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Signaling through exposed phosphatidylserine (PS) is fundamental for the TGFbeta1-dependent, noninflammatory phagocytosis of apoptotic cells. This same mechanism operates in the internalization of amastigotes of Leishmania (L) amazonensis (L(L)a) in a process quoted as apoptotic mimicry. Now we show that the host modulates PS exposure by the amastigotes(More)
Programmed cell death by apoptosis of unnecessary or potentially harmful cells is clearly beneficial to multicellular organisms. Proper functioning of such a program demands that the removal of dying cells proceed without an inflammatory reaction. Phosphatidylserine (PS) is one of the ligands displayed by apoptotic cells that participates in their(More)
Mimicking mammalian apoptotic cells by exposing phosphatidylserine (PS) is a strategy used by virus and parasitic protozoa to escape host protective inflammatory responses. With Leishmania amazonensis (La), apoptotic mimicry is a prerogative of the intramacrophagic amastigote form of the parasite and is modulated by the host. Now we show that differently(More)
T-cell DNA synthesis and T-helper cell function in response to isolated insulin chains and naturally occurring insulin variants was assessed in insulin immune guinea pigs. Two distinct antigenic determinants, recognized by T cells, were defined. One localized in the B chain and the other one constituted by amino acids A8, A9, and A10 of the insulin A-chain(More)
CD4(+) T cells produce hematopoietic-related cytokines and are essential for hematopoiesis stimulation during infection and hematologic recovery after bone marrow transplantation. However, it remains unclear if T cells are necessary to maintain normal hematopoiesis. We report here that, in T-cell-deficient mice, terminal differentiation of myeloid(More)
Cell death by apoptosis is characterized by specific biochemical changes, including the exposure of multiple ligands, expected to tag the dying cell for prompt recognition by phagocytes. In non-pathological conditions, an efficient clearance is assured by the redundant interaction between apoptotic cell ligands and multiple receptor molecules present on the(More)
Immune response (Ir) genes are linked to the species histocompatibility complex and define as yet uncharacterised phenotypic products which control the immune response to thymus dependent antigens. Antibody formation and antigen induced T lymphocyte proliferation are two examples of immune phenomena which, in vivo and in vitro, operate under Ir gene(More)
Apoptosis, a form of programmed cell death (PCD), has been described as essential for normal organogenesis and tissue development, as well as for the proper function of cell-renewal systems in adult organisms. Apoptosis is also pivotal in the pathogenesis of several different diseases. In this paper we discuss, from two different points of view, the role of(More)
Diffuse cutaneous leishmaniasis (DCL) is a rare clinical manifestation of leishmaniasis, characterized by an inefficient parasite-specific cellular response and heavily parasitized macrophages. In Brazil, Leishmania (Leishmania) amazonensis is the main species involved in DCL cases. In the experimental model, recognition of phosphatidylserine (PS) molecules(More)
Multicellular organisms can clearly benefit from the non-inflammatory elimination by apoptosis of unnecessary and potentially harmful cells. Recently accumulated data show that unicellular organisms such as pathogenic trypanosomatids can also take advantage of different apoptotic features [1]. As a matter of fact, similarities between multicellular(More)