The Character of Dissociative Changes in Escherichia Coli Affecting Immunizing Values

[摘要] A gradient series of dissociates derived from a single S organism of a virulent strain of Es. coli have been examined for their comparative immunizing values for white mice, particularly in reference to the relative importance of virulence and content in soluble specific substance.Virulence of this strain, as exhibited following intraabdominal inoculation, is primarily related to an aggressin- or leucocyteparalyzing element. This aggressin is found only in cultures with SSS-containing capsules. It is apparently associated with the SSS substance, but not identical with it, as in the dissociative changes toward the R phase it may become greatly depleted before any decrease in the SSS element has occurred. Further, in reverse dissociation, R toward S, the SSS element may be largely regained without evidence of the reappearance of the aggressin-factor.The vaccination experiments with the S phase and its gradient dissociates indicated that the aggressin-factor is of somewhat greater importance for immunization than the SSS content, but that the highest degree of protection is afforded when both factors are present in the immunizing antigen in maximum degree.The immunizing antigens are located largely in the ectoplasmic or capsular region of the bacillus.The immunizing value of the S phase was found to be approximately six times that of the R phase and also definitely superior to that of the intermediate or O phase.The nature of the defensive mechanism for this Es. coli strain in normal and immunized mice is discussed.

[学科分类] 生物科学（综合）