Stimulating effect of E.coli L-form cytoplasmic membranes on the macrophage functions of influenza virus infected mice

Abstract

To evaluate their defense level against bacterial infection of patients with liver cirrhosis, we compared the luminol-dependent chemiluminescence (CL) response of peripheral blood from 40 patients with that from 40 healthy volunteers. Small quantities of heparinized whole blood (100 μl; final dilution, 1:10) were used for phagocytes, and CL was measured on addition of nonopsonized zymosan or Escherichia coli without special opsonization. Whole blood CL in cirrhotic patients was significantly lower than that in the healthy controls. The incidence of lower CL response in patients increased as disease stage advanced. Polymorphonuclear leukocytes (PMN) from cirrhotic patients exibited a slightly lower CL response than those from controls, but this was not statistically significant. In contrast, the CL response of monocytes in patients was significantly lower than that of controls. The opsonizing capacity of the patients’ sera and ascitic fluid was also decreased. In fact, the levels of opsonins such as complement in the patients’ sera and both immunoglobulins and complement in the ascitic fluids were found to be lower in cirrhotic patients. On the basis of these findings, defect of opsonophagocytic function seems to participate in the increased susceptibility to infection in cirrhotic patients. Furthermore, whole blood CL induced by nonopsonized zymosan at the onset of relatively severe bacterial infections such as sepsis, pneumonia, or spontaneous bacterial infection was less augmented in the blood of cirrhotic patients than that in noncirrhotic patients. To clarify the reason why whole blood exhibits a lower CL response in the acute phase of bacterial infections, we investigated the priming effects of lipopolysaccharide (LPS) or tumor necrosis factor-α (TNF-α), well-known CL activators, on the CL response of whole blood obtained from cirrhotic patients in comparison with that from healthy persons. The priming effects were significantly decreased in patients’ blood when compared with that of healthy persons. These low responses of patients’ blood to LPS or TNF-α support our finding that phagocytes are not fully activated when gram-negative bacterial infections occur.