brasiliensis-sensitized mice exhibited efficient fungicidal activity in vitro [14]. In addition, neutrophil fungicidal activity is higher in resistant mice than in susceptible mice [15]. Pina et al. [16], in a complete study of neutrophil depletion during murine infection, have shown that these cells are essential for host defence to Pb infection and that host genetic pattern exerts an important influence on neutrophil functions. Together,

the findings reported to date clearly demonstrate that neutrophils may play an important effector and immunomodulatory role, especially in the early stages of infection, contributing to Pb host resistance. Nonetheless, some studies show that neutrophil APO866 functions, including fungus killing, require activation

with cytokines and other factors. In our laboratory, IFN-γ, TNF-α, granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-15 have been observed to activate human neutrophils for fungicidal activity by a mechanism dependent on H2O2 and superoxide anion [17, 18]. The specific detection of microorganisms by innate cells is mediated by pattern recognition receptors (PRR), germ line-encoded receptors that see more recognize microbial structures referred to as pathogen-associated molecular pattern [19]. Toll-like receptors (TLR) are essential PRR that mediate recognition of microbial structures, such as those of fungi, as well as the subsequent inflammatory and adaptative responses [20–23]. Because neutrophils and TLR are respectively the prototypical cell and MycoClean Mycoplasma Removal Kit receptor of innate immune response, the role of individual TLR on neutrophil functions has been investigated [24–27], including that involved in the response of these

cells to fungi [28]. Various stimuli have been shown to regulate expression of TLR in neutrophils, including pathogen structures and TLR ligands, such as lipopolysaccharide (LPS), and pro-inflammatory cytokines, such as IL-1β, TNF-α, GM-CSF and IFN-γ [24, 26, 29–31]. In view of these observations, studies conducted to evaluate the role of TLR on neutrophil functions against Pb may contribute to a better understanding of parasite/host relationship in the mycosis. In the present study, we aimed at evaluating TLR2 and TLR4 expression on human neutrophils activated with GM-CSF, IL-15, TNF-α or IFN-γ and challenged with Pb18, a virulent strain of the fungus. Moreover, we asked if these receptors have a role on fungicidal activity, H2O2 and IL-6, IL-8, TNF-α and IL-10 production by activated and challenged cells. Healthy individuals.  Twenty-eight healthy blood donors from University Hospital of the Botucatu Medical School, São Paulo State University, Brasil (age range 20–50 years) were included in the present work. The study was approved by Ethics Committee of Botucatu Medical School, and informed consent was obtained from all the blood donors. Fungi.  The high virulent strain of P.