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Macrophage adherence to the inner corneal surface and formation of MGCs in the stroma are common signs of chronic inflammation following corneal infection. To determine whether macrophage adherence (known clinically as KPs) and giant cell formation were specific to innate immune activation via particular TLR ligands, macrophage activation was examined in a murine model of TLR-mediated corneal inflammation. The corneal epithelium was debrided and highly purified TLR ligands were topically applied once to the cornea of TLR7(-/-), TLR9(-/-), Cx3cr1(gfp/+), CD11c(eYFP), and IL-4(-/-) mice. At 1 week post-treatment macrophage activation and phenotype was evaluated in the cornea. Treatment with TLR2, TLR3, TLR4, and TLR5 ligands caused an increase in the number of activated stromal macrophages in the central cornea at 1 week post-treatment. However, treatment with TLR9 ligand CpG-ODN and the TLR7/8 ligand R848/Resiquimod led to an accumulation of macrophages on the corneal endothelium and formation of multinucleated giant macrophages in the corneal stroma. We suggest that giant cell formation, which is a characteristic feature of granuloma formation in many tissues, may be a unique feature of TLR9- and TLR7/8-mediated macrophage activation., (© Society for Leukocyte Biology.)

Background: E-cadherin is a tumour suppressor protein, which is normally expressed on keratinocytes and antigen-presenting Langerhans cells (LCs) in the epidermis. We have previously shown that E-cadherin is lost from tissues infected with the high-risk cancer-causing human papillomavirus (HPV) type 16., Objectives: To test if E-cadherin dysregulation is associated with the cancer risk of the infecting HPV and to establish if it is conserved among HPVs in the α, β, γ and μ genera., Methods: Forty-seven lesions infected with low- or high-risk HPV types spanning four HPV genera were stained for E-cadherin, P-cadherin and CD1a to detect LCs., Results: Surface E-cadherin was reduced in tissues infected with members of the α4, α7 and α9 species and the γ and μ genera but was equivalent to normal epidermis in the β only-infected lesions tested and patchy in α10-infected tissues. There was a direct relationship between atypical E-cadherin expression and a significant reduction in LCs. Expression of P-cadherin, a protein that is increased in the E-cadherin constitutive knockout mouse, was increased in lesions with reduced E-cadherin., Conclusions: These data show that E-cadherin dysregulation by HPV is widely conserved across the majority of HPV genera. E-cadherin expression was reduced or lost in epidermis irrespective of the cancer risk of the infecting HPV type or the ability of the virus to degrade retinoblastoma protein or p53. A correlation between dysregulated E-cadherin and reduced numbers of LCs supports viral regulation of surface E-cadherin contributing to viral evasion of the host immune system., (© 2010 The Authors. BJD © 2010 British Association of Dermatologists.)