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Effect of small DNA viruses on function of plasmacytoid dendritic cells
Janovec, Václav ; Hirsch, Ivan (advisor) ; Růžek, Daniel (referee) ; Filipp, Dominik (referee)
Plasmacytoid dendritic cells (pDC) are a highly specialized subset of immune cells that sense viral nucleic acids by endosomal toll-like receptors 7 and 9 (TLR7/9). Activation of TLR7/9 leads to the production of type I interferons (IFN-I). Moreover, pDC contribute to the antiviral response by presenting viral antigens to T lymphocytes and link innate and adaptive immunity. pDC need to be properly regulated in order to limit excessive production of IFN-I that is associated with autoimmune diseases. Therefore, pDC possess a battery of regulatory receptors (RR) that limit TLR7/9-mediated cytokine production. This thesis focuses on the mechanism of RR-mediated inhibition of IFN-I production in pDC and explores interactions between pDC and two enveloped viruses, that possess the ability to hijack RR in pDC: hepatitis B virus (HBV) and human immunodeficiency virus (HIV). We showed, that MEK-ERK signaling pathway plays an active role in RR-mediated inhibition of IFN-I in pDC. Our results indicate that in line with other studies of our group, pharmacological targeting of MEK1/2-ERK signaling could be a strategy to re-establish immunogenic activity of pDC. Then, we investigated whether antiretroviral therapy (ART) in a cohort of 21 treatment-naive chronic HIV-infected patients has restored the number and...
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Role of RNA helicases in antiviral defense
Krbušek, David ; Vopálenský, Václav (advisor) ; Janovec, Václav (referee)
Hepatitis C virus is an important human pathogen against which there is no immunization yet. This virus is detected by the immune system of the eukaryotic host cell by pattern recognition receptors of the RLR receptor family, which is part of the innate immune system. These RLR receptors detect the presence of hepatitis C virus and initiate a signaling cascade triggering an antiviral immune response. In this thesis, the role of cytoplasmic PRRs involved in antiviral defense during hepatitis C virus infection of eukaryotic cells has been described and determined. Key words Helicase, RIG-I, MDA5, pattern-recognition receptors, HCV, virus
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Biological treatment and its influence on the course of latent viral infections in patients with psoriasis
Laurin, Josef ; Šmahelová, Jana (advisor) ; Janovec, Václav (referee)
There are more than 80 identified autoimmune diseases. One of the most prevalent ones is psoriasis. Its prevalence is around 2-5 % worldwide. The treatment of this inflammatory skin disease can be divided as follows: in cases of low severity, topical therapies are used for local treatment and in the cases of insufficient effect, stronger therapies are used. Phototherapy is used for moderate severity, and systemic therapy is used in moderate to severe disease. Systemic agents include cytostatic methotrexate, immunosuppressant cyclosporin, or retinoids (vitamin A analogues). However, even systemic therapies may not yield the desired effects or may have adverse effects on the overall condition of the patient. In those cases, biological therapy comes to use. Biological therapy is usually conducted using antibodies and fusion proteins, which are made using recombinant technologies. Tumour necrosis factor α (TNF-α) and interleukin 12, 17 and 23 (IL-12, IL-17 and IL-23) inhibitors are the most commonly used in the treatment of psoriasis. During the inhibition of the immune system, it has been confirmed that a reactivation of viral infections can occur. These reactivations may subsequently lead to the development of various diseases caused by latent viral infections.
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Oncolytic viruses in cancer immunotherapy
Zupko, Jakub ; Bartůňková, Jiřina (advisor) ; Janovec, Václav (referee)
Oncolytic virotherapy is a field dedicated to exploiting viruses in the battle against cancer, where their specific cytolytic effects are sorely needed. This work focuses on the mechanisms and limitations of oncolytic virotherapy, on the recent advances in the field and on the potential oncolytic viruses hold for the future.
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Development of vaccines against porcine circovirus type 2
Janovec, Václav ; Drda Morávková, Alena (advisor) ; Pokorná, Dana (referee)
Porcine circovirus type 2 is a single stranded DNA virus that belongs to the genus Circovirus in the family Circoviridae. This virus is associated with many kinds of diseases in pigs and causes significant economic losses in swine-breeding. In this study, two approaches of vaccination were tested in order to develop an effective vaccine against PCV2. The first approach was to test DNA vaccines. For this purpose, eukaryotic expression plasmids encoding two form of PCV2 Cap protein were constructed. The expression plasmids encoding murine TNF-α and IFN-α1 were also prepared for co-immunization with antigen encoding plasmid to enhance the immune response. The second approach is based on the previous finding that chimeric pentamers of VP1 mouse polyomavirus capsid protein fused with PCV2 can induce protective immunity against PCV2. These chimeric pentamers were further modified by AA substitutions in PCV2 Cap immunodominant epitope in order to enhance protective antibody response directed against PCV2. The chimeric pentamers and DNA vaccines were tested for ability to induce antibody immune response against PCV2 in mice. The results showed that chimeric pentamers are more potent inducers of protective antibody immune response against PCV2 compared to DNA vaccines. However, the protective antibody...
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Immunity and polyomaviruses
Janovec, Václav ; Drda Morávková, Alena (advisor) ; Belovičová, Martina (referee)
Human polyomaviruses JC and BK belongs to the group of small non-enveloped DNA viruses, and are widespread in the human population. After usually asymptomatic primary infection subsequently persist throughout life in the body in a state of persistence. Thus, this thesis aims to summarize present knowledge concerning the involvement of immune mechanisms involved in immune surveillance against persistent JC and BK viruses. The published findings show that the immune surveillance against human polyomaviruses is a very complex process where an important factor is the involvement and cooperation of non-specific and specific immune defense. Long-term immune surveillance against persistent viruses is mainly mediated by specific T lymphocytes. If this immune surveillance disrupted, it can lead to reactivation of the virus. The change in cytokine environment and the genetic makeup of an individual are another important factors in cases of reactivation. The two human polyomaviruses were developed mechanisms that allow them seemed to partially escape immune surveillance. It also raises the question whether this immune escape contribute to induce tumorigenesis.
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