The saliva of blood-feeding parasites is a rich source of peptidase inhibitors that help to overcome the host's defence during host-parasite interactions. Using proteomic analysis, the cystatin OmC2 was demonstrated in the saliva of the soft tick Ornithodoros moubata, an important disease vector transmitting African swine fever virus and the spirochaete Borrelia duttoni. A structural, biochemical and biological characterization of this peptidase inhibitor was undertaken in the present study. Recombinant OmC2 was screened against a panel of physiologically relevant peptidases and was found to be an effective broad-specificity inhibitor of cysteine cathepsins, including endopeptidases (cathepsins L and S) and exopeptidases (cathepsins B, C and H). The crystal structure of OmC2 was determined at a resolution of 2.45 A (1 A=0.1 nm) and was used to describe the structure-inhibitory activity relationship. The biological impact of OmC2 was demonstrated both in vitro and in vivo. OmC2 affected the function of antigen-presenting mouse dendritic cells by reducing the production of the pro-inflammatory cytokines tumour necrosis factor alpha and interleukin-12, and proliferation of antigen-specific CD4+ T-cells. This suggests that OmC2 may suppress the host's adaptive immune response. Immunization of mice with OmC2 significantly suppressed the survival of O. moubata in infestation experiments. We conclude that OmC2 is a promising target for the development of a novel anti-tick vaccine to control O. moubata populations and combat the spread of associated diseases.

• MeSH
• imunologické faktory chemie   fyziologie   MeSH
• krystalizace MeSH
• krystalografie rentgenová MeSH
• molekulární sekvence - údaje MeSH
• myši inbrední C3H MeSH
• myši inbrední C57BL MeSH
• myši transgenní MeSH
• myši MeSH
• Ornithodoros chemie   imunologie   MeSH
• sekvence aminokyselin MeSH
• slinné cystatiny chemie   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

Ixodes ricinus tick saliva-activated transmission of Borrelia burgdorferi sensu stricto spirochetes was studied on the C3H/HeN mouse model. The influence of the feeding of uninfected nymphs on the proliferation and distribution of intradermally inoculated spirochetes was compared with the effect of co-inoculated saliva or salivary gland extract (SGE), respectively. Spirochete loads in murine tissues were evaluated using real-time q-PCR. SGE induced significantly increased spirochete numbers in the skin on the days 4 and 6 post-infection (p.i.). On the other hand, decreased bacterial load in the heart of SGE-treated mice was demonstrated in comparison with control animals. The inoculation of tick saliva increased spirochete load in the urinary bladder on day 6 p.i., while the number of spirochetes in the heart declined on day 6 p.i. The feeding of I. ricinus nymphs raised the spirochete load in the bladder on the days 4 and 6 p.i. On day 6, the number of spirochetes found in the heart was significantly lower than in controls. The prevalence of spirochetes in ticks infected by feeding on mice was more than 10 times higher when the mice were infected with the mixture of spirochetes and saliva or SGE, in comparison with spirochetes alone. The presence of SGE in the infectious inoculum increased the spirochete burden per tick from 0 to almost 28,000. Taken together, these results show a very early effect of tick saliva on the proliferation and distribution of Borrelia spirochetes in the host, probably due to the effect of saliva on the host innate immunity mechanisms.

• MeSH
• Borrelia burgdorferi růst a vývoj   MeSH
• klíště mikrobiologie   MeSH
• kůže mikrobiologie   MeSH
• lymeská nemoc mikrobiologie   přenos   veterinární   MeSH
• močový měchýř mikrobiologie   MeSH
• myši inbrední C3H MeSH
• myši MeSH
• počet mikrobiálních kolonií MeSH
• sliny mikrobiologie   MeSH
• srdce mikrobiologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH

A previously reported procedure for the introduction of Borrelia spirochetes into tick larvae by immersion in a suspension of spirochetes was tested on Ixodes ricinus (L.) ticks and three of the most medically important European Borrelia genomic species, B. burgdorferi sensu stricto, B. garinii and B. afzelii. The procedure was compared with “classical” infection of nymphs by feeding on infected mice. Both methods yielded comparable results (infection rate 44–65%) with the exception of B. afzelii, which produced better results using the immersion method (44%) compared with feeding on infected mice (16%). Nymphs infected by the immersion method at the larval stage were able to transmit the infection to naive mice as shown by serology and PCR detection of spirochetal DNA in organs. The immersion method is faster than feeding on infected mice and provides more reproducible conditions for infection. It can be exploited for studies on both pathogen transmission and Borrelia-vector interactions.

• MeSH
• Borrelia burgdorferi komplex růst a vývoj   MeSH
• DNA bakterií genetika   MeSH
• ELISA MeSH
• klíště mikrobiologie   MeSH
• larva mikrobiologie   MeSH
• lymeská nemoc mikrobiologie   přenos   MeSH
• myši MeSH
• nymfa mikrobiologie   MeSH
• polymerázová řetězová reakce MeSH
• protilátky bakteriální krev   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH

The role of antibodies in the immune response to microsporidiosis was studied using a novel anti-exospore monoclonal antibody (MAb) P5/H1, which recognizes surface antigens of Encephalitozoon cuniculi. The effect of the MAb on microsporidial infection in vivo was to prolong the survival of previously CD4+ reconstituted, perorally infected and intraperitoneally MAb-treated SCID mice. The MAb decreased the numbers of E. cuniculi spores in peritoneal smears obtained post mortem. These results suggest a possible role for antibodies in protection against perorally acquired E. cuniculi infection.

• MeSH
• analýza přežití MeSH
• CD4-pozitivní T-lymfocyty imunologie   MeSH
• Encephalitozoon cuniculi imunologie   MeSH
• encephalitozoonóza imunologie   terapie   MeSH
• financování organizované MeSH
• imunoterapie metody   MeSH
• monoklonální protilátky farmakologie   imunologie   MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• neparametrická statistika MeSH
• spory hub imunologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH