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Staphylococcal Enterotoxin‐A‐Induced In‐Vitro Adhesion of HL‐60 Cells to Endothelial Cells Involves both Selectin and Integrin Families of Cell Adhesion Molecules
Author(s) -
Kalland T
Publication year - 1998
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1046/j.1365-3083.1998.00322.x
Subject(s) - extravasation , cell adhesion molecule , peripheral blood mononuclear cell , stimulation , adhesion , chemistry , endothelial stem cell , microbiology and biotechnology , immunology , biology , in vitro , biochemistry , endocrinology , organic chemistry
In‐vivo exposure to the bacterial superantigen Staphylococcal enterotoxin‐A (SEA) induces an inflammatory response characterized by rapid extravasation of leucocytes and release of excessive amounts of cytokines. We have utilized an in‐vitro adhesion assay to understand the molecular mechanisms responsible for SEA‐induced extravasation of leucocytes. Stimulation of human umbilical cord endothelial cells (HUVEC) with increasing concentrations of recombinant SEA (rSEA) did not influence the in‐vitro adhesion of HL‐60 cells to HUVEC, whereas stimulation of HUVEC by interleukin (IL)‐1β supported adhesion of HL‐60 cells. Increased adhesion of HL‐60 cells to HUVEC was noted upon stimulation of endothelium with culture medium obtained from human peripheral blood mononuclear cells (PBM) stimulated with recombinant SEA for 24 (CM–SEA 24 h), 72 (CM–SEA 72 h) and 120 h (CM–SEA 120 h), but not after stimulation with culture medium obtained from control human peripheral blood mononuclear cells (CM), suggesting that soluble factors present in the supernatants play a major role in SEA‐induced cell adhesion. While CM–SEA 24 and 72 h induced both a rapid (4 h) and delayed type of adhesion, CM–SEA 120 h only induced a delayed type of adhesion. Stimulation of PBM by SEA resulted in increased levels of IL‐1β, IL‐2 and interferon (IFN)‐γ after 24 h. Further stimulation for 72–120 h resulted in a significant increase in the levels of IL‐1β, IFN‐γ and tumour necrosis factor (TNF). Stimulation of PBM with SEA also resulted in increased levels of soluble and L‐selectin in the cell supernatants. Increased cell‐surface expression of E‐selectin, ICAM‐1, HLA‐DR and VCAM‐1 was detected on HUVEC stimulated with CM–SEA media. While E‐selectin and VCAM were induced on HUVEC within a few hours, induction of ICAM and HLA‐DR required a longer induction period. Adhesion of HL‐60 cells to HUVEC treated with CM–SEA was inhibited by monoclonal antibodies (MoAbs) against both the selectin and integrin families of cell adhesion molecules, suggesting that multiple pathways contribute to SEA‐induced leucocyte extravasation. The results suggested that selectin‐dependent adhesion was more prominent during the early phase while integrin‐induced adhesion occurred at a later stage.