title: Affinity measurement of single chain antibodies: a mathematical method facilitated by statistical software SigmaPlot.
abstract: Because they are monovalent for antigen, single chain antibodies display a different antibody-antigen interaction pattern from that of full-length antibodies. Using the law of mass action and considering the antibody-antigen binding pattern at OD-100% and OD-50% points, we introduced a formula for estimating single chain antibody affinity. Sigmoid curves of optical density values versus antibody concentrations were drawn and used to determine antibody concentrations at OD-50% points using statistical software SigmaPlot. The OD-50% points were then used to calculate the affinity via the mathematical formula. A software-adapted format of the equation is also presented for further facilitation of the calculation process. The accuracy of this method for affinity calculation was proved by surface plasma resonance. This method offers a precise evaluation of antibody affinity without requiring special material or apparatus, making it possible to be performed in any biological laboratory with minimum facilities.
authors.affiliation: 1 Biotechnology Research Center, Tabriz University of Medical Sciences , Tabriz, Iran .
authors.forename: Yaghoub
authors.initials: Y
authors.lastname: Safdari
authors.forename: Safar
authors.initials: S
authors.lastname: Farajnia
authors.forename: Mohammad
authors.initials: M
authors.lastname: Asgharzadeh
authors.forename: Masoumeh
authors.initials: M
authors.lastname: Khalili
authors.forename: Hossein Zarei
authors.initials: HZ
authors.lastname: Jaliani
mesh_terms: D000906:Antibodies / Q000097:blood*; D000915:Antibody Affinity / Q000276:immunology*; D000937:Antigen-Antibody Reactions / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D057127:Single-Chain Antibodies / Q000032:analysis / Q000276:immunology*; D012984:Software; D020349:Surface Plasmon Resonance
chemical_list: D000906:Antibodies; D057127:Single-Chain Antibodies