HERC5 and the ISGylation Pathway: Critical Modulators of the Antiviral Immune Response

Mammalian cells have developed an elaborate network of immunoproteins that serve to identify and combat viral pathogens. Interferon-stimulated gene 15 (ISG15) is a 15.2 kDa tandem ubiquitin-like protein (UBL) that is used by specific E1-E2-E3 ubiquitin cascade enzymes to interfere with the activity of viral proteins. Recent biochemical studies have demonstrated how the E3 ligase HECT and RCC1-containing protein 5 (HERC5) regulates ISG15 signaling in response to hepatitis C (HCV), influenza-A (IAV), human immunodeficiency virus (HIV), SARS-CoV-2 and other viral infections. Taken together, the potent antiviral activity displayed by HERC5 and ISG15 make them promising drug targets for the development of novel antiviral therapeutics that can augment the host antiviral response. In this review, we examine the emerging role of ISG15 in antiviral immunity with a particular focus on how HERC5 orchestrates the specific and timely ISGylation of viral proteins in response to infection.

Modulation of dendritic cell immune functions by plant components

Dendritic cells (DCs) are the key linkage between innate and adoptive immune response. DCs are classified as specialized antigen-presenting cells that initiate T-cell immune responses during infection and hypersensitivity, and maintain immune tolerance to self-antigens. Initiating T-cell immune responses may be beneficial in infectious diseases or cancer management, while, immunosuppressant or tolerogenic responses could be useful in controlling autoimmunity, allergy or inflammatory diseases. Several types of plant-derived components show promising properties in influencing DC functions. Various types of these components have been proven useful in clinical application and immune-based therapy. Therefore, focusing on the benefits of plant-based medicine regulating DC functions may be useful, low-cost, and accessible strategies for human health. This review illustrates recent studies, investigating the role of plant components in manipulating DC phenotype and function towards immunostimulating or immunosuppressing effects either in vitro or in vivo.

Effects of radix ginseng on microbial infections: a narrative review

OBJECTIVE

To summarized the antimicrobial-like effects of Radix Ginseng, which provide important information to the relevant researchers and clinicians, and will benefit the clinical treatment of infectious diseases.

METHODS

PubMed and Google were used to search for and collect scientific publications related to Radix Ginseng and microbial infections. The authors read, classified, and discussed the associated scientific results or evidences, and summarized the corresponding results.

RESULTS

In this review, recent studies on the beneficial effects of Radix Ginseng extracts on microbial and biofilm infections were reviewed. The importance and significance of Radix Ginseng's beneficial effects are discussed. Evidence for the favorable effects of Radix Ginseng extracts on viral, bacterial, fungal, and parasitic infections and the possible underlying mechanisms are summarized.

CONCLUSION

Radix Ginseng might be a promising supplemental remedy for the prevention and treatment of infectious diseases.

Real-time cell analysis--a new method for dynamic, quantitative measurement of infectious viruses and antiserum neutralizing activity

A newly developed electronic cell sensor array--the xCELLigence real-time cell analysis (RTCA) system is tested currently for dynamic monitoring of cell attachment, proliferation, damage, and death. In this study, human enterovirus (HEV71) infection of human rhabdomyosarcoma (RD) was used as an in vitro model to validate the application of this novel system as a straightforward and efficient assay for quantitative measurement of infectious viruses based on virus-induced cytopathic effect (CPE). Several experimental tests were performed including the determination of optimal seeding density of the RD cells in 96-well E-plates, RTCA real-time monitoring of the virus induced CPE and virus titer calculation, and viral neutralization test to determine HEV71 antibody titer. Traditional 50% tissue culture infective dose (TCID50) assay was also conducted for methodology comparison and validation, which indicated a consistent result between the two assays. These findings indicate that the xCELLigence RTCA system can be a valuable addition to current viral assays for quantitative measurement of infectious viruses and quantitation of neutralization antibody titer in real-time, warranting for future research and exploration of applications to many other animal and human viruses.

Compound CVT-E002 attenuates allergen-induced airway inflammation and airway hyperresponsiveness, in vivo

Immune modulation has been a sought after means of therapy for atopic diseases. CVT-E002 is an extract derived from North American Ginseng shown to promote T-helper-1-like responses. We determined what effect CVT-E002 could have in a mouse model of atopic asthma. We report that oral CVT-E002 inhibited the development of allergic airway inflammation and airway hyperresponsiveness. This correlated with an increased presence of interferon-γ in the lung, and also increased regulatory T cells and IL-10. The ability of CVT-E002 to induce regulatory T-cell development was also seen in human in vitro co-cultures.