A Study of Immunity in Rabbits from Two to Three Years After Infection with Vaccine Virus with Attempts to Recover Active Virus

[摘要] 1. 1. Of 4 rabbits tested for active immunity nearly 3 years after vaccinal infection, 1 was not immune, 1 showed a slight, and 2 a moderate degree of resistance to cutaneous reinfection.2. 2. No active virus was recovered from 2 to 3 years after vaccinal infection from selected tissues of the 7 rabbits studied. From the testes of 1 of these animals and the spleen of 2 others, no virus had been detected after 1 year. However, from a skin scar but not from the spleen of 1 rabbit, vaccine virus had been recovered 3 months after infection.3. 3. Sera from the 7 rabbits, about 2½ years after the last vaccinal infection, neutralized from 10 to 10,000 minimal skin doses of vaccine virus.4. 4. Sera from 2 of the 7 rabbits, more than 2½ years after last infection, showed agglutinins to vaccinal elementary bodies to a titer of 1:16; the other 5 sera showed none. No precipitins to dermal filtrate were found in any of the sera.5. 5. The results are discussed with reference to the problem of persistence of virus and duration of immunity.

[学科分类] 生物科学（综合）