Development of a fast dipstick dye immunoassay (DDIA) for detection IgG antibody to toxoplasmosis
Objective To establish a rapid, immunodiagnostic assay for the diagnosis of toxoplasmosis immunoglobulin G (IgG). Methods Goat anti-human IgG was conjugated with a blue colloidal dye (D-1) produced in China and used to detect IgG of Toxoplasma gondii in toxoplasmosis patients. The labeled second antibody-antibody complex was captured by soluble antigen of Toxoplasma onto a nitrocellulose membrane dipstick by means of immunochromagraphy. The optimal detecting condition of DDIA was determined by orthogonal experiment. A total of 88 human sera samples obtained in epidemiological investigation of toxoplasmosis were tested with DDIA, its results were compared with that tested by SERION ELISA classic Toxoplasma gondii IgG kit produced from Germany. Results The optimal detection condition of DDIA was that the concentration of soluble antigen of Toxoplasma was 1mg/ml, the concentration of human IgG was 2mg/ml, the detective volume of human serum was 10μl; the total correspondence rate, the positive correspondence rate and negative correspondence rate of DDIA was 97.7%(86/88), 100%(52/52) and 94.4%(34/36) respectively compared with imported IgG-ELISA kit of Toxoplasmosis. Conclusion DDIA has good correspondence rate with imported IgG-ELISA kit of Toxoplasmosis. So DDIA has potential value for immunodiagnosis of toxoplasmosis.