| Autor: |
Galvão da Silva AP; Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil., de Almeida Abrahamsohn I |
| Jazyk: |
angličtina |
| Zdroj: |
Immunology [Immunology] 2001 Nov; Vol. 104 (3), pp. 349-54. |
| DOI: |
10.1046/j.1365-2567.2001.01311.x |
| Abstrakt: |
The cytokine interleukin-12 (IL-12) is essential for resistance to Trypanosoma cruzi infection because it stimulates the synthesis of interferon-gamma (IFN-gamma), a major activator of the parasiticidal effect of macrophages. A less studied property of IL-12 is its ability to amplify the proliferation of T or natural killer (NK) lymphocytes. We investigated the role of endogenously produced IL-12 in the maintenance of parasite antigen (T-Ag)-specific lymphoproliferative responses during the acute phase of T. cruzi infection. We also studied whether treatment with recombinant IL-12 (rIL-12) would stimulate T-Ag-specific or concanavalin A (Con A)-stimulated lymphoproliferation and abrogate the suppression that is characteristic of the acute phase of infection. Production of IL-12 by spleen-cell cultures during T. cruzi infection increased in the first days of infection (days 3-5) and decreased as infection progressed beyond day 7. The growth-promoting activity of endogenous IL-12 on T-Ag-specific proliferation was observed on day 5 of infection. Treatment of cultures with rIL-12 promoted a significant increase in Con A-stimulated proliferation by spleen cells from normal or infected mice. Enhanced T-Ag-specific proliferation by rIL-12 was seen in spleen cell cultures from infected mice providing that nitric oxide production was inhibited by treatment with the competitive inhibitor NG-monomethyl-L-arginine (NMMA). Enhancement of proliferation promoted by IL-12 occurred in the presence of neutralizing anti-interleukin-2 (IL-2) antibody, suggesting that this activity of IL-12 was partly independent of endogenous IL-2. Thymidine incorporation levels achieved with rIL-12 treatment of the cultures were approximately 50% of those stimulated by rIL-2 in the same cultures. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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