Influence of thia-benzimidazole Wy 18251 of cancer patients' lymphocyte reactivity.

The influence of thiazolobenzimidazole Wy 18251 on reactivity of cancer patients' lymphocytes was investigated. Doses of 0.2 to 20 micrograms/ml added to lymphocytes for 72 hrs did not influence spontaneous 3H-thymidine uptake nor PHA-induced blastogenic response. 50 micrograms/ml of Wy 18251 significantly enhanced blastogenic response of lymphocytes in 5 out of 8 patients. Augmentation of response to mitogens was mainly observed when PHA was added in a concentration leading to suboptimal stimulation. These results suggest that Wy 18251 is active on suboptimal stimulated lymphocytes but ineffective on unstimulated or optimal stimulated human lymphocytes. Further studies are required to give insight in this mechanism of stimulation.