[Several biological properties of the surface antigens of the agent of pseudotuberculosis]

Capsular substance and extracellular proteins of the causative agent of pseudotuberculosis caused in the organism of guinea pigs a specific immunological reconstruction with the accumulation in the blood of antibodies in low titres, chiefly of macroglobulin type. The blood sera of these animals failed to protect the mice from lethal pseudotuberculosis infection in experiments of passive protection. Surface antigens of pseudotuberculosis causative agents produced a sensitizing action on the guinea pig organism; this was shown in vitro with the macrophages of the abdominal cavity of these animals. Extracellular proteins decreased the completeness of phagocytosis by neutrophilic leukocytes (demonstrated in vitro with the donor blood leukocytes).