Functional antibody responses are improved with a bivalent vaccine.

<p>Plasma was collected on day 56 and pooled from mice immunized on days 0, 21 and 42 to determine nicotine binding capacity by equilibrium dialysis (A). Fourteen days later, mice were injected with an amount of nicotine tartrate equivalent to 12 cigarettes (0.2 mg/kg). Mice were sacrificed after 5 minutes and nicotine levels were measured on brain (B) and plasma (C) by LC-MS/MS.