Protozoal strains of reduced infectivity - prepd. by treating virulent strain with mutagen, useful as vaccine prepn.

摘要

Prodn. of variant parasite strains of reduced infectivity comprises treating, in vitro, a virulent protozoal strain with at least one chemical mutagen so as to form clones. The pref. parasites are Trypanosoma cruzi, T.rhodesiense, T.gambiense, T.brucei, T.vivax, T.congolense, Leishmania donovani, L. tropica and Plasmodium falciparum and the mutagens are N-methyl-N'-nitro-N-nitrosoguanidine (I), ethyl methanesulphonate and-or N-methyl-N-nitrosourea. Also new are the variant parasite strains thermselves and live or killed vaccines contg. them. These clones have intact viability but reduced infectivity and are not derived from mouse tumours and are the known variants of reduced infectivity.