“…In this sense, our laboratory previously reported the efficacy of the tetanus toxoid-conjugated morphine vaccine. 51–57 The M 6 -TT vaccine was capable of generating high titers of antibodies capable of capturing morphine, heroin, and their metabolites 51 , 52 and reducing heroin- or morphine-induced antinociception, 53 , 55 , 56 self-administration, 51 , 52 and locomotor activity, 54 , 57 in Wistar rats and BALB/c, C57Bl/6 and DBA/2 mice. 54 …”