Human cathelicidin (LL-37), a multifunctional peptide, is expressed by ocular surface epithelia and has potent antibacterial and antiviral activity.
LL-37 is expressed in ocular surface epithelia and shows significant antibacterial and antiviral activity in vitro, but further research is needed to confirm its clinical relevance.
Where it sits
this study against the rest of the ll-37 corpusSummary and findings
This study measured the expression of LL-37 in human conjunctival and corneal epithelia and assessed its antibacterial and antiviral activity. LL-37 was expressed by these epithelial cells, and its antibacterial activity was evaluated against various pathogens. The study found LL-37 to have significant antimicrobial properties in vitro.
Abstract
<h4>Purpose</h4>This study determined whether LL-37 (cathelicidin) is expressed by conjunctival and corneal epithelia as part of ocular host defense. The antimicrobial activity of LL-37 was also assessed in vitro against Pseudomonas aeruginosa (PA), Staphylococcus aureus (SA), Staphylococcus epidermidis (SE), herpes simplex virus type 1 (HSV-1), and adenovirus (Ad).<h4>Methods</h4>Expression of LL-37/hCAP 18 mRNA and LL-37 protein was determined by reverse transcription-polymerase chain reaction (RT-PCR) and immunoblotting, respectively, in scraped human corneal epithelium and primary cultured human corneal and conjunctival epithelial cells. The EC50 values for three strains of PA and one each of SA and SE were determined for LL-37. LL-37 antiviral inhibition of HSV-1 and adenovirus was assessed by direct inactivation assays. Toxicity of LL-37 to A549 cells was evaluated by a MTT assay.<h4>Results</h4>LL-37/hCAP18 mRNA and LL-37 peptide were expressed by human corneal and conjunctival epithelial cells. Antibacterial activity for LL-37 was demonstrated (EC50 values for the three PA strains were 2.8 +/- 1.3, 1.9 +/- 0.3, and 3.6 +/- 2.1; for SA: 1.6 +/- 1.5; for SE: 1.3 +/- 1.9 microg/ml). LL-37 produced a significant reduction (p < 0.001 ANOVA) in HSV-1 and Ad19 viral titers with distinctly different time-kill curves (p < 0.001). LL-37 (up to 111 microM) produced no toxicity in A549 cells.<h4>Conclusions</h4>Corneal and conjunctival epithelia express LL-37 as part of mucosal innate immunity to protect against bacterial and viral ocular infections.
Background
Not reported in abstract.
Methods
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Results
Not reported in abstract.
Interpretation
Not reported in abstract.
Limitations
Not reported in abstract.