Chagas' disease. Immunotoxin inhibition of Trypanosoma cruzi release from infected host cells in vitro.
Virulent tissue culture-derived Trypanosoma cruzi trypomastigotes were readily killed by immune IgG-ricin A chain conjugates (ITR) in vitro. Forty micrograms of ITR immobilized 10(6) trypomastigotes after 48 hours of incubation at 37 degrees C. ITR showed antibody specificity and 125I-labeled anti-T. cruzi IgG bound to parasitized host cells 9-fold more than to nonparasitized host cells. The degree of specificity was evaluated further in experiments in which 10 micrograms of ITR showed 78% inhibition of [3H]thymidine incorporation by T. cruzi. In contrast, nonimmune IgG-ricin A chain conjugate neither immobilized nor inhibited [3H]thymidine incorporation by the parasite. Furthermore, 20 micrograms of ITR significantly inhibited T. cruzi trypomastigote release from infected host cells and thus prevented reinfection of other cells in vitro.
Teixeira
A R
AR
Laboratory of Immunopathology, Faculty of Health Sciences, University of Brasília, Brazil.
Santana
J M
JM
D000818:Animals; D000913:Antibodies, Protozoan / Q000008:administration & dosage*; D002478:Cells, Cultured; D014355:Chagas Disease / Q000469:parasitology* / Q000628:therapy*; D004247:DNA / Q000096:biosynthesis; D006801:Humans; D007167:Immunotherapy; D000922:Immunotoxins / Q000008:administration & dosage*; D066298:In Vitro Techniques; D012276:Ricin / Q000008:administration & dosage; D014349:Trypanosoma cruzi / Q000166:cytology / Q000254:growth & development*
D000913:Antibodies, Protozoan; D000922:Immunotoxins; D004247:DNA; D012276:Ricin