Studies on immunomodulatory properties of isoniazid. IV. Effect of isoniazid on T lymphocyte activation by phorbol ester tumor promoter.

Human peripheral blood T cells or continuous T cell lines were treated with phorbol myristate (PMA), a direct protein kinase C activator. The effect of isoniazid on PMA-treated cells was investigated. It was found that low doses of isoniazid augmented proliferation of T cells treated with PMA or stimulated with PMA and phytohemagglutinin. Similar results were shown in the Jurkat cell line. There was no influence of isoniazid upon proliferation of PMA-treated HT-2 cells, interleukin 2-dependent cell line. The obtained results suggest that, at least one target mechanism of isoniazid is located in T cell activation pathway after protein kinase C activation.