Infectivity of amastigotes of Trypanosoma cruzi

The infectivity amastigotes of Trypanosoma cruzi, isolated from the supernatant of the J774G8 macrophage-like cell line infected with trypomastigotes to normal macrophages in vitro was tested. After a period of 1 h of T. cruzi-macrophage interaction about 2% of the mouse peritoneal macrophages had ingested amastigotes. In contrast 12% of the macrophages had ingested epimastigotes. Treatment of the amastigotes with trypsin did not interfere with their ingestion by macrophages. Once inside the macrophages the amastigotes divided and after some days transformed into trypomastigotes. When i.p. inoculated into mice the amastigotes were highly infective, inducing high levels of parasitaemia and tissue parasitism. As previously described for trypomastigotes, amastigotes were not lysed when incubated in the presence of fresh guinea-pig serum. Contrasting with what has been described for trypomastigotes, the resistance of amastigotes to complement-mediated lysis persisted after treatment with trypsin.

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Active entry of bloodstream forms of Trypanosoma cruzi into macrophages

Parasitology ◽

10.1017/s0031182000048617 ◽

1979 ◽

Vol 78 (1) ◽

pp. 89-98 ◽

Cited By ~ 33

Author(s):

T. L. Kipnis ◽

V. L. G. Calich ◽

W. Dias da Silva

Keyword(s):

Trypanosoma Cruzi ◽

Cytochalasin B ◽

Previous Treatment ◽

Peritoneal Macrophages ◽

Experimental Conditions ◽

Specific Antibodies ◽

Previously Treated ◽

Mouse Peritoneal Macrophages ◽

Intracellular Amastigote

SUMMARYThe uptake of bloodstream forms of Trypanosoma cruzi, Y and CL stocks, by mouse peritoneal macrophages and their intracellular differentiation and multiplication has been compared in vitro. After 48 h the number of macrophages showing intracellular amastigote forms was higher when the Y stock was used. The number of parasitized cells increased with the time of contact between parasites and macrophages. Prior treatment of the parasites with anti-T. cruzi antibodies and/or complement increased the number of infected macrophages, but did not interfere with their subsequent differentiation within the macrophages. The number of parasitized cells was greater when macrophages were obtained from mice previously treated with lipopolysaccharide, peptone or thioglycollate. Uptake was not appreciably affected when macrophages were pre-treated with trypsin or anti-macrophage serum, or when the parasites and macrophages were incubated in the presence of cytochalasin B. In the same experimental conditions, epimastigotes of T. cruzi were not able to differentiate into amastigotes. Their uptake was potentiated by previous treatment with specific antibodies and/or complement and was blocked by cytochalasin B. These results confirm that epimastigotes derived from T. cruzi cultures are phagocytosed and suggest that bloodstream forms penetrate actively into macrophages.

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Effect of lentinan on pinocytosis in mouse peritoneal macrophages and the murine macrophage cell line C4MØ in vitro

International Journal of Immunopharmacology ◽

10.1016/0192-0561(86)90093-7 ◽

1986 ◽

Vol 8 (8) ◽

pp. 919-924 ◽

Cited By ~ 5

Author(s):

G ABEL ◽

J SZOLLOSI ◽

G CHIHARA ◽

J FACHET

Keyword(s):

Cell Line ◽

Peritoneal Macrophages ◽

Murine Macrophage ◽

Macrophage Cell Line ◽

Macrophage Cell ◽

Murine Macrophage Cell Line ◽

Mouse Peritoneal Macrophages

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Transfection of Trypanosoma cruzi with Host CD40 Ligand Results in Improved Control of Parasite Infection

Infection and Immunity ◽

10.1128/iai.73.10.6552-6561.2005 ◽

2005 ◽

Vol 73 (10) ◽

pp. 6552-6561 ◽

Cited By ~ 12

Author(s):

Mustapha Chamekh ◽

Vincent Vercruysse ◽

Mohammed Habib ◽

Maxime Lorent ◽

Michel Goldman ◽

...

Keyword(s):

Trypanosoma Cruzi ◽

Protective Immunity ◽

Costimulatory Molecule ◽

Cd40 Ligand ◽

Peritoneal Macrophages ◽

Challenge Infection ◽

Reverse Transcription Pcr ◽

3T3 Fibroblasts ◽

Mouse Peritoneal Macrophages

ABSTRACT We have previously shown that infection by Trypanosoma cruzi, a parasitic protozoan, is reduced by injection of CD40 ligand (CD40L)-transfected 3T3 fibroblasts (D. Chaussabel, F. Jacobs, J. de Jonge, M. de Veerman, Y. Carlier, K. Thielemans, M. Goldman, and B. Vray, Infect. Immun. 67:1929-1934, 1999). This prompted us to transfect T. cruzi with the murine CD40L gene and to study the consequences of this transfection on the course of infection. For this, epimastigotes (Y strain) were electroporated with the pTEX vector alone or the pTEX-CD40L construct, and transfected cells were selected for their resistance to Geneticin G418. Then strain Y-, pTEX-, and pTEX-CD40L-transfected epimastigotes were transformed by metacyclogenesis into mammalian infective forms called Y, YpTEX, and YpTEX-CD40L trypomastigotes. Transfection of the CD40L gene and expression of the CD40L protein were assessed by reverse transcription-PCR and Western blot analysis. The three strains of parasites were infective in vitro for mouse peritoneal macrophages. When organisms were inoculated into mice, a very low level of parasitemia and no mortality were seen with the YpTEX-CD40L strain compared to the Y and YpTEX strains. Furthermore, the proliferative capacity and the secretion of gamma interferon were both preserved in spleen cells (SCs) from YpTEX-CD40L-infected mice but not with SCs from Y- and YpTEX-infected mice. These results suggest that the CD40L produced by transfected T. cruzi is involved in the modulation of an antiparasite immune response. Moreover, mice surviving YpTEX-CD40L infection resisted a challenge infection with the wild-type strain. Taken together, our data demonstrate the feasibility of generating a T. cruzi strain expressing a bioactive host costimulatory molecule that counteracts the immunodeficiency induced by the parasite during infection and enhances protective immunity against a challenge infection.

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Activation of macrophages in vivo and in vitro. Correlation between hydrogen peroxide release and killing of Trypanosoma cruzi.

Journal of Experimental Medicine ◽

10.1084/jem.149.5.1056 ◽

1979 ◽

Vol 149 (5) ◽

pp. 1056-1068 ◽

Cited By ~ 183

Author(s):

C Nathan ◽

N Nogueira ◽

C Juangbhanich ◽

J Ellis ◽

Z Cohn

Keyword(s):

Trypanosoma Cruzi ◽

Peritoneal Macrophages ◽

Trypanocidal Activity ◽

Dose Dependent Fashion ◽

Hydrogen Peroxide Release ◽

Inflammatory Macrophages ◽

Dose Dependent ◽

Mouse Peritoneal Macrophages

As reported previously, mouse peritoneal macrophages could be activated to kill intracellular trypomastigotes of Trypanosoma cruzi, the agent of Chagas' disease, in either of two ways: by immunizing and boosting the mice (3), or by culturing resident or inflammatory macrophages in spleen cell factor(s) (SCF) in vitro (2). Macrophages activated in vivo became less trypanocidal with time in culture, and cells activated in vitro lost trypanocidal capacity when CSF was removed (2). In the present study, the ability of macrophages to release H2O2 in response to phorbol myristate acetate (PMA) could be induced in vivo and in vitro, and reversed in vitro, in a manner correlating closely with changes in trypanocidal activity. Macrophages could be activated in vitro with SCF in a time-dependent and dose-dependent fashion, so that they released as much H2O2 as macrophages activated in vivo. The sensitivity of epimastigotes and trypomastigotes to enzymatically generated H2O2 suggested that the generation of H2O2 by activated macrophages could be plausible explanation for their trypanocidal activity. Of the biochemical correlates of macrophage activation reported to date, increased ability to release H2O2 seems most closely allied to enhanced capacity to kill an intracellular pathogen.

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Trypanosoma cruzi: the immunological induction of macrophage plasminogen activator requires thymus-derived lymphocytes.

Journal of Experimental Medicine ◽

10.1084/jem.146.1.172 ◽

1977 ◽

Vol 146 (1) ◽

pp. 172-183 ◽

Cited By ~ 37

Author(s):

N Nogueira ◽

S Gordon ◽

Z Cohn

Keyword(s):

Trypanosoma Cruzi ◽

Spleen Cell ◽

Plasminogen Activator ◽

Peritoneal Macrophages ◽

Enzyme Secretion ◽

Cell Populations ◽

Spleen Cells ◽

Trypanocidal Activity ◽

Mouse Peritoneal Macrophages

In this article we describe methods in which unstimulated mouse peritoneal macrophages were induced to secrete high livels of plasminogen activator under in vitro conditions. The exposure of sensitized peritoneal or spleen cell populations from Trypanosoma cruzi-infected animals to either viable or heat-killed trypanosomes lead to the release of an inducing factor(s). Maximal levels of plasminogen activator secretion are achieved by the incubation of such factors (s) with unstimulated macrophages for 48 h. A significant increase in enzyme secretion was already observed after a 24 h incubation. The production of the inducing factor(s) by sensitized cells was immunologically specific and unrelated antigens did not stimulate the production of the factor(s) by sensitized peritoneal or spleen cell populations. The inducing factor(s) was produced by nylon-wool-fractionated spleen and peritoneal cells which had been depleted of marcrophages. Pretreatment of sensitized spleen cells with anti-theta serum and C abolished the production of the activating factor(s). The active supernatant fluids were able to induce secretion of macrophage plasminogen activator across H-2 barriers. Attempts to induce trypanocidal activity in unstimulated macrophages have not been successful.

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