ÿþ<HTML><HEAD><TITLE>XI International Meeting on Paracoccidioidomycosis</TITLE><link rel=STYLESHEET type=text/css href=css.css></HEAD><BODY aLink=#ff0000 bgColor=#FFFFFF leftMargin=0 link=#000000 text=#000000 topMargin=0 vLink=#000000 marginheight=0 marginwidth=0><table align=center width=700 cellpadding=0 cellspacing=0><tr><td align=left bgcolor=#cccccc valign=top width=550><font face=arial size=2><strong><font face=Verdana, Arial, Helvetica, sans-serif size=3><font size=1>XI International Meeting on Paracoccidioidomycosis</font></font></strong><font face=Verdana size=1><b><br></b></font><font face=Verdana, Arial,Helvetica, sans-serif size=1><strong> </strong></font></font></td><td align=right bgcolor=#cccccc valign=top width=150><font face=arial size=2><strong><font face=Verdana, Arial, Helvetica, sans-serif size=1><font  size=1>Resume:5-1</font></em></font></strong></font></td></tr><tr><td colspan=2><br><br><table align=center width=700><tr><td><b>Oral / Poster</b><br><table width="100%"><tr><td width="60">5-1</td><td><b>IL-6 AND IL-17 ARE IMPORTANTE TO CONTROL EXPERIMENTAL PARACOCCIDIOIDES BRASILIENSIS INFECTION</b></td></tr><tr><td valign=top>Authors:</td><td><u>Fernanda Agostinho Rocha </u>  (FMRP - Faculdade de Medicina de Ribeirão Preto) ; Fabrine Salles Massafera Tristão   (FMRP - Faculdade de Medicina de Ribeirão PretoFMRP - Faculdade de Medicina de Ribeirão Preto) ; Vinícius Augusto dos Reis Soares Souza   (FMRP - Faculdade de Medicina de Ribeirão Preto) ; João Santana da Silva   (FMRP - Faculdade de Medicina de Ribeirão Preto) </td></tr></table><p align=justify><b><font size=2>Abstract</font></b><p align=justify class=tres><font size=2><b>Background:</b> T helper cells type 17 (Th17) are described as an arm of the adaptive immune system that enhances host protection against several infections. After Th17 differentiation, in the presence of TGF-&#946; and interleukin (IL)-6 or IL-21, these cells are able to produce the cytokines IL-21, IL-22 and principally IL-17. Considering the better understanding of the mechanisms involved in resistance to <i>P. brasiliensis</i> (Pb) infection is necessary, our aim was to evaluate the role of the cytokines IL-6 and IL-17 during the experimental paracoccidioidomycosis. 
<b>Methods and results:</b> To determine the possible role of IL-6 and IL-17 during Pb-infection, male C57BL/6 and genetically deficient IL-6 (IL-6KO) and IL-17R (IL-17RKO) mice were intravenously inoculated with 1x106 yeast forms of Pb18. Initially, we evaluated at 7 and 30 days of infection the mRNA expression of ROR&#947;T, Stat3, IL-6 and IL-17 by Real Time-PCR. Moreover, the IL-6 and IL-17 production was measured in the lungs of infected mice by ELISA at 7 and 30 days post-infection (dpi). Our results showed that infection did not alter mRNA expression of ROR&#947;T and Stat3, however, IL-6 and IL-17 mRNA expression and production was increased in comparison with uninfected mice. Evaluating the susceptibility to Pb18-infection, the IL-6KO mice showed higher mortality rate than wild type (WT) group. The IL-17RKO mice had similar survival in comparison to WT mice. After recovery of yeasts cells in the lung, liver and spleen from IL-6KO and IL-17RKO infected mice, we evaluated the role of these cytokines during experimental PCM. At 15 and 30 dpi, the colony forming units recovery in the lung from both knockout mice were increased in comparison to WT mice. Histopathological analysis showed that IL-6 deficiency assisted to increased inflammation at lung tissue. Liver and spleen from IL-6KO, but not IL-17RKO mice, had higher number of yeast cells at 15dpi when compared with WT organs. The absence of IL-6 or IL-17R induced lower production of IFN-&#947;(15dpi) and IL-10 (30dpi) compared with WT lung. The IL-17 production were decreased in IL-6KO (30dpi) while the IL-17RKO mice showed increased production of this cytokine in relation to WT lung mice. 
<b>Conclusion:</b> Taken together, these results demonstrate that IL-6 and IL-17 contribute to control of experimental Pb-infection. 
<b>Financial support:</b> CAPES/INCT and FAPESP.
</font></p><br><b>Keyword: </b>&nbsp;cytokine, Paracoccidioides brasiliensis, Th17 response</td></tr></table></tr></td></table></body></html>