Abstract
Vaccination against nicotine blocks or attenuates nicotine-related behaviors relevant to addiction in rats. Passive immunization with nicotine-specific antibodies is an alternative to vaccination with the potential advantages of allowing control of antibody dose and affinity. In the current study, the effects of two antibodies on the distribution of nicotine to brain were evaluated during chronic nicotine administration in rats; the monoclonal antibody Nic311 (Kd = 60 nM) and nicotine-specific antiserum (Kd = 1.6 nM). Nicotine was administered via repeated i.v. bolus doses over 2 days and antibody was administered during the first day. Neither antibody appreciably reduced the chronic accumulation of nicotine in brain, despite high protein binding of nicotine in serum (98.9%) and a 73% reduction in the unbound serum nicotine concentration with the highest Nic311 dose. However, both antibodies substantially reduced the early distribution of nicotine to brain 5 min after a dose. The higher affinity antibody was no more effective than Nic311. The highest Nic311 dose produced serum antibody levels 10 times higher than those reported with vaccination. The efficacy of Nic311 was dose-related, with the highest dose producing a 76% decrease in the early distribution of nicotine to brain. These findings, along with previous data, suggest that the primary effect of passive immunization is to slow, rather than prevent, the distribution of nicotine to brain. In the setting of chronic nicotine dosing, antibodies with a moderate affinity for nicotine produced substantial effects on the early distribution of nicotine to brain and were as effective as higher affinity antibodies.
Footnotes
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This study was supported by National Institutes of Health Grants DA10714, T32-DA07097, P50-DA013333, and 5442RR005991-15 to the National Cell Culture Center.
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doi:10.1124/jpet.105.097873.
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ABBREVIATIONS: Nic311, nicotine-specific monoclonal antibody; Nic-IgG, nicotine-specific rabbit antiserum; ELISA, enzyme-linked immunosorbent assay; ANOVA, analysis of variance.
- Received November 6, 2005.
- Accepted January 6, 2006.
- The American Society for Pharmacology and Experimental Therapeutics
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