Search Results (1,000)

Background: Humanized mice transplanted with CD34⁺ hematopoietic cells (HPCs) are broadly used to study human immune responses and infections in vivo and for testing therapies pre-clinically. However, until now, it was not clear whether interactions between the mouse major histocompatibility complexes (MHCs) and/or the human leukocyte antigens (HLAs) were necessary for human T-cell development and immune reactivity. Methods: We evaluated the long-term (20-week) human hematopoiesis and human T-cell development in NOD Scid Gamma (NSG) mice lacking the expression of MHC class I and II (NSG-DKO). Triplicate experiments were performed with HPCs obtained from three donors, and humanization was confirmed in the reference strain NOD Rag Gamma (NRG). Further, we tested whether humanized NSG-DKO mice would respond to a lentiviral vector (LV) systemic delivery of HLA-A*02:01, HLA-DRB1*04:01, human GM-CSF/IFN-α, and the human cytomegalovirus gB antigen. Results: Human immune reconstitution was detectable in peripheral blood from 8 to 20 weeks after the transplantation of NSG-DKO. Human single positive CD4⁺ and CD8⁺ T-cells were detectable in lymphatic tissues (thymus, bone marrow, and spleen). LV delivery harnessed the detection of lymphocyte subsets in bone marrow (αβ and γδ T-cells and NK cells) and the expression of HLA-DR. Furthermore, RNA sequencing showed that LV delivery increased the expression of different human reactome pathways, such as defense responses to other organisms and viruses. Conclusions: Human T-cell development and reactivity are independent of the expression of murine MHCs in humanized mice. Therefore, humanized NSG-DKO is a promising new model for studying human immune responses, as it abrogates the xenograft mouse MHC interference. Full article

Cytomegalovirus (CMV) poses a significant threat to post-hematopoietic cell transplantation (HCT). Control strategies include letermovir prophylaxis or ganciclovir pre-emptive therapy (PET). Without prophylaxis, 65–90% of seropositive recipients develop a clinically significant CMV infection. Due to PET drawbacks, letermovir prophylaxis is preferable, as it reduces CMV-related events and improves overall survival. However, refractory or resistant CMV-CS remains a challenge, with maribavir showing limited efficacy. This systematic review followed the Cochrane Manual and PRISMA guidelines and was registered in PROSPERO. Searches were conducted in PubMed, Scopus, Embase, and Web of Science. Out of 1895 identified records, 614 duplicates were removed, and subsequent screening excluded 1153 studies. Eleven included studies (2012–2024) involved 255 HCT recipients receiving adoptive immunotherapy (AI), primarily CMV-specific T-cell therapy. GvHD occurred in 1.82% of cases. Adverse events occurred in 4.4% of cases, while mild CRS was observed in 1.3% of patients. Efficacy, evaluated in 299 patients across eleven studies, showed an average response rate of 78.2%. CMV-CS recurrence was observed in 24.4% of 213 patients, and death due to CMV was reported in 9.7% of 307 patients across nine studies. Adoptive hCMV-specific T-cell immunotherapy appears to be a safe, effective alternative for refractory CMV-CS in HCT. Full article

Background: The sexual transmissibility of enteric pathogens, including Salmonella spp., has been described in men who have sex with men (MSM). However, the factors seen in MSM with Salmonella spp. are poorly understood. Method: We aimed to systematically review the literature to explore any factors seen in MSM with Salmonella spp. (MSM). We searched six databases—Medline, PubMed, CINAHL, Embase, Emcare, and Global Health—in April 2024 for manuscripts which contained primary peer-reviewed data in English and the measurement of any risk factors observed in MSM with Salmonella spp. This review was registered on PROSPERO (CRD42023472864). Results: Eleven manuscripts were included in the final review and highlighted demographic (living with HIV), behavioural (oral–anal sex, receptive and penetrative anal sex, hand licking to stimulate their partner, group sex, non-condom use), and biological (co-infection with CMV, Mycobacterium avium complex, Strongyloides stercoralis, Blastocystis hominis, Klebsiella spp. Herpes simplex virus, Cytomegalovirus, Cryptosporidium, Histoplasmosis, Shigella spp.; previous infection with Treponema pallidum, Neisseria gonorhoeae, Chlamydia trachomatis and hepatitis B; and antimicrobial treatment failure) factors seen in MSM with Salmonella spp. Conclusion: Despite a limited number of manuscripts and individuals, this review highlighted some potential demographic, behavioural, and biological factors implicated in the transmission of Salmonella spp. in MSM. These data will provide insights for future guidelines, public health control strategies, and research. Full article

Congenital cytomegalovirus (cCMV) is the most common cause of congenital infection and the leading cause of non-genetic sensorineural hearing loss in childhood. While treatment trials have been conducted in symptomatic children, defining asymptomatic infection can be complex. We performed a scoping review to understand how infection severity is defined and treated globally, as well as the various indications for initiating treatment. We conducted an electronic search of MEDLINE, EMBASE, Scopus, and the Cochrane Library, using combinations of the following terms: “newborn”, “baby”, “child”, “ganciclovir”, “valganciclovir”, and “cytomegalovirus” or “CMV”. We included eligible prospective and retrospective studies, case series, and randomized clinical trials (RCTs) published up to May 2024. A total of 26 studies were included, of which only 5 were RCTs. There was significant heterogeneity between studies. The most commonly considered criteria for symptomatic infection were microcephaly (23/24 studies), abnormal neuroimaging (22/24 studies), chorioretinitis/ocular impairment (21/24 studies), and hearing impairment (20/24 studies). Two studies also included asymptomatic newborns in their treatment protocols. Outcome measures varied widely, focusing either on different hearing assessments or neurocognitive issues. Our literature analysis revealed significant variability and heterogeneity in the definition of symptomatic cCMV infection and, consequently, in treatment approaches. A consensus on core outcomes and well-conducted RCTs are needed to establish treatment protocols for specific groups of newborns with varying manifestations of cCMV. Full article

Knowledge about the underlying causes of the individual occurrence of symptoms during acute COVID-19 disease and during the post-acute sequelae of COVID-19 is limited. In a German COVID-19 follow-up study, we assessed whether elevated antibody responses to herpesviruses were associated with symptom occurrence in acute COVID-19 disease (n = 96 participants) and during 20 months of follow-up (n = 62 participants). Serum samples were analyzed for their antibodies to herpes simplex virus (HSV)-1 and -2, Epstein–Barr virus (EBV), and Cytomegalovirus (CMV) using fluorescent bead-based multiplex serology. The association of herpesvirus antibodies with symptom occurrence (fatigue, fever, dyspnea, decrease in taste, concentration problems) was assessed using multivariate logistic regression models. High EBV antibody levels were significantly associated with a more than fourfold increased odds of experiencing fatigue during acute COVID-19 disease and during follow-up. High CMV antibody levels were significantly associated with a more than threefold increased odds of experiencing concentration problems and a decrease in taste during the follow-up. The HSV-1 and -2 antibody levels were not elevated in the individuals that experienced symptoms. In conclusion, our findings indicate that herpesvirus infections, specifically EBV and CMV infections, might play a role in symptom development during acute and post-acute COVID-19 disease. It remains to be elucidated whether the elevated EBV and CMV antibodies determined in our study are indicators of herpesvirus reactivation. Full article

Currently, the guidelines for audiological and vestibular follow-up in children with congenital cytomegalovirus (CMV) are not well-defined. The general recommendation is to evaluate hearing in all children with congenital CMV at the same intervals: once every 3–6 months up to 1 year of age, once every 6 months from 1 to 3 years of age, and once a year from 3 to 6 years of age. Additionally, there are no universally accepted protocols for the vestibular follow-up of children with congenital CMV, although video head impulse test (v-HIT) and cervical vestibular-evoked myogenic potentials (cVEMPs) are sometimes used. This narrative review critically evaluates existing audiological and vestibular follow-up approaches for children with congenital CMV, highlighting the need for personalized protocols. Tailoring follow-up schedules with different timing and methods based on risk factors, such as the trimester of maternal infection, CMV PCR results in amniotic fluid, and valganciclovir use, would indeed allow for more precise evaluations, timely interventions, and optimized resource allocation. This strategy would also alleviate the logistical and emotional burdens on families by ensuring that high-risk children receive more frequent and appropriate assessments and early interventions, while lower-risk children avoid unnecessary testing. Full article

The objective was to review the existing literature reporting on spontaneous abortion (SA) and intrauterine fetal demise (IUFD) associated with cytomegalovirus (CMV) infection. A review using standardized terminology such as ‘intrauterine fetal death’, ‘congenital cytomegalovirus’ and ‘CMV’ was performed using PubMed and Embase (Medline) using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. Twenty-one studies met inclusion criteria. CMV was identified as a potential or likely factor in a median of 7.1% of SA or IUFD in study cohorts. Of the studies, 11 used fetal remains, 18 used placenta, 6 used serum, and 1 used post-mortem dried blood spot as specimens for testing for CMV. Features commonly observed were fetal thrombotic vasculopathy, hydrops fetalis and chronic villitis. CMV is frequently noted in studies evaluating viral etiologies of SA or IUFD. Large population-based studies are needed to estimate the incidence of CMV-associated SA or IUFD. CMV and congenital CMV should be included on the differential diagnosis in all cases of SA or IUFD of unknown etiology. Full article

Apical lesions are diseases of infectious origin that can cause destruction of the surrounding periapical tissue, including bone tissue and periodontal ligaments, resulting in the loss of the affected teeth. Currently, the microorganisms present in pulp and apical disease are mostly studied as bacteria. However, in recent years, interest has been aroused in the study of viruses that could be present in apical lesions, and how these could affect the progression of disease. In the present study, we conducted a systematic review of the literature to evaluate and synthesize the scientific evidence on the presence of viruses and their possible role in pulpal and apical disease. This systematic review was performed according to the PRISMA reporting guidelines. The search for studies was performed in the PubMed and Web of Science databases. A total of seven studies published in the last 10 years were included. The types of samples used for virus analysis varied from one study to another. In all the included studies, the presence of any of the types of viruses studied was found, either in pulp or apical tissue. Herpesviridae family, Epstein–Barr virus (EBV) and Human cytomegalovirus (HCMV) stood out as the most commonly present in apical lesions. Further studies are required to clarify and understand the pathogenic role of viruses in pulpal and periapical disease. Full article

The synthetic peptide TAT-I24 (GRKKRRQRRRPPQCLAFYACFC) exerts antiviral activity against several double-stranded (ds) DNA viruses, including herpes simplex viruses, cytomegalovirus, some adenoviruses, vaccinia virus and SV40 polyomavirus. In the present study, in vitro profiling of this peptide was performed with the aim of characterizing and improving its properties for further development. As TAT-I24 contains three free cysteine residues, a potential disadvantageous feature, peptide variants with replacements or deletions of specific residues were generated and tested in various cell systems and by biochemical analyses. Some cysteine replacements had no impact on the antiviral activity, such as the deletion of cysteine 14, which also showed improved biochemical properties, while the cyclization of cysteines 14 and 20 had the most detrimental effect on antiviral activity. At concentrations below 20 µM, TAT-I24 and selected variants did not induce hemolysis in red blood cells (RBCs) nor modulated lipopolysaccharide (LPS)-induced release of cytokines, such as interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), in human peripheral blood mononuclear cells (PBMCs). These data indicate that TAT-I24 or its peptide variants are not expected to cause unwanted effects on blood cells. Full article

The role of the respiratory microbiome has been deeply explored for at least two decades. Its characterization using modern methods is now well-defined, and the impacts of many microorganisms on health and diseases have been elucidated. Moreover, the acquired knowledge in related fields enables patient stratification based on their risk for disease onset, and the microbiome can play a role in defining possible phenotypes. The interplay between the lung and gut microbiomes is crucial in determining the microbial composition and immuno-inflammatory reaction. Asthma is still not a well-defined condition, where hyperreactivity and the immune system play important roles. In this disease, the microbiome is mostly represented by Proteobacteria, Streptococcus, and Veillonella, while Cytomegalovirus and Epstein–Barr viruses are the most prevalent viruses. A mycobiome may also be present. The passage from infancy to adolescence is examined by evaluating both the clinical picture and its relationship with possible variations of the microbiome and its effects on asthma. Otherwise, asthma is considered a heterogeneous disease that often starts in childhood and follows a particular personalized track, where adolescence plays a pivotal role in future prognosis. Under this point of view, the microbiota, with its possible variations due to many factors, both internal and external, can modify its composition; consequently, its inflammatory action and role in the immunological response has obvious consequences on the clinical conditions. Full article

Human exploration of the solar system will expose crew members to galactic cosmic radiation (GCR), with a potential for adverse health effects. GCR particles (protons and ions) move at nearly the speed of light and easily penetrate space station walls, as well as the human body. Previously, we have shown reactivation of latent herpesviruses, including herpes simplex virus, Varicella zoster virus, Epstein–Barr virus, and cytomegalovirus (CMV), during stays at the International Space Station. Given the prevalence of latent CMV and the known propensity of space radiation to cause alterations in many cellular processes, we undertook this study to understand the role of GCR in reactivating latent CMV. Latently infected Kasumi cells with CMV were irradiated with ¹³⁷Cs gamma rays, 150 MeV protons, 600 MeV/n carbon ions, 600 MeV/n iron ions, proton ions, and simulated GCR. The CMV copy number increased significantly in the cells exposed to radiation as compared with the non-irradiated controls. Viral genome sequencing did not reveal significant nucleotide differences among the compared groups. However, transcriptome analysis showed the upregulation of transcription of the UL49 ORF, implicating it in the switch from latent to lytic replication. These findings support our hypothesis that GCR may be a strong contributor to the reactivation of CMV infection seen in ISS crew members. Full article

After primary infection, human cytomegalovirus (HCMV) establishes lifelong persistence, underpinned by latent carriage of the virus with spontaneous reactivation events. In the immune-competent, primary infection or reactivation from latency rarely causes disease. However, HCMV can cause significant disease in immune-compromised individuals such as immune-suppressed transplant patients. Latency, where the viral genome is carried in the absence of the production of infectious virions, can be established in undifferentiated cells of the myeloid lineage. A number of stimuli can cause virus reactivation from latency to occur, beginning with the induction of viral immediate-early (IE) lytic gene expression. The suppression of viral IE gene expression to establish and maintain latent infection is known to result from a balance of viral and cellular factors. One key viral factor involved in this is the G protein-coupled receptor US28. Recently, we have shown that US28 is targeted for degradation by a modified nanobody (PCTD-Vun100bv) based on the novel PACTAC (PCSK9-antibody clearance-targeting chimeras) approach for targeted protein degradation. Furthermore, we have shown that this PCTD-Vun100bv-induced degradation of US28 results in IE gene expression in experimentally latently infected CD14+ monocytes. However, HCMV also establishes latency in CD34+ bone marrow cells, the progenitors of CD14+ cells. Here, we show that PCTD-Vun100bv also causes US28 degradation in these CD34+ primary cells, again resulting in the induction of viral IE gene expression. Additionally, we show that PCTD-Vun100bv can target US28 in naturally latently infected CD14+ monocytes from an HCMV-seropositive donor, allowing these latently infected cells to be killed by HCMV-specific cytotoxic T cells from that same donor. These observations support the view that targeting US28 for degradation during natural latency could be a tractable ‘shock-and-kill’ strategy to target the latent HCMV reservoir in myeloid cells. Full article

Background. Cyclin-dependent kinase 8 (CDK8) is a multifaceted regulator and represents a catalytic component of the transcriptional Mediator complex. CDK8 activity, on the one hand, increases transcriptional elongation by the recruitment of Mediator/super elongation complexes, but, on the other hand, negatively regulates CDK7-controlled transcriptional initiation through inactivating cyclin H phosphorylation. Recently, these combined properties of CDK8 have also suggested its rate-limiting importance for herpesviral replication. Objectives. In this paper, we focused on human cytomegalovirus (HCMV) and addressed the question of whether the pharmacological inhibition or knock-down of CDK8 may affect viral replication efficiency in cell culture models. Methods. A number of human and animal herpesviruses, as well as non-herpesviruses, were used to analyze the importance of CDK8 for viral replication in cell culture models, and to assess the antiviral efficacy of CDK8 inhibitors. Results. Using clinically relevant CDK8 inhibitors (CCT-251921, MSC-2530818, and BI-1347), HCMV replication was found strongly reduced even at nanomolar drug concentrations. The EC₅₀ values were consistent for three different HCMV strains (i.e., AD169, TB40, and Merlin) analyzed in two human cell types (i.e., primary fibroblasts and astrocytoma cells), and the drugs comprised a low level of cytotoxicity. The findings highlighted the following: (i) the pronounced in vitro SI values of anti-HCMV activity obtained with CDK8 inhibitors; (ii) a confirmation of the anti-HCMV efficacy by CDK8–siRNA knock-down; (iii) a CDK8-dependent reduction in viral immediate early, early, and late protein levels; (iv) a main importance of CDK8 for viral late-stage replication; (v) several mechanistic aspects, which point to a strong impact on viral progeny production and release, but a lack of CDK8 relevance for viral entry or nuclear egress; (vi) a significant anti-HCMV drug synergy for combinations of inhibitors against host CDK8 and the viral kinase vCDK/pUL97 (maribavir); (vii) finally, a broad-spectrum antiviral activity, as seen for the comparison of selected α-, β-, γ-, and non-herpesviruses. Conclusions. In summary, these novel data provide evidence for the importance of CDK8 as a positive regulator of herpesviral replication efficiency, and moreover, suggest its exploitability as an antiviral target for novel strategies of host-directed drug development. Full article

The human cytomegalovirus (HCMV) glycoprotein B (gB) is the viral fusogen required for entry into cells and for direct cell-to-cell spread of the virus. We have previously demonstrated that the exchange of the carboxy-terminal domain (CTD) of gB for the CTD of the structurally related fusion protein G of the vesicular stomatitis virus (VSV-G) resulted in an intrinsically fusion-active gB variant (gB/VSV-G). In this present study, we employed a dual split protein (DSP)-based cell fusion assay to further characterize the determinants of fusion activity in the CTD of gB. We generated a comprehensive library of gB CTD truncation mutants and identified two mutants, gB-787 and gB-807, which were fusion-competent and induced the formation of multinucleated cell syncytia in the absence of other HCMV proteins. Structural modeling coupled with site-directed mutagenesis revealed that gB fusion activity is primarily mediated by the CTD helix 2, and secondarily by the recruitment of cellular SH2/WW-domain-containing proteins. The fusion activity of gB-807 was inhibited by gB-specific monoclonal antibodies (MAbs) targeting the antigenic domains AD-1 to AD-5 within the ectodomain and not restricted to MAbs directed against AD-4 and AD-5 as observed for gB/VSV-G. This finding suggested a differential regulation of the fusion-active conformational state of both gB variants. Collectively, our findings underscore a pivotal role of the CTD in regulating the fusogenicity of HCMV gB, with important implications for understanding the conformations of gB that facilitate membrane fusion, including antigenic structures that could be targeted by antibodies to block this essential step in HCMV infection. Full article

Recombinant AAV (rAAV) vectors are increasingly favored for gene therapy due to their useful features of vectorology, such as transfection of dividing and nondividing cells, the presence of tissue-specific serotypes, and biosafety considerations. This study investigates the impact of commonly used therapeutic drugs—acetaminophen, budesonide, and simvastatin—on rAAV transduction efficiency in HEK-293 cells. Cells were transduced with an AAV mosaic vector under the control of a cytomegalovirus (CMV) promoter encoding green fluorescent protein (GFP). Transduction efficiency was assessed by qPCR and fluorescent microscopy. Analysis of functional interactions between genes potentially involved in rAAV transduction in drug-exposed cells was also performed. This study showed a clear effect of drugs on rAAV transmission. Notably, acetaminophen enhanced transduction efficiency by 9-fold, while budesonide and simvastatin showed 2-fold and 3-fold increases, respectively. The gene analysis illustrates the possible involvement of genes related to cell membranes in the potentiation of rAAV transduction induced by the drugs under investigation. Attention should be paid to S100A8, which is a common drug-modified gene for drugs showing anti-inflammatory effects (budesonide and simvastatin), demonstrating an interaction with the gene encoding the receptor for AAV (HGFR). This study underscores the significance of assessing rAAV pharmacokinetics/pharmacodynamics (PKs/PDs) and drug–gene therapy interactions in optimizing gene therapy protocols. Full article