Effects of experimental conditions on the production of interleukin-1 alpha and -1 beta by human endothelial cells cultured in vitro.
We have characterized the production of IL-1 alpha and -beta in primary and passaged cultures of quiescent human umbilical vein endothelial cells (HUVECs) using highly specific and sensitive solid-phase enzyme immunoassays. Primary cultures produced both immunoreactive IL-1 alpha and IL-1 beta following stimulation with lipopolysaccharide with the alpha form predominating over the beta. Most of the IL-1 produced remained cell-associated. Primary, but not passaged, cultures were significantly contaminated by macrophage-like cells, possibly accounting for higher production of IL-1, especially IL-1 beta. Gel filtration of secreted proteins derived from cultured HUVECs showed that the immunoreactive IL-1 alpha exhibited the expected molecular weight (17 kDa), but cell-associated IL-1s appeared to be a mixture of the 17 kDa protein and of higher molecular weight precursors. Mitogens in the culture medium (serum and endothelial cell growth supplement) were powerful stimuli of endothelial IL-1 production and accounted for the relatively high basal IL-1 levels observed in the cultured endothelial cells. The proliferative phenotype of the endothelium is possibly linked to the expression of high level of IL-1, which until now was thought to be an autocrine inhibitor of endothelial cell mitosis.
Marceau
F
F
Centre de Recherche de l'Hôtel-Dieu de Québec, Canada.
Grassi
J
J
Frobert
Y
Y
Bergeron
C
C
Poubelle
P E
PE
D002478:Cells, Cultured; D003470:Culture Media; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D007375:Interleukin-1 / Q000032:analysis / Q000096:biosynthesis*
D003470:Culture Media; D007375:Interleukin-1