AS-101: a modulator of in vitro T-cell proliferation.

AS-101 is a tellurate compound originally designed as a drug with cytostatic activity. Nevertheless, in vivo it was found to be an immunomodulator agent due to a stimulation of cytokine production. Mitotic Index (MI) as an indicator of cytotoxicity and cell proliferation kinetics (CPK) in lymphocytes cultures are parameters used in the evaluation of the antineoplastic activity of drugs, such as mitomycin-C and cisplatin. For this reason, we evaluated the effects of AS-101 upon these two parameters. The results show that AS-101 produces an inhibition of MI in proliferating lymphocytes higher than the inhibition mediated by cisplatin. When CPK was evaluated, AS-101 induced a retardation not related with dose, while cisplatin produced a stepwise inhibition. This effect contrasts with the stimulation observed when AS-101 was added to non-proliferating lymphocytes which was measured as an increased [3H]thymidine incorporation in culture. The results confirm the mode of action of AS-101 as a real modulating agent of cell proliferation.