CD4+ T cells apoptosis in Plasmodium vivax infection is mediated by activation of both intrinsic and extrinsic pathways.
Malar J
; 14: 5, 2015 Jan 05.
Article
em En
| MEDLINE
| ID: mdl-25559491
ABSTRACT
BACKGROUND:
Reduction in the number of circulating blood lymphocytes (lymphocytopaenia) has been reported during clinical episodes of malaria and is normalized after treatment with anti-malaria drugs. While this phenomenon is well established in malaria infection, the underlying mechanisms are still not fully elucidated. In the present study, the occurrence of apoptosis and its pathways in CD4+ T cells was investigated in naturally Plasmodium vivax-infected individuals from a Brazilian endemic area (Porto Velho - RO).METHODS:
Blood samples were collected from P. vivax-infected individuals and healthy donors. The apoptosis was characterized by cell staining with Annexin V/FITC and propidium iodide and the apoptosis-associated gene expression profile was carried out using RT2 Profiler PCR Array-Human Apoptosis. The plasma TNF level was determined by ELISA. The unpaired t-test or Mann-Whitney test was applied according to the data distribution.RESULTS:
Plasmodium vivax-infected individuals present low number of leukocytes and lymphocytes with a higher percentage of CD4+ T cells in early and/or late apoptosis. Increased gene expression was observed for TNFRSF1B and Bid, associated with a reduction of Bcl-2, in individuals with P. vivax malaria. Furthermore, these individuals showed increased plasma levels of TNF compared to malaria-naive donors.CONCLUSIONS:
The results of the present study suggest that P. vivax infection induces apoptosis of CD4+ T cells mediated by two types of signaling by activation of the TNFR1 death receptor (extrinsic pathway), which is amplified by Bid, and by decreased expression of the anti-apoptotic protein Bcl-2 (intrinsic pathway). The T lymphocytes apoptosis could reflect a strategy of immune evasion triggered by the parasite, enabling their persistence but also limiting the occurrence of immunopathology.
Texto completo:
1
Coleções:
01-internacional
Contexto em Saúde:
3_ND
Base de dados:
MEDLINE
Assunto principal:
Linfócitos T CD4-Positivos
/
Malária Vivax
/
Apoptose
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Proteínas Proto-Oncogênicas c-bcl-2
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Receptores Tipo I de Fatores de Necrose Tumoral
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Interações Hospedeiro-Patógeno
Limite:
Adult
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Female
/
Humans
/
Male
/
Middle aged
País/Região como assunto:
America do sul
/
Brasil
Idioma:
En
Revista:
Malar J
Ano de publicação:
2015
Tipo de documento:
Article