Human monocyte scavenger receptors are pattern recognition receptors for (1-->3)-beta-D-glucans.
Glucans are cell wall constituents of fungi and bacteria that bind to pattern recognition receptors and modulate innate immunity, in part, by macrophage activation. We used surface plasmon resonance to examine the binding of glucans, differing in fine structure and charge density, to scavenger receptors on membranes isolated from human monocyte U937 cells. Experiments were performed at 25 degrees C using a biosensor surface with immobilized acetylated low density lipoprotein (AcLDL). Inhibition of the binding by polyinosinic acid, but not polycytidylic acid, confirmed the interaction of scavenger receptors. Competition studies showed that there are at least two AcLDL binding sites on human U937 cells. Glucan phosphate interacts with all sites, and the CM-glucans and laminarin interact with a subset of sites. Polymer charge has a dramatic effect on the affinity of glucans with macrophage scavenger receptors. However, it is also clear that human monocyte scavenger receptors recognize the basic glucan structure independent of charge.
Rice
Peter J
PJ
Department of Pharmacology, James H. Quillen College of Medicine, East Tennessee State University, Building 119 Room 1-29, Dogwood Lane, Johnson City, TN 37614-1708, USA. rice@etsu.edu
Kelley
Jim L
JL
Kogan
Grigorij
G
Ensley
Harry E
HE
Kalbfleisch
John H
JH
Browder
I William
IW
Williams
David L
DL
D001665:Binding Sites; D001667:Binding, Competitive; D002266:Carboxymethylcellulose Sodium / Q000378:metabolism; D015815:Cell Adhesion Molecules; D002462:Cell Membrane / Q000378:metabolism; D005936:Glucans / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008077:Lipoproteins, LDL / Q000378:metabolism; D009000:Monocytes / Q000378:metabolism*; D011066:Poly C / Q000378:metabolism; D011069:Poly I / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism; D011971:Receptors, Immunologic / Q000737:chemistry / Q000378:metabolism*; D011973:Receptors, LDL / Q000737:chemistry / Q000378:metabolism*; D051116:Receptors, Scavenger; D012566:Sizofiran / Q000378:metabolism; D020298:U937 Cells; D047071:beta-Glucans
D015815:Cell Adhesion Molecules; D005936:Glucans; D008077:Lipoproteins, LDL; D011134:Polysaccharides; D011971:Receptors, Immunologic; D011973:Receptors, LDL; D051116:Receptors, Scavenger; C032629:acetyl-LDL; D047071:beta-Glucans; D011069:Poly I; D011066:Poly C; D012566:Sizofiran; C008247:laminaran; C033363:beta-1,3-glucan; D002266:Carboxymethylcellulose Sodium