Azathioprine and 6-mercaptopurine (6-MP) suppress the human mixed lymphocyte reaction (MLR) by different mechanisms.
6-MP inhibitory effects on the MLR were reversed by AIC (46%), adenine (32%), hypoxanthine (89%), adenosine (86%) and inosine (93%). AIC, adenine, hypoxanthine and inosine had no effect on azathioprine inhibition of the MLR. Adenosine at 10 microM caused 29% reversal and had no effect at 100-400 microM on azathioprine inhibition of the MLR. Reversal of 6-MP suppression of the MLR was decreased with the delay of adenosine addition. Guanine, xanthine and guanosine caused no reversal of 6-MP or azathioprine inhibitory effects on the MLR. These results show that azathioprine and 6-MP suppress the MLR by different mechanisms.
D000225:Adenine / Q000494:pharmacology; D000241:Adenosine / Q000494:pharmacology; D000620:Aminoimidazole Carboxamide / Q000494:pharmacology; D001379:Azathioprine / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis; D006147:Guanine / Q000494:pharmacology; D006801:Humans; D019271:Hypoxanthine; D007042:Hypoxanthines / Q000494:pharmacology; D066298:In Vitro Techniques; D007288:Inosine / Q000494:pharmacology; D007959:Lymphocyte Culture Test, Mixed; D008214:Lymphocytes / Q000187:drug effects*; D015122:Mercaptopurine / Q000494:pharmacology*; D019820:Xanthine; D014970:Xanthines / Q000494:pharmacology
D007042:Hypoxanthines; D014970:Xanthines; D019820:Xanthine; D019271:Hypoxanthine; D000620:Aminoimidazole Carboxamide; D007288:Inosine; D006147:Guanine; D004247:DNA; D015122:Mercaptopurine; D000225:Adenine; D000241:Adenosine; D001379:Azathioprine