Clinical Observation on the Immunity to Bacillary Dysentery

Abstract

The Shigella group consists of numerous sero-types characterized by the possession of a distinctive antigen. Regarding the acquired immunity to bacillary dysentery, therefore, especially in cases of relapse or reinfection the Shigella sero-types must be confirmed and investigated in detail in contrast with strains in the first attack. The pathogenic organisms in cases of recrudescence, relapse and reinfection, together with changes of the serum agglutination titers during the course of the disease have been examined, and the development of immunity after recovery from dysentery has been observed clinically. The results were as follows:
1) In cases of “clinical recrudescence” the same Shigella sero-types were usually observed.
2) In cases of “clinical relapse” there were cases recognized as true relapses where the same Shigella sero-types were observed and cases recognized in fact as reinfections where the different types were found.
3) In cases of “clinical reinfection” readmitted there were cases recognized as true reinfections where the different Shigella sero-types were found and cases recognized in f act as relapses where the same types were observed.
4) The clinical symptoms in the subsequent attack were as follows;
a) The symptoms were similar to those in the first attack when infected with strains possessing entirely different antigenic structure.
b) They were less severe in the second attack than in the first attack when infected with strains possessing similar antigenic structure belonging to the same group (Flexner group).
5) The above results indicate that, after recovery, a certain degree of acquired immunity or cross-immunity develops to the same or similar Shigella types, but no immunity develops to the different types belonging to another group.