Prevention of experimental hematogenous and retrograde pyelonephritis by antibodies against enterobacterial common antigen.

Rabbits were immunized with common antigen (CA) derived from Salmonella typhimurium. Animals with CA hemagglutinin titers of 1-320 to 1-81,920 were injected with 10(7) viable Proteus mirabilis via the retrograde and hematogenous routes. Nonimmune control groups were challenged similarly. From the retrogradely challenged groups sacrificed at 4 weeks, pyelonephritis was found in 89% of the control animals but not in those immunized. Bacteriuria was present in 89% of the controls but in only 61% of the immunized group. Hematogenously challenged, immune animals sacrificed at 6 weeks did not show histological evidence of renal pathology, and only 6% had bacteriuria. Eighty-six per cent of the nonimmune controls showed both pyelonephritis and bacteriuria. The protective effect is specific because of the following. (i) Active and passive CA immunization did not prevent pyelonephritis due to Pseudomonas aeruginosa which does not produce this antigen. (ii) Passive immunization with a CA antiserum conferred protection against a P. mirabilis challenge. (iii) Passive administration of an antiserum from which CA antibodies had been differentially absorbed abolished the protective activity.