Development of a new colloidal gold immunochromatographic strip for rapid detecting subgroup A of avian leukosis virus using colloidal gold nanoparticles

This study focuses on developing a new colloidal gold immunochromatographic strip for the rapid and specific detection of subgroup A of avian leukosis virus (ALV-A) in clinical practice based on immunochemistry responses using colloidal gold nanoparticles, monoclonal antibody (MAb) and polyclonal antibody (PAb). The solution containing colloidal gold particles (Phi 20 nm) is prepared by the reduction of chloroauric acid and sodium citrate. The MAb and PAb are used to target ALV-A as colloidal gold-MAb conjugates and capture antibodies, and their optimum concentrations are 10 mu g/mL and 2.0 mg/mL, respectively. The optimum pH in the reaction system for the colloidal gold-MAb complex is pH 8.3. The specificity results show that the developed strip can detect ALV-A but not ALV-B/J/K. The sensitivity of the strip is 32(similar to)64 TCID50/mL for ALV-A detection and 8(similar to)80 ng/mL for ALV-A gp85 protein. The strip remains stable in storage at 4 degrees C for 180 d and can detect ALV-A in many tissue samples, including blood, cloacal swab, and egg albumin samples as well as cell samples in vitro. Additionally, it does not require any equipment, and its assay time and cost are much less than those of ELISA. Therefore, this strip is convenient, rapid and effective for detecting ALV-A in avian clinical applications.