Characterization of antigenic variants of hepatitis C virus in immune evasion

Hepatitis C Virus: Insights Into Its History, Treatment, Challenges, and Future Directions

Hepatitis C virus (HCV) is a global public health concern with significant impacts. It primarily spreads through blood-to-blood contact, such as sharing needles among drug users. Given the wide prevalence of risk factors, HCV continues to pose a major threat. Hence, it is crucial to understand its characteristics, structure, and genotypes to prevent, treat, and potentially eradicate it. This narrative review aims to explore the history of HCV treatment, highlight the breakthroughs achieved with direct-acting antiviral (DAA) therapy, address potential barriers to HCV eradication, and discuss future treatment possibilities. For this article, relevant studies were identified using various databases, including PubMed, ClinicalTrials.gov, and Journal Storage. The literature search revealed that after identifying HCV and studying its characteristics, interferon alfa and ribavirin became primary treatment options. However, due to their limited coverage against different HCV genotypes, ethnic variations, and suboptimal sustained virological response, the development of DAAs became essential. Combining various DAAs, such as sofosbuvir and velpatasvir, for a duration of 12 weeks has become the standard HCV treatment, with effectiveness against most genotypes. Additionally, ongoing clinical trials have shown promising results for other drugs such as CDI31244/sofosbuvir/velpatasvir, sofosbuvir/coblopasvir, and daclatasvir/asunaprevir. Despite the success of DAAs and ongoing efforts to discover more effective treatments, the high costs of DAAs pose a significant challenge to eradicating HCV, as not all patients can afford these expensive therapies. Furthermore, the ability of HCV to mutate limits the potential for vaccine development. Therefore, it is crucial to focus on developing more cost-effective strategies to control the spread of HCV and create novel, highly effective, and affordable DAAs.

Intracellular Pathogens: Host Immunity and Microbial Persistence Strategies

Infectious diseases caused by pathogens including viruses, bacteria, fungi, and parasites are ranked as the second leading cause of death worldwide by the World Health Organization. Despite tremendous improvements in global public health since 1950, a number of challenges remain to either prevent or eradicate infectious diseases. Many pathogens can cause acute infections that are effectively cleared by the host immunity, but a subcategory of these pathogens called "intracellular pathogens" can establish persistent and sometimes lifelong infections. Several of these intracellular pathogens manage to evade the host immune monitoring and cause disease by replicating inside the host cells. These pathogens have evolved diverse immune escape strategies and overcome immune responses by residing and multiplying inside host immune cells, primarily macrophages. While these intracellular pathogens that cause persistent infections are phylogenetically diverse and engage in diverse immune evasion and persistence strategies, they share common pathogen type-specific mechanisms during host-pathogen interaction inside host cells. Likewise, the host immune system is also equipped with a diverse range of effector functions to fight against the establishment of pathogen persistence and subsequent host damage. This article provides an overview of the immune effector functions used by the host to counter pathogens and various persistence strategies used by intracellular pathogens to counter host immunity, which enables their extended period of colonization in the host. The improved understanding of persistent intracellular pathogen-derived infections will contribute to develop improved disease diagnostics, therapeutics, and prophylactics.

Cytokine profile in chronic hepatitis C: An observation

The data addressing cytokine profile in chronically infected HCV patients are conflicting, ranging from Th1 or Th2 cytokine prevalence to the expression of both types of cytokines. Therefore, the aim of this study was to evaluate cytokine profile in these patients. Cytokine sera levels in HCV patients and healthy controls were evaluated using 13plex FlowCytomix Multiplex. Median values of both proinflammatory and anti-inflammatory cytokines were lower in HCV patients then in controls. In addition, the number of subjects producing detectable quantities of cytokines was significantly lower in the group of HCV patients. Yet, cytokine levels in those patients were remarkably heterogeneous ranging from low to extremely high, much higher than the maximal values in control group. Similarly, grouping data according to HCV genotype, HCV RNA load, ALT/AST ratio and the stage of fibrosis showed marked standard deviations, reflecting high intragroup diversity. No correlation was found between each disease-related factor and cytokine levels. Patients investigated in our and similar studies were disparate pursuant to characteristics of the hosts, pathogen and course of the disease. Therefore, the inconsistency of the literature data regarding cytokine pattern in chronic HCV patients may be a consequence of the disregarded/overlooked heterogeneity of these patients.

Designing and Development of a DNA Vaccine Based On Structural Proteins of Hepatitis C Virus

BACKGROUND

Hepatitis C virus (HCV) infection is one of the most prevalent infectious diseases responsible for high morbidity and mortality worldwide. Therefore, designing new and effective therapeutics is of great importance. The aim of the current study was to construct a DNA vaccine containing structural proteins of HCV and evaluation of its expression in a eukaryotic system.

METHODS

Structural proteins of HCV (core, E1, and E2) were isolated and amplified from JFH strain of HCV genotype 2a using PCR method. The PCR product was cloned into pCDNA3.1 (+) vector and finally were confirmed by restriction enzyme analysis and sequencing methods. The eukaryotic expression of the vector was confirmed by RT-PCR.

RESULTS

A recombinant vector containing 2241bp fragment of HCV structural genes was constructed. The desired plasmid was sequenced and corresponded to 100% identity with the submitted sequences in GenBank. RT-PCR results indicated that the recombinant plasmid could be expressed efficiently in the eukaryotic expression system.

CONCLUSION

Successful cloning of structural viral genes in pCDNA3.1 (+) vector and their expression in the eukaryotic expression system facilitates the development of new DNA vaccines against HCV. A DNA vaccine encoding core-E1-E2 antigens was designed. The desired expression vector can be used for further attempts in the development of vaccines.

Control of the inflammatory response mechanisms mediated by natural and induced regulatory T-cells in HCV-, HTLV-1-, and EBV-associated cancers

Virus infections are involved in chronic inflammation and, in some cases, cancer development. Although a viral infection activates the immune system's response that eradicates the pathogen mainly through inflammatory mechanisms, it is now recognized that this inflammatory condition is also favorable to the development of tumors. Indeed, it is well described that viruses, such as hepatitis C virus (HCV), Epstein Barr virus (EBV), human papillomavirus (HPV) or human T-cell lymphotropic virus type-1 (HTLV-1), are important risk factors for tumor malignancies. The inflammatory response is a fundamental immune mechanism which involves several molecular and cellular components consisting of cytokines and chemokines that are released by various proinflammatory cells. In parallel to this process, some endogenous recruited components release anti-inflammatory mediators to restore homeostasis. The development of tools and strategies using viruses to hijack the immune response is mostly linked to the presence of regulatory T-cells (Treg) that can inhibit inflammation and antiviral responses of other effector cells. In this review, we will focus on current understanding of the role of natural and induced Treg in the control and the resolution of inflammatory response in HCV-, HTLV-1-, and EBV-associated cancers.

Genetic and epidemiological insights into the emergence of peste des petits ruminants virus (PPRV) across Asia and Africa

Small ruminants are important components in the livelihood of millions of households in many parts of the world. The spread of the highly contagious peste des petits ruminants (PPR) disease, which is caused by an RNA virus, PPRV, across Asia and Africa remains a major concern. The present study explored the evolutionary and epidemiological dynamics of PPRV through the analyses of partial N-gene and F-gene sequences of the virus. All the four previously described PPRV lineages (I-IV) diverged from their common ancestor during the late-19(th) to early-20(th) century. Among the four lineages, PPRV-IV showed pronounced genetic structuring across the region; however, haplotype sharing among the geographic regions, together with the presence of multiple genetic clusters within a country, indicates the possibility of frequent mobility of the diseased individuals across the region. The gradual decline in the effective number of infections suggests a limited genetic variation, which could be attributed to the effective vaccination that has been practiced since 1990s. However, the movement of infected animals across the region likely contributes to the spread of PPRV-IV. No evidence of positive selection was identified from this study.