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Detection of early apoptosis and cell death in T CD4+ and CD8+ cells from lesions of patients with localized cutaneous leishmaniasis
Bertho, A.L.;Santiago, M.A.;Da-Cruz, A.M.;Coutinho, S.G.;
Brazilian Journal of Medical and Biological Research , 2000, DOI: 10.1590/S0100-879X2000000300010
Abstract: human localized cutaneous leishmaniasis (lcl), induced by leishmania braziliensis, ranges from a clinically mild, self-healing disease with localized cutaneous lesions to severe forms which can present secondary metastatic lesions. the t cell-mediated immune response is extremely important to define the outcome of the disease; however, the underlying mechanisms involved are not fully understood. a flow cytometric analysis of incorporation of 7-amino actinomycin d and cd4+ or cd8+ t cell surface phenotyping was used to determine whether different frequencies of early apoptosis or accidental cell death occur at different stages of lcl lesions. when all cells obtained from a biopsy sample were analyzed, larger numbers of early apoptotic and dead cells were observed in lesions from patients with active disease (mean = 39.5 ± 2.7%) as compared with lesions undergoing spontaneous healing (mean = 17.8 ± 2.2%). cells displaying normal viability patterns obtained from active lcl lesions showed higher numbers of early apoptotic events among cd8+ than among cd4+ t cells (mean = 28.5 ± 3.8 and 15.3 ± 3.0%, respectively). the higher frequency of cell death events in cd8+ t cells from patients with lcl may be associated with an active form of the disease. in addition, low frequencies of early apoptotic events among the cd8+ t cells were observed in two patients with self-healing lesions. although the number of patients in the latter group was small, it is possible to speculate that, during the immune response, differences in apoptotic events in cd4+ and cd8+ t cell subsets could be responsible for controlling the cd4/cd8 ratio, thus leading to healing or maintenance of disease.
Detection of early apoptosis and cell death in T CD4+ and CD8+ cells from lesions of patients with localized cutaneous leishmaniasis  [cached]
Bertho A.L.,Santiago M.A.,Da-Cruz A.M.,Coutinho S.G.
Brazilian Journal of Medical and Biological Research , 2000,
Abstract: Human localized cutaneous leishmaniasis (LCL), induced by Leishmania braziliensis, ranges from a clinically mild, self-healing disease with localized cutaneous lesions to severe forms which can present secondary metastatic lesions. The T cell-mediated immune response is extremely important to define the outcome of the disease; however, the underlying mechanisms involved are not fully understood. A flow cytometric analysis of incorporation of 7-amino actinomycin D and CD4+ or CD8+ T cell surface phenotyping was used to determine whether different frequencies of early apoptosis or accidental cell death occur at different stages of LCL lesions. When all cells obtained from a biopsy sample were analyzed, larger numbers of early apoptotic and dead cells were observed in lesions from patients with active disease (mean = 39.5 ± 2.7%) as compared with lesions undergoing spontaneous healing (mean = 17.8 ± 2.2%). Cells displaying normal viability patterns obtained from active LCL lesions showed higher numbers of early apoptotic events among CD8+ than among CD4+ T cells (mean = 28.5 ± 3.8 and 15.3 ± 3.0%, respectively). The higher frequency of cell death events in CD8+ T cells from patients with LCL may be associated with an active form of the disease. In addition, low frequencies of early apoptotic events among the CD8+ T cells were observed in two patients with self-healing lesions. Although the number of patients in the latter group was small, it is possible to speculate that, during the immune response, differences in apoptotic events in CD4+ and CD8+ T cell subsets could be responsible for controlling the CD4/CD8 ratio, thus leading to healing or maintenance of disease.
T-cell responses associated with resistance to Leishmania infection in individuals from endemic areas for Leishmania (Viannia) braziliensis
Bittar, Rita C;Nogueira, Ricardo S;Vieira-Gon?alves, Ricardo;Pinho-Ribeiro, Vanessa;Mattos, Marise S;Oliveira-Neto, Manoel Paes;Coutinho, Sergio G;Da-Cruz, Alda M;
Memórias do Instituto Oswaldo Cruz , 2007, DOI: 10.1590/S0074-02762007005000069
Abstract: subclinical or asymptomatic infection is documented in individuals living in endemic areas for leishmaniasis suggesting that the development of an appropriate immune response can control parasite replication and maintain tissue integrity. a low morbidity indicates that intrinsic factors could favor resistance to leishmania infection. herein, leishmanial t-cell responses induced in subjects with low susceptibility to leishmaniasis as asymptomatic subjects were compared to those observed in cured cutaneous leishmaniasis (ccl) patients, who controlled the disease after antimonial therapy. all of them have shown maintenance of specific long-term immune responses characterized by expansion of higher proportions of cd4+ as compared to cd8+ leishmania reactive t-lymphocytes. asymptomatic subjects had lower indexes of in vitro leishmania induced lymphoproliferative responses and interferon-gamma (ifn-g) production in comparison to ccl patients. on the other hand, interleukin (il-10) production was much higher in asymptomatics than in ccl, while no differences in il-5 levels were found. in conclusion, long lived t-cell responses achieved by asymptomatic individuals differed from those who had developed symptomatic leishmaniasis in terms of intensity of lymphocyte activation (proliferation or ifn-g) and regulatory mechanisms (il-10). the absence of the disease in asymptomatics could be explained by their intrinsic ability to create a balance between immunoregulatory (il-10) and effector cytokines (ifn-g), leading to parasite destruction without producing skin tissue damage. the establishment of profiles of cell-mediated immune responses associated with resistance against leishmania infection is likely to make new inroads into understanding the long-lived immune protection against the disease.
Cell populations in lesions of cutaneous leishmaniasis of leishmania (L.) amazonensis- infected rhesus macaques, Macaca mulatta
Amaral, VF;Pirmez, C;Gon?alves, AJS;Ferreira, V;Grimaldi Jr, G;
Memórias do Instituto Oswaldo Cruz , 2000, DOI: 10.1590/S0074-02762000000200012
Abstract: the cellular nature of the infiltrate in cutaneous lesion of rhesus monkeys experimentally infected with leishmania (l.) amazonensis was characterized by immunohistochemistry. skin biopsies from infected animals with active or healing lesions were compared to non-infected controls (three of each type) to quantitate inflammatory cell types. inflammatory cells (composed of a mixture of t lymphocyte subpopulations, macrophages and a small number of natural killer cells and granulocytes) were more numerous in active lesions than in healing ones. t-cells accounted for 44.7 ± 13.1% of the infiltrate in active lesions (versus cd2+ = 40.3 ± 5.7% in healing lesions) and t-cell ratios favor cd8+ cells in both lesion types. the percentage of cells expressing class ii antigen (hla-dr+) in active lesions (95 ± 7.1%) was significantly higher (p < 0.005) from the healing lesions (42.7 ± 12.7%). moreover, the expression of the activation molecules cd25 (@ 16%), the receptor for interleukin-2, suggests that many t cells are primed and proliferating in active lesions. distinct histopathological patterns were observed in lesions at biopsy, but healing lesions contained more organized epithelioid granulomas and activated macrophages, followed by fibrotic substitution. the progression and resolution of skin lesions appears to be very similar to that observed in humans, confirming the potential for this to be used as a viable model to study the immune response in human cutaneous leishmaniasis.
Cell populations in lesions of cutaneous leishmaniasis of leishmania (L.) amazonensis- infected rhesus macaques, Macaca mulatta  [cached]
Amaral VF,Pirmez C,Gon?alves AJS,Ferreira V
Memórias do Instituto Oswaldo Cruz , 2000,
Abstract: The cellular nature of the infiltrate in cutaneous lesion of rhesus monkeys experimentally infected with Leishmania (L.) amazonensis was characterized by immunohistochemistry. Skin biopsies from infected animals with active or healing lesions were compared to non-infected controls (three of each type) to quantitate inflammatory cell types. Inflammatory cells (composed of a mixture of T lymphocyte subpopulations, macrophages and a small number of natural killer cells and granulocytes) were more numerous in active lesions than in healing ones. T-cells accounted for 44.7 ± 13.1% of the infiltrate in active lesions (versus CD2+= 40.3 ± 5.7% in healing lesions) and T-cell ratios favor CD8+ cells in both lesion types. The percentage of cells expressing class II antigen (HLA-DR+) in active lesions (95 ± 7.1%) was significantly higher (P < 0.005) from the healing lesions (42.7 ± 12.7%). Moreover, the expression of the activation molecules CD25 (@ 16%), the receptor for interleukin-2, suggests that many T cells are primed and proliferating in active lesions. Distinct histopathological patterns were observed in lesions at biopsy, but healing lesions contained more organized epithelioid granulomas and activated macrophages, followed by fibrotic substitution. The progression and resolution of skin lesions appears to be very similar to that observed in humans, confirming the potential for this to be used as a viable model to study the immune response in human cutaneous leishmaniasis.
Linfocitos T citotóxicos CD8+ en la leishmaniasis cutánea
Hernández-Ruiz,Joselín; Becker,Ingeborg;
Salud Pública de México , 2006, DOI: 10.1590/S0036-36342006000500009
Abstract: objective: review of the literature on the role of cd8+ t cell in the immune response against leishmania species that cause cutaneous leishmaniasis. the role of macrophages, dendritic cells, cd4 t cells and nk cells has been extensively analyzed in leishmaniasis, yet very little knowledge has been gained on cd8+ t cells in this disease. murine models of leishmaniasis suggest that cd8+ t cells participate through ifng production, yet their cytotoxic capacity may also play a crucial role, as has been found in human disease. it is an enigma what mechanisms underlie the cd8+ t cell activation. it is possible that dendritic cells activate cd8+ t cells through mechanisms that include antigen traspresentation. a better understanding of cd8+ t cells in the immune response against leishmania will undoubtedly provide new insights into the physiopathogenesis of the disease that could lead to new therapeutic approaches against leishmaniasis.
Immunologic patterns associated with cure in human American cutaneous leishmaniasis
Coutinho, S.G.;Da-Cruz, A.M.;Bertho, A.L.;Santiago, M.A.;De-Luca, P.;
Brazilian Journal of Medical and Biological Research , 1998, DOI: 10.1590/S0100-879X1998000100019
Abstract: patients with american cutaneous leishmaniasis were studied before therapy (active lesion) and at the end of therapy (cured patients). assays of lymphocyte proliferative responses of peripheral blood mononuclear cells induced in vitro by leishmania braziliensis promastigote antigens (lb) were performed. antigen-stimulated cells were harvested for cd4 and cd8 phenotype analysis and the levels of gamma interferon (ifn-g) and interleukin 4 (il-4) produced were also determined in the culture supernatants. two different patterns of lb-induced t cell responses were observed: a) predominance of responding cd4+ cells and mixed type 1 and type 2 cytokine production (ifn-g and il-4) during the active disease, and b) similar proportions of responding cd4+ and cd8+ cells, and type 1 cytokine production (presence of ifn-g and very low il-4) at the end of therapy (healed lesions). this last pattern is probably associated with a beneficial t cell response
Immunologic patterns associated with cure in human American cutaneous leishmaniasis  [cached]
Coutinho S.G.,Da-Cruz A.M.,Bertho A.L.,Santiago M.A.
Brazilian Journal of Medical and Biological Research , 1998,
Abstract: Patients with American cutaneous leishmaniasis were studied before therapy (active lesion) and at the end of therapy (cured patients). Assays of lymphocyte proliferative responses of peripheral blood mononuclear cells induced in vitro by Leishmania braziliensis promastigote antigens (Lb) were performed. Antigen-stimulated cells were harvested for CD4 and CD8 phenotype analysis and the levels of gamma interferon (IFN-g) and interleukin 4 (IL-4) produced were also determined in the culture supernatants. Two different patterns of Lb-induced T cell responses were observed: a) predominance of responding CD4+ cells and mixed type 1 and type 2 cytokine production (IFN-g and IL-4) during the active disease, and b) similar proportions of responding CD4+ and CD8+ cells, and type 1 cytokine production (presence of IFN-g and very low IL-4) at the end of therapy (healed lesions). This last pattern is probably associated with a beneficial T cell response
Lipopolysaccharide-Induced Cellular Activation May Participate in the Immunopathogenesis of Visceral Leishmaniasis Alone or in HIV Coinfection  [PDF]
Joanna Reis Santos-Oliveira,Alda Maria Da-Cruz
International Journal of Microbiology , 2012, DOI: 10.1155/2012/364534
Abstract: Visceral Leishmaniasis (VL) is an infectious disease which constitutes a serious public health problem, integrating the list of neglected tropical diseases. The disease is characterized by a Leishmania-specific immune suppression T-cell depletion and a decrease of other hematopoietic cells. In parallel, an immunostimulatory response also occurs, represented by polyclonal B lymphocytes, T-cell activation, and systemic proinflammatory responses. Parasite antigens were believed to mediate both suppression and activation mechanisms, but these concepts are constantly being revised. Similar to reports on HIV/AIDS, we have proposed that gut parasitation by amastigotes and lymphocyte depletion could also affect gut-associated lymphoid tissue, leading to mucosal barrier breach and predisposing to microbial translocation. An increment of plasmatic lipopolysaccharide (LPS) levels observed in Brazilian VL patients was implicated in the reduced blood CD4+ and CD8+ T cell counts, systemic T-cell activation, pro-inflammatory cytokines and MIF plasma levels, suggesting that a bacterial molecule not associated with Leishmania infection can exert deleterious effects on immune system. Recent results also pointed that the proinflammatory response was potentiated in VL/HIV-AIDS coinfected patients. The LPS-mediated cell activation adds another concept to the immunopathogenesis of VL and can bring a rational for new therapeutic interventions that could ameliorate the management of these patients. Visceral leishmaniasis (VL) is an infectious disease caused by protozoans of Leishmania sp. genus. VL is a serious public health problem integrating the list of neglected tropical diseases. In a recent World Health Organization report, 0.2 to 0.4 million cases were globally estimated in the last five years [1]. Ninety percent of them occur in only six countries: India, Bangladesh, Sudan, South Sudan, Brazil, and Ethiopia [1, 2]. The infection is transmitted by sandflies, and nowadays, L. (Leishmania)donovani and L. infantum (sin. L. chagasi) are the main species causing VL [3]. These protozoans are intracellular obligate parasites that infect macrophage cell lineages from lymphoid organs such as bone marrow, spleen, liver, and lymph nodes. VL is classically characterized by fever, hepatosplenomegaly, cachexia, blood cytopenia, and a high parasite burden [4, 5]. It has a high mortality rate, and even in treated patients, the case fatality rates are of 10–20% [1], especially in HIV-coinfected patients [6]. Immunological response is directly involved in the disease’s clinical outcome,
B7-H1 Blockade Increases Survival of Dysfunctional CD8+ T Cells and Confers Protection against Leishmania donovani Infections  [PDF]
Trupti Joshi,Susana Rodriguez,Vladimir Perovic,Ian A. Cockburn,Simona St?ger
PLOS Pathogens , 2009, DOI: 10.1371/journal.ppat.1000431
Abstract: Experimental visceral leishmaniasis (VL) represents an exquisite model to study CD8+ T cell responses in a context of chronic inflammation and antigen persistence, since it is characterized by chronic infection in the spleen and CD8+ T cells are required for the development of protective immunity. However, antigen-specific CD8+ T cell responses in VL have so far not been studied, due to the absence of any defined Leishmania-specific CD8+ T cell epitopes. In this study, transgenic Leishmania donovani parasites expressing ovalbumin were used to characterize the development, function, and fate of Leishmania-specific CD8+ T cell responses. Here we show that L. donovani parasites evade CD8+ T cell responses by limiting their expansion and inducing functional exhaustion and cell death. Dysfunctional CD8+ T cells could be partially rescued by in vivo B7-H1 blockade, which increased CD8+ T cell survival but failed to restore cytokine production. Nevertheless, B7-H1 blockade significantly reduced the splenic parasite burden. These findings could be exploited for the design of new strategies for immunotherapeutic interventions against VL.
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