Tick-borne encephalitis virus (TBEV) is a tick-borne flavivirus that induces severe central nervous system disorders. It has recently raised concerns due to an expanding geographical range and increasing infection rates. Existing vaccines, though effective, face low coverage rates in numerous TBEV endemic regions. Our previous work demonstrated the immunogenicity and full protection afforded by a TBEV vaccine based on virus-like particles (VLPs) produced in Leishmania tarentolae cells in immunization studies in a mouse model. In the present study, we explored the impact of adjuvants (AddaS03TM, Alhydrogel®+MPLA) and administration routes (subcutaneous, intramuscular) on the immune response. Adjuvanted groups exhibited significantly enhanced antibody responses, higher avidity, and more balanced Th1/Th2 response. IFN-γ responses depended on the adjuvant type, while antibody levels were influenced by both adjuvant and administration routes. The combination of Leishmania-derived TBEV VLPs with Alhydrogel® and MPLA via intramuscular administration emerged as a highly promising prophylactic vaccine candidate, eliciting a robust, balanced immune response with substantial neutralization potential.

• MeSH
• adjuvancia imunologická * aplikace a dávkování   MeSH
• adjuvantní vakcína aplikace a dávkování   MeSH
• imunogenicita vakcíny MeSH
• injekce intramuskulární MeSH
• interferon gama imunologie   MeSH
• klíšťová encefalitida * prevence a kontrola   imunologie   MeSH
• Leishmania * imunologie   MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• neutralizující protilátky krev   imunologie   MeSH
• protilátky virové * krev   imunologie   MeSH
• syntetické vakcíny * imunologie   aplikace a dávkování   MeSH
• Th1 buňky imunologie   MeSH
• virové vakcíny * imunologie   aplikace a dávkování   MeSH
• viry klíšťové encefalitidy * imunologie   MeSH
• VLP vakcíny * imunologie   aplikace a dávkování   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Tick-borne encephalitis virus (TBEV) is a causative agent of tick-borne encephalitis (TBE), one of the most important human infections involving the central nervous system. Although effective vaccines are available on the market, they are recommended only in endemic areas. Despite many attempts, there are still no specific antiviral therapies for TBEV treatment. Previously, we synthesized a series of uridine derivatives of 2-deoxy sugars and proved that some compounds show antiviral activity against viruses from the Flaviviridae and Orthomyxoviridae families targeting the late steps of the N-glycosylation process, affecting the maturation of viral proteins. In this study, we evaluated a series of uridine derivatives of 2-deoxy sugars for their antiviral properties against two strains of the tick-borne encephalitis virus; the highly virulent TBEV strain Hypr and the less virulent strain Neudoerfl. Four compounds (2, 4, 10, and 11) showed significant anti-TBEV activity with IC50 values ranging from 1.4 to 10.2 μM and low cytotoxicity. The obtained results indicate that glycosylation inhibitors, which may interact with glycosylated membrane TBEV E and prM proteins, might be promising candidates for future antiviral therapies against TBEV.

• MeSH
• antivirové látky chemie   farmakologie   MeSH
• deoxycukry chemie   farmakologie   MeSH
• kultivované buňky MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• molekulární struktura MeSH
• nádorové buněčné linie MeSH
• plakové testy MeSH
• proteosyntéza účinky léků   MeSH
• uridin analogy a deriváty   chemie   farmakologie   MeSH
• viry klíšťové encefalitidy účinky léků   fyziologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

The emerging virus SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2 virus), agent of COVID-19, appeared in December 2019 in Wuhan, China, and became a serious threat to global health and public safety. Many COVID-19 vaccines have been approved and licensed around the world. Most of the developed vaccines include S protein and induce an antibody-based immune response. Additionally, T-cell response to the SARS-CoV-2 antigens could be beneficial for combating the infection. The type of immune response is greatly dependent not only on the antigen, but also on adjuvants used in vaccine formulation. Here, we compared the effect of four different adjuvants (AddaS03, Alhydrogel/MPLA, Alhydrogel/ODN2395, Quil A) on the immunogenicity of a mixture of recombinant RBD and N SARS-CoV-2 proteins. We have analyzed the antibody and T-cell response specific to RBD and N proteins and assessed the impact of adjuvants on virus neutralization. Our results clearly indicated that Alhydrogel/MPLA and Alhydrogel/ODN2395 adjuvants elicited the higher titers of specific and cross-reactive antibodies to S protein variants from various SARS-CoV-2 and SARS-CoV-1 strains. Moreover, Alhydrogel/ODN2395 stimulated high cellular response to both antigens, as assessed by IFN-γ production. Importantly, sera collected from mice immunized with RBD/N cocktail in combination with these adjuvants exhibited neutralizing activity against the authentic SARS-CoV-2 virus as well as particles pseudotyped with S protein from various virus variants. The results from our study demonstrate the immunogenic potential of RBD and N antigens and point out the importance of adjuvants selection in vaccine formulation in order to enhance the immunological response. IMPORTANCE Although several COVID-19 vaccines have been approved worldwide, continuous emergence of new SARS-CoV-2 variants calls for new efficient vaccines against them, providing long-lasting immunity. As the immune response after vaccination is dependent not only on antigen used, but also on other vaccine components, e.g., adjuvants, the purpose of this work was to study the effect of different adjuvants on the immunogenicity of RBD/N SARS-CoV-2 cocktail proteins. In this work, it has been shown that immunization with both antigens plus the different adjuvants studied elicited higher Th1 and Th2 responses against RBD and N, which contributed to higher neutralization of the virus. The obtained results can be used for design of new vaccines, not only against SARS-CoV-2, but also against other important viral pathogens.

• MeSH
• COVID-19 * prevence a kontrola   MeSH
• hydroxid hlinitý MeSH
• imunogenicita vakcíny MeSH
• lidé MeSH
• myši MeSH
• neutralizující protilátky MeSH
• protilátky virové MeSH
• SARS-CoV-2 MeSH
• vakcíny proti COVID-19 MeSH
• virové vakcíny * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Tick-borne encephalitis virus (TBEV) is a major cause of neurological infections in many regions of central, eastern and northern Europe and northern Asia. In approximately 15% of cases, TBEV infections lead to the development of severe encephalitis or meningitis. The main route of TBEV transmission is tick bites; however, ingestion of dairy products from infected animals (goats, cattle and sheep) is also a frequent cause of the disease. Therefore, vaccination of livestock in virus endemic regions could also contribute to the decrease in TBEV infection among humans. Although few vaccines against TBEV based on inactivated viruses are available for humans, due to high costs, vaccination is not mandatory in most of the affected countries. Moreover, there is still no vaccine for veterinary use. Here, we present a characterization and immunogenicity study of a new potential TBEV vaccine based on virus-like particles (VLPs) produced in Leishmania tarentolae cells. VLPs, which mimic native viral particles but do not contain genetic material, show good immunogenic potential. For the first time, we showed that the protozoan L. tarentolae expression system can be successfully used for the production of TBEV virus-like particles with highly efficient production. We confirmed that TBEV recombinant structural proteins (prM/M and E) from VLPs are highly recognized by neutralizing antibodies in in vitro analyses. Therefore, VLPs in combination with AddaVax adjuvant were used in immunization studies in a mouse model. VLPs proved to be highly immunogenic and induced the production of high levels of neutralizing antibodies. In a challenge experiment, immunization with VLPs provided full protection from lethal TBE in mice. Thus, we suggest that Leishmania-derived VLPs may be a good candidate for a safe alternative human vaccine with high efficiency of production. Moreover, this potential vaccine candidate may constitute a low-cost candidate for veterinary use.

• MeSH
• klíšťová encefalitida * prevence a kontrola   MeSH
• Leishmania * MeSH
• lidé MeSH
• myši MeSH
• neutralizující protilátky MeSH
• ovce MeSH
• protilátky virové MeSH
• skot MeSH
• virové vakcíny * MeSH
• viry klíšťové encefalitidy * genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Tick-borne encephalitis virus (TBEV), of the genus Flavivirus, is a causative agent of severe encephalitis in regions of endemicity of northern Asia and central and northern Europe. Interferon-induced transmembrane proteins (IFITMs) are restriction factors that inhibit the replication cycles of numerous viruses, including flaviviruses such as West Nile virus, dengue virus, and Zika virus. Here, we demonstrate the role of IFITM1, IFITM2, and IFITM3 in the inhibition of TBEV infection and in protection against virus-induced cell death. We show that the most significant role is that of IFITM3, including the dissection of its functional motifs by mutagenesis. Furthermore, through the use of CRISPR-Cas9-generated IFITM1/3-knockout monoclonal cell lines, we confirm the role and additive action of endogenous IFITMs in TBEV suppression. However, the results of coculture assays suggest that TBEV might partially escape interferon- and IFITM-mediated suppression during high-density coculture infection when the virus enters naive cells directly from infected donor cells. Thus, cell-to-cell spread may constitute a strategy for virus escape from innate host defenses. IMPORTANCE TBEV infection may result in encephalitis, chronic illness, or death. TBEV is endemic in northern Asia and Europe; however, due to climate change, new centers of endemicity have arisen. Although effective TBEV vaccines have been approved, vaccination coverage is low, and due to the lack of specific therapeutics, infected individuals depend on their immune responses to control the infection. IFITM proteins are components of the innate antiviral defenses that suppress cell entry of many viral pathogens. However, no studies on the role of IFITM proteins in TBEV infection have been published thus far. Understanding antiviral innate immune responses is crucial for the future development of antiviral strategies. Here, we show the important role of IFITM proteins in the inhibition of TBEV infection and virus-mediated cell death. However, our data suggest that TBEV cell-to-cell spread may be less prone to both interferon- and IFITM-mediated suppression, potentially facilitating escape from IFITM-mediated immunity.

• MeSH
• buněčné linie MeSH
• cytopatogenní efekt virový MeSH
• exprese genu MeSH
• genový knockdown MeSH
• interakce hostitele a patogenu * genetika   imunologie   MeSH
• interakční proteinové domény a motivy MeSH
• interferony metabolismus   MeSH
• klíšťová encefalitida genetika   imunologie   metabolismus   virologie   MeSH
• lidé MeSH
• membránové proteiny chemie   genetika   metabolismus   MeSH
• multigenová rodina MeSH
• náchylnost k nemoci MeSH
• odolnost vůči nemocem genetika   imunologie   MeSH
• replikace viru MeSH
• sekvence aminokyselin MeSH
• vazba proteinů MeSH
• viry klíšťové encefalitidy fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH