title: Antibodies reactive to cleaved sites in complement proteins enable highly specific measurement of soluble markers of complement activation.
abstract: An emerging number of diseases and therapeutic approaches with defined involvement of the complement system justify a need for specific markers reflecting activation of particular effector arms of the complement cascade. Measurement of such soluble markers in circulation is a challenge since the specificity of antibodies must be limited to activated complement fragments but not predominant and ubiquitous parental molecules. Existing assays for the measurement of soluble, activated complement proteins are based on the detection of conformational neoepitopes. We tested an alternative approach based on detection of short linear neoepitopes exposed at the cleavage sites after activation of the actual complement component. Obtained antibodies reactive to C4d and C5b fragments enabled us to set up highly specific sandwich ELISAs, which ensured trustful measurements without false positive readouts characteristic for some of the widely used assays.
authors: Department of Laboratory Medicine Malmö, Section of Medical Protein Chemistry, Lund University, Inga Marie Nilssons Street 53, 20502 Malmö, Sweden.
authors: Anna M
authors: AM
authors: Blom
authors: Immune and Gene Therapy Laboratory, Department of Oncology-Pathology, Karolinska Institute, 17176 Stockholm, Sweden; Department of Hematology, Karolinska University Hospital Solna, 17176 Stockholm, Sweden.
authors: Anders
authors: A
authors: Österborg
authors: Department of Immunology, Oslo University Hospital Rikshospitalet, 0372 Oslo, Norway; K.G. Jebsen IRC, University of Oslo, 0372 Oslo, Norway; Research Laboratory NLSH, 8092 Bodø, Norway; K.G. Jebsen TREC, University of Tromsø, 9019 Tromsø, Norway; Centre of Molecular Inflammation Research, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
authors: Tom E
authors: TE
authors: Mollnes
authors: Department of Laboratory Medicine Malmö, Section of Medical Protein Chemistry, Lund University, Inga Marie Nilssons Street 53, 20502 Malmö, Sweden; Region Skåne, Laboratory Medicine, Clinical Chemistry, Inga Marie Nilssons Street 53, 20502 Malmö, Sweden. Electronic address: marcin.okroj@med.lu.se.
authors: Marcin
authors: M
authors: Okroj
mesh_terms: D000818:Animals; D000906:Antibodies / Q000737:chemistry / Q000302:isolation & purification; D000971:Antineoplastic Combined Chemotherapy Protocols; D003167:Complement Activation; D015935:Complement C4b / Q000737:chemistry / Q000276:immunology; D050776:Complement C5b / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D019337:Hematologic Neoplasms / Q000097:blood* / Q000188:drug therapy / Q000276:immunology / Q000473:pathology; D006801:Humans; D010446:Peptide Fragments / Q000097:blood* / Q000737:chemistry / Q000276:immunology; D059748:Proteolysis; D011817:Rabbits; D012680:Sensitivity and Specificity
chemical_list: D000906:Antibodies; D010446:Peptide Fragments; D015935:Complement C4b; C032261:complement C4d; D050776:Complement C5b
keywords: Antibodies; C4d; C5b; Complement system; Leukemia; Lymphoma