Immunology of pyelonephritis in the primate model: live versus heat-killed bacteria.

We produced nonobstructive pyelonephritis in the rhesus monkey (Macaca mulatta) by means of a retrograde inoculation of Escherichia coli to the point of pyelotubular backflow. To evaluate the immune response separate from the effects of infection, we introduced heat-killed bacteria in the same fashion. The disease from live bacteria is self-limited and associated with both a local and generalized immune response. The most marked cellular response is in the regional lymph nodes and is more specific to the bacterial antigen than is generalized stimulation of the immune system. Dead bacteria, while eliciting the formation of serum antibody to the O antigen, appear to ablate the cellular response seen with live bacteria. Loss of renal tubules with attended scarring and loss of renal function does occur from live bacteria. This does not appear to be due to the antigen alone (unless a heat labile antigen is responsible), because heat-killed bacteria do not cause renal scarring. Thus, renal damage seems dependent on an active infection and not on the immune response.