Specific inhibition of mRNA accumulation for lymphokines in human T cell line Jurkat by mycobacterial lipoarabinomannan antigen.

The immunomodulatory effect of Mycobacterium tuberculosis-derived lipoarabinomiinnan (LAM) on mitogen/antigen-induced expression of mRNAs for a number of cytokines in human monocytic cell line Mono-Mac-6 and in T cell line Jurkat was investigated. Interestingly. LAM exhibited a down-regulatory effect on the accumulation of mRNAs for IL-2, IL-3. granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-2 receptor alpha (IL-2Rα) in T cells co-stimulated with phytohaemagglutinin-P (PHA) and 4β-phorbol-12-myristyl-13-acetate (PMA). In human Mono-Mac-6 cells. LAM has a weak inhibitory effect on the lipopolysacharide (LPS)-induced mRNA accumulation for IL-lβ. a slight stimulatory effect on in mRNAs accumulation for IL-8 and tumour necrosis factor-alpha (TNE-α). but clearly no effect on mRNA accumulation for intercellular adhesion molecule-1 (ICAM-1). These findings imply that LAM may contribute to the immnunologic defects associated with a number of mycobacterial infections by modulating these mediators. [ABSTRACT FROM AUTHOR]