References of "Tabart, Jérémy"
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See detailImmunization and Dermatophytes
Mignon, Bernard ULg; Tabart, Jérémy; Baldo, Aline ULg et al

in Current Opinion in Infectious Diseases (2008), 21(2), 134-140

PURPOSE OF REVIEW: Despite the availability of effective vaccines for certain animal species, vaccination against dermatophytosis requires improvement and further development in both animals and humans ... [more ▼]

PURPOSE OF REVIEW: Despite the availability of effective vaccines for certain animal species, vaccination against dermatophytosis requires improvement and further development in both animals and humans. This review provides an update on the current situation and focuses on recent advances in host-dermatophyte relationships that could have implications for future vaccination against the most prevalent of the fungal diseases. RECENT FINDINGS: Numerous dermatophytic virulence factors have recently been isolated and characterized at the molecular level, notably secreted proteases involved in the invasion of the keratin network. Their precise roles in the different steps of the infectious process and in immunopathogenesis are being studied, while all aspects of the host immune response against dermatophytes, including the innate response, are becoming increasingly documented. In addition, new molecular tools are now available for studying dermatophytes, which will accelerate research on this topic. SUMMARY: The growth of knowledge concerning all aspects of the host-dermatophyte relationship should contribute towards sound strategies for the development of effective and safe vaccines against dermatophytosis. [less ▲]

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See detailSecreted subtilisins of Microsporum canis are involved in adhesion of arthroconidia to feline corneocytes
Mathy, Anne ULg; Tabart, Jérémy; Mignon, Bernard ULg et al

Poster (2008)

Microsporum canis is a pathogenic fungus that causes a superficial skin infection called dermatophytosis mainly in cats, dogs and humans. Like other dermatophytoses, the physiopathology of this dermatosis ... [more ▼]

Microsporum canis is a pathogenic fungus that causes a superficial skin infection called dermatophytosis mainly in cats, dogs and humans. Like other dermatophytoses, the physiopathology of this dermatosis remains largely unknown. From a fungal perspective, the infection process can be divided in three steps: adhesion of M. canis arthroconidia to corneocytes, conidial germination, and fungal invasion of the keratin network. The mechanisms involved in adherence of M. canis to epidermis have never been investigated. However, several previously characterized secreted fungal endoproteases like subtilisins (Sub), including the keratinolytic protease Sub3, are secreted in vivo and could be involved in the first pathogenic steps. The objective of this study were (1) to develop an in vitro model to study M. canis adherence to feline corneocytes and (2) to assess whether the Sub are involved in fungal adhesion. An arthroconidial suspension was spread over the surface of reconstituted feline epidermis (RFE). Co-cultures were incubated for varying lengths of time and adherent conidia were labelled using Calcofluor white and counted. In subsequent assays arthroconidia were exposed to the serine protease inhibitor chymostatin or a mixture of two anti-Sub3 monoclonal antibodies (Mabs) one hour prior to the adherence assay. In our model, adherence of M. canis arthroconidia to RFE is time-dependent, beginning within two hours and still increasing after six hours. Chymostatin and Mabs inhibit M. canis adherence to RFE by 53 and 23 % respectively, which suggests that subtilisins and particularly Sub3, are fungal virulence factors involved in the adherence process. [less ▲]

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See detailPathogenesis of dermatophytosis
Vermout, Sandy; Tabart, Jeremy; Baldo, Aline ULg et al

in Mycopathologia (2008), 166(5-6), 267-275

Despite the superficial localization of most dermatophytosis, host-fungus relationship in these infections is complex and still poorly elucidated. Though many efforts have been accomplished to ... [more ▼]

Despite the superficial localization of most dermatophytosis, host-fungus relationship in these infections is complex and still poorly elucidated. Though many efforts have been accomplished to characterize secreted dermatophytic proteases at the molecular level, only punctual insights have been afforded into other aspects of the pathogenesis of dermatophytosis, such as fungal adhesion, regulation of gene expression during the infection process, and immunomodulation by fungal factors. However, new genetic tools were recently developed, allowing a more rapid and high-throughput functional investigation of dermatophyte genes and the identification of new putative virulence factors. In addition, sophisticated in vitro infection models are now used and will open the way to a more comprehensive view of the interactions between these fungi and host epidermal cells, especially keratinocytes. [less ▲]

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See detailReconstructed interfollicular feline epidermis as a model for the screening of antifungal drugs against Microsporum canis.
Tabart, Jeremy; Baldo, Aline ULg; Vermout, Sandy et al

in Veterinary Dermatology (2008), 19(3), 130-133

A fully differentiated reconstructed interfollicular feline epidermis (RFE) was recently developed in vitro. It was shown to be relevant for the study of Microsporum canis-epidermal interactions. In this ... [more ▼]

A fully differentiated reconstructed interfollicular feline epidermis (RFE) was recently developed in vitro. It was shown to be relevant for the study of Microsporum canis-epidermal interactions. In this study, RFE was evaluated as a potential model for the in vitro screening of drugs against M. canis. As a preliminary step, the minimum inhibitory concentration of miconazole nitrate against M. canis IHEM 21239 grown on Sabouraud's dextrose agar was determined to be 0.3 microg mL(-1). RFE grown at the air-liquid interface was cultured for 24 h in RFE culture medium, supplemented with either miconazole (range 0.1-1 microg mL(-1)) or its solvent (dimethylsulfoxide). Then, RFE was inoculated in triplicate with 1 x 10(5 )M. canis arthroconidia and incubated for five additional days. To evaluate fungal growth, RFE was processed for routine histopathology, three serial sections being performed across the block at 100 microm intervals. No fungal growth was detected invading or on the surface of infected RFE in the presence of miconazole concentrations equal to or higher than 0.3 microg mL (final concentration in the culture medium). This study demonstrates that RFE is an adequate model for the in vitro screening of drugs against M. canis and potentially against other skin pathogens. [less ▲]

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See detailSecreted subtilisins of Microsporum canis are involved in adherence of arthroconidia to feline corneocytes.
Baldo, Aline ULg; Tabart, Jeremy; Vermout, Sandy et al

in Journal of Medical Microbiology (2008), 57(Pt 9), 1152-1156

Microsporum canis is a pathogenic fungus that causes a superficial cutaneous infection called dermatophytosis, mainly in cats and humans. The mechanisms involved in adherence of M. canis to epidermis have ... [more ▼]

Microsporum canis is a pathogenic fungus that causes a superficial cutaneous infection called dermatophytosis, mainly in cats and humans. The mechanisms involved in adherence of M. canis to epidermis have never been investigated. Here, a model was developed to study the adherence of M. canis to feline corneocytes through the use of a reconstructed interfollicular feline epidermis (RFE). In this model, adherence of arthroconidia to RFE was found to be time-dependent, starting at 2 h post-inoculation and still increasing at 6 h. Chymostatin, a serine protease inhibitor, inhibited M. canis adherence to RFE by 53%. Moreover, two mAbs against the keratinolytic protease subtilisin 3 (Sub3) inhibited M. canis adherence to RFE by 23%, suggesting that subtilisins, and Sub3 in particular, are involved in the adherence process. [less ▲]

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See detailSecreted dipeptidyl peptidases as potential virulence factors for Microsporum canis.
Vermout, Sandy; Baldo, Aline ULg; Tabart, Jeremy et al

in FEMS Immunology & Medical Microbiology (2008), 54(3), 299-308

Dermatophytoses caused by Microsporum canis are frequently encountered in cats and dogs; they are highly contagious and readily transmissible to humans. In this study, two single genes, respectively ... [more ▼]

Dermatophytoses caused by Microsporum canis are frequently encountered in cats and dogs; they are highly contagious and readily transmissible to humans. In this study, two single genes, respectively coding for dipeptidyl peptidases IV and V (DppIV and DppV), were isolated and characterized. Both proteins share homology with serine proteases of the S9 family, some of which display properties compatible with implication in pathogenic processes. Both genes are expressed in vivo in experimentally infected guinea-pigs and in naturally infected cats, and when the fungus is grown on extracellular matrix proteins as the sole nitrogen and carbon source. DppIV and V were produced as active recombinant proteases in the yeast Pichia pastoris; the apparent molecular weight of rDppV is 83 kDa, whereas rDppIV appears as a doublet of 95 and 98 kDa. Like other members of its enzymatic subfamily, rDppIV has an unusual ability to cleave Pro-X bonds. This activity does not enhance the solubilization of keratin by fungal secreted endoproteases, and the protease probably acts solely on small soluble peptides. RDppV showed no ability to induce delayed-type hypersensitivity (DTH) skin reactions in guinea-pigs, despite the known immunogenic properties of homologous proteins. [less ▲]

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See detailReconstructed interfollicular feline epidermis as a model for Microsporum canis dermatophytosis
Tabart, Jérémy; Baldo, Aline ULg; Vermout, Sandy et al

in Journal of Medical Microbiology (2007), 56(7), 971-975

Microsporum canis is a pathogenic fungus that causes a superficial cutaneous infection called dermatophytosis. The complexity of mechanisms involved in dermatophytic infections makes relevant in vivo ... [more ▼]

Microsporum canis is a pathogenic fungus that causes a superficial cutaneous infection called dermatophytosis. The complexity of mechanisms involved in dermatophytic infections makes relevant in vivo studies particularly difficult to perform. The aim of this study was to develop a new in vitro model of M. canis dermatophytosis using feline fetal keratinocytes in reconstructed interfollicular epidermis, and to investigate its relevance in studying the host-pathogen relationship. Histological analysis of reconstructed interfollicular feline epidermis (RFE) revealed a fully differentiated epidermis. A proliferation assay showed replicating cells only in the basal layer, indicating that RFE is a well-stratified living tissue, leading to the formation of a horny layer. Histopathological analysis of RFE infected by M. canis arthroconidia revealed that the fungus invades the stratum corneum and produces SUB3, a keratinase implicated in the infectious process. In view of these results, an M. canis dermatophytosis model on RFE seems to be a useful tool to investigate mechanisms involved in natural M. canis feline infections. [less ▲]

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