Receptors Tolllike Receptors

Toll-like receptors (TLRs) have a major role in mediating cellular immunity. The family comprises 13 members. They are expressed by macrophages, neutrophils, DCs and epithelial cells. Two members, TLR2 and TLR4 are implicated in fungal recognition, apparently in response to fungal surface polysaccharides (Uematsu & Akira, 2006). Signaling is mediated via two pathways:

(a) TLR2/TLR4 signaling dependent on the adaptor protein MyD88, leading to the activation of the nuclear transcription factor NFK-B and transcription of inflammatory Th1-response cytokines including TNF-a, IL-6, IL-12, and IL1-P.

(b) TLR-4 signaling dependent on the adaptor proteins TRAM and TRIF, leading to the activation of the nuclear transcription factor IRF3 and transcription of IFN-P and interferon inducible genes.

There is some disparity in the data regarding the relative roles of TLR2 and TLR4 in the recognition of A. fumigatus by macrophages during dormancy and germination. Different groups show a major role for either TLR2 alone (Mambula et al., 2002), TLR4 alone (Wang et al., 2001; Netea et al., 2003), or both receptors together (Meier et al., 2003; Gersuk et al., 2006). In contrast, Dubordeau et al. (2006) recently demonstrated that TLR2 and TLR4 are not involved in the cytokine response to A. fumigatus infection, nor do they contribute to resistance against infection in knockout mice. According to these authors, the main pathway involved in the cytokine response of alveolar macrophages to A. fumigatus infection is via ERK signaling.

Cure Your Yeast Infection For Good

Cure Your Yeast Infection For Good

The term vaginitis is one that is applied to any inflammation or infection of the vagina, and there are many different conditions that are categorized together under this ‘broad’ heading, including bacterial vaginosis, trichomoniasis and non-infectious vaginitis.

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