Diurnal variations in tear glycoproteins: evidence for an epithelial origin for the major non-reducible =450 kDa sialoglycoprotein(s)

Sack, Robert A.; Bogart, Bruce Ian; Beaton, Ann; Sathe, Sonal; Lew, George

doi:10.1076/ceyr.16.6.577.5069

Cited by 23 publications

(18 citation statements)

References 24 publications

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“…Therefore, it appears that the Acanthamoeba MBP is also relatively resistant to trypsin. Because tears are rich in proteases (44,45), MBP resistance to proteolytic attack may be critical to the pathogenesis of Acanthamoeba infection.…”

Section: Discussionmentioning

confidence: 99%

Cloning and Characterization of a Novel Mannose-binding Protein of Acanthamoeba

Gárate

Cao

Bateman

et al. 2004

Journal of Biological Chemistry

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Acanthamoebae produce a painful, blinding infection of the cornea. The mannose-binding protein (MBP) of Acanthamoeba is thought to play a key role in the pathogenesis of the infection by mediating the adhesion of parasites to the host cells. We describe here the isolation and molecular cloning of Acanthamoeba MBP. The MBP was isolated by chromatography on the mannose affinity gel. Gel filtration experiments revealed that the Acanthamoeba lectin is a ϳ400-kDa protein that is constituted of multiple 130-kDa subunits. Cloning and sequencing experiments indicated that the Acanthamoeba MBP gene is composed of 6 exons and 5 introns that span 3.6 kb of the amoeba genome and that MBP cDNA codes for a precursor protein of 833 amino acids. That the cloned cDNA encodes authentic MBP was demonstrated by showing that: (i) recombinant MBP possesses mannose binding activity, and (ii) polyclonal antibodies prepared against Acanthamoeba MBP bound to the recombinant protein. Sequence analysis revealed that the MBP contains a large N-terminal extracellular domain, a transmembrane domain, and a short C-terminal cytoplasmic domain. Despite extensive BLAST searches using the MBP sequence, no significant matches were retrieved. The most striking feature of the Acanthamoeba MBP sequence is the presence of a cysteine-rich region containing 14 CXCXC motifs within the extracellular domain. In summary, we have isolated, cloned, and characterized a novel MBP from Acanthamoeba. Because the presence of antibodies to MBP in tears provides protection against infection, the availability of the MBP cDNA sequence and rMBP should help develop: (i) a tear-based test to identify individuals who are at risk of developing the keratitis and (ii) strategies to immunize high-risk individuals.Acanthamoebae are causative agents of two distinct disease entities. In immunocompromised individuals, this protozoan parasite produces chronic granulomatous amoebic encephalitis and disseminating infections including dermatitis and pneumonitis (1, 2). Granulomatous amoebic encephalitis is nearly always fatal because of the lack of an effective treatment. In immunocompetent individuals, Acanthamoebae provoke a debilitating vision-threatening corneal infection known as Acanthamoeba keratitis (AK) 1 (3-5). AK is characterized by intense pain and a slowly worsening clinical course. Contact lens wear is a major risk factor (3, 6, 7). In the developed world, ϳ85% of the cases are diagnosed in contact lens wearers (7). However, in the developing countries, where contact lens use is infrequent, the disease is more commonly found in non-contact lens wearers (8). The mechanism by which Acanthamoebae produce granulomatous amoebic encephalitis and AK has not been fully elucidated. It is generally accepted that the two major predisposing factors in the pathogenesis of AK are minor corneal trauma caused by contact lens wear or other noxious agents and exposure to contaminated solutions including lens care products and tap water (9, 10). The adhesion of parasites to the host cells ...

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Section: Discussionmentioning

confidence: 99%

Cloning and Characterization of a Novel Mannose-binding Protein of Acanthamoeba

Gárate

Cao

Bateman

et al. 2004

Journal of Biological Chemistry

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“…Human tear fluid (0.150 to 1 ml) was separated isocratically on an SW 3000 preparative column in 0.5 M NaCl-0.1 M phosphate buffer (pH 5.0) at a flow rate of 2 ml/min with the eluent monitored at 254 nm. Fractions were collected based upon the apparent molecular size in a fashion similar to that detailed previously with an SW 400 analytical column (34). This profile was determined based upon the literature, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, and Western blot probing with antibodies specific for various mucin species, secretory IgA, IgG, lactoferrin, free secretory component tear-specific lipochalin, and lysozyme, much of which has been previously detailed.…”

Section: Methodsmentioning

confidence: 99%

Surfactant Protein D Is Present in Human Tear Fluid and the Cornea and Inhibits Epithelial Cell Invasion byPseudomonas aeruginosa

Evans

Hawgood

et al. 2005

Infect Immun

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We have previously shown that human tear fluid protects corneal epithelial cells against Pseudomonas aeruginosa in vitro and in vivo and that protection does not depend upon tear bacteriostatic activity. We sought to identify the responsible tear component(s). The hypothesis tested was that collectins (collagenous calciumdependent lectins) were involved. Reflex tear fluid was collected from healthy human subjects and examined for collectin content by enzyme-linked immunosorbent assay (

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“…They are involved not only in the defence against microbial invasion of the eye, but also in maintaining tear film stability and lubrication between the eye and the eyelids. Tear protein composition may show a between-day variation [22] and is evidence for a nocturnal change of tear fluid protein composition [27]. The concentration of tear proteins also depends on age, when the level of lysozyme in tears decreases while that of IgA increases [19].…”

Section: Discussionmentioning

confidence: 98%

“…Diurnal variations in tear glycoproteins were studied by PAGE [27], and evidence was obtained for a nocturnal inflammatory constitutive tear fluid by observing tear proteins in a diurnal tear cycle [26]. By this method, a between-day variation of tear protein levels in normal young adults was observed [22].…”

Section: Introductionmentioning

confidence: 99%

The effect of sample treatment on separation profiles of tear fluid proteins: Qualitative and semi-quantitative protein determination by an automated analysis system

Schmut

Horwath‐Winter

Zenker

et al. 2002

Graefe's Arch Clin Exp Ophthalmol

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Tear proteins - in contrast to serum or aqueous humour proteins - are very sensitive to changes in sample buffer temperature as well as incubation time with buffer. To obtain comparable results for tear fluid proteins, the sample buffer applied and the incubation time and temperature must be observed carefully. This can be demonstrated by both the new Agilent 2100 Bioanalyzer method and PAGE. These results are of importance when comparing tear fluid protein pattern for the diagnosis and course control of dry-eye syndrome and of other diseases of the anterior part of the eye.

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Diurnal variations in tear glycoproteins: evidence for an epithelial origin for the major non-reducible =450 kDa sialoglycoprotein(s)

Cited by 23 publications

References 24 publications

Cloning and Characterization of a Novel Mannose-binding Protein of Acanthamoeba

Cloning and Characterization of a Novel Mannose-binding Protein of Acanthamoeba

Surfactant Protein D Is Present in Human Tear Fluid and the Cornea and Inhibits Epithelial Cell Invasion byPseudomonas aeruginosa

The effect of sample treatment on separation profiles of tear fluid proteins: Qualitative and semi-quantitative protein determination by an automated analysis system

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