Studies on immunomodulatory properties of isoniazid. III. Effect of isoniazid on proliferation of interleukin-dependent and interleukin-independent cell line.

The effect of various concentrations of isoniazid on proliferation of the interleukin 2-dependent cell line, HT-2 and continuous T cell line Jurkat was studied. It was found that high doses of isoniazid increased proliferation of the HT-2 cells in presence of suboptimal doses of interleukin 2. Low doses had no effect on proliferation. The unstimulated Jurkat cells increased proliferation in presence of low doses of isoniazid while phytohemagglutinin-stimulated cells responded to high doses of the drug only. It is hypothesized that biphasic effect of isoniazid is caused by cumulation of direct and indirect effects of T cell activation as well as toxic influence on the cells.