Interleukin-21 receptor signalling is important for innate immune protection against HSV-2 infections

Small Noncoding RNA (sncRNA1) within the Latency-Associated Transcript Modulates Herpes Simplex Virus 1 Virulence and the Host Immune Response during Acute but Not Latent Infection

HSV-1 latency-associated transcript (LAT) plays a major role in establishing latency and reactivation; however, the mechanism by which LAT controls these processes is largely unknown. In this study, we sought to establish the role of the small noncoding RNA1 (sncRNA1) encoded within LAT during HSV-1 ocular infection. Our results suggest that sncRNA1 has a protective role during acute ocular infection by modulating the innate immune response to infection.

The antiviral activity of arbidol hydrochloride against herpes simplex virus type II (HSV-2) in a mouse model of vaginitis

Objective

HSV-2 infection has increased significantly in recent years, which is closely associated with cervical cancer and HIV infection. The lack of success in vaccine development and the emergence of drug resistance to commonly used drugs emphasize the urgent need for alternative antivirals against HSV-2 infection. Arbidol (ARB) has been demonstrated to be a broad spectrum antiviral drug that exhibits immunomodulatory properties that affect the HSV-2 life cycle. This study investigated the efficacy and mechanism of ARB against HSV-2 in vivo and in vitro to further explore the clinical application of ARB.

Methods

The efficacy of ARB on HSV-2 infection in vitro was examined by CPE and MTT assays. A vaginitis model was established to monitor changes in histopathology and inflammatory cytokine (IL-2, IL-4, TNF-α and TGF-β) expression by H&E staining and ELISA, respectively, and the efficacy of ARB was evaluated accordingly. Furthermore, flow cytometry was used to determine the ratio of CD4⁺/CD8⁺ T cells in the peripheral blood of the vaginitis animals. Considering the balance of efficacy and pharmacokinetics, ARB ointment was strictly prepared to observe formulation efficacy differences compared to the oral dosing form.

Results

The results showed that, in vitro, the TC₅₀ and IC₅₀ of ARB were 32.32 μg/mL and 4.77 μg/mL (SI = 6.82), respectively, indicating that ARB presents effective activity against HSV-2 in a dose-dependent manner. The results of the time-course assay suggested that 25 μg/mL ARB affected the late stage of HSV-2 replication. However, ARB did not inhibit viral attachment or cell penetration. The in vivo results showed that ARB ointment can improve the survival rate, prolong the survival time and reduce the reproductive tract injury in mice infected with HSV-2, regulate cytokine expression; and balance the CD4⁺ and CD8⁺ T lymphocyte ratio in the peripheral blood to participate in the regulation of immune response.

Conclusion

ARB showed anti-HSV-2 activity in vitro in a dose-dependent manner and played a role in inhibiting the late replication cycle of the virus. The vaginitis model was successfully established, according to immunomodulation outcomes, responded better to ARB in ointment form than in oral form.

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ARB showed anti-HSV-2 activity in vitro in a dose-dependent manner.

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ARB inhibited the late replication cycle of HSV-2.

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ARB ointment participated in the regulation of immune response to reduce the reproductive tract injury.

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ARB in ointment form responded to vaginitis better than in oral form.

Interleukin-21 and its association with chronic periodontitis

Context:

Interleukin-21 (IL-21) is a pleiotropic cytokine, well documented to contribute to the development of Th17 cells which have been shown to play an important role in the pathogenesis of periodontitis. Periodontal disease is a chronic infection of tooth-supporting tissue.

Aim:

This study evaluates the saliva and serum levels of IL-21 in patients with chronic periodontitis and periodontally healthy individuals.

Settings and Design:

The present study was carried out in the Department of Microbiology in association with Department of Oral Medicine and Radiology, Maratha Mandal's N.G.H Institute of Dental Sciences and Research Centre, Belgavi, Karnataka.

Materials and Methods:

Fifty samples of each group were included in the present study. The levels of IL-21 were assessed using a commercially available enzyme-linked immunosorbent assay (ELISA) kit and the results were expressed as pg/mL.

Statistical Analysis Used:

Statistical analysis was performed using SPSS 17.0 software. Data were expressed as mean ± standard deviation and interquartile ranges and comparison of controls and cases by Mann–Whitney test.

Results:

Serum and salivary levels of IL-21 were significantly higher in chronic periodontitis group than in controls (P < 0.001). Clinical periodontal parameters correlated positively with serum IL-21 levels.

Conclusions:

IL-21 is highly expressed in patients with chronic periodontitis and correlated well with clinical parameters of periodontal destruction. Therefore, IL-21 appears to play a role in tissue destruction and can be used as diagnostic biomarker in chronic periodontitis. Saliva can be considered to be a useful alternative to serum as a diagnostic sample.

Transcriptional Analysis of the Guinea Pig Mucosal Immune Response to Intravaginal Infection with Herpes Simplex Virus Type 2

Genital herpes infection in guinea pigs closely models human infection but tools for immune characterization are limited. Immunity to HSV infection at the vaginal epithelial surface was characterized in guinea pigs using PCR-based array analysis of vaginal swab samples. IFNγ was one of the most significantly upregulated genes throughout the infection and over 40% of genes with significantly altered expression were linked to IFNγ based on INTERFEROME analysis. IFNγ transcripts and biologically active IFNγ at the genital mucosa were confirmed by RTPCR and IFNγ reporter cells. Gene ontology analysis revealed activation of many biological processes related to genital immunity shared by humans and mice demonstrating the similarities of the local immune response to primary genital HSV-2 infection in guinea pigs and other established models. This transcription-based array will be useful for dissection of immunity during reactivation from latency, an infection outcome that is not well recapitulated by other animal models.

The DNA methylation profile of activated human natural killer cells

Natural killer (NK) cells are now recognized to exhibit characteristics akin to cells of the adaptive immune system. The generation of adaptive memory is linked to epigenetic reprogramming including alterations in DNA methylation. The study herein found reproducible genome wide DNA methylation changes associated with human NK cell activation. Activation led predominately to CpG hypomethylation (81% of significant loci). Bioinformatics analysis confirmed that non-coding and gene-associated differentially methylated sites (DMS) are enriched for immune related functions (i.e., immune cell activation). Known DNA methylation-regulated immune loci were also identified in activated NK cells (e.g., TNFA, LTA, IL13, CSF2). Twenty-one loci were designated high priority and further investigated as potential markers of NK activation. BHLHE40 was identified as a viable candidate for which a droplet digital PCR assay for demethylation was developed. The assay revealed high demethylation in activated NK cells and low demethylation in naïve NK, T- and B-cells. We conclude the NK cell methylome is plastic with potential for remodeling. The differentially methylated region signature of activated NKs revealed similarities with T cell activation, but also provided unique biomarker candidates of NK activation, which could be useful in epigenome-wide association studies to interrogate the role of NK subtypes in global methylation changes associated with exposures and/or disease states.

CD1d Expression and Invariant NKT Cell Responses in Herpesvirus Infections

Invariant natural killer T (iNKT) cells are a highly conserved subset of unconventional T lymphocytes that express a canonical, semi-invariant T cell receptor and surface markers shared with the natural killer cell lineage. iNKT cells recognize exogenous and endogenous glycolipid antigens restricted by non-polymorphic CD1d molecules, and are highly responsive to the prototypical agonist, α-galactosylceramide. Upon activation, iNKT cells rapidly coordinate signaling between innate and adaptive immune cells through the secretion of proinflammatory cytokines, leading to the maturation of antigen-presenting cells, and expansion of antigen-specific CD4+ and CD8+ T cells. Because of their potent immunoregulatory properties, iNKT cells have been extensively studied and are known to play a pivotal role in mediating immune responses against microbial pathogens including viruses. Here, we review evidence that herpesviruses manipulate CD1d expression to escape iNKT cell surveillance and establish lifelong latency in humans. Collectively, published findings suggest that iNKT cells play critical roles in anti-herpesvirus immune responses and could be harnessed therapeutically to limit viral infection and viral-associated disease.

Prophylactic and therapeutic modulation of innate and adaptive immunity against mucosal infection of herpes simplex virus

Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) are the most common cause of genital ulceration in humans worldwide. Typically, HSV-1 and 2 infections via mucosal route result in a lifelong latent infection after peripheral replication in mucosal tissues, thereby providing potential transmission to neighbor hosts in response to reactivation. To break the transmission cycle, immunoprophylactics and therapeutic strategies must be focused on prevention of infection or reduction of infectivity at mucosal sites. Currently, our understanding of the immune responses against mucosal infection of HSV remains intricate and involves a balance between innate signaling pathways and the adaptive immune responses. Numerous studies have demonstrated that HSV mucosal infection induces type I interferons (IFN) via recognition of Toll-like receptors (TLRs) and activates multiple immune cell populations, including NK cells, conventional dendritic cells (DCs), and plasmacytoid DCs. This innate immune response is required not only for the early control of viral replication at mucosal sites, but also for establishing adaptive immune responses against HSV antigens. Although the contribution of humoral immune response is controversial, CD4(+) Th1 T cells producing IFN-γ are believed to play an important role in eradicating virus from the hosts. In addition, the recent experimental successes of immunoprophylactic and therapeutic compounds that enhance resistance and/or reduce viral burden at mucosal sites have accumulated. This review focuses on attempts to modulate innate and adaptive immunity against HSV mucosal infection for the development of prophylactic and therapeutic strategies. Notably, cells involved in innate immune regulations appear to shape adaptive immune responses. Thus, we summarized the current evidence of various immune mediators in response to mucosal HSV infection, focusing on the importance of innate immune responses.

A novel murine cytomegalovirus vaccine vector protects against Mycobacterium tuberculosis

Tuberculosis remains a global health problem so that a more effective vaccine than bacillus Calmette–Guérin is urgently needed. Cytomegaloviruses persist lifelong in vivo and induce powerful immune and increasing (“inflationary”) responses, making them attractive vaccine vectors. We have used an m1–m16-deleted recombinant murine CMV (MCMV) expressing Mycobacterium tuberculosis Ag 85A to show that infection of mice with this recombinant significantly reduces the mycobacterial load after challenge with M. tuberculosis, whereas control empty virus has a lesser effect. Both viruses induce immune responses to H-2^d–restricted epitopes of MCMV pp89 and M18 Ags characteristic of infection with other MCMVs. A low frequency of 85A-specific memory cells could be revealed by in vivo or in vitro boosting or after challenge with M. tuberculosis. Kinetic analysis of M. tuberculosis growth in the lungs of CMV-infected mice shows early inhibition of M. tuberculosis growth abolished by treatment with NK-depleting anti–asialo ganglio-N-tetraosylceramide Ab. Microarray analysis of the lungs of naive and CMV-infected mice shows increased IL-21 mRNA in infected mice, whereas in vitro NK assays indicate increased levels of NK activity. These data indicate that activation of NK cells by MCMV provides early nonspecific protection against M. tuberculosis, potentiated by a weak 85A-specific T cell response, and they reinforce the view that the innate immune system plays an important role in both natural and vaccine-induced protection against M. tuberculosis.