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Polymorphonuclear leukocyte cells and elastase in tears.

Abstract：

PURPOSE:To characterize the effects that mode of sampling and overnight eye closure have on the nature of caseinolytic activity recovered in tear fluid. METHODS:Reflex, open and closed (R, O and C) eye tear fluids were collected by microcapillary tubes or from the inferior formix by Schirmer strip. Microcapillary collected samples were centrifuged and recovered cells cytochemically characterized and probed by immunofluorescence microscopy, or alternatively extracted in acidic PBS. Tear supernatants, pellets and Schirmer strip extracts were subjected to casein zymography or SDS-PAGE and immunoprobed for plasmin/plasminogen. To identify caseinolytic activity, samples were immunoprecipitated with antibodies to plasmin/plasminogen or to elastase, and the immunoprecipitated materials were subjected to zymographic analysis. RESULTS:Immunoblot assays revealed R and O samples contained low levels of plasminogen (approximately 1.1 micrograms/ml) and only trace levels of plasmin (< 0.1 ng/ml). Insufficient levels of caseinolytic activity were present to allow zymographic detection. Cytochemical analysis revealed that R and O pellets consisted almost exclusively of desquamated epithelium. Immunoblot analysis revealed that C fluid was associated with an increase in plasminogen and its partial conversion to plasmin (approximately 3.2 ng/ microliter), high molecular weight covalent complexes and degradative products. Zymographic analysis disclosed much greater caseinolytic activity than could be attributed to plasmin or its cleavage products. This consisted primarily of three bands (30-26 kDa) which were identified as polymorphonuclear leukocyte (PMN) cell elastase based on size and antigenicity. This is derived from PMNs recovered from the C pellet. Elastase could also be recovered from Schirmer strips from 90% of donors, provided that the strips were extracted in sample loading buffer. The activity was restricted to the portion of the strip that had been in contact with the ocular tissue. CONCLUSIONS:The main source of caseinolytic activity in C fluid is elastase. This arises from PMNs that undergo recruitment, activation and degranulation in the C environment. In contrast, the elastase recovered in Schirmer strip extracts is derived from intact PMNs that adhere to the strip during sample collection. This would suggest that PMN cells undergo a low level of recruitment into the open eye environment.

journal_name

Curr Eye Res

journal_title

Current eye research

authors

Sakata M,Sack RA,Sathe S,Holden B,Beaton AR

doi

10.1076/ceyr.16.8.810.8992

subject

Has Abstract

pub_date

1997-08-01 00:00:00

pages

810-9

issue

eissn

0271-3683

issn

1460-2202

journal_volume

pub_type

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Polymorphonuclear leukocyte cells and elastase in tears.