Evaluation of Resistance to Staphylococcal Enterotoxic B: Naturally Acquired Antibodies of Man and Monkey
ARMY MEDICAL RESEARCH INST OF INFECTIOUS DISEASES FORT DETRICK MD
Pagination or Media Count:
Sera from residents of the United States and Southeast Asia were surveyed for the presence of antibody to highly purified staphylococcal enterotoxin B SEB. Hemagglutination of ovine erythrocytes coupled to SEB was the method for detecting antibody, and immune-precipitation reaction in agar gel served as an indicator of IgG antibody activity. Approximately 70 of sera from the U.S. had HA antibody and 30 had precipitins, whereas all samples from Southeast Asia had HA activity and 90 had precipitating activity. Seroconversion occurred in individuals who had no known history of exposure to SEB. Experimental intoxication of rhesus monkeys indicated that repeated parenteral exposure to SEB was required to achieve the titers of antibody observed in human sera. Rechallenge by gavage was less effective, in that antibody stimulation occurred only in monkeys that were fed repeatedly with 100 median effective doses ED50. Resistance to a primary iv challenge with 1-25 ED50 was correlated with titers of naturally acquired HA antibody, but resistance to higher does was related to presence of precipitins. Ten weeks after primary exposure, many monkeys lacking humoral antibody were resistant to a second iv challenge. In contrast, illness following primary challenge with 1- 100 ED50 by gavage was unrelated to values of antibody, and the initial exposure had no affect on the response of seronegative monkeys to a second challenge by gavage.
- Medicine and Medical Research