Adherence of rat basophilic leukemia (RBL-2H3) cells to fibronectin-coated surfaces enhances secretion.
Rat basophilic leukemia (RBL-2H3) cells are a useful in vitro model for studies of mast cells and basophils. We examined the adherence of RBL-2H3 cells to different extracellular matrix proteins and the effect of such attachment on secretion. The cells bound to fibronectin-coated surfaces with maximum binding by 1 h at 37 degrees C. There was less attachment to laminin, collagen type I, and collagen type IV. There was no adherence to uncoated surfaces or in the absence of Ca2+. Binding to fibronectin was blocked by a synthetic peptide containing the sequence Arg-Gly-Asp. Therefore, the binding of RBL-2H3 cells to fibronectin may be mediated by surface molecules that belong to the integrin family. Adherence to fibronectin-coated surfaces resulted in cell spreading, a reorganization of the cytoskeletal elements, and a redistribution of the secretory granules. Attachment to fibronectin also dramatically enhanced high affinity IgE receptor-mediated histamine release. This enhancement was maximum by 1 h of adherence and lasted for at least 6 h. There was also enhanced secretion by the Ca2+ ionophore A23187. Thus, adherence to fibronectin can enhance both receptor and non-receptor-mediated release. Addition of soluble fibronectin to RBL-2H3 cells in suspension had no effect on secretion. Therefore, enhanced histamine release required cell attachment to immobilized fibronectin. These results suggest that secretion from mast cells/basophils may be modulated by their interaction with the extracellular matrix.
Hamawy
M M
MM
Laboratory of Immunology, National Institute of Dental Research, National Institutes of Health, Bethesda, MD 20892.
Oliver
C
C
Mergenhagen
S E
SE
Siraganian
R P
RP
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000944:Antigens, Differentiation, B-Lymphocyte / Q000502:physiology; D001491:Basophils / Q000378:metabolism*; D000001:Calcimycin / Q000494:pharmacology; D002448:Cell Adhesion; D005353:Fibronectins / Q000502:physiology*; D006636:Histamine Release; D008407:Mast Cells / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology; D051381:Rats; D011961:Receptors, Fc / Q000502:physiology; D017455:Receptors, IgE; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000944:Antigens, Differentiation, B-Lymphocyte; D005353:Fibronectins; D009842:Oligopeptides; D011961:Receptors, Fc; D017455:Receptors, IgE; D000001:Calcimycin