SOME PROBLEMS IN HUMORAL SMALLPOX IMMUNITY

Abstract : The ratio of humoral antismallpox antibodies has been studied. Neutralizing antibodies were found in 99.1%, antihemagglutinins -- in 86.7%, complement-fixating antibodies -- in 50% of sera examined. A direct relationship was found between the level of antihemagglutinins and neutralizing antibodies. Following revaccination, a gradual drop in antihemagglutinin level was observed and in 1.5-2.5 years antihemagglutinins were contained in 60.25% of the inoculants at a low titer (1:10) or were absent entirely. Neutralizing antibodies disappeared considerably more slowly and by the same period of time had been determined in 80% of inoculants at a titer not less than 1:5. The level of neutralizing antibodies depended on the total number of inoculations and intervals between such treatments. A high level of these antibodies was observed in revaccinations performed at an interval of 6-12 months. The level of neutralizing antibodies in revaccinations made after two years was considerably lower (averaging 1:5). In persons reacting negatively to inoculation, before revaccination: the mean antibody level was higher than in persons reacting positively. However, significant individual fluctuations in the character of skin reaction not coinciding with the antibody level was noted.