The effect of the passages of Acanthamoeba strains through mice tissues on their virulence and its biochemical markers.

The aim of this study was to determine the enzymatic differences in the process of increasing the degree of virulence in attenuated Acanthamoeba strains as well as strains freshly isolated from the natural environment. The data obtained in our studies indicate that by intranasal infection of mice, one can restore virulence in primary virulent strains and make virulent strains that primarily were noninvasive. The levels of peroxidase and proteinase activity measured thoroughly correlated with the increase in the degree of virulence observed during the process of making the amoeba virulent by inoculating them into mice. We observed that in cases in which the activity of peroxidase and proteinase was higher than 0.150 units/mg protein and 8 units/mg protein, respectively, some of the animals infected with the strains showing this activity of peroxidase and proteinase died. In nonvirulent strains as well as in poorly virulent strains, we observed a decidedly lower activity of these enzymes.