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Clinical and Diagnostic Laboratory Immunology, July 2002, p. 935-937, Vol. 9, No. 4
1071-412X/02/$04.00+0 DOI: 10.1128/CDLI.9.4.935-937.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.
Department of Dermatology, Teikyo University School of Medicine, Tokyo,1 Departments of Veterinary Internal Medicine,2 Pathobiology, Nihon University School of Veterinary Medicine, Kanagawa, Japan3
Received 6 November 2001/ Returned for modification 5 March 2002/ Accepted 3 April 2002
| ABSTRACT |
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) was confirmed by enzyme-linked immunosorbent assay in a medium where human epidermal keratinocytes were cocultured with Trichophyton mentagrophytes for 1 to 12 h. IL-8 and TNF-
mRNAs were also detected in the keratinocytes cocultured with T. mentagrophytes. | TEXT |
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Six isolates of a most common dermatophyte, Trichophyton mentagrophytes (four isolates from human patients and two isolates from animal patients), were used in this study. All isolates were identified by conventional methods (morphological characteristics of macroconidia and spiral hyphae, urease reaction, and hair perforating test) (10) and by molecular analysis of chitin synthase 1 gene sequences (8). These strains were been maintained by culturing at 25°C on 1/10 Sabouraud's glucose agar containing peptone (0.1%), glucose (0.2%), KH2PO4 (0.1%), MgSO47H2O (0.1%), and agar (2%) and were subcultured more than twice every 2 weeks before use.
Human epidermal keratinocytes of foreskin (Cosmo Bio, Tokyo, Japan) were cultured in the serum-free medium K110 keratinocyte growth medium (Cosmo Bio) at 37°C and 5% CO2 for 5 days.
Coculture of epidermal keratinocytes and microconidia of T. mentagrophytes was carried out based on a previously described method (7). In the preliminary studies it was determined that the number of the microconidia per human epidermal keratinocyte needed for optimal stimulation varied widely among dermatophytes tested (data not shown). On the basis of these studies, a 1:1 ratio of microconidia to keratinocytes was chosen for subsequent experiments. Moreover, no good results were obtained in preliminary experiments when heat-killed microconidia were used. Therefore, microconidia were collected by being scraped from the white powdery colonies of T. mentagrophytes grown on 1/10 Sabouraud's glucose agar and were suspended with 0.04% Tween 80 distilled water (pH 7.4) in a glass homogenizer. These microconidia were washed twice in phosphate-buffered saline and were resuspended in K110 medium. The human epidermal keratinocytes (104 cells/well) were incubated on a microplate with 96 wells at 37°C and 5% CO2 for 16 h, and then the microconidia of T. mentagrophytes (104 cells/well) were distributed to the wells. After 1 to 12 h of coculture these supernatants were obtained and kept at -20°C until use for cytokine assay with enzyme-linked immunosorbent assay (ELISA).
Every assay was carried out with a Cytoscreen Immunoassay kit (BioSource International, Camerillo, Calif.), and this assay system was sensitive to more than 1 pg/ml. All experiments were done in triplicate; results were expressed as means ± standard deviations. Comparisons among tests were done by the Student's t test, with statistical significance considered to be P < 0.01.
After 1 to 12 h of coculture of epidermal keratinocytes and microconidia of T. mentagrophytes, the interleukin-8 (IL-8) and tumor necrosis factor alpha (TNF-
) levels in the supernatants were determined by ELISA. The culture supernatants of keratinocytes alone were used as the control. IL-8 and TNF-
were detected in the supernatant and increased following coculture, although the levels of other cytokines (IL-1ß, IL-6, and monocyte chemoattractant protein 1 [MCP-1]) were very low or undetectable in these assays (Fig. 1). The IL-8 level in the supernatant increased at 3 h after coculture of keratinocytes with T. mentagrophytes. On the other hand, TNF-
levels in the supernatant increased suddenly after coculturing. However, IL-1ß, IL-6, and MCP-1 levels were not detected in each culture supernatant of epidermal keratinocytes and T. mentagrophytes examined at every culturing time.
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were 5'-ATG AAA GTC TCT GCC GCC CT CA-3' (primer MCP-1 S1; nt 598 to 617 in mRNA for the human MCP gene; DDBJ/EMBL/GenBank accession no. M10988) and 5'-GAG ATC TGT GCT GAC CCC AA-3' (primer MCP-1 R1; nt 197 to 216) (13) and 5'-AGG CGC TCC CCA AGA AGA CA-3' (primer TNF-
S2; nt 129 to 148 in mRNA for human TNF; DDBJ/EMBL/GenBank accession no. M10988) and 5'-TCC TTG GCA AAA CTG CAC CT-3' (primer TNF-
R1; nt 164 to 183) (15). The cDNA samples from epidermal keratinocytes were amplified by PCR in a reaction mixture (30 µl) containing 10 mM Tris-HCl (pH 8.3), 50 mM KCl, 1.5 mM MgCl2, 0.001% gelatin, 200 mM each deoxynucleoside triphosphate, 1.0 U of Taq polymerase (Takara, Kyoto, Japan), and 0.5 µg of a pair of primers. The PCR amplification was carried out for 30 cycles consisting of template denaturation (1 min at 94°C), primer annealing (1 min at 55°C), and polymerization (2 min at 72°C). The PCR products were electrophoresed through 3% (IL-1ß, IL-6, and IL-8) or 2% (MCP-1 and TNF-
) agarose gels and then were stained with ethidium bromide and observed under UV irradiation.
After coculturing epidermal keratinocytes and T. mentagrophytes at 0, 1, 3, and 12 h, IL-8 and TNF-
mRNAs in human epidermal keratinocytes were detected by RT-PCR (Fig. 2). IL-8 and TNF-
mRNAs were detected in epidermal keratinocytes after 1 to 12 h of coculture, although these mRNAs in epidermal keratinocyte were not detectable at the beginning of coculture. These results suggested that T. mentagrophytes stimulated the production of IL-8 and TNF-
mRNAs in human epidermal keratinocytes.
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production from human epidermal keratinocytes without activated macrophages. This finding was also confirmed by detecting mRNAs of IL-8 and TNF-
in the keratinocytes cocultured with T. mentagrophytes. In addition, T. mentagrophytes could not induce IL-1ß, IL-6, or MCP-1 in this study. These results suggested that IL-8 and TNF-
might be main cytokines released from human epidermal keratinocytes when T. mentagrophytes infects human and animals. Therefore, T. mentagrophytes seems to have direct and unique effects on cytokine production from keratinocytes. Further analysis is required to understand the process of IL-8 and TNF-
production from keratinocytes and the relationships to the host defense mechanisms against T. mentagrophytes infections.
Nucleotide sequence accession numbers.
The sequences determined in this study were deposited in the DDBJ, EMBL, and GenBank databases and were given accession numbers as follows: primer IL-1ß 1S, no. D49950; primer IL-6 1S, no. X04602; primer IL-8 1S, no. M10988; primer MCP-1 S1, no. M10988; primer TNF-
S2, no. M10988.
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| REFERENCES |
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and interferon-
in regulation of keratinocyte-derived adhesion molecules and chemotactic factors. J. Clin. Investig. 85:605-608.
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| Antimicrob. Agents Chemother. | Clin. Microbiol. Rev. | Infect. Immun. |
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