Abstract
Abstract: :
Purpose: Toll–like receptors (TLRs) function as initial cellular recognition molecules for incoming pathogens. This study aims to quantitate the induction of TLRs by HSV strains and HCMV in corneal and conjunctival cells. Methods: Monolayers of human corneal epithelial cells (HCE), human corneal fibroblasts (HCRF),human conjunctival epithelial cells (HcjE), and human conjunctival fibroblasts (HCjVF) were infected with one of the following live or UV–inactivated viruses: HSV type 1 (KOS, McKrae, MP strain), HSV type 2 (MS strain), HCMV (AD169 strain). Multiplicity of infection was adjusted to 1.0 (for UV–inactivated virus, it was before UV irradiation). Total RNAs were extracted at 8 hours post infection (PI) for live viruses and 24hous PI for UV–inactivated viruses. Expression of TLR–2, 3, 4, 5, 7, 8 and 9 was quantitated by real time PCR. Results: Compared to uninfected control cells, virus infected HCE showed increased expression of TLR–2 (2–3x with HSV–1), TLR–3 (9–12X with HSV–1, 25–33X with UV–HSV–1, 14X with UV–HSV–2, 3.7X with HCMV, 20X with UV–HCMV), TLR–4 (2–4X with UV–HSV–1, 2X with UV–HSV–2) TLR–8 (2–14X with HSV–1, 4–7X with UV–HSV–1, 2X with UV–HSV–2) and TLR–9 (16–26X with HSV–1, 2–15X with UV–HSV–1, 16X with HSV–2, 3.6X with HCMV, 4.7X with UV–HCMV). HCRF expressed TLR–2 (2–6Xwith HSV–1), TLR–3 (3.8 with HSV–1, 4–22X with UV–HSV–1, 4.5X with UV–HSV–2, 4.3 X with HCMV, 23X with UV–HCMV), TLR–4 (5.8X with HSV–1, 4–11X with UV–HSV–1, 5.4X with UV–HCMV), TLR–8 (3.6–8X with HSV–1, 8.6 X with UV–HSV–1, 16X with UV–HSV–2, 37X with UV–HCMV) TLR–9(4–17X with HSV–1, 1.8–5X with UV–HSV–1). HCjE expressed TLR–2 (3X with UV–HSV–1, 9X with HCMV), TLR–3 (3X with UV–HSV–1, 23X with UV–HCMV), and TLR–4 (3X with UV–HSV–1, 3X with HCMV) but not TLR–8 or TLR–9. HCjVF expressed TLR–3 (2.7X with UV–HSV–1, 2.9X with HCMV), TLR–4 (2.8X with HSV–1, 9.7X with UV–HCMV), TLR–8 (2.3X with UV–HSV–1), TLR–9 (2–11X with HSV–1, 39X with UV–HSV–1, 9X with UV–HSV–2) but not TLR–2 and TLR–5. Conclusions:TLRs 2,3,4,8 and 9 are expressed during herpes virus infection. Corneal cells express more varied TLRs than conjunctival cells. These results suggest that the cornea which lacks systemic immune surveillance is ready to cope with wider range of pathogen associated molecules than the conjunctiva. Induction of TLRs are different with the infecting strains of HSV–1.HCMV induced TLRs in fibroblasts more strongly than in epithelial cells.