An improved dot ELISA to detect fowl adenovirus type-1 antigen

An improved dot immunobinding assay to detect fowl adenovirus type-1 is described. The method consists of spotting of antigen on nitrocellulose membrane sheet, blocking with either 5% acetic acid or with 5% defatted milk powder and fixation of either antigen or antigen-antibody complex, with either 50% methanol or 0.25% glutaraldehyde or 0.2% tannic acid. The results revealed that fixation of both antigen and antigen-antibody complex resulted in 4-fold increase in sensitivity when acetic acid was used as blocking agent. The use of two substrates simultaneously resulted in more colour intensity and clarity than using both substrates separately.