Immobilizing Antibodies in Pyelonephritis

Type-Specific immobilizing antibodies were found in serum and urine in the course of retrograde experimental pyelonephritis due to Proteus mirabilis. Serum antibodies were detected 3 to 5 days after infection, reached high levels at 7 to 15 days and persisted until the animals were killed. Six-day serum contained both 2ME-resistant and 2ME-sensitive antibodies, but 13- or 19-day serum antibodies were not affected by 2ME. Upon gradient ultracentrifugation of 19-day sera, the highest immobilizing titer was found in 7 S fractions. Immobilizing antibodies were also demonstrated in dialyzed urine during infection, after infection had been suppressed or eradicated by antibiotics, and after immunization with formalin-treated bacteria by intravenous or intrarenal injection. Urinary immobilizing antibodies correlated well with the location and concentration of 7 S marker on the density gradient and appeared to be stable in infected urine.