Abstract
The occurrence of brain tumors is associated with broad suppression of the immune system function; however, the mechanisms involved in this impairment are not fully characterized. In this study, we have examined mechanisms involved in diminished T lymphocyte reactivity in patients with glioblastomas as compared to patients with other types of brain tumors. We found that the proliferative response of T lymphocytes stimulated with phytohemagglutinin or anti-CD3 was significantly reduced in these patients as compared to patients with meningiomas, oligodendrogliomas and healthy individuals. Stimulated T cells appear to express lower levels of theα-subunit (p55) of the IL-2 receptor (IL-2R), and increased levels of soluble IL-2R in cell supernatants, whereas no significant differences were observed in the level of the β (p75)- orγ-subunits. In addition, we found that competent T cells of glioblastoma patients exhibit lower levels of tyrosine phosphorylation in response to IL-2 as compared with cells of healthy donors. The decrease in the levels of IL-2 and its receptor was selective since no significant changes were observed in the secretion of other Th1- and Th2-derived cytokines (IFN-γand IL-4) and the expression of their respective receptors. These results indicate that the diminished response of T cells obtained from patients with glioblastomas may be due to a selective defect in the production of IL-2 and in the expression of functional IL-2R due to a decreased expression of the membranal IL-2Rαand to lower levels of tyrosine phosphorylation in response to IL-2.
Original language | English |
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Pages (from-to) | 49-56 |
Number of pages | 8 |
Journal | NeuroImmunoModulation |
Volume | 4 |
Issue number | 1 |
DOIs | |
State | Published - 1 Jan 1997 |
Externally published | Yes |
Keywords
- Brain tumors
- Cytokines
- Interleukin-2 receptor
- Lymphocytes
- Soluble receptor
- Tyrosine phosphorylation
ASJC Scopus subject areas
- Immunology
- Endocrinology
- Neurology
- Endocrine and Autonomic Systems