Publications by authors named "Stipan Jonjic"

Human cytomegalovirus (HCMV) rarely infects the brain following infection of adult individuals. However, the virus readily infects the brain during congenital HCMV (cHCMV) infection, frequently causing severe neurodevelopmental and neurological sequelae. Interestingly, although the incidence of cHCMV infection is 0.

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Article Synopsis
  • Cytomegalovirus (CMV) infection can harm newborns, leading to the need for effective treatments to combat both viral and immune damage.
  • Research in a mouse model shows that cellular prion protein (PrP) helps regulate T cell immunity, with PrP-null mice demonstrating better control over CMV through stronger CD8 T cell responses.
  • The study identifies that CMV increases PrP levels via ADAM10, which hinders T cell responses in neonates, and confirms similar downregulation of PrP in human CMV-infected cells, emphasizing the findings' relevance to human health.
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In systemic lupus erythematosus, loss of immune tolerance, autoantibody production and immune complex deposition are required but not sufficient for organ damage. How inflammatory signals are initiated and amplified in the setting of autoimmunity remains elusive. Here we set out to dissect layers and hierarchies of autoimmune kidney inflammation to identify tissue-specific cellular hubs that amplify autoinflammatory responses.

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Cytomegalovirus (CMV), a representative member of the Betaherpesvirinae subfamily of herpesviruses, is common in the human population, but immunocompetent individuals are generally asymptomatic when infected with this virus. However, in immunocompromised individuals and immunologically immature fetuses and newborns, CMV can cause a wide range of often long-lasting morbidities and even death. CMV is not only widespread throughout the population but it is also widespread in its hosts, infecting and establishing latency in nearly all tissues and organs.

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Article Synopsis
  • * Cytomegaloviruses (CMVs) can create sustained immune responses, making them promising candidates as vaccine vectors against COVID-19.
  • * In a study using a recombinant murine CMV (MCMV) vaccine, not only was robust and long-lasting protection against COVID-19 observed in mice, but it also effectively neutralized variants like Omicron BA.1 after just one dose.
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Meningococcal glycoconjugate vaccines sourced from capsular polysaccharides (CPSs) of pathogenic Neisseria meningitidis strains are well-established measures to prevent meningococcal disease. However, the exact structural factors responsible for antibody recognition are not known. CPSs of Neisseria meningitidis serogroups Y and W differ by a single stereochemical center, yet they evoke specific immune responses.

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The aim of this study was to characterize the systemic cytokine signature of critically ill COVID-19 patients in a high mortality setting aiming to identify biomarkers of severity, and to explore their associations with viral loads and clinical characteristics. We studied two COVID-19 critically ill patient cohorts from a referral centre located in Central Europe. The cohorts were recruited during the pre-alpha/alpha (November 2020 to April 2021) and delta (end of 2021) period respectively.

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Human cytomegalovirus (HCMV) infection in infants infected in utero can lead to a variety of neurodevelopmental disorders. However, mechanisms underlying altered neurodevelopment in infected infants remain poorly understood. We have previously described a murine model of congenital HCMV infection in which murine CMV (MCMV) spreads hematogenously and establishes a focal infection in all regions of the brain of newborn mice, including the cerebellum.

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Innate lymphoid cells (ILCs) are largely tissue-resident cells that participate in the maintenance of tissue homeostasis and react early to inflammatory events. Mature ILCs are divided into three major groups based on the transcription factors required for their development and function. Under physiological conditions, ILCs are present within the choroid plexus and meninges while the CNS parenchyma is almost devoid of these cells.

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Despite the availability of currently approved antiviral drugs, infections with human cytomegalovirus (HCMV) still cause clinically challenging, sometimes life-threatening situations. There is an urgent need for enhanced anti-HCMV drugs that offer improved efficacy, reduced dosages and options for long-term treatment without risk of the development of viral drug resistance. Recently, we reported the pronounced anti-HCMV efficacy of pharmacological inhibitors of cyclin-dependent kinases (CDKs), in particular, the potential of utilizing drug synergies upon combination treatment with inhibitors of host CDKs and the viral CDK-like kinase pUL97 (vCDK/pUL97).

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Article Synopsis
  • Infections in newborns trigger different immune responses compared to adults, particularly affecting NK cells during murine cytomegalovirus infection.
  • The infection leads to a significant reduction in NK cell maturation and functionality, primarily due to inflammatory responses disrupting key transcription factors.
  • Ultimately, perinatal infections result in lasting impairments in NK cell function, including decreased IFN-γ production and reduced bone marrow capacity to produce new NK cells.
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In recent years, reoviruses have been of major interest in immunotherapy because of their oncolytic properties. Preclinical and clinical trials, in which reovirus was used for the treatment of melanoma and glioblastoma, have paved the way for future clinical use of reovirus. However, little is known about how reovirus infection affects the tumor microenvironment and immune response towards infected tumor cells.

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TIGIT is an inhibitory receptor expressed on lymphocytes and can inhibit T cells by preventing CD226 co-stimulation through interactions in cis or through competition of shared ligands. Whether TIGIT directly delivers cell-intrinsic inhibitory signals in T cells remains unclear. Here we show, by analysing lymphocytes from matched human tumour and peripheral blood samples, that TIGIT and CD226 co-expression is rare on tumour-infiltrating lymphocytes.

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The genomes of both human cytomegalovirus (HCMV) and murine cytomegalovirus (MCMV) were first sequenced over 20 years ago. Similar to HCMV, the MCMV genome had initially been proposed to harbor ≈170 open reading frames (ORFs). More recently, omics approaches revealed HCMV gene expression to be substantially more complex comprising several hundred viral ORFs.

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Article Synopsis
  • Human cytomegalovirus (HCMV) can cause serious birth defects, and currently, there is no vaccine available.
  • Researchers tested live attenuated vaccine viruses created from CMV mutants lacking STAT2 antagonists in mice, which showed promising immune responses and protection against infections.
  • Female mice vaccinated before pregnancy passed protective antibodies to their offspring, highlighting the critical role of maternal antibodies in providing immunity against HCMV in congenital infections.
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Article Synopsis
  • - Current COVID-19 vaccines provide strong but short-lived immune responses, leading to booster fatigue, highlighting the need for longer-lasting alternatives.
  • - Researchers tested a murine cytomegalovirus (MCMV) as a vaccine vector for COVID-19, demonstrating that it elicits robust and enduring immune protection in both young and aged mice.
  • - The MCMV vaccine not only maintained but improved protective immunity over six months, enabling rapid virus clearance and effective responses against major variants like Omicron and Beta.
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Human cytomegalovirus is responsible for morbidity and mortality in immune compromised patients and is the leading viral cause of congenital infection. Virus-encoded microRNAs (miRNAs) represent interesting targets for novel antiviral agents. While many cellular targets that augment productive infection have been identified in recent years, regulation of viral genes such as the major viral immediate early protein 72 (IE72) by hcmv-miR-UL112-1 may contribute to both the establishment and the maintenance of latent infection.

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Studies assessing the dynamics and duration of antibody responses following SARS-CoV-2 infection or vaccination are an invaluable tool for vaccination schedule planning, assessment of risk groups and management of pandemics. In this study, we developed and employed ELISA assays to analyze the humoral responses to Nucleocapsid and Spike proteins in vaccinated health-care workers (HCW) and critically ill COVID-19 patients. Sera of more than 1000 HCWs and critically ill patients from the Clinical Hospital Center Rijeka were tested across a one-year period, encompassing the spread of major SARS-CoV-2 variants of concern (VOCs).

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Article Synopsis
  • The article outlines methods for infecting adult and newborn mice with murine cytomegalovirus (MCMV) to study congenital CMV infection.
  • It includes procedures for growing MCMV in cell cultures and preparing a more virulent strain from the salivary glands of infected mice.
  • The article also describes a plaque assay technique to measure MCMV levels in infected tissues or virus stocks, along with methods for preparing murine embryonic fibroblasts for MCMV propagation.
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Morphogenesis of herpesvirus particles is highly conserved; however, the capsid assembly and genome packaging of human cytomegalovirus (HCMV) exhibit unique features. Examples of these include the essential role of the small capsid protein (SCP) and the existence of the β-herpesvirus-specific capsid-associated protein pp150. SCP and pp150, as well as the UL77 and UL93 proteins, are important capsid constituents, yet their precise mechanism of action is elusive.

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Herpes simplex virus 1 (HSV-1) expresses a large number of miRNAs, and their function is still not completely understood. In addition, HSV-1 has been found to deregulate host miRNAs, which adds to the complexity of the regulation of efficient virus replication. In this study, we comprehensively addressed the deregulation of host miRNAs by massive-parallel sequencing.

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The global pandemic caused by SARS-CoV-2 is a major public health problem. Virus entry occurs via binding to ACE2. Five SARS-CoV-2 variants of concern (VOCs) were reported so far, all having immune escape characteristics.

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While SARS-CoV-2 detection in sputum and swabs from the upper respiratory tract has been used as a diagnostic tool, virus quantification showed poor correlation to disease outcome and thus, poor prognostic value. Although the pulmonary compartment represents a relevant site for viral load analysis, limited data exploring the lower respiratory tract is available, and its association to clinical outcomes is relatively unknown. Using bronchoalveolar lavage (BAL) and serum samples, we quantified SARS-CoV-2 copy numbers in the pulmonary and systemic compartments of critically ill patients admitted to the intensive care unit of a COVID-19 referral hospital in Croatia during the second and third pandemic waves.

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