Dr. Mail Code 8416 San Diego. Background Dr. Reed graduated from Harvard University Medical School and then received her M.Sc. in Clinical Tropical Medicine from the University of London in 1982. The virulence factors of the infecting parasite appear to be very important in determining the outcome of infection. In the past few years, we have appreciated that there are really two morphologically identical species, Entamoeba histolytica, which can invade and Entamoeba dispar, which can not.
Cysteine proteinases are important virulence factors, which are encoded by at least six genes.
Noninvasive E. dispar has at least four of the same genes, but releases significantly less cysteine proteinase activity. We are investigated differences in the synthesis and release of cysteine proteinases in E. histolytica and noninvasive E. dispar. We have developed the first vector which will integrate into the E. histolytica genome using pseudotyped retroviruses. We can now take advantage of transgenic amebae expressing different cysteine proteinase genes or antisense RNA as well as novel new cysteine proteinase inhibitors to further our understanding of a key virulence factor of E. histolytica. Toxoplasmosis is one of the most common parasitic infections of man.