High levels of intracellular IL-4 are expressed in circulating apoptotic T cells in patients with tuberculosis and in community controls.

Autor: Veenstra, Hanne, Baumann, Ralf, Lukey, Pauline T., Beyers, Nulda, van Helden, Paul D., Walzl, Gerhard
Předmět:
Zdroj: Tuberculosis (14729792); Jan2008, Vol. 88 Issue 1, p21-30, 10p
Abstrakt: Summary: Data concerning T helper cell phenotypes in response to Mycobacterium tuberculosis infection remain controversial. T lymphocyte intracellular interleukin-4 production in response to CD3 stimulation was determined by flow cytometry in 21 TB patients and 14 community controls. In supplementary experiments the association of interleukin-4 expression with apoptosis was investigated. A low percentage of CD4 T cells in both patients and controls expressed high levels of interleukin-4 (IL-4high). A larger subset of both CD4 and CD8 T cells of all subjects expressed low levels of intracellular IL-4 (IL-4low). Stimulated and unstimulated cells expressed IL-4low and IL-4high. IL-4low percentages were lower in TB patients at diagnosis compared to controls while IL-4high percentages were higher in patients. Most IL-4high cells co-expressed active caspase-3, a marker for apoptosis. This co-expression was also shown in experimentally induced apoptotic Jurkat cells and peripheral blood neutrophils and monocytes. IL-4 levels may therefore not necessarily indicate a skewed Th cell phenotype, as our data suggest that IL-4 production by CD4 and CD8 T cells can occur constitutively in healthy controls with latent TB infection and in TB patients. Cellular IL-4 production may represent a normal cellular growth factor mechanism which is disturbed at the onset of apoptosis. [Copyright &y& Elsevier]
Databáze: Supplemental Index
Externí odkaz: