Effect of erythrocytes treated with enterobacterial common antigen on experimental Salmonella typhimurium infection of mice.

The immunogenicity of enterobacterial common antigen (CA)-treated horse or mouse erythrocytes was determined in Swiss white albino mice by comparing survival rates with control mice, immunized with P. aeruginosa fraction-treated RBC and challenged in parallel with 10 LD50 S. typhimurium. The administration of small amounts of CA on horse, but not mouse, RBC significantly delayed mortality; protection was only marginally less than that evoked with 12-fold larger amounts of CA in the absence of RBC. Survival in infected animals was transient; independent of immunogen or control preparation employed, all mice were dead by day 15 after challenge.