Evaluation of resistance to staphylococcal enterotoxin B: naturally acquired antibodies of man and monkey

Abstract

Sera from res'dents 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 lgG antibody activity. Approximately 70 % of sera from the U.S. had HA antibody and 30 % had precipitins, whereas all samples Irom South-east Asia had HA activity and 90 % had precipitating activity. Scroconversion oc-curred 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 antibod y, observed in human sera. Rechalhenge by gavage was less effective, in that antibody stimulation occurred only in monkeys that were fed repeatedly with 100 median effective doses (EO 0o). Resistance to a primary iv challenge with 1-25 EDo0 was correlated with titers of naturally acquired HA antibody, but resistance to higher doses was related to presence of precipitins. Ten weeks after primary exposure, many monkeys lackin