More than 90% of the viral plaques from brains of animals inoculated with rLm-np118 and subsequently infected with RA59-gfp/gp33 expressing virus were fluorescent and thus retained the ability to express EGFP activity. On the other hand, only 15% of the plaques from the brains of mice that were protected by inoculation by rLm-gp33 were fluorescent. Lysates from the brains of animals infected with RA59-gfp contained similar percentages of EGFP expressing plaques whether or not they had been inoculated with rLm expressing gp33 (Table 2).