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Protective immunity to blood-stage malaria is attributed to Plasmodium-specific IgG and effector-memory T helper 1 (Th1) cells. However, mice lacking the costimulatory receptor CD28 (CD28KO) maintain chronic parasitemia at low levels and do not succumb to infection, suggesting that other immune responses contribute to parasite control. We report here that CD28KO mice develop long-lasting non-sterile immunity and survive lethal parasite challenge. This protection correlated with a progressive increase of anti-parasite IgM serum levels during chronic infection. Serum IgM from chronically infected CD28KO mice recognize erythrocytes infected with mature parasites, and effectively control Plasmodium infection by promoting parasite lysis and uptake. These antibodies also recognize autoantigens and antigens from other pathogens. Chronically infected CD28KO mice have high numbers of IgM+ plasmocytes and experienced B cells, exhibiting a germinal-center independent Fas+GL7-CD38+CD73- phenotype. These cells are also present in chronically infected C57BL/6 mice although in lower numbers. Finally, IgM+ experienced B cells from cured C57BL/6 and CD28KO mice proliferate and produce anti-parasite IgM in response to infected erythrocytes. This study demonstrates that CD28 deficiency results in the generation of germinal-center independent IgM+ experienced B cells and the production of protective IgM during experimental malaria, providing evidence for an additional mechanism by which the immune system controls Plasmodium infection
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Malaria-associate pregnancy has a significant impact on infant morbidity and mortality. The detrimental effects of malaria infection during pregnancy have been shown to correlate with immune activation in the placental tissue. Herein we sought to evaluate the effect of Toll-like receptors (TLRs) activation on placental malaria (PM) development by using the Plasmodium berghei NK65GFP infection model. We observed that activation of the innate immune system by parasites leads to PM due to local inflammation. We identified TLR4 activation as the main pathway involved in the inflammatory process in the placental tissue since the absence of functional TLR4 in mice leads to a decrease in the pro-inflammatory responses, which resulted in an improved pregnancy outcome. Additionally, a similar result was obtained when infected pregnant mice were treated with IAXO-101, a TLR4/CD14 blocker. Together, this study illustrates the importance of TLR4 signalling for the generation of the severe inflammatory response involved in PM pathogenesis. Therefore, our results implicate that TLR4 blockage could be a potential candidate for therapeutic interventions to reduce malaria-induced pathology both in the mother and the fetus.
Assuntos
Malária/metabolismo , Placenta/metabolismo , Complicações Infecciosas na Gravidez/metabolismo , Receptor 4 Toll-Like/metabolismo , Animais , Feminino , Feto/metabolismo , Feto/parasitologia , Interações Hospedeiro-Parasita/efeitos dos fármacos , Malária/genética , Malária/parasitologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Placenta/parasitologia , Plasmodium berghei/fisiologia , Gravidez , Complicações Infecciosas na Gravidez/genética , Complicações Infecciosas na Gravidez/parasitologia , Resultado da Gravidez , Transdução de Sinais/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/farmacologia , Receptor 4 Toll-Like/antagonistas & inibidores , Receptor 4 Toll-Like/genéticaRESUMO
Malaria is a widespread infectious disease caused by the parasite Plasmodium. During pregnancy, malaria infection leads to a range of complications that can affect both the mother and fetus, including stillbirth, infant mortality, and low birth weight. In this study, we utilized a mouse model of placental malaria (PM) infection to determine the importance of the protein MyD88 in the host immune response to Plasmodium during pregnancy. Initially, we demonstrated that Plasmodium berghei NK65GFP adhered to placental tissue via chondroitin sulfate A and induced PM in mice with a C57BL/6 genetic background. To evaluate the involvement of MyD88 in the pathology of PM, we performed a histopathological analysis of placentas obtained from MyD88(-/-) and wild-type (WT) mice following infection on the 19th gestational day. Our data demonstrated that the detrimental placental alterations observed in the infected mice were correlated with the expression of MyD88. Moreover, in the absence of this protein, production of interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α) was significantly reduced in the infected mice. More importantly, in contrast to fetuses from infected WT mice, which exhibited a reduction in body weight, the fetuses from infected MyD88(-/-) mice did not display significant weight loss compared to their noninfected littermates. In addition, we observed a decrement of maternal care associated with malaria infection, which was attenuated in the MyD88-deficient mice. Collectively, the results of this study illustrate the pivotal importance of the MyD88 signaling pathway in the pathogenesis of placental malaria, thus presenting new possibilities for targeting MyD88 in therapeutic interventions.
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Interações Hospedeiro-Patógeno , Malária/imunologia , Fator 88 de Diferenciação Mieloide/metabolismo , Placenta/imunologia , Plasmodium berghei/imunologia , Complicações Infecciosas na Gravidez/imunologia , Transdução de Sinais , Animais , Modelos Animais de Doenças , Feminino , Histocitoquímica , Malária/parasitologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Placenta/parasitologia , Gravidez , Complicações Infecciosas na Gravidez/parasitologiaRESUMO
Este trabalho tem como objetivo implantar novas tecnologias na área de bioterismo, com a formação de um núcleo de desenvolvimento de Fertilização In Vitro (FIV) para criação de um banco de embriões de camundongos isogênicos, transgênicos ou "nocautes", estudando inicialmente a superovulação e viabilidade embrionária de diferentes linhagens de camundongos. As fêmeas com oito semanas foram estimuladas com os hormônios PMSG e HCG, em seguida, eutanasiadas para obtenção dos oócitos e os machos, das respectivas linhagens, foram também eutanasiados para obtenção dos espermatozóides. Após a fertilização in vitro, os embriões em duas células foram coletados e transferidos para fêmeas pseudográvidas. Os resultados da FIV mostraram que as linhagens 129sv ABR, CPA, C5BL/10 e ALOX apresentaram maior número de oócitos em relação às demais linhagens testadas: A/J, BALB/c IL-4, BALB/c SCID, C57BL/6 TLR2, CBA, C57BL/6 CD1, BALB/c CARECA, C57BL/6 IL-4 e C57BL/6 TLR4. Com relação ao - nº de oócitos/ nº de embriões em duas células - as linhagens A/J (42/30) e CBA (20/14), apesar de apresentarem um número de oócitos inferior quando comparamos com os animais da linhagem 129 (165/53), apresentaram um maior número de embriões em duas células. Com a linhagem C57BL/10.A, o número de oócitos (119) foi maior em comparação com a linhagem A/J e CBA, no entanto, o número de embriões em duas células obtidos pela linhagem C57BL/10.A (22) foi menor em comparação com os animais da linhagem A/J e CBA. A linhagem XPA, apresentou grande número de oócitos e também de embriões em duas células (116/76). A eficiência da FIV foi validada pelos primeiros nascimentos de embriões, obtidos com animais das linhagens C57BL/6 IL4, C57BL/6 TLR2 e da linhagem 129sv ABR. Em conjunto, os nossos resultados mostram que a resposta à superovulação é um fenômeno linhagem específico, além disso, dentro da particularidade de cada linhagem, os embriões que se diferenciaram em duas células são capazes de ser gerados em fêmeas receptoras e se desenvolveram até o nascimento. Com essa ferramenta, abrimos novas possibilidades de avanços tecnológicos na área de bioterismo. Certificado CEUA nº 098/11 HCFMUSP.(AU)
This study aimed to deploy new technologies in the Laboratory Animal Science, with the formation of a core development in vitro fertilization (IVF) to create an embryo bank of inbred mice, transgenic or knockout, initially studying the super ovulation and embryo viability of different strains of mice. Females 8 weeks, were stimulated with PMSG and HCG hormones then euthanized to obtain the oocytes and males, their lines were also euthanized to obtain sperm. After in vitro fertilization, the embryo into two cells were collected and transferred to pseudo-pregnant females. The IVF results showed that strains 129sv ABR, XPA, and C57BL/10.A ALOX had a higher number of oocytes compared with other tested strains: A/J, BALB/c IL-4, BALB/c SCID, C57BL/TLR2 6, CBA, C57BL/6 CD1, BALB/c BALD, C57BL/6 IL -4 and C57BL/6 TLR4. With respect to -n oocyte/embryo -n into two cells - the strains A/J (42/30) and CBA (20/14), although with a lower number of oocytes when compared with the strain 129 (165/53), showed a higher number of embryos in two cells. With the line C57BL/10.A, the number of oocytes (119) was higher in comparison with strain A/J and CBA, however, the number of two-cell embryos obtained by C57BL/10.A (22) was lower compared with animals from the strain A/J and CBA. The strain XPA, showed a large number of oocytes and embryos also two cells (116/76). The efficiency of IVF, has been validated by the first births of embryos obtained from animals of the strains C57BL/6 IL4, C57BL/6 and TLR2 strain 129sv ABR. Together, our results showed that the response to ovulation is a super strain-specific phenomenon, moreover, within the particularity of each strain, the embryos which differentiated into two cells are able to be generated in recipient females and develop to the birth. With this tool, we have opened new possibilities for technological advances in the Laboratory Animal Science. Certified CEUA Nº 098/11 HCFMUSP.(AU)
Assuntos
Animais , Fertilização in vitro , Camundongos/classificação , Superovulação/metabolismo , Embrião de Mamíferos/citologiaRESUMO
Este trabalho tem como objetivo implantar novas tecnologias na área de bioterismo, com a formação de um núcleo de desenvolvimento de Fertilização In Vitro (FIV) para criação de um banco de embriões de camundongos isogênicos, transgênicos ou "nocautes", estudando inicialmente a superovulação e viabilidade embrionária de diferentes linhagens de camundongos. As fêmeas com oito semanas foram estimuladas com os hormônios PMSG e HCG, em seguida, eutanasiadas para obtenção dos oócitos e os machos, das respectivas linhagens, foram também eutanasiados para obtenção dos espermatozóides. Após a fertilização in vitro, os embriões em duas células foram coletados e transferidos para fêmeas pseudográvidas. Os resultados da FIV mostraram que as linhagens 129sv ABR, CPA, C5BL/10 e ALOX apresentaram maior número de oócitos em relação às demais linhagens testadas: A/J, BALB/c IL-4, BALB/c SCID, C57BL/6 TLR2, CBA, C57BL/6 CD1, BALB/c CARECA, C57BL/6 IL-4 e C57BL/6 TLR4. Com relação ao - nº de oócitos/ nº de embriões em duas células - as linhagens A/J (42/30) e CBA (20/14), apesar de apresentarem um número de oócitos inferior quando comparamos com os animais da linhagem 129 (165/53), apresentaram um maior número de embriões em duas células. Com a linhagem C57BL/10.A, o número de oócitos (119) foi maior em comparação com a linhagem A/J e CBA, no entanto, o número de embriões em duas células obtidos pela linhagem C57BL/10.A (22) foi menor em comparação com os animais da linhagem A/J e CBA. A linhagem XPA, apresentou grande número de oócitos e também de embriões em duas células (116/76). A eficiência da FIV foi validada pelos primeiros nascimentos de embriões, obtidos com animais das linhagens C57BL/6 IL4, C57BL/6 TLR2 e da linhagem 129sv ABR. Em conjunto, os nossos resultados mostram que a resposta à superovulação é um fenômeno linhagem específico, além disso, dentro da particularidade de cada linhagem, os embriões que se diferenciaram em duas células são capazes de ser gerados em fêmeas receptoras e se desenvolveram até o nascimento. Com essa ferramenta, abrimos novas possibilidades de avanços tecnológicos na área de bioterismo. Certificado CEUA nº 098/11 HCFMUSP.
This study aimed to deploy new technologies in the Laboratory Animal Science, with the formation of a core development in vitro fertilization (IVF) to create an embryo bank of inbred mice, transgenic or knockout, initially studying the super ovulation and embryo viability of different strains of mice. Females 8 weeks, were stimulated with PMSG and HCG hormones then euthanized to obtain the oocytes and males, their lines were also euthanized to obtain sperm. After in vitro fertilization, the embryo into two cells were collected and transferred to pseudo-pregnant females. The IVF results showed that strains 129sv ABR, XPA, and C57BL/10.A ALOX had a higher number of oocytes compared with other tested strains: A/J, BALB/c IL-4, BALB/c SCID, C57BL/TLR2 6, CBA, C57BL/6 CD1, BALB/c BALD, C57BL/6 IL -4 and C57BL/6 TLR4. With respect to -n oocyte/embryo -n into two cells - the strains A/J (42/30) and CBA (20/14), although with a lower number of oocytes when compared with the strain 129 (165/53), showed a higher number of embryos in two cells. With the line C57BL/10.A, the number of oocytes (119) was higher in comparison with strain A/J and CBA, however, the number of two-cell embryos obtained by C57BL/10.A (22) was lower compared with animals from the strain A/J and CBA. The strain XPA, showed a large number of oocytes and embryos also two cells (116/76). The efficiency of IVF, has been validated by the first births of embryos obtained from animals of the strains C57BL/6 IL4, C57BL/6 and TLR2 strain 129sv ABR. Together, our results showed that the response to ovulation is a super strain-specific phenomenon, moreover, within the particularity of each strain, the embryos which differentiated into two cells are able to be generated in recipient females and develop to the birth. With this tool, we have opened new possibilities for technological advances in the Laboratory Animal Science. Certified CEUA Nº 098/11 HCFMUSP.
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Animais , Camundongos/classificação , Fertilização in vitro , Superovulação/metabolismo , Embrião de Mamíferos/citologiaRESUMO
The pivotal role of spleen CD4(+) T cells in the development of both malaria pathogenesis and protective immunity makes necessary a profound comprehension of the mechanisms involved in their activation and regulation during Plasmodium infection. Herein, we examined in detail the behaviour of non-conventional and conventional splenic CD4(+) T cells during P. chabaudi malaria. We took advantage of the fact that a great proportion of CD4(+) T cells generated in CD1d(-/-) mice are I-A(b)-restricted (conventional cells), while their counterparts in I-A(b-/-) mice are restricted by CD1d and other class IB major histocompatibility complex (MHC) molecules (non-conventional cells). We found that conventional CD4(+) T cells are the main protagonists of the immune response to infection, which develops in two consecutive phases concomitant with acute and chronic parasitaemias. The early phase of the conventional CD4(+) T cell response is intense and short lasting, rapidly providing large amounts of proinflammatory cytokines and helping follicular and marginal zone B cells to secrete polyclonal immunoglobulin. Both TNF-α and IFN-γ production depend mostly on conventional CD4(+) T cells. IFN-γ is produced simultaneously by non-conventional and conventional CD4(+) T cells. The early phase of the response finishes after a week of infection, with the elimination of a large proportion of CD4(+) T cells, which then gives opportunity to the development of acquired immunity. Unexpectedly, the major contribution of CD1d-restricted CD4(+) T cells occurs at the beginning of the second phase of the response, but not earlier, helping both IFN-γ and parasite-specific antibody production. We concluded that conventional CD4(+) T cells have a central role from the onset of P. chabaudi malaria, acting in parallel with non-conventional CD4(+) T cells as a link between innate and acquired immunity. This study contributes to the understanding of malaria immunology and opens a perspective for future studies designed to decipher the molecular mechanisms behind immune responses to Plasmodium infection.
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Antígenos CD1d/fisiologia , Linfócitos T CD4-Positivos/imunologia , Malária/imunologia , Parasitemia/imunologia , Plasmodium chabaudi/imunologia , Baço/imunologia , Animais , Anticorpos Antiprotozoários/sangue , Linfócitos T CD4-Positivos/patologia , Citocinas/metabolismo , Ensaio de Imunoadsorção Enzimática , Feminino , Interferon gama/metabolismo , Complexo Principal de Histocompatibilidade/imunologia , Malária/parasitologia , Malária/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Parasitemia/patologia , Baço/patologia , Fator de Necrose Tumoral alfa/metabolismoRESUMO
The peritoneal cavity (PerC) is a singular compartment where many cell populations reside and interact. Despite the widely adopted experimental approach of intraperitoneal (i.p.) inoculation, little is known about the behavior of the different cell populations within the PerC. To evaluate the dynamics of peritoneal macrophage (MØ) subsets, namely small peritoneal MØ (SPM) and large peritoneal MØ (LPM), in response to infectious stimuli, C57BL/6 mice were injected i.p. with zymosan or Trypanosoma cruzi. These conditions resulted in the marked modification of the PerC myelo-monocytic compartment characterized by the disappearance of LPM and the accumulation of SPM and monocytes. In parallel, adherent cells isolated from stimulated PerC displayed reduced staining for ß-galactosidase, a biomarker for senescence. Further, the adherent cells showed increased nitric oxide (NO) and higher frequency of IL-12-producing cells in response to subsequent LPS and IFN-γ stimulation. Among myelo-monocytic cells, SPM rather than LPM or monocytes, appear to be the central effectors of the activated PerC; they display higher phagocytic activity and are the main source of IL-12. Thus, our data provide a first demonstration of the consequences of the dynamics between peritoneal MØ subpopulations by showing that substitution of LPM by a robust SPM and monocytes in response to infectious stimuli greatly improves PerC effector activity.
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Diferenciação Celular , Macrófagos Peritoneais/citologia , Macrófagos Peritoneais/microbiologia , Cavidade Peritoneal/citologia , Cavidade Peritoneal/microbiologia , Trypanosoma cruzi/fisiologia , Animais , Antígenos de Diferenciação/metabolismo , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Parede Celular/química , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Antígenos HLA-D/metabolismo , Interleucina-12/metabolismo , Lipopolissacarídeos/farmacologia , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Monócitos/citologia , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Monócitos/microbiologia , Óxido Nítrico/metabolismo , Solubilidade , Trypanosoma cruzi/citologia , Zimosan/química , Zimosan/farmacologiaRESUMO
Intravenous challenge with Trypanosoma cruzi can be used to investigate the process and consequences of blood parasite clearance in experimental Chagas disease. One hour after intravenous challenge of chronically infected mice with 5x10(6) trypomastigotes, the liver constituted a major site of parasite accumulation, as revealed by PCR. Intact parasites and/or parasite remnants were visualized at this time point scattered in the liver parenchyma. Moreover, at this time, many of liver-cleared parasites were viable, as estimated by the frequency of positive cultures, which considerably diminished after 48 h. Following clearance, the number of infiltrating cells in the hepatic tissue notably increased: initially (at 24 h) as diffuse infiltrates affecting the whole parenchyma, and at 48 h, in the form of large focal infiltrates in both the parenchyma and perivascular spaces. Phenotypic characterization of liver-infiltrating cells 24 h after challenge revealed an increase in Mac1(+), CD8(+) and CD4(+) cells, followed by natural killer (NK) cells. As evidence that liver-infiltrating CD4(+) and CD8(+) cells were activated, increased frequencies of CD69(+)CD8(+), CD69(+)CD4(+) and CD25(+)CD122(+)CD4(+) cells were observed at 24 and 48 h after challenge, and of CD25(-)CD122(+)CD4(+) cells at 48 h. The major role of CD4(+) cells in liver protection was suggested by data showing a very high frequency of interferon (IFN)-gamma-producing CD4(+) cells 24 h after challenge. In contrast, liver CD8(+) cells produced little IFN-gamma, even though they showed an enhanced potential for secreting this cytokine, as revealed by in vitro T cell receptor (TCR) stimulation. Confirming the effectiveness of the liver immune response in blood parasite control during the chronic phase of infection, no live parasites were detected in this organ 7 days after challenge.
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Doença de Chagas/imunologia , Doença de Chagas/parasitologia , Fígado/imunologia , Fígado/parasitologia , Trypanosoma cruzi/imunologia , Animais , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Feminino , Imuno-Histoquímica , Interferon gama/metabolismo , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Subunidade beta de Receptor de Interleucina-2/metabolismo , Células Matadoras Naturais/imunologia , Fígado/citologia , Camundongos , Camundongos Endogâmicos C57BL , Reação em Cadeia da Polimerase , Trypanosoma cruzi/genética , Trypanosoma cruzi/fisiologiaRESUMO
The physiopathology of Chagas' disease has been largely defined in murine infections with virulent strains which partially represent parasite diversity. This report reviews our studies with Sylvio X10/4 parasites, a Trypanosoma cruzi clone that induces no acute phase but in C3H/He mice leads to chronic myocarditis resembling the human disease.
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Doença de Chagas/parasitologia , Trypanosoma cruzi/fisiologia , Animais , Doença de Chagas/imunologia , Doença Crônica , Modelos Animais de Doenças , Interações Hospedeiro-Parasita , Camundongos , Parasitemia/imunologia , Parasitemia/parasitologia , Trypanosoma cruzi/patogenicidadeRESUMO
The role of B7/CD28 costimulatory pathway in the polyclonal and specific lymphocyte activation induced by blood stages of Plasmodium chabaudi AS was investigated in CD28 gene knockout (CD28(-/-)) and C57BL/6 (CD28(+/+)) mice. Analysis of the spleen during the acute infection revealed a similar increase in T and B cell populations in both groups of mice. Moreover, CD28(-/-) mice were able to develop a polyclonal IgM response to P. chabaudi. On the contrary, the polyclonal IgG2a response was markedly reduced in the absence of CD28. Production of IFN-gamma; up-regulation of CD69, CD40L, CD95 (Fas), and CD95L (Fas ligand); and induction of apoptosis were also affected by the lack of CD28. Interestingly, the ability to control the first parasitemia peak was not compromised in acutely infected CD28(-/-) mice, but CD28(-/-) mice failed to eradicate the parasites that persisted in the blood for >3 mo after infection. In addition, drug-cured CD28(-/-) mice were unable to generate memory T cells, develop an anamnesic IgG response, or eliminate the parasites from a secondary challenge. The incapacity of CD28(-/-) mice to acquire a full protective immunity to P. chabaudi correlated with an impaired production of specific IgG2a. Moreover, reinfected CD28(-/-) mice were protected by the adoptive transfer of serum from reinfected CD28(+/+) mice containing specific IgG2a. Our results demonstrate that the polyclonal lymphocyte response is only partially affected by the absence of CD28, but this coreceptor is essential to generate specific T and B cell responses required for complete protection against P. chabaudi malaria.
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Linfócitos B/imunologia , Antígenos CD28/fisiologia , Malária/sangue , Malária/imunologia , Plasmodium chabaudi/imunologia , Linfócitos T/imunologia , Animais , Linfócitos B/metabolismo , Linfócitos B/parasitologia , Antígenos CD28/genética , Células Clonais , Epitopos de Linfócito B/genética , Epitopos de Linfócito B/imunologia , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , Feminino , Imunização Secundária , Memória Imunológica/genética , Malária/genética , Malária/parasitologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Plasmodium chabaudi/crescimento & desenvolvimento , Esplenomegalia/genética , Esplenomegalia/imunologia , Linfócitos T/metabolismo , Linfócitos T/parasitologiaRESUMO
Challenge of 1-yr Trypanosoma cruzi chronically infected mice with trypomastigotes results in a consistent reduction of parasite dissemination that correlates with spleen activation and increase in the anti-T. cruzi effector immune mechanisms. That is, parasite challenge results not only in elimination of the inoculum but also in a drastic decrease in basal subpatent parasitemia levels as revealed by transferring blood samples to immunosuppressed mice. Parasite elimination correlated with (1) a brief and intense burst in the ability of spleen cells to produce interferon-gamma, (2) an increase in total IgG2a-producing spleen cells, (3) higher parasite-specific IgG2a serum levels, and (4) an accumulation of non-B, non-T class II+ cells in the spleen. Furthermore, challenged, chronically infected mice had increased numbers of B, CD4+, and CD8+ large spleen cells. Besides reinforcing the activation of protective Th1 effector mechanisms, challenge with T. cruzi also induced Th2 effector molecules, such as interleukin (IL)-10 and IL-4, and IL-4-dependent IgG1. Our results are the first evidence that the immune system of T. cruzi chronically infected mice can be optimized in its ability to restrict parasite dissemination, opening the possibility that therapeutic vaccination could be used to reduce the parasite load and pathology of patients with chronic Chagas' disease.
Assuntos
Doença de Chagas/imunologia , Parasitemia/imunologia , Baço/imunologia , Trypanosoma cruzi/imunologia , Animais , Anticorpos Antiprotozoários/sangue , Doença Crônica , Citocinas/biossíntese , Feminino , Hospedeiro Imunocomprometido/imunologia , Imunoglobulinas/biossíntese , Imunoglobulinas/sangue , Subpopulações de Linfócitos/citologia , Subpopulações de Linfócitos/imunologia , Camundongos , Camundongos Endogâmicos A , Baço/citologiaRESUMO
Chagas' disease is a chronic infection caused by Trypanosoma cruzi and represents an important public health burden in Latin America. Frequently the disease evolves undetectable for decades, while in a significant fraction of the affected individuals it culminates in death by heart failure. Here, we describe a novel murine model of the chronic infection with T. cruzi using a stable clone isolated from a human patient (Sylvio X10/4). The infection in the C3H/HePAS mouse strain progresses chronically and is mainly characterized by intense cardiac inflammatory lesions that recapitulate the chronic cardiac pathology observed in the human disease. Moderate striated muscle lesions are also present in C3H/HePAS mice. Viable parasites are detected and recovered from the chronic heart lesions of C3H/HePAS mice, supporting the current notion that development of heart pathology in Chagas' disease is related to parasite persistence in the inflamed tissue. By contrast, in infected A/J mice, chronic inflammatory lesions are targeted to the liver and the skeletal muscle, while pathology and parasites are undetectable in the heart. The phenotypic analysis of F(1) (A/J x C3H/HePAS) and F(2) (A/J x C3H/HePAS) mice suggests that the genetic predisposition to develop the inflammatory lesions caused by T. cruzi (Sylvio X10/4 clone) is heterogeneous because the heart and liver pathology segregate in the F(2) generation. These findings raise the hypothesis that the pathology heterogeneity observed in humans with Chagas' disease (absence and presence of cardiac or digestive chronic lesions) may be attributable to host genetic factors.
Assuntos
Doença de Chagas/genética , Predisposição Genética para Doença , Coração/parasitologia , Fígado/parasitologia , Músculo Esquelético/parasitologia , Trypanosoma cruzi/patogenicidade , Animais , Cardiomiopatia Chagásica/genética , Cardiomiopatia Chagásica/mortalidade , Cardiomiopatia Chagásica/patologia , Doença de Chagas/mortalidade , Doença de Chagas/patologia , Doença Crônica , Humanos , Fígado/patologia , Camundongos , Camundongos Endogâmicos A , Camundongos Endogâmicos C3H , Camundongos Endogâmicos , Músculo Esquelético/patologia , Miocárdio/patologiaRESUMO
Recent studies have provided evidence that macrophages from Th1-prone mouse strains respond with an M1 profile, and macrophages from Th2-prone mouse strains respond with an M2 profile, characterized by the dominant production of NO or TGF-beta 1, respectively. We have shown that peritoneal macrophages from IL-12p40 gene knockout mice have a bias toward the M2 profile, spontaneously secreting large amounts of TGF-beta 1 and responding to rIFN-gamma with weak NO production. Moreover, IL-12p40KO macrophages are more permissive to Trypanosoma cruzi replication than their wild-type littermate cells. Prolonged incubation with rIL-12 fails to reverse the M2 polarization of IL-12p40KO macrophages. However, TGF-beta 1 is directly implicated in sustaining the M2 profile because its inhibition increases NO release from IL-12p40KO macrophages. IFN-gamma deficiency is apparently not the reason for TGF-beta 1 up-regulation, because rIFN-gamma KO macrophages produce normal amounts of this cytokine. These findings raise the possibility that IL-12 has a central role in driving macrophage polarization, regulating their intrinsic ability to respond against intracellular parasites.