Pneumococcal Infections in Humans Are Associated with Increased Apoptosis and Trafficking of Type 1 Cytokine-Producing T Cells
AUTOR(ES)
Kemp, Kåre
FONTE
American Society for Microbiology
RESUMO
Streptococcus pneumoniae infections are associated with considerable morbidity and mortality throughout the world. The immunopathology is characterized by an intense inflammatory reaction, including a strong acute-phase response and increased numbers of neutrophils in the circulation. However, little is known regarding the T-cell response during in vivo infections in humans. The purpose of this study was to test the hypothesis that activated T cells producing type 1 cytokines were engaged in the host response to pneumococcal infections. The phenotype and function of T cells were studied in 22 patients at admission to a department of infectious diseases and after antibiotic treatment for 1 week compared with an age-matched, healthy control group. Pneumococcal infections induced lymphopenia in the circulation due to the disappearance of activated T lymphocytes with a type 1 cytokine profile. In contrast, the numbers of naive T cells and interleukin-4-producing T cells did not change. Activated type 1 cytokine-producing cells reappeared in the circulation in relation to the treatment and clinical improvement. The underlying mechanisms during infection may include sequestration in the peripheral tissues and/or apoptosis. In fact, increased activation-induced apoptosis in the remaining peripheral lymphocytes and elevated levels of soluble Fas ligand were detected at admission to the hospital. In conclusion, these data suggest that activated T lymphocytes with a type 1 cytokine profile are highly engaged in the in vivo immune response to S. pneumoniae.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=128234Documentos Relacionados
- Differences in the Frequency of Cytokine-Producing Cells in Antigenemic and Nonantigenemic Individuals with Bancroftian Filariasis
- Balanced cytokine-producing pattern in mice immunized with an avirulent Trypanosoma cruzi
- Subcutaneous vaccination with irradiated, cytokine-producing tumor cells stimulates CD8+ cell-mediated immunity against tumors located in the "immunologically privileged" central nervous system.
- Reciprocal Regulation of Th1- and Th2-Cytokine-Producing T Cells during Clearance of Parasitemia in Plasmodium falciparum Malaria
- Flow Cytometric Determination of Cellular Sources and Frequencies of Key Cytokine-Producing Lymphocytes Directed against Recombinant LACK and Soluble Leishmania Antigen in Human Cutaneous Leishmaniasis