Immunofluorescence Test for the Rapid Diagnosis of Red Sea Bream Iridovirus Infection using Monoclonal Antibody.

Abstract

By using indirect immunofluorescence (IF) test with a monoclonal antibody (MAb) against red sea bream iridovirus (RSIV), the detection method of the RSIV specific antigen was examined from imprints or frozen sections of spleens of artificially infected red sea bream Pagrus major. Immunofluorescence-positive cells were not detected from uninfected fish and those of day 1 and 3 post infection. However, a few IF-positive cells were detected from day 5 post infection and many IF-positive cells including typically enlarged cells were detected from moribund or dead fish. This method was applied to 11 species of cultured marine fishes that showed disease condition or suspected iridovirus infection. The IF-positive cells were detected from all these naturally infected fishes of 11 species. The detection rate of infected fish by IF test using MAb was much higher than that by the currently used Giemsa staining method. The results indicate that the IF test using the RSIV specific MAb is a rapid and effective method for confirmative diagnosis of the iridovirus infection in cultured marine fishes.