title: A quantitative lateral flow assay to detect complement activation in blood.
abstract: Complement is a major effector arm of the innate immune system that responds rapidly to pathogens or altered self. The central protein of the system, C3, participates in an amplification loop that can lead to rapid complement deposition on a target and, if excessive, can result in host tissue damage. Currently, complement activation is routinely monitored by assessing total C3 levels, which is an indirect and relatively insensitive method. An alternative approach would be to measure downstream C3 activation products such as C3a and iC3b. However, in vitro activation can produce falsely elevated levels of these biomarkers. To circumvent this issue, a lateral flow immunoassay system was developed that measures iC3b in whole blood, plasma, and serum and avoids in vitro activation by minimizing sample handling. This assay system returns results within 15 min and specifically measures iC3b while having minimal cross-reactivity to other C3 split products. While evaluating the potential of this assay, it was observed that circulating iC3b levels can distinguish healthy individuals from those with complement activation-associated diseases. This tool is engineered to provide an improved method to assess complement activation at point of care and could facilitate studies to monitor disease progression in a variety of inflammatory conditions.
authors: Division of Rheumatology, Washington University School of Medicine, St. Louis, MO 63110, USA; Kypha, St. Louis, MO 63108, USA. Electronic address: elizabeth.schramm2@gmail.com.
authors: Elizabeth C
authors: EC
authors: Schramm
authors: Kypha, St. Louis, MO 63108, USA.
authors: Nick R
authors: NR
authors: Staten
authors: Kypha, St. Louis, MO 63108, USA.
authors: Zhouning
authors: Z
authors: Zhang
authors: Department of Neurological Surgery, Columbia University Medical Center, New York, NY 10032, USA.
authors: Samuel S
authors: SS
authors: Bruce
authors: Department of Neurological Surgery, Columbia University Medical Center, New York, NY 10032, USA.
authors: Christopher
authors: C
authors: Kellner
authors: Division of Rheumatology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors: John P
authors: JP
authors: Atkinson
authors: Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
authors: Vasileios C
authors: VC
authors: Kyttaris
authors: Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
authors: George C
authors: GC
authors: Tsokos
authors: Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors: Michelle
authors: M
authors: Petri
authors: Department of Neurological Surgery, Columbia University Medical Center, New York, NY 10032, USA.
authors: E
authors: E
authors: Sander Connolly
authors: Kypha, St. Louis, MO 63108, USA. Electronic address: paul@kypha.net.
authors: Paul K
authors: PK
authors: Olson
mesh_terms: D001774:Blood Chemical Analysis / Q000379:methods*; D002543:Cerebral Hemorrhage / Q000097:blood / Q000276:immunology; D003167:Complement Activation; D003176:Complement C3 / Q000276:immunology; D003179:Complement C3b / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000276:immunology; D013997:Time Factors
chemical_list: D003176:Complement C3; D003179:Complement C3b
keywords: Complement activation; Intracerebral hemorrhage (ICH); Lateral flow assay; Lupus; iC3b biomarker