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https://www.arca.fiocruz.br/handle/icict/22869
ANTIGEN-SPECIFIC IMMUNOSUPPRESSION IN VISCERAL LEISHMANIASIS IS CELL MEDIATED
Author
Affilliation
University of Bahia. Department of Medicine. Division of Immunology. Salvador, BA, Brasil
University of Bahia. Department of Medicine. Division of Immunology. Salvador, BA, Brasil
University of Bahia. Department of Medicine. Division of Immunology. Salvador, BA, Brasil
University of Bahia. Department of Medicine. Division of Immunology. Salvador, BA, Brasil
Cornell University Medical College. Department of Medicine. Division of International Medicine.New York, USA
University of Bahia. Department of Medicine. Division of Immunology. Salvador, BA, Brasil
University of Bahia. Department of Medicine. Division of Immunology. Salvador, BA, Brasil
University of Bahia. Department of Medicine. Division of Immunology. Salvador, BA, Brasil
Cornell University Medical College. Department of Medicine. Division of International Medicine.New York, USA
Abstract
Visceral leishmaniasis is associated with an antigen-specific
immunosuppression during the acute disease. Patients become
responsive- to Leishmania antigen in both in vivo and in vitro
assays after successful antimony therapy. The cell type involved
in the suppression of lymphocyte reactivity to Leishmania
antigen was studied by selective depletion of mononuclear
cell (MNC) populations and in co-cultivation experiments.
Adherent cells were depleted on plastic and by passage
on nylon wool columns. High-avidity Fc' cells were depleted
by adherence to BSA-anti-BSA complexes and OKT4' and
OKT8+ cells were depleted by treatment with monoclonal antibody
(anti-OKT4' and OKT8) and complement. Depletion
of MNC preparations of adherent cells, high-avidity Fc' cells,
OKT4+ cells and OKT8+ cells failed to restore the lymphocyte
reactivity to Leishmania antigen. Antimony therapy was assodiated
with restoration of the proliferative responses of unseparated
MNC (before treatment 460±76 cpm and after treatment
4,293±1,442 cpm). Co-culture of frozen cells obtained before
chemotherapy with autologous MNC obtained after treatment
reduced the response of posttreatment cells to Leishmania antigen
by 80%. We conclude that the antigenic specific suppression
of lymphocyte proliferation in visceral leishmaniasis is
cell mediated.
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