Inflammatory cell recruitment, distribution, and chemiluminescence response at IgG precoated- and thiol functionalized gold surfaces

The role of complement activation by artificial surfaces relative to inflam matory response is not well understood. This study was performed to evaluat e the inflammatory cell recruitment, distribution, and ex vivo metabolic ac tivation of surfaces with different plasma protein adsorption and complemen t activation properties in vitro. The implants were (1) pure gold (referenc e), (2) albumin-precoated (3) IgG-precoated gold, and (4) 3-mercapto-1,2-pr opanediol [mercaptoglycerol (MG)] and (5) glutathione (GSH) immobilized to gold. The implant disks were inserted subcutaneously in rats for 24 h, and the number of inflammatory cells that were recruited to the implant adjacen t to the surrounding fluid phase (exudate) and the surfaces were quantified by DNA measurements. The oxidative burst was analyzed ex vivo using sponta neous and phorbol myristate acetate (PMA)-stimulated, luminol-enhanced chem iluminescence (CL). The in vitro surface-induced anti-rat C3 binding was ev aluated by ellipsometry and antibody techniques after plasma incubations fo r 1 and 30 min. The ellipsometric results showed that immobilized mercaptog lycerol and IgG-coated, but not the immobilized glutathione or the referenc e Au, bound anti-C3. The in vivo results revealed that the largest amount o f cells was associated with the IgG-coated surfaces, followed by immobilize d GSH and MG, albumin-coated, and gold surfaces, respectively. No spontaneo us es vivo luminol-enhanced CL was recorded from the cells irrespective of surface functionality or localization. A downregulation of surface-associat ed and exudate leukocyte CL was observed ex vivo, irrespective of surface f unctionality. The results do not indicate a clear relationship between the degree of complement activation in vitro and leukocyte recruitment and adhe sion in vivo for differently functionalized surfaces. (C) 1999 John Wiley & Sons, Inc.