Response of Orally Immunized Rats to a Second Injection of Pneumococcus and the Minimum Duration of Immunity

[摘要] Introduction. The results obtained in the immunization of rats against intraperitoneal injections of pneumococcus, Type I, by feeding either the tissues of animals killed by that organism or by feeding the living organisms, have been reported elsewhere (1, 2). It has been demonstrated that rats so treated possess a degree of immunity which enables them to tolerate an intraperitoneal injection of 1000 or more times the dose which kills controls. Most of the animals which thus survived were kept and tested a second time. The interval of time elapsing between the first and second tests varied from one to four months. The object was to learn whether a second injection, approximately equal to the first, can be tolerated and if so how long after the first. The results of such an experiment do not indicate how long the immunity originally conferred lasts.

[学科分类] 生物科学（综合）