NAb Assays

Antibody neutralization assays determine the concentration of a neutralizing antibody (NAb) required to inactivate a known concentration of the antibody’s target or to detect a cell’s natural production of NAbs. NAb targets include antigenic enzymes, cytokines, surface receptors, toxins, viruses, other infectious agents, or drugs. In cell-free antibody neutralization assays, a known concentration of the target is added to varying concentrations of NAbs or varying concentrations of cell culture supernatant. Neutralization is measured with a target-specific assay, such as an enzyme activity assay. In cell-based antibody neutralization assays, cells are cultured in the presence of varying concentrations of NAb and target or in the presence of varying concentrations of target alone to detect the native production of NAbs. The amount of neutralization is usually determined based on cell viability with fluorescent assays such as CellTiter-Blue, flow cytometry, plaque assays, or microscopy. The applications of antibody neutralization assays include immunology research, the development of antiretroviral NAb therapeutics, identifying inactivating cellular responses to novel therapeutics, and the identification of antitoxins. (Credit: Brooke Anderson-White)