Persistence of Neutralizing Antibody for a Year following Vaccination of Monkeys with Lansing Poliomyelitis Virus.

SummaryThe level of serum neutralizing antibody to Lansing poliomyelitis virus has been followed in three rhesus monkeys. After a course of intramuscular vaccination with active virus, which rendered the animals resistant to intracerebral challenge with a large dose of virus, they received a final vaccinating dose intramuscularly. During the year following this final dose, no more vaccine was given. Their antibody levels, optimum at the start, fell gradually during the first 8 months, then remained at a moderate level for the last 4 months. At the end of the year, a booster dose of active virus given intramuscularly raised their antibody to optimum levels once more, from which they gradually drifted downward.