Preparation and characterization of anti-morphine vaccine antibody

AIM: To prepare anti-morphine vaccine antibody with high titer and good specificity and to identify its properties. METHODS: Chemically synthesized 6-succinylmorphine (M-6-S) was cross-linked to BSA in pH 9.0 carbonate buffer. After being purified by gel filtration and (NH4)2SO4 salting out, the immunogen was used to immunize BALB/c mice and SD rats. The titer and specificity of antisera were identified by ELISA and neutralization inhibition test, respectively. The effect of the immunization was examined by the radiant heat tail-flick (TF) reflex test. RESULTS: The titers of antiserum from immunized BALB/c mice and SD rats were up to 1:200,000 and over 1:20,000, respectively. Neutralization inhibition test proved that the anti-morphine vaccine antibody had the cross-reactions to following drugs with analogous structure as morphine: 6-monoacetylmorphine, heroin and codeine. The TF reflex test showed: (1) TF reflexes were notable inhibited after intraperitoneal injection of 2 mg/kg morphine, and (2) percentage of the maximum possible effect (% MPE) reduced 74.7%, (3) the TF latency recovered to the baseline level much more rapidly compared with the control rats. CONCLUSION: The M-6-S-BSA vaccine has been prepared successfully. The BALB/c mice and SD rats immunized with the vaccine can produce anti-morphine antibody with high titer and satisfactory specificity, which may significantly reduce rats' antinociception against morphine.