Biosimilar Antibodies

C5, Human, ELISA, Hycult Biotech, HK390

C5, a key 190kDa protein in the complement system, is vital for both innate and adaptive immune responses. It spearheads protective actions against pathogens, paving the way for adaptive immunity. Present in blood, tissues, and body fluids, C5 forms part of the complex complement system. Its activation, through classical, lectin, and alternative pathways, leads to the formation of the Membrane Attack Complex (MAC). This complex is critical for neutralizing harmful microorganisms and damaged cells. Yet, uncontrolled C5 activation is linked to diseases like asthma, lupus, and multiple sclerosis. Genetic mutations causing C5 deficiency result in recurrent bacterial infections, highlighting its crucial role in immunity. C5’s importance extends beyond immune defense, positioning it as a target for treating various immune-related disorders. This underscores the significance of C5 in immune system function and disease management.

C5, Human, mAb 10B6, Hycult Biotech, HM2414

The complement system plays important roles in both innate and adaptive immune response and can produce an inflammatory and protective reaction to challenges from pathogens. Complement C5 is a central molecule in all three pathways and after cleavage by its convertases , it initiates the terminal pathway in order to generate the cytolytic MAC.C5 is mainly synthesised in the liver as a single polypeptide chain and is present in serum in a concentration of 50-80 μm/ml. Besides, local synthesis of C5 is also supported by other cell types including monocytes/macrophages, neutrophils, fibroblasts, and astrocytes. Before secretion the molecule is glycosylated and secreted into plasma as a 190 kDa glycoprotein consisting of a disulphide linked alpha-chain (111 kDa) and beta-chain (75 kDa). The complement has become an interesting therapeutic target. Especially after the success of Eculizumab, a monoclonal antibody against C5, in the treatment for aHUS and PNH and the application in clinical trials for many other diseases. Monoclonal antibody #10B6 is human specific and acts as an equivalent of Eculizumab. The antibody recognizes the beta chain and competes for binding to the same epitope as Eculizumab. It shows high binding to C5 with a negligible off rate. Besides C5 the antibody also recognizes C5b6, but not C6. Using haemolytic assays shows efficient inhibition of AP as well as CP, with a comparable dose-response curve to Eculizumab in the CP.Antibody #10B6 has been tested in western blotting, ELISA and functional studies. The inhibition can be determined with our Alternative pathway ( HK3012 ) and classical pathway ( HK3010 ) assays.

C5, Rat, mAb, clone 4G2, Hycult Biotech, HM3044

Monoclonal C5 antibody clone 4G2 recognizes human, rabbit and rat complement C5. The complement system plays important roles in both innate and adaptive immune response and can produce an inflammatory and protective reaction to challenges from pathogens. Complement C5 is a central molecule in all three pathways and after cleavage by its convertases, it initiates the terminal pathway in order to generate the cytolytic MAC. C5 is mainly synthesised in the liver as a single polypeptide chain and is present in serum in a concentration of 50-80 µm/ml. Besides, local synthesis of C5 is also supported by other cell types including monocytes/macrophages, neutrophils, fibroblasts, and astrocytes. Before secretion the molecule is glycosylated and secreted into plasma as a 190 kDa glycoprotein consisting of a disulphide linked alpha-chain (111 kDa) and beta-chain (75 kDa). The complement has become an interesting therapeutic target. Especially after the success of Eculizumab, a monoclonal antibody against C5, in the treatment for aHUS and PNH and the application in clinical trials for many other diseases. Monoclonal antibody 4G2 acts as an equivalent of Eculizumab and recognizes human and rabbit C5, however the affinity for rat C5 is even stronger. This cross reactivity makes it a powerful tool in translational animal studies. Besides C5 the antibody also recognizes C5b6, but not C6. The antibody recognizes intact alpha chain and binds to an epitope distinct from Eculizumab. Using haemolytic assays the antibody shows efficient inhibition of AP as well as CP, in all mentioned models. Clone 4G2 shows strong binding to C5 with a relatively slow off rate in rat. Suggesting to be functional in in vivo studies. Indeed, 4G2 was applied in a rat prophylactic Myasthenia gravis model. In this study the animals were protected from disease and for destruction of the muscle endplates. Antibody 4G2 has been tested in western blotting, ELISA, and functional studies (Ref. 1) 1) Zelek_W et al; Development and characterization of novel anti-C5 monoclonal antibodies capable of inhibiting complement in multiple species; Immunology, 157, 283–295

C5, Mouse, mAb BB5.1, Hycult Biotech, HM1073

The monoclonal antibody BB5.1 binds the fifth component of mouse complement (C5). The complement system is a group of plasma and cell membrane proteins that play a key role in the immune system. All three pathways (classical, alternative & lectin) lead to the cleavage of C3 and eventually the formation of the cytolytic membrane attack complex C5b-9. If the activation cascade is allowed to proceed beyond the cleaving of C3 into C3a and C3b, an additional C3b molecule binds to the C3 convertases. This generates the C5 convertase (C3bBbC3b for the alternative pathway and C4bC2bC3b for the classical and lectin pathways). C5 convertase cleaves C5, releases the potent anaphylactic peptide C5a and generates C5b. C5b can initiate the terminal pathway , which recruits the components C6, C7, C8 and C9 to the surface of the target and inserts the C9 complex as a pore (termed the terminal complement complex) into the membrane. C5a is the most potent anaphylatoxin and a powerful chemotaxin for neutrophils and monocytes, with the ability to promote margination, extravasation, and activation of these cells. Thus, blocking C5 may be required for optimal inhibition of the inflammatory response. At the same time, inhibition of the complement cascade at C5 does not impair the generation of C3b through the classical and alternative pathways, preserving C3b-mediated opsonization of pathogenic microorganisms as well as opsonization and solubilization of immune complexes. C5 is synthesised in the liver as a single polypeptide chain and is present in serum in a concentration of 50-80  µm/ml. Before secretion the molecule is glycosylated and secreted into plasma as a 190 kDa glycoprotein consisting of a disulphide linked alpha-chain (111 kDa) and beta-chain (75 kDa). Monoclonal antibody BB5.1 has been shown to precipitate the two chains of C5 from normal mouse serum and inhibited C5-dependent hemolysis in a functional complement test. Furthermore, BB5.1 administration completely inhibits terminal complement activity in murine models for antibody-mediated rejection (AMR) during heart and kidney transplantation. In another mouse model, both pre-treatment as well as intervention with monoclonal antibody BB5.1 attenuates disease development during anti-MPO IgG-induced glomerulonephritis. Blockage of C5 activation by BB5.1 protects against renal ischemia-reperfusion injury by inhibition of late apoptosis and inflammation. In Lupus disease, combination therapy of anti-IL-10/anti-C5 (BB5.1) can both prevent and reduce the effect of the humoral immune response. White paper – sTCC/sC5b-9 complement Terminal complement activation plays a central role in inflammation and tissue injury. Cleavage of C5 by the C5 convertase generates C5a, a potent pro-inflammatory anaphylatoxin, and C5b, which initiates formation of the terminal complement complex (C5b-9). Blocking C5 effectively inhibits terminal pathway activity while preserving upstream C3-mediated opsonization, making C5 a key therapeutic and research target. The sTCC ELISA (cat.# HK328) is a highly specific assay for quantifying soluble terminal complement complex (sTCC/sC5b-9) in human plasma and serum. It enables reliable assessment of terminal complement activation, supporting disease monitoring, pharmacodynamic studies, and development of complement-targeted therapies. Discover in our white paper how sTCC/sC5b-9 serves as a robust and informative biomarker for complement activation. Read the full whitepaper

C5, Mouse, pAb, Hycult Biotech, HP8013

C5 is involved in the activation of the lythic pathway within the complement system which is an important factor in innate immunity. The complement pathways can be divided in the activation pathways and lytic pathway. The activation pathways lead via C3 to the cleavage of the fifth complement component C5 into C5a and C5b. C5a induces smooth muscle contraction, increases vascular permeability, causes degranulation of mast cells and basophils, and release of lysosomal enzymes. In addition C5a stimulates the directed migration of neutrophils, eosinophils, basophils and monocytes. Studies indicate the modulation of the acute-phase response in liver and an overall immune response by inducing synthesis of cytokines such as TNF-alpha, IL-1beta, IL-6 and IL-8. C5b initiates the assembly of the membrane attack complex (MAC) that mediates cytolysis.

C5a/C5a des Arg, Human, mAb 2942, Hycult Biotech, HM2078

Monoclonal antibody 2942 reacts with a neo-epitope on human C5a/C5a des-Arg that is formed by proteolytic cleavage of C5 into C5a and C5b during complement activation. C5a is a single chain glycopeptide composed of 74-amino-acids, which is rapidly converted to the less potent derivate C5a des-Arg upon removal of the C-terminal arginine by carboxypeptidase B. C5a acts as a potent anaphylatoxin by binding to its high affinity receptor C5aR (or CD88) on the membrane of target cells inducing smooth muscle contraction, increased vascular permeability, degranulation of mast cells and basophils, and the release of lysosomal enzymes. In addition C5a stimulates the directed migration of neutrophils, eosinophils, basophils and monocytes. C5a is involved in inflammatory reactions seen in gram-negative bacterial sepsis, trauma, ischemic heart disease, post-dialysis syndrome and a variety of autoimmune diseases. Elevation of C5a is associated with increased cardiovascular risk in patients with advanced atherosclerosis. Also, C5a is closely associated with the capillary leak syndrome in leukemic children after bone marrow transplantation. C5a is also a marker in urine for predicting the onset of acute graft rejection after kidney transplantation and has been shown to be present in extracellular deposits in patients suffering from age-related macular degeneration (AMD). General comment: Please notice that under given conditions it is known that C5 can expose epitopes normally only found in the cleaved activation products (ref.2).

C5a/C5a des Arg, Human, mAb 2952, Hycult Biotech, HM2079

Monoclonal antibody 2952 reacts with a neo-epitope on C5a (des-Arg) that is formed upon cleavage of C5 into C5a and C5b. C5 is involved in the activation of the lythic pathway within the complement system which is an important factor in innate immunity. The complement pathways can be divided in the activation pathways and lytic pathway. The activation pathways lead via C3 to the cleavage of the fifth complement component C5. C5a induces smooth muscle contraction, increases vascular permeability, causes degranulation of mast cells and basophils, and release of lysosomal enzymes. In addition C5a stimulates the directed migration of neutrophils, eosinophils, basophils and monocytes. Recent studies indicate the modulation of the acute-phase response in liver and an overall immune response by inducing synthesis of cytokines such as TNF-alpha IL-1beta, IL-6 and IL-8. General comment: Please notice that under given conditions it is known that C5 can expose epitopes normally only found in the cleaved activation products (ref.5).

COMING SOON: C5a/C5a des Arg, Human, mAb C17/5, Hycult Biotech, HM2445

C5a, Human, ELISA kit, Hycult Biotech, HK3490

C5a plays a pivotal role in the complement system, a key player in innate immunity. During the activation of complement protein 5 (C5), C5a, a potent anaphylatoxin comprising 74 amino acids, is produced. Initially short-lived, C5a is swiftly transformed in serum into the more stable C5a-desArg, maintaining biological activity and providing a reliable measure of complement activation levels in various samples. C5a exerts profound physiological effects, inducing smooth muscle contraction, vasodilation, increased vascular permeability, and inflammatory mediator release from basophils and mast cells. It also serves as a chemotactic agent, drawing eosinophils, basophils, and monocytes to sites of inflammation. The clinical relevance of C5a extends to inflammatory responses in conditions like gramnegative bacterial sepsis, trauma, ischemic heart disease, post-dialysis syndrome, and autoimmune diseases. Elevated C5a levels have been associated with increased cardiovascular risk and the capillary leak syndrome following bone marrow transplantation. Notably, C5a is a significant urinary biomarker for imminent acute graft rejection post-kidney transplantation. Employing a specialized monoclonal antibody that recognizes a unique neo-epitope on C5adesArg, the human C5a ELISA kit is designed for precision, eliminating the chance of crossreactivity with C5. This precision positions the C5a ELISA kit as an essential tool for researchers delving into the complement system’s intricacies.

C5aR, Human, mAb S5/1, Hycult Biotech, HM2094

The monoclonal antibody S5/1 recognizes the human receptor for C5a (CD88). The C5a receptor- is a seven transmembrane GTP-binding-protein-coupled receptor of 45kDa which binds with high affinity to human anaphylatoxin C5a. Upon C5a binding- G-protein-dependent cellular- responses are initiated such as increased intracellular Ca2+, granule fusion with the cell membrane, enzyme release and oxidative burst suggesting that C5aR is an important mediator of inflammation. The C5a receptor is expressed on a broad range of cell types, including- neutrophils, monocytes/macrophages, dendritic cells, astrocytes and microglia. Interestingly, C5a receptor signalling has been associated with several inflammatory diseases including rheumatoid arthritis.- Clone S5/1 was raised against a synthetic peptide comprising the N-terminal domain of the C5aR (Met1-Asn31). The antibody has been shown to inhibit the binding of C5a to its receptor.