Topical exposure to exogenous ultraviolet-irradiated urocanic acid enhances Mycobacterium ulcerans infection in a Crl:IAF(HA)-hrBR hairless guinea-pig model of Buruli ulcer disease
| العنوان: | Topical exposure to exogenous ultraviolet-irradiated urocanic acid enhances Mycobacterium ulcerans infection in a Crl:IAF(HA)-hrBR hairless guinea-pig model of Buruli ulcer disease |
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| المؤلفون: | B. A. Valentine, R. B. Cope, Luiz E. Bermudez, Bernadette V. Stang |
| المصدر: | Photodermatology, Photoimmunology and Photomedicine. 20:14-20 |
| بيانات النشر: | Wiley, 2004. |
| سنة النشر: | 2004 |
| مصطلحات موضوعية: | Male, Buruli ulcer, Photochemistry, Ultraviolet Rays, Guinea Pigs, Immunology, Mycobacterium Infections, Nontuberculous, Dermatology, Biology, Microbiology, Guinea pig, Lesion, chemistry.chemical_compound, Immune system, Isomerism, Antigen, Skin Ulcer, medicine, Animals, Immunology and Allergy, Hypersensitivity, Delayed, Radiology, Nuclear Medicine and imaging, Skin, Antigens, Bacterial, Mycobacterium ulcerans, integumentary system, Urocanic Acid, Skin Diseases, Bacterial, General Medicine, Intradermal Tests, medicine.disease, biology.organism_classification, Hairless, Urocanic acid, chemistry, medicine.symptom |
| الوصف: | Ultraviolet radiation (UVR) pre-exposure enhances Mycobacterium ulcerans infection in the Crl:IAF(HA)-hrBR hairless guinea-pig, possibly via a photoimmunosuppressive mechanism. The trans-cis photoisomerization of epidermal urocanic acid is an important initiator of the web of events leading to photoimmunosuppression. Thus, the hypothesis tested in this paper was that topical pre-exposure to UVR-irradiated urocanic acid mixture containing cis-urocanic acid (UVR-UCA) enhances the ulcerative form of M. ulcerans infection in the Crl:IAF(HA)-hrBR hairless guinea-pig model of human Buruli ulcer disease.Groups of six animals were subjected to daily topical treatment with either 0 (vehicle only), 0.1, 0.5 or 1 mg of trans (tUCA) or UVR-UCA (contained a cis : trans urocanic acid isomer ratio of 1 : 9) for three consecutive days. A sham treatment group was also included in the experiment. Three days following their final treatment, the guinea-pigs were intradermally infected in the right dorsal flank with 1.5 x 107 CFU of M. ulcerans in 0.1 ml of phosphate-buffered saline (PBS) and sham infected with 0.1 ml of PBS in the left dorsal flank. The resultant skin lesions were then measured over the next 21 days. At day 21 postinfection, the animals were tested for delayed-type hypersensitivity (DTH) reactivity to M. ulcerans cell fragment antigens (MCF).Distinct, well-demarcated, dermally situated skin nodules were present at infected, but not sham-infected, skin sites by day 3 postinfection, and the lesions progressed to frank ulcers by day 5. Between days 5 and 21, the mean lesion diameters of the UVR-UCA-treated animals were significantly (P0.001) greater than those of the sham, vehicle only or tUCA-treated groups. UVR-UCA-treated guinea-pigs also had significantly (P0.001) suppressed DTH responses to MCF compared with the other treatment groups. There were no significant (P0.4) differences between the lesion sizes and DTH responses of the tUCA, vehicle only or sham treatment groups. These results demonstrate that topical exposure to UVR-UCA promotes M. ulcerans infection and suppresses DTH responses to M. uclerans antigens in infected animals. These results lend credence to the hypothesis that UVR-mediated enhancement of Buruli ulcer disease in the Crl:IAF(HA)-hrBR hairless guinea-pig model occurs via modulation of cis-urocanic acid-susceptible immune pathways. |
| تدمد: | 1600-0781 0905-4383 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fa8751eb35983d603c1fbd1e734d54b8 https://doi.org/10.1111/j.1600-0781.2004.00073.x |
| حقوق: | CLOSED |
| رقم الأكسشن: | edsair.doi.dedup.....fa8751eb35983d603c1fbd1e734d54b8 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 16000781 09054383 |
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