Abstract
Enzyme linked immunosorbent assay (ELISA) was developed for the quantitative assay of Bombyx mori cytoplasmic polyhedrosis virus (CPV) in larval feces. The double antibody sandwich method was more sensitive than the indirect method, and nonspecific reactions against the feces extract were not observed. Alkaline phosphatase was suitable for use as conjugate enzyme to the anti-CPV IgG, while peroxidase gave rise to nonspecific reactions. The addition of 2% of polyvinyl pyrrolidone (MW 40, 000) to the extraction buffer (100mM Tris-HCl, pH8.0) was necessary to eliminate the background association with the coupling of feces extract to the microtest plate. The double antibody sandwich method enabled to detect 8ng/ml of purified CPV using alkaline phosphatase conjugated anti-CPVIgG. The addition of 1% extract of non injected larval feces did non inhibit the reactions for the detection of CPV. There was a positive correlation between the amount of CPV in the feces and the value obtained by ELISA.
