Tick saliva has been extensively studied in the context of tick-host interactions because it is involved in host homeostasis modulation and microbial pathogen transmission to the host. Accumulated knowledge about the tick saliva composition at the molecular level has revealed that serine protease inhibitors play a key role in the tick-host interaction. Serpins are one highly expressed group of protease inhibitors in tick salivary glands, their expression can be induced during tick blood-feeding, and they have many biological functions at the tick-host interface. Indeed, tick serpins have an important role in inhibiting host hemostatic processes and in the modulation of the innate and adaptive immune responses of their vertebrate hosts. Tick serpins have also been studied as potential candidates for therapeutic use and vaccine development. In this review, we critically summarize the current state of knowledge about the biological role of tick serpins in shaping tick-host interactions with emphasis on the mechanisms by which they modulate host immunity. Their potential use in drug and vaccine development is also discussed.

• Klíčová slova
• anti-tick vaccine, immunomodulation, serpins, therapeutic effects, tick host interaction, tick saliva,
• MeSH
• inhibitory serinových proteinas fyziologie   MeSH
• klíšťata * metabolismus   MeSH
• serpiny * metabolismus   MeSH
• slinné žlázy metabolismus   MeSH
• sliny metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• inhibitory serinových proteinas MeSH
• serpiny * MeSH

Iripin-5 is the main Ixodes ricinus salivary serpin, which acts as a modulator of host defence mechanisms by impairing neutrophil migration, suppressing nitric oxide production by macrophages and altering complement functions. Iripin-5 influences host immunity and shows high expression in the salivary glands. Here, the crystal structure of Iripin-5 in the most thermodynamically stable state of serpins is described. In the reactive-centre loop, the main substrate-recognition site of Iripin-5 is likely to be represented by Arg342, which implies the targeting of trypsin-like proteases. Furthermore, a computational structural analysis of selected Iripin-5-protease complexes together with interface analysis revealed the most probable residues of Iripin-5 involved in complex formation.

• Klíčová slova
• Iripin-5, Ixodes ricinus, X-ray structure, serine protease inhibitors, serpins, tick saliva,
• MeSH
• antiflogistika * chemie   izolace a purifikace   MeSH
• erytrocyty MeSH
• inhibitory enzymů * chemie   izolace a purifikace   MeSH
• klíště metabolismus   MeSH
• králíci MeSH
• kultivované buňky MeSH
• makrofágy MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• neutrofily MeSH
• serpiny * chemie   izolace a purifikace   MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antiflogistika * MeSH
• inhibitory enzymů * MeSH
• serpiny * MeSH

Tick saliva is a rich source of antihemostatic, anti-inflammatory, and immunomodulatory molecules that actively help the tick to finish its blood meal. Moreover, these molecules facilitate the transmission of tick-borne pathogens. Here we present the functional and structural characterization of Iripin-8, a salivary serpin from the tick Ixodes ricinus, a European vector of tick-borne encephalitis and Lyme disease. Iripin-8 displayed blood-meal-induced mRNA expression that peaked in nymphs and the salivary glands of adult females. Iripin-8 inhibited multiple proteases involved in blood coagulation and blocked the intrinsic and common pathways of the coagulation cascade in vitro. Moreover, Iripin-8 inhibited erythrocyte lysis by complement, and Iripin-8 knockdown by RNA interference in tick nymphs delayed the feeding time. Finally, we resolved the crystal structure of Iripin-8 at 1.89 Å resolution to reveal an unusually long and rigid reactive center loop that is conserved in several tick species. The P1 Arg residue is held in place distant from the serpin body by a conserved poly-Pro element on the P' side. Several PEG molecules bind to Iripin-8, including one in a deep cavity, perhaps indicating the presence of a small-molecule binding site. This is the first crystal structure of a tick serpin in the native state, and Iripin-8 is a tick serpin with a conserved reactive center loop that possesses antihemostatic activity that may mediate interference with host innate immunity.

• Klíčová slova
• Ixodes ricinus, blood coagulation, crystal structure, parasite, saliva, serpin, tick,
• MeSH
• aktivace komplementu účinky léků   imunologie   fyziologie   MeSH
• erytrocyty metabolismus   MeSH
• exprese genu genetika   MeSH
• hemokoagulace účinky léků   fyziologie   MeSH
• klíště enzymologie   genetika   metabolismus   MeSH
• komplement metabolismus   MeSH
• lymeská nemoc MeSH
• nymfa MeSH
• proteiny členovců metabolismus   MeSH
• regulace genové exprese genetika   MeSH
• serpiny metabolismus   ultrastruktura   MeSH
• slinné žlázy metabolismus   MeSH
• sliny chemie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• komplement MeSH
• proteiny členovců MeSH
• serpiny MeSH

In Europe, Ixodes ricinus is the most important vector of human infectious diseases, most notably Lyme borreliosis and tick-borne encephalitis virus. Multiple non-natural hosts of I. ricinus have shown to develop immunity after repeated tick bites. Tick immunity has also been shown to impair B. burgdorferi transmission. Most interestingly, multiple tick bites reduced the likelihood of contracting Lyme borreliosis in humans. A vaccine that mimics tick immunity could therefore potentially prevent Lyme borreliosis in humans. A yeast surface display library (YSD) of nymphal I. ricinus salivary gland genes expressed at 24, 48 and 72 h into tick feeding was constructed and probed with antibodies from humans repeatedly bitten by ticks, identifying twelve immunoreactive tick salivary gland proteins (TSGPs). From these, three proteins were selected for vaccination studies. An exploratory vaccination study in cattle showed an anti-tick effect when all three antigens were combined. However, immunization of rabbits did not provide equivalent levels of protection. Our results show that YSD is a powerful tool to identify immunodominant antigens in humans exposed to tick bites, yet vaccination with the three selected TSGPs did not provide protection in the present form. Future efforts will focus on exploring the biological functions of these proteins, consider alternative systems for recombinant protein generation and vaccination platforms and assess the potential of the other identified immunogenic TSGPs.

• MeSH
• antigeny krev   imunologie   izolace a purifikace   MeSH
• Borrelia burgdorferi izolace a purifikace   MeSH
• imunizace MeSH
• infestace klíšťaty imunologie   parazitologie   MeSH
• klíště imunologie   MeSH
• kousnutí klíštětem imunologie   MeSH
• králíci MeSH
• lidé MeSH
• lymeská nemoc krev   parazitologie   přenos   MeSH
• metody zobrazení buněčného povrchu metody   MeSH
• peptidová knihovna MeSH
• peptidové fragmenty imunologie   MeSH
• Saccharomyces cerevisiae MeSH
• skot MeSH
• slinné proteiny a peptidy imunologie   MeSH
• slinné žlázy imunologie   MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• lidé MeSH
• mužské pohlaví MeSH
• skot MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antigeny MeSH
• peptidová knihovna MeSH
• peptidové fragmenty MeSH
• slinné proteiny a peptidy MeSH

Tick saliva is a rich source of pharmacologically and immunologically active molecules. These salivary components are indispensable for successful blood feeding on vertebrate hosts and are believed to facilitate the transmission of tick-borne pathogens. Here we present the functional and structural characterization of Iripin-3, a protein expressed in the salivary glands of the tick Ixodes ricinus, a European vector of tick-borne encephalitis and Lyme disease. Belonging to the serpin superfamily of protease inhibitors, Iripin-3 strongly inhibited the proteolytic activity of serine proteases kallikrein and matriptase. In an in vitro setup, Iripin-3 was capable of modulating the adaptive immune response as evidenced by reduced survival of mouse splenocytes, impaired proliferation of CD4+ T lymphocytes, suppression of the T helper type 1 immune response, and induction of regulatory T cell differentiation. Apart from altering acquired immunity, Iripin-3 also inhibited the extrinsic blood coagulation pathway and reduced the production of pro-inflammatory cytokine interleukin-6 by lipopolysaccharide-stimulated bone marrow-derived macrophages. In addition to its functional characterization, we present the crystal structure of cleaved Iripin-3 at 1.95 Å resolution. Iripin-3 proved to be a pluripotent salivary serpin with immunomodulatory and anti-hemostatic properties that could facilitate tick feeding via the suppression of host anti-tick defenses. Physiological relevance of Iripin-3 activities observed in vitro needs to be supported by appropriate in vivo experiments.

• Klíčová slova
• Ixodes ricinus, X-ray crystallography, adaptive immunity, blood coagulation, inflammation, saliva, serpin, tick,
• MeSH
• adaptivní imunita účinky léků   MeSH
• aktivace lymfocytů účinky léků   MeSH
• antikoagulancia izolace a purifikace   farmakologie   MeSH
• cytokiny metabolismus   MeSH
• hemokoagulace účinky léků   MeSH
• hmyzí proteiny izolace a purifikace   farmakologie   MeSH
• imunologické faktory izolace a purifikace   farmakologie   MeSH
• inhibitory proteas izolace a purifikace   farmakologie   MeSH
• klíště metabolismus   MeSH
• králíci MeSH
• kultivované buňky MeSH
• lidé MeSH
• lymfocyty účinky léků   imunologie   metabolismus   MeSH
• morčata MeSH
• myši inbrední C3H MeSH
• myši inbrední C57BL MeSH
• myši transgenní MeSH
• myši MeSH
• proliferace buněk účinky léků   MeSH
• slezina účinky léků   imunologie   metabolismus   MeSH
• slinné proteiny a peptidy izolace a purifikace   farmakologie   MeSH
• sliny metabolismus   MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• lidé MeSH
• morčata MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antikoagulancia MeSH
• cytokiny MeSH
• hmyzí proteiny MeSH
• imunologické faktory MeSH
• inhibitory proteas MeSH
• slinné proteiny a peptidy MeSH

During feeding on vertebrate hosts, ticks secrete saliva composed of a rich cocktail of bioactive molecules modulating host immune responses. Although most of the proteinaceous fraction of tick saliva is of little immunogenicity, repeated feeding of ticks on mammalian hosts may lead to impairment of tick feeding, preventing full engorgement. Here, we challenged rabbits with repeated feeding of both Ixodes ricinus nymphs and adults and observed the formation of specific antibodies against several tick salivary proteins. Repeated feeding of both I. ricinus stages led to a gradual decrease in engorged weights. To identify the salivary antigens, isolated immunoglobulins from repeatedly infested rabbits were utilized for a protein pull-down from the saliva of pilocarpine-treated ticks. Eluted antigens were first identified by peptide mass fingerprinting with the aid of available I. ricinus salivary gland transcriptomes originating from early phases of tick feeding. To increase the authenticity of immunogens identified, we also performed, for the first time, de novo assembly of the sialome from I. ricinus females fed for six days, a timepoint used for pilocarpine-salivation. The most dominant I. ricinus salivary immunogens identified in our study were zinc-dependent metalloproteases of three different families. To corroborate the role of metalloproteases at the tick/host interface, we fed ticks micro-injected with a zinc metalloprotease inhibitor, phosphoramidon, on a rabbit. These ticks clearly failed to initiate feeding and to engorge. However, neither feeding to ticks immune blood of repeatedly infested rabbits, nor phosphoramidon injection into ticks, prevented their engorgement when fed in vitro on an artificial membrane system. These data show that Zn metalloproteases play a decisive role in the success of tick feeding, mediated by complex molecular interactions between the host immune, inflammatory, and hemostatic processes, which are absent in in vitro feeding. This basic concept warrants further investigation and reconsideration of the current strategies towards the development of an effective "anti-tick" vaccine.

• Klíčová slova
• Ixodes ricinus, acquired resistance, antigen, immunoprecipitation, metalloprotease, ticks, vaccine,
• MeSH
• infestace klíšťaty * MeSH
• klíště * MeSH
• králíci MeSH
• metaloproteasy MeSH
• proteiny členovců MeSH
• slinné proteiny a peptidy MeSH
• slinné žlázy MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• metaloproteasy MeSH
• proteiny členovců MeSH
• slinné proteiny a peptidy MeSH

BACKGROUND: The hard tick Hyalomma dromedarii is one of the most injurious ectoparasites affecting camels and apparently best adapted to deserts. As long-term blood feeders, ticks are threatened by host defense system compounds that can cause them to be rejected and, ultimately, to die. However, their saliva contains a cocktail of bioactive molecules that enables them to succeed in taking their blood meal. A recent sialotranscriptomic study uncovered the complexity of the salivary composition of the tick H. dromedarii and provided a database for a proteomic analysis. We carried out a proteomic-informed by transcriptomic (PIT) to identify proteins in salivary glands of both genders of this tick species. RESULTS: We reported the array of 1111 proteins identified in the salivary glands of H. dromedarii ticks. Only 24% of the proteins were shared by both genders, and concur with the previously described sialotranscriptome complexity. The comparative analysis of the salivary glands of both genders did not reveal any great differences in the number or class of proteins expressed their enzymatic composition or functional classification. Indeed, few proteins in the entire proteome matched those predicted from the transcriptome while others corresponded to other proteins of other tick species. CONCLUSION: This investigation represents the first proteomic study of H. dromedarii salivary glands. Our results shed light on the differences between the composition of H. dromedarii male and female salivary glands, thus enabling us to better understand the gender-specific strategy to feed successfully.

• Klíčová slova
• Hyalomma dromedarii, LC–MS/MS, PIT, Proteome, Salivary glands,
• MeSH
• klíšťata genetika   metabolismus   MeSH
• proteiny členovců genetika   metabolismus   MeSH
• proteom metabolismus   MeSH
• proteomika MeSH
• slinné žlázy metabolismus   MeSH
• sliny metabolismus   MeSH
• stanovení celkové genové exprese MeSH
• transkriptom MeSH
• velbloudi MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• proteiny členovců MeSH
• proteom MeSH

The last three decades of research into tick salivary components have revealed several proteins with important pharmacological and immunological activities. Two primary interests have driven research into tick salivary secretions: the search for suitable pathogen transmission blocking or "anti-tick" vaccine candidates and the search for novel therapeutics derived from tick salivary components. Intensive basic research in the field of tick salivary gland transcriptomics and proteomics has identified several major protein families that play important roles in tick feeding and overcoming vertebrate anti-tick responses. Moreover, these families contain members with unrealized therapeutic potential. Here we review the major tick salivary protein families exploitable in medical applications such as immunomodulation, inhibition of hemostasis and inflammation. Moreover, we discuss the potential, opportunities, and challenges in searching for novel tick-derived drugs.

• Klíčová slova
• anti-inflammatory proteins, hemostasis, immunomodulation, salivary proteins, therapeutics, ticks,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Hematophagous arthropods are responsible for the transmission of a variety of pathogens that cause disease in humans and animals. Ticks of the Ixodes ricinus complex are vectors for some of the most frequently occurring human tick-borne diseases, particularly Lyme borreliosis and tick-borne encephalitis virus (TBEV). The search for vaccines against these diseases is ongoing. Efforts during the last few decades have primarily focused on understanding the biology of the transmitted viruses, bacteria and protozoans, with the goal of identifying targets for intervention. Successful vaccines have been developed against TBEV and Lyme borreliosis, although the latter is no longer available for humans. More recently, the focus of intervention has shifted back to where it was initially being studied which is the vector. State of the art technologies are being used for the identification of potential vaccine candidates for anti-tick vaccines that could be used either in humans or animals. The study of the interrelationship between ticks and the pathogens they transmit, including mechanisms of acquisition, persistence and transmission have come to the fore, as this knowledge may lead to the identification of critical elements of the pathogens' life-cycle that could be targeted by vaccines. Here, we review the status of our current knowledge on the triangular relationships between ticks, the pathogens they carry and the mammalian hosts, as well as methods that are being used to identify anti-tick vaccine candidates that can prevent the transmission of tick-borne pathogens.

• Klíčová slova
• Anaplasma, Babesia, Borrelia, Ixodes, Midgut, Rickettsia, Saliva, TBEV, Tick, Vaccine,
• MeSH
• Borrelia MeSH
• infekce přenášené vektorem MeSH
• klíště mikrobiologie   virologie   MeSH
• klíšťová encefalitida prevence a kontrola   MeSH
• kousnutí klíštětem prevence a kontrola   MeSH
• lidé MeSH
• lymeská nemoc prevence a kontrola   MeSH
• nemoci přenášené klíšťaty prevence a kontrola   přenos   MeSH
• proteiny členovců imunologie   MeSH
• sliny MeSH
• vakcíny imunologie   MeSH
• viry klíšťové encefalitidy MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• proteiny členovců MeSH
• vakcíny MeSH

To successfully feed, ticks inject pharmacoactive molecules into the vertebrate host including cystatin cysteine protease inhibitors. However, the molecular and cellular events modulated by tick saliva remain largely unknown. Here, we describe and characterize a novel immunomodulatory cystatin, Iristatin, which is upregulated in the salivary glands of feeding Ixodes ricinus ticks. We present the crystal structure of Iristatin at 1.76 Å resolution. Purified recombinant Iristatin inhibited the proteolytic activity of cathepsins L and C and diminished IL-2, IL-4, IL-9, and IFN-γ production by different T-cell populations, IL-6 and IL-9 production by mast cells, and nitric oxide production by macrophages. Furthermore, Iristatin inhibited OVA antigen-induced CD4+ T-cell proliferation and leukocyte recruitment in vivo and in vitro. Our results indicate that Iristatin affects wide range of anti-tick immune responses in the vertebrate host and may be exploitable as an immunotherapeutic.

• Klíčová slova
• Cathepsin, Crystal structure, Immune responses, Ixodes ricinus, Saliva,
• MeSH
• cystatiny klasifikace   genetika   farmakologie   MeSH
• cytokiny metabolismus   MeSH
• epoxidové sloučeniny metabolismus   MeSH
• fylogeneze MeSH
• imunosupresiva chemie   metabolismus   farmakologie   MeSH
• klíště chemie   genetika   metabolismus   MeSH
• krystalografie rentgenová MeSH
• makrofágy účinky léků   metabolismus   MeSH
• oxid dusnatý metabolismus   MeSH
• proteiny členovců chemie   genetika   farmakologie   MeSH
• proteolýza účinky léků   MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• slinné cystatiny chemie   genetika   farmakologie   MeSH
• T-lymfocyty účinky léků   metabolismus   MeSH
• tyrosin analogy a deriváty   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cathestatin C MeSH Prohlížeč
• cystatiny MeSH
• cytokiny MeSH
• epoxidové sloučeniny MeSH
• imunosupresiva MeSH
• oxid dusnatý MeSH
• proteiny členovců MeSH
• slinné cystatiny MeSH
• tyrosin MeSH