* Corresponding author. Tel.: # 1-302-831-6697; fax:# 1-302-831- 1048. E-mail address: yung@che.udel.edu (L.L. Yung) Biomaterials 21 (2000) 405 } 414 High-molecular-weight kininogen preadsorbed to glass surface markedly reduces neutrophil adhesion Lin-Yue L. Yung*, Florencia Lim, Mohammad M.H. Khan, Satya P. Kunapuli , Leonard Rick, Robert W. Colman, Stuart L. Cooper Department of Chemical Engineering, University of Delaware, Newark, DE 19716, USA Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA Received 23 April 1999; accepted 9 September 1999 Abstract Adsorbed proteins on biomaterial surfaces determine whether cells adhere, but rheological variables are also critical. Neutrophil adhesion under well-de"ned radial #ow conditions was studied on glass preadsorbed with plasma proteins or plasma protein domain fragments. Fibrinogen, low-molecular-weight kininogen (LK), high-molecular-weight kininogen (HK), cleaved HK (HKa), and recombinant HK domains 3 and 5 (D and D ) were used. The number of adherent cells on the HK and HKa surfaces was less than 10% that found on the "brinogen absorbed surface. The degree of spreading was minimal and detachment of adherent neutrophils was observed. HK and HKa contain binding sites for both anionic surfaces and neutrophils in the same domain (D ). When adsorbed to surfaces, HK and HKa did not have the neutrophil binding sites available and therefore exhibited an anti-adhesive e!ect. Although D contains anionic surface binding sites, its small molecular size required a higher number of adsorbed molecules to cover the surface before a signi"cant decrease in cell adhesion was observed. Since LK and D do not possess speci"c anionic surface binding sites, the adsorption of these proteins on glass was very low compared to HK and HKa. Thus, extensive cell adhesion and spreading were observed on the surfaces partially covered with preadsorbed LK and D . 2000 Elsevier Science Ltd. All rights reserved. Keywords: Leukocyte adhesion; High molecular weight kininogen; Protein adsorption; Anionic surfaces 1. Introduction Leukocyte adhesion to biomaterial surfaces is an im- portant factor in the host response to biomaterials be- cause the number of adherent leukocytes is related to their in#ammatory response after implantation [1,2]. Circulating leukocytes interact with the vascular en- dothelium via cell surface adhesion receptors, which in- clude the immunoglobulin superfamily, the integrin family, and the selectin family. Obviously, the initial leukocyte interaction with biomaterials is potentially limited by the lack of various adhesion ligands and recep- tors on arti"cial surfaces compared with the vascular endothelium. However, following exposure of plasma to an arti"cial surface, rapid deposition of plasma proteins opens a channel for cell}surface interaction since many potential ligands for leukocyte receptors are available on plasma proteins. For example, leukocytes bind to "brino- gen and kininogens via CD11b/18 (Mac-1) [3], to "bronectin via VLA-5 ( ) [4], and to complement C3b via CD35 (CR1) [5]. As a result of leukocyte ad- hesion, several reactions may be initiated such as leukocyte spreading, formation of microthrombi through platelet}platelet and platelet}leukocyte interactions, de- tachment of thrombi by action of leukocyte proteases, and detachment of adherent platelets and adsorbed pro- teins by leukocytes. In addition, release of leukocyte neutral proteases, such as elastase and cathepsin G, may give rise both to local and systemic vascular reactions or tissue destruction. Kininogens are plasma proteins which are natural substrates of plasma and tissue kallikrein and yield, on hydrolysis, the nonapeptide bradykinin. In 1967, two forms of puri"ed human plasma kininogen (kinin precursors) were described by Jacobsen and Kriz [6]: high-molecular-weight kininogen (HK) and low-mole- cular-weight kininogen (LK). HK is an -globulin (Mr"120 kDa) with a plasma concentration of 80 g/ml [7]. LK is a -globulin (Mr"68 kDa) with a plasma concentration of approximately 160 g/ml [8]. HK consists 0142-9612/00/$ - see front matter 2000 Elsevier Science Ltd. All rights reserved. PII: S 0 1 4 2 - 9 6 1 2 ( 9 9 ) 0 0 2 0 3 - 3