As tumors progress they develop ways to escape recognition and attack by cells of the immune system. However, the mechanisms by which tumors modify the immune system have not been clearly determined.
New insight into the way in which chronic lymphocytic leukemia (CLL) cells limit immune cell attack has now been provided by John Gribben and colleagues, at Barts and The London School of Medicine, United Kingdom.
For immune cells known as CD4+ and CD8+ T cells to become activated they must contact other cells known as APCs. The area of contact is known as the immunological synapse and it is highly organized. In the study, CD4+ and CD8+ T cells from patients with CLL were found to exhibit defective immunological synapse formation with APCs. Further, if CD4+ and CD8+ T cells from healthy individuals were cultured with CLL APCs, they also showed defective immunological synapse formation.
As treatment with an immune system--modifying drug improved immunological synapse formation, the authors suggest that approaches to overcoming immunological synapse defects might improve the efficacy of new ways to treat cancer that are currently being developed and that are based on enhancing the antitumor activity of CD4+ and CD8+ T cells.
Journal reference: Chronic lymphocytic leukemia T cells show impaired immunological synapse formation that can be reversed with an immunomodulating drug. Journal of Clinical Investigation. June 12, 2008
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