[Effectiveness of various immunoglobulin preparations administered by the intravenous route in peritonitis in the rat model].

Intraabdominal sepsis in rats was induced as a sublethal infection (mortality rate of controls: 60%-80%) and as a lethal infection (mortality rate of controls: 100%). The effectivity of different immunoglobulin (IgG) preparations alone or together with an antibiotic combination therapy (gentamicin + piperacillin) was then tested. In sublethal infection, 5 intravenous administrations of three 7S-IgG preparations and a plasmin-treated preparation at a dosage of 0.5 g/kg b.w. were able to reduce lethality only slightly, whereas a 5S-IgG preparation was able to reduce lethality by 30% significantly. Intraperitoneal administration of two 7S-IgG preparations (s-sulfitolysis, 42 degrees C/ammonium sulfate) and the 5S-IgG preparation reduced lethality to 27%, 37% and 47%, respectively, whereas another 7S-IgG (iodoacetamide/dithiothreitol) and a plasmin-treated preparation failed to reduce lethality significantly. The convincing results obtained with the 5S-IgG preparation are probably due to the fact that Fc-mediated side-effects could be avoided. The better effectivity of intraperitoneal compared to intravenous administration can be explained by much higher concentrations of specific antibodies at the site of infection. In the lethal infection model the mortality of animals treated with antibiotics only was 50%. The additional intravenous administration of 7S-IgG (42 degrees C/ammonium sulfate), a plasmin-treated preparation and a 5S-IgG was unable to reduce mortality any further. These findings are in contrast to several publications which postulate synergism of antibiotics and immunoglobulins.