The Journal Of Infectious Diseases
Aspergillus fumigatus causes invasive aspergillosis, a potentially fatal infection in oncohematological patients. Innate immune detection of A. fumigatus involves Toll-like receptor (TLR) 4 and TLR2, which forms a heterodimer with either TLR1 or TLR6. The role of those coreceptors in Aspergillus sensing is unknown. Cytokine production was measured in bone marrow-derived macrophages (BMDMs) from wild-type (WT) and TLR-deficient mice after incubation with a WT and an immunogenic RodA-deficient (rodA-47) strain of A. fumigatus and in lungs from these mice after intranasal mold inoculation. Aspergillus fumigatus-mediated NF-B activation was measured in HEK293T cells transfected with plasmids expressing mouse or human TLRs. Bone marrow-derived macrophages from TLR1- and TLR6-deficient mice produced lower amounts of interleukin 12p40, CXCL2, interleukin 6, and tumor necrosis factor than BMDMs from WT mice after stimulation with A. fumigatus. Lungs from TLR1- and TLR6-deficient mice had diminished CXCL1 and CXCL2 production and increased fungal burden after intranasal inoculation of rodA A. fumigatus compared with lungs from WT mice. rodA strain-mediated NF-B activation was observed in HEK293T cells expressing mouse TLR2/1, mouse TLR2/6, and human TLR2/1 but not human TLR2/6. Innate immune detection of A. fumigatus is mediated by TLR4 and TLR2 together with TLR1 or TLR6 in mice and TLR1 but not TLR6 in humans.