A tissue culture infection test in routine rabies diagnosis.

A cell culture infection test was developed for the isolation of rabies virus from field cases submitted for rabies diagnosis. The procedure involved the addition of a suspension of suspect brain tissue to a suspension of murine neuroblastoma cells in 96-well microtiter plates. The cultures were then incubated at 35-36 degrees C for four days at which time they were fixed, stained with a fluorescein-labelled hamster antirabies antibody conjugate and examined with a fluorescence microscope. Rabies antigen in cells was readily visible as brilliant, apple-green fluorescent particles. This technique was compared with the standard mouse inoculation test and was at least as sensitive to infection with small amounts of virus, required a much shorter test period and was substantially more economical than the mouse inoculation test. The new cell culture test is now in use at this laboratory, replacing the mouse inoculation test.