RESUMO
Multiparametric flow cytometry offers a powerful approach to single-cell analysis with broad applications in research and diagnostics. Despite advances in instrumentation, progress in methodology has lagged. Currently there is no simple and efficient method for antibody labeling or quantifying the number of antibodies bound per cell. Herein, we describe a DNA-directed assembly approach to fluorescent labeling that overcomes these barriers. Oligonucleotide-tagged antibodies and microparticles can be annealed to complementary oligonucleotides bearing fluorophores to create assay-specific labeling probes and controls, respectively. The ratio of the fluorescence intensity of labeled cells to the control particles allows direct conversion of qualitative data to quantitative units of antibody binding per cell. Importantly, a single antibody can be labeled with any fluorophore by using a simple mix-and-match labeling strategy. Thus, any antibody can provide a quantitative probe in any fluorescent channel, thus overcoming major barriers to the use of flow cytometry as a technique for systems biology and clinical diagnostics.
Assuntos
Anticorpos/metabolismo , DNA/metabolismo , Citometria de Fluxo/métodos , Corantes Fluorescentes/metabolismo , Antígenos/metabolismo , Oligonucleotídeos/metabolismo , Espectrometria de FluorescênciaRESUMO
The monoclonal antibody 1A6 binds to human intercellular adhesion molecule 1 (ICAM-1, CD54) and inhibits infection by 90% of human rhinovirus (HRV) serotypes. To make a therapeutic molecule for preventing and treating HRV infection, we humanized a single chain antibody (scFv), 1A6, by a structure-guided complementarity-determining region (CDR) grafting procedure. Our final humanized 1A6 scFv does not retain any mouse back mutations in the framework. Without changing the CDR sequences, the humanized 1A6 scFv demonstrates over 50-fold improvement in both affinity for ICAM-1 and protection efficacy against HRV infection in vitro.
Assuntos
Anticorpos Monoclonais/genética , Anticorpos Monoclonais/imunologia , Molécula 1 de Adesão Intercelular/imunologia , Rhinovirus/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/uso terapêutico , Anticorpos Antivirais/química , Anticorpos Antivirais/genética , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/uso terapêutico , Afinidade de Anticorpos , Regiões Determinantes de Complementaridade , Humanos , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Infecções por Picornaviridae/prevenção & controle , Infecções por Picornaviridae/terapia , Infecções por Picornaviridae/virologia , Engenharia de Proteínas , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Proteínas Recombinantes de Fusão/uso terapêutico , Homologia de Sequência de AminoácidosRESUMO
We have developed a technology for improving avidity by making bivalent, trivalent, or tetravalent recombinant polypeptides. We designed tripartite proteins consisting of the Fab fragment of an antibody fused with a hinge derived from human immunoglobulin D that was further linked to polymerization domains derived from human coiled-coil proteins. We report here on the application of this method with a Fab domain directed against the major human rhinovirus receptor, intercellular adhesion molecule 1 (ICAM-1). Multivalent anti-ICAM-1 molecules were produced in bacteria and purified as soluble preassembled homogeneous proteins at high yield. These proteins successfully blocked rhinovirus infection in vitro, with the efficiency increasing from monomer to dimer, trimer, and tetramer. The diminished dissociation rate of these multivalent antibodies and their improved efficacy in preventing rhinovirus infection provide a foundation for producing prophylactic and therapeutic molecules against human rhinovirus, the causative agent of the majority of common colds.
