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Assays for Studying the Role of Vitronectin in Bacterial Adhesion and Serum Resistance
Published on: October 16, 2018
Vitronectin: Possible contribution to the closed-eye external host-defense mechanism
R A Sack1, P A Underwood, K O Tan
1Cooperative Research Center for Eye Research and Technology, University of New South Wales, Sydney, Australia.
Ocular Immunology and Inflammation
|July 25, 2012
Summary
Vitronectin (VN) increases in human tears during eye closure, forming a protective layer against microbes. This study investigates its role in the eye's defense system.
Area of Science:
- Ophthalmology
- Immunology
- Biochemistry
Background:
- Eye closure alters the tear film from a dynamic reflex state to a stagnant, secretory IgA-rich layer.
- This shift activates complement and plasminogen, recruiting polymorphonuclear (PMN) cells for microbial defense.
- Mechanisms preventing self-damage in this altered tear environment are unclear.
Purpose of the Study:
- To investigate the presence and localization of vitronectin (VN) in the human ocular environment.
- To determine if VN concentration and form change with eye status (reflex, open, closed).
- To assess VN's potential role in the host-defense system of the closed eye.
Main Methods:
- Collected human reflex, open-eye, and closed-eye tear samples.
- Utilized SDS-PAGE and immunoblotting with anti-VN monoclonal antibodies (MAbs) for detection.
- Quantified VN using a sandwich ELISA assay and examined bovine corneas via immunohistochemistry.
Main Results:
- Vitronectin (VN) concentration significantly increased from reflex to open to closed eyes (0.08 to 3.65 μ/ml).
- VN shifted from an intact 75kDa form to a biologically active 65kDa breakdown product.
- Immunohistochemistry showed VN localized in the corneal epithelium and stromal keratocytes.
Conclusions:
- Vitronectin (VN) is present and increases in human tears with eye closure.
- VN's presence and breakdown products suggest a role in the closed-eye host-defense system.
- VN may protect ocular surfaces from microbial damage and autolytic processes.
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