Induction of antibodies to morphine during chronic morphine treatment in rodents and opiate addicts.

The phenomenon of induction of antibodies to morphine in morphine-treated animals and opiate addicts was shown by means of ELISA. The reaction of the immune system to injections of a morphine solution had the characteristics of a primary immune response. Opiate addicts differed from normal controls in the level of antibodies to morphine of IgM class. Elevated levels of such antibodies could be detected in about 70-80% of addicts with regular longterm opiate use when the time since the last drug intake did not exceed 60 days. Antibodies to morphine could serve as indicators of chronic opiate use especially in periods long after the last drug intake.