Immunogenicity of Escherichia coli O antigen in upper urinary tract infection

The role of immunogenicity of the infecting organism (Escherichia coli) in the antibody response to O antigen in upper urinary tract infection was investigated. Heat-killed vaccines were prepared from "immunogenic" organisms which had produced upper urinary tract infection associated with high titers of hemagglutinating antibody to O antigen and "nonimmunogenic" organisms which had produced upper urinary tract infection without a rise in antibody titer. "Immunogenic" 06 vaccine produced high titers of antibody in patients regarded as possibly "poor producers" of antibody, but "nonimmunogenic" 011 vaccine was not associated with a rise in titer in patients previously regarded as "good producers". These vaccines were significantly different in immunogenicity (P less than 0.05). Five vaccines were tested in 50 rats. The difference in hemagglutinating titers to O antigen between 06 and 011 was highly significant (P less than 0.001). Immunogenicity of the infecting organism appears to be a significant factor in determining antibody response to O antigen in upper tract infection.