Protection against Fatal Murine Chagas' Disease with a Leishmania braziliensis panamensis Stock

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  • * Department of Pathology, Division of Parasitology and Tropical Medicine, and Department of Medicine, Division of Infectious Disease, Albert Einstein College of Medicine, Bronx, New York 10461
  • | ** Department of Biological Sciences and Bureau of Biological Research, Rutgers University, New Brunswick, New Jersey 08903
  • | Department of Medical Microbiology and Parasitology, University of Ife, Ile-Ife, Nigeria
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Past attempts to immunize mice against a fatal Trypanosoma cruzi infection utilizing related hemoflagellates have been unsuccessful. In the present study, C57BL/6 mice received a footpad inoculation of 107 promastigotes of Leishmania braziliensis panamensis. Six and 9 weeks subsequent to this inoculation mice were infected intraperitoneally with the Tulahuen strain of T. cruzi. All immunized mice survived infection over the 6-month period of observation whereas control mice regularly died. There was an early transient T. cruzi parasitemia in the immunized mice. Culture of blood and organs as well as histopathological examination of various organs 6 months post-challenge failed to yield any evidence of T. cruzi. Heat-killed and freeze-thawed extracts of promastigotes did not confer any protection. These observations raise the possibility that certain leishmanial species might confer natural protection against a T. cruzi infection and that this information could be useful in the development of a vaccine.