphocyte/chemistry
• Female
• Genomics
• Genotype
• HLA Antigens/immunology
• Hepacivirus
• Hepatitis C/immunology
• Hepatitis C/virology
• Hepatitis C, Chronic/immunology
• Hepatitis C, Chronic/virology
• Humans
• Male
• Peptides/chemistry

• British Columbia
• Epidemiology
• Hepatitis C virus
• Phylogenetics
• Recent transmission clusters
• Sequencing
• Seroconversion
• Surveillance

Genetic and cellular studies have shown that the host’s innate and adaptive immune responses are an important correlate of viral infection outcome. The features of the host’s immune response (host resistance) reflect the coevolution between hosts and pathogens that has occurred over millennia, and that has also resulted in a number of strategies developed by viruses to improve fitness and survival within the host (viral adaptation). In this review, we discuss viral adaptation to host immune pressure via protein–protein interactions and sequence-specific mutations. Specifically, we will present the “state of play” on viral escape mutations to host T-cell responses in the context of the hepatitis C virus, and their influence on infection outcome.

• adaptive immune response
• hepatitis C virus
• immune escape
• viral adaptation

Over the past two decades, much has been learned about how human viruses evade T cell immunity to establish persistent infection. The lessons are particularly relevant to two hepatotropic viruses, HBV and HCV, that are very significant global public health problems. Although HCV and HBV are very different, the natural history of persistent infections with these viruses in humans shares some common features including failure of T cell immunity. During recent years, large sequence studies of HCV have characterized intra-host evolution as well as sequence diversity between hosts in great detail. Combined with studies of CD8+ T cell phenotype and function, it is now apparent that the T cell response shapes viral evolution. In turn, HCV sequence diversity influences the quality of the CD8+ T cell response and thus infection outcome. Here, we review published studies of CD8+ T cell selection pressure and mutational escape of the virus. Potential consequences for therapeutic strategies to restore T cell immunity against persistent human viruses, most notably HBV, are discussed.

• Antiviral interferon therapy
• Diagnostics
• Genotypes
• Hepatitis C virus
• Pakistan
• Untypable variants

• Antiviral Agents/therapeutic use
• Developing Countries
• Genotype
• Hepacivirus/genetics
• Hepatitis C/diagnosis
• Hepatitis C/drug therapy
• Hepatitis C/epidemiology
• Hepatitis C/virology
• Humans
• Molecular Diagnostic Techniques
• Pakistan/epidemiology
• Predictive Value of Tests
• Prevalence
• Prognosis
• Reproducibility of Results

• epstein-barr virus
• hepatitis c virus
• ifn-γ
• il-15

• Adolescent
• Adult
• Aged
• Alanine Transaminase/blood
• Antibodies, Viral/blood
• Aspartate Aminotransferases/blood
• Chronic Disease
• Coinfection/immunology
• Coinfection/virology
• DNA, Viral/isolation & purification
• Egypt
• Enzyme-Linked Immunosorbent Assay
• Epstein-Barr Virus Infections/complications
• Epstein-Barr Virus Infections/immunology
• Female
• Flow Cytometry
• Hepacivirus/genetics
• Hepacivirus/immunology
• Hepatitis C, Chronic/complications
• Hepatitis C, Chronic/immunology
• Herpesvirus 4, Human/genetics
• Herpesvirus 4, Human/immunology
• Humans
• Interferon-gamma/blood
• Interleukin-15/blood
• Male
• Middle Aged
• Polymerase Chain Reaction
• RNA, Viral/isolation & purification
• Young Adult

• B lymphocytes
• NK cells
• T lymphocytes
• immune evasion
• innate immunity
• interferons

• deep sequencing technology
• next-generation sequencing
• pyrosequencing
• sequencing-by-synthesis

The hepatitis B virus (HBV)-polymerase region overlaps pre-S/S genes with high epitope density and plays an essential role in viral replication. We investigated whether genetic variation in the polymerase region determined long-term dynamics of viral load and the risk of hepatitis B progression in a population-based cohort study.

We sequenced the HBV-polymerase region using baseline plasma from treatment-naïve individuals with HBV-DNA levels≥1000 copies/mL in a longitudinal viral-load study of participants with chronic HBV infection followed-up for 17 years, and obtained sequences from 575 participants (80% with HBV genotype Ba and 17% with Ce).

Patterns of viral sequence diversity across phases (i.e., immune-tolerant, immune-clearance, non/low replicative, and hepatitis B e antigen (HBeAg)-negative hepatitis phases) of HBV-infection, which were associated with viral and clinical features at baseline and during follow-up, were similar between HBV genotypes, despite greater diversity for genotype Ce vs. Ba. Irrespective of genotypes, however, HBeAg-negative participants had 1.5-to-2-fold higher levels of sequence diversity than HBeAg-positive participants (P<0.0001). Furthermore, levels of viral genetic divergence from the population consensus sequence, estimated by numbers of nucleotide substitutions, were inversely associated with long-term viral load even in HBeAg-negative participants. A mixed model developed through analysis of the entire HBV-polymerase region identified 153 viral load-associated single nucleotide polymorphisms in overall and 136 in HBeAg-negative participants, with distinct profiles between HBV genotypes. These polymorphisms were most evident at sites within or flanking T-cell epitopes. Seven polymorphisms revealed associations with both enhanced viral load and a more than 4-fold increased risk of hepatocellular carcinoma and/or liver cirrhosis.

The data highlight a role of viral genetic divergence in the natural course of HBV-infection. Interindividual differences in the long-term dynamics of viral load is not only associated with accumulation of mutations in HBV-polymerase region, but differences in specific viral polymorphisms which differ between genotypes.

HIV, unlike other viruses, may benefit from immune recognition by preserving the sequence of its T cell epitopes, thereby enhancing transmission between cells.

The immune system should constitute a strong selective pressure promoting viral genetic diversity and evolution. However, HIV shows lower sequence variability at T-cell epitopes than elsewhere in the genome, in contrast with other human RNA viruses. Here, we propose that epitope conservation is a consequence of the particular interactions established between HIV and the immune system. On one hand, epitope recognition triggers an anti-HIV response mediated by cytotoxic T-lymphocytes (CTLs), but on the other hand, activation of CD4⁺ helper T lymphocytes (T_H cells) promotes HIV replication. Mathematical modeling of these opposite selective forces revealed that selection at the intrapatient level can promote either T-cell epitope conservation or escape. We predict greater conservation for epitopes contributing significantly to total immune activation levels (immunodominance), and when T_H cell infection is concomitant to epitope recognition (trans-infection). We suggest that HIV-driven immune activation in the lymph nodes during the chronic stage of the disease may offer a favorable scenario for epitope conservation. Our results also support the view that some pathogens draw benefits from the immune response and suggest that vaccination strategies based on conserved T_H epitopes may be counterproductive.

A key component of the immune response against viruses and other pathogens is the recognition of short foreign protein sequences called epitopes. However, viruses can escape the immune system by mutating, so epitopes should accumulate high levels of genetic variability. This has been documented in several human viruses, but in HIV, unexpectedly, epitopes tend to be relatively conserved. Here, we propose that this is a consequence of the peculiar interactions that occur between HIV and the immune system. As with other viruses, recognition of HIV epitopes promotes the activation of cytotoxic and helper T lymphocytes, which then orchestrate a cellular immune response. However, HIV infects helper T lymphocytes as their target cell in the body and does so more efficiently when these cells have been activated to participate in an immune response. Mathematical modeling showed that, in some cases, HIV may take advantage of immune activation, thus favoring epitope conservation. This should be more likely to occur with epitopes that trigger more vigorous T-cell responses, and during the process known as “trans-infection,” in which helper T lymphocytes are infected while being activated. Our results highlight the potential advantages of an HIV vaccination strategy based on epitopes that stimulate cytotoxic T lymphocytes without specifically stimulating helper T lymphocytes.

• Algorithms
• Amino Acid Sequence
• Computer Simulation
• Conserved Sequence
• Epitopes, T-Lymphocyte/genetics
• Epitopes, T-Lymphocyte/immunology
• Evolution, Molecular
• Genetic Variation
• HIV Antigens/genetics
• HIV Antigens/immunology
• HIV Infections/immunology
• HIV-1/genetics
• HIV-1/immunology
• Host-Pathogen Interactions
• Humans
• Immune Evasion/genetics
• Immunity, Cellular
• Models, Genetic
• Viral Load
• Virus Replication

Replication of the hepatitis C virus (HCV) is an error-prone process. This high error rate results in the emergence of viral populations (quasispecies) within hosts and contributes to interhost variability. Numerous studies have demonstrated that both viral and host factors contribute to this viral diversity, which can ultimately affect disease outcome. As the host's immune response is an important correlate of infection outcome for HCV, many of these viral variations are strongly influenced by T-cell immune pressure and accordingly constitute an efficient strategy to subvert such pressures (viral adaptations). This paper will review the data on viral diversity observed between and within hosts infected with HCV from the acute to the chronic stage of infection and will focus on viral adaptation to the host's T-cell immune response.

• Adult
• Aged
• Evolution, Molecular
• Female
• Genetic Variation
• Genome, Viral
• Genotype
• Hepacivirus/classification
• Hepacivirus/genetics
• Hepatitis C, Chronic/genetics
• Hepatitis C, Chronic/virology
• Humans
• Interferons
• Interleukins/genetics
• Male
• Middle Aged
• Phylogeny
• Risk Factors
• Sequence Analysis, DNA

• Adult
• Cluster Analysis
• Female
• Genetic Variation
• Genotype
• Hepacivirus/classification
• Hepacivirus/genetics
• Hepacivirus/isolation & purification
• Hepatitis C/epidemiology
• Hepatitis C/virology
• Humans
• Male
• Middle Aged
• Molecular Epidemiology
• Molecular Sequence Data
• Phylogeny
• RNA, Viral/genetics
• Renal Dialysis/adverse effects
• Reverse Transcriptase Polymerase Chain Reaction
• Sequence Analysis, DNA
• Tunisia/epidemiology
• Viral Nonstructural Proteins

• CD8-Positive T-Lymphocytes/immunology
• CD8-Positive T-Lymphocytes/virology
• Disease Outbreaks/statistics & numerical data
• Disease Susceptibility/epidemiology
• Disease Susceptibility/immunology
• Epitopes, T-Lymphocyte/immunology
• Genotype
• Germany/epidemiology
• HLA-A3 Antigen/genetics
• HLA-B Antigens/genetics
• HLA-B27 Antigen/genetics
• HLA-B8 Antigen/genetics
• Hepatitis C, Chronic/epidemiology
• Hepatitis C, Chronic/immunology
• Humans
• Immunodominant Epitopes/immunology
• Ireland/epidemiology
• Risk Factors

• Adaptive Immunity
• Hepacivirus/immunology
• Hepacivirus/pathogenicity
• Hepatitis C/immunology
• Hepatitis C/pathology
• Hepatitis C/virology
• Host-Pathogen Interactions
• Humans
• Immune Evasion
• Immunity, Innate

• Adult
• Antiviral Agents/pharmacology
• Biota
• Drug Resistance, Viral
• Female
• Hepacivirus/classification
• Hepacivirus/drug effects
• Hepacivirus/genetics
• Hepacivirus/isolation & purification
• Hepatitis C/virology
• High-Throughput Nucleotide Sequencing/methods
• Humans
• Male
• Middle Aged
• Mutation
• Oligopeptides/pharmacology
• Polymerase Chain Reaction/methods
• Proline/analogs & derivatives
• Proline/pharmacology
• Virology/methods