title: Activated T-lymphocytes express occludin, a component of tight junctions.
abstract: T-lymphocytes routinely traffic from the lymphoid and vascular compartments to the tissues during immune surveillance and inflammatory responses. This egress occurs without compromising endothelial barrier, which is maintained by tight junctions (zonula occludens). We report that T-lymphocytes up-regulate the expression of occludin, a major component of the tight junction in response to stimulation with phorbol ester (PMA) + calcium ionophore, CD3 antibody or T-cell receptor (TCR) antibody. Only activated T-lymphocytes express occludin; this adhesion molecule is nearly absent in resting T-lymphocytes. By immunofluorescence, occludin is seen in lymphocyte aggregates, but does not appear to mediate aggregation since only 50% of the cells in these clusters express occludin. Occludin is expressed between 8 and 24 h following stimulation, and persists for at least 48 h. These data indicate that activated T cells produce occludin which may regulate lymphocyte adhesion and trafficking.
authors.affiliation: Louisiana State University Medical Center, Shreveport 71130, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Alexander
authors.forename: T
authors.initials: T
authors.lastname: Dayton
authors.forename: C
authors.initials: C
authors.lastname: Davis
authors.forename: S
authors.initials: S
authors.lastname: Hill
authors.forename: T H
authors.initials: TH
authors.lastname: Jackson
authors.forename: O
authors.initials: O
authors.lastname: Blaschuk
authors.forename: M
authors.initials: M
authors.lastname: Symonds
authors.forename: N
authors.initials: N
authors.lastname: Okayama
authors.forename: C G
authors.initials: CG
authors.lastname: Kevil
authors.forename: F S
authors.initials: FS
authors.lastname: Laroux
authors.forename: S M
authors.initials: SM
authors.lastname: Berney
authors.forename: D
authors.initials: D
authors.lastname: Kimpel
mesh_terms: D000818:Animals; D008213:Lymphocyte Activation; D008565:Membrane Proteins / Q000096:biosynthesis*; D062793:Occludin; D051381:Rats; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000648:ultrastructure; D019108:Tight Junctions / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D062793:Occludin; C568987:Ocln protein, rat