The anamnestic effect in tuberculin skin testing: measurement and time relations. Experiments in BCG-vaccinated guinea pigs.

The repeat-test effect, an example of anamnestic effect in cellular immunity, was investigated in BCG-vaccinated guinea pigs, using 25 TU Mantoux tests to influence as well as assess skin reactivity to tuberculin. Two different methods of quantitating the effect were tried and found valuable. The effect could be regularly observed 12 weeks or more after BCG-vaccination, and with less regularly 6 to 9 weeks after BCG-vaccination. The effect was found whether the interval between the first (interim) test and the second (repeat) test was as short as 3 days or as long as 44 weeks.