Immunological and antimicrobial molecules in human tears: a review and preliminary report*

Abstract

The human tear film is a multi-layered and chemically complex structure, which performs numerous functions relating to the health of the corneal surface. One of the core functions of the tear film is to protect the eye against invasion by pathogens. Thus its middle layer, the ‘core aqueous stratum’, harbours a myriad of immunologicaland antimicrobial proteins. In this review we discuss the most abundant of these proteins (immunoglobulins, toll-like receptors, cytokines, lactoferrin, lysozyme, lipocalins, surfactant protein-Aand -D and defensins). In order to illustrate how the levels of immunological/antimicrobial proteins in tears change in response to eye disease, we review literature in which levels of these proteins have been measured in tears of patients with dry eye disease (DED) and keratoconus (KC). Finally, we report results of a preliminary study to measure the concentration of secretory immunoglobulin A (sIgA) in the tears of DED and KC patients. The study showed a significant decrease of sIgA levels in DED compared to control. Further analysis must be done to determine whether or not DED and KC may be associated with differential expression of immune proteins. (S Afr Optom 2012 71(3) 123-132)

Cytokine Antibody Arrays: A Useful Tool in Biotechnology for the Screening of Specific Biomarkers in Eyes Diseases

“…Finally, membranes were revealed inside the CCD camera of the Fujifilm LAS-3000 Imager. The obtained images were analyzed by ImageJ imaging analyzer [13]. This software provided a numerical expression of intensity in arbitrary units for every single analyzed spot.…”

Lipid composition of human meibum

“…Current models suggest that the polar glycocalyx directly anchors a continuous aqueousmucin layer in which salts and hydrophilic substances are dissolved 3 . The middle layer of the PTF is referred to as the core aqueous stratum in which proteins, oxygen and nutrients are predominantly found 4,5 . The aqueous layer protects the ocular surface by creating a suitable environment for the cornea 5 .…”

“…The middle layer of the PTF is referred to as the core aqueous stratum in which proteins, oxygen and nutrients are predominantly found 4,5 . The aqueous layer protects the ocular surface by creating a suitable environment for the cornea 5 . The outermost layer of the tear film is the biphasic tear film lipid layer (TFLL), consisting of a 'thick' outer non-polar…”

In vitroStudy on the Antimicrobial Activity of Human Tears with Respect to Age

“…As described previously, tears are mainly composed of water, salts, antibodies and lysozymes having both antimicrobial and immunological activities. It provides bacteriostatic as well as bactericidal properties to tear's fluid [9]. The antibacterial properties of lysozyme are well known and are also used in the food industry to limit the proliferation of lactic acid bacteria spoilage in the production of wine and beer.…”