| Resumo: |
_Trichophyton rubrum_ is the main agent causing dermatophytosis (1). Keratinocytes are
considered to be the first physical barrier of defense against pathogens (2). But not
only a physical barrier. They recognize antigens through Toll like receptors (TLR) (3).
The activation of this TLR, present on the surface of the keratinocytes, induce the
expression of different pro-inflammatory cytokines, co-stimulatory molecules and
antimicrobial peptides such as [beta]-defensins (4).
The main objective of this work is to determine if lipopolysaccharides of G – bacteria
(LPS), lipotheichoic acid from G+ bacteria (LTA), and conidias, isolated from _T. rubrum_
were able to activate the expression of TLR2 and TLR6 on the cell surface of a primary
culture of human keratinocytes through Flow cytometry. Furthermore we are looking for
the presence of [beta]-defensins 1 and 2, IL-1b and IL-8 in the supernatant, of the above
mentioned culture of cells, by Western blot.
From the flow cytometry data, the preliminary results showed an important dispersion
in terms of proliferation, increase in size and granularity of keratinocytes, from primary
cultures of skin from healthy donors, stimulated 6 hours with conidias of _T. rubrum_, and
LTA, but not when non stimulated, or stimulated with LPS (Fig 1).
When keratinocytes from primary cultures of skin from healthy donors were cultivated
48 hours, it was found dispersion in terms of proliferation, increase in size and
granularity when stimulated with conidias of _T. rubrum_, and LPS but not when non
stimulated, or stimulated with LTA (Fig 2).
The keratinocytes expressed increased levels of TLR2 and TLR6 when were
stimulated with LTA and less to _T. rubrum_, in the 6 hours cultures, but this last cells still
showed increased size (Fig 3).
The Keratinocytes expressed increased levels of TLR2 in the 48 hours cultures when
were stimulated with LPS and _T. rubrum_.(Fig 4)
Besides, [beta]-defensin-2 was detected in the supernatant of cultures of keratinocytes
stimulated with LPS (Fig 5).
It can preliminary be concluded that keratinocytes from primary cultures of human skin from healthy donors, are cells that respond as typical immune cells, after stimulation
with _T. rubrum_, LTA and LPS in different conditions, and that this mechanism may be
very important, for the protection of local environment. 

References
1.- Arenas R., Dermatofitosis en México. Rev Iberoam Micol 2002; 19: 63-67.
2.- Kupper T. and Fuhlbrigge R. Immune surveillance in the skin: mechanims and clinical consecuences.
Nat Rev Immunol 2004; 4: 211-222
3.- Kôllish G., Naderi B., Voelcker V., Wallich R., Behrendt H., Ring J., Bauer S., Jacob T., Mempel M. and
Olelrt M. Various members of the Toll-Like receptor family contribute to the innate immune response of
human epidermal keratinocytes. Immunology 2005; 114: 531-541.
4.- Akira, S. and Takeda K. 2004. Toll-like Receptor Signalling. Nature Reviews Immunology 4:499-511.
|
