Jm. Vandenbogaerde et al., SERUM-PROTEINS FACILITATE NEUTROPHIL INDUCTION OF ENDOTHELIAL-LEUKOCYTE ADHESION MOLECULE-1, Surgery, 123(2), 1998, pp. 199-204
Background. Although the individual actions of neutrophils and serum p
roteins such as complement in acute inflammation are well characterize
d, less is known about their effects in combination. We investigated t
he combined effects of neutrophil contact and active serum proteins on
the expression of endothelial leukocyte adhesion molecule 1 (ELAM-1).
Methods. Confluent monolayers of human umbilical vein endothelial cel
ls were incubated with neutrophils in the presence and absence of fres
h human serum. Flow cytometry was used to assess expression of endothe
lial intercellular adhesion molecule 1 (ICAM-1) and ELAM-1. In additio
n neutrophils were retained in a semipermeable insert, which allowed t
heir secretions to contact the endothelium but restricted neutrophil-e
ndothelial contact. Results, ELAM-1 expression was significantly incre
ased on the cells coincubated with neutrophils and fresh human serum (
25.8%; p < 0.01). There was no significant change in ELAM-1 expression
on endothelial cells incubated with fresh human serum alone (3.9%; p
> 0.01) or in those incubated with neutrophils and heat-inactivated se
rum (9.3 %; p > 0.01). In the absence of neutrophil contact, ELAM-1 ex
pression was increased only in the presence of fresh human serum (9.6%
; p < 0.05). Conclusions, These findings suggest that serum proteins m
ay potentiate the volume or potency of neutrophil-derived diffusable m
ediators of ELAM-1 expression. These effects are eliminated with the h
eat inactivation of serum proteins, implicating a heat sensitive media
tor such as the complement cascade.