Immune complex nephritis in Schistosoma mansoni- infected mice

Swiss outbred mice infected with 80–100 cercariae of Schistosoma mansoni developed in 60 % of the cases a wide range of glomemlar lesions involving mainly the mesangium. The lesions were associated with the presence of granular deposits of murine immunoglobulins and C3, suggesting an immune complex mechanism. In addition, nephritic glomeruli in about 20 % of the cases could be stained by a specific rabbit antischistosoma serum after removal of excess host immunoglobulins. The presence of circulating immune complexes in the serum of infected animals was suggested by the increased molecular weight of circulating C3. The onset of the immunopathologic lesions appeared to be related to duration, intensity and type of infection. Single-sex parasite infection, in fact, led to significant reduction of glomerular lesions.     

Immune complex glomerulonephritis mediated by thyroid antigens.

Hypothyroidism, microscopic hematuria, and proteinuria developed in an 11-year-old girl. A renal biopsy specimen showed increased mesangial cells and matrix with focal glomerular basement membrane thickening. Three years later, a pronounced increase in proteinuria was detected. Elevated levels of antibody to thyroid microsomal antigen and thyroglobulin were found in the serum. A renal biopsy specimen showed a pronounced increase in mesangial cells and matrix with generalized glomerular basement membrane thickening. Electron microscopic studies demonstrated granular deposits in the capillary walls and mesangium. Immunofluorescent studies revealed granular deposits of IgG, IgM, and C3, primarily on the glomerular basement membrane. By indirect immunofluorescence, granular glomerular basement membrane and mesangial staining were detected with antibody specific for thyroglobulin and thyroid microsomal antigen. These observations suggest development of immune complex glomerulonephritis mediated by thyroid antigens.     

Immune complex crescentic glomerulonephritis associated with pulmonary aspergillosis

We describe a case of immune complex crescentic glomerulonephritis associated with invasive pulmonary Aspergillus fumigatus infection. Immunofluorescent and immunoperoxidase investigations showed the presence of Aspergillus fumigatus antigen in the glomerular immune complexes.     

Immune responsiveness in mice heavily infected with Mycobacterium kansasii.

Growth of Mycobacterium kansasii TMC 1203 in B6D2 F1 hybrid mice was associated with increased splenic cellular proliferation, hyperplasia and the generation of non-specific antibacterial resistance. Both responses were dose dependent; the larger the inoculum, the more rapid and extensive the cellular response. However, such mice were still unable to reduce the mycobacterial load within the tissues, apparently because of their inherent resistance to inactivation by immunologically activated macrophages. On the other hand, mice infected with the non-persistent strain of M. kansasii 1214 exhibited only a transient increase in non-specific (anti-listeria) resistance which rapidly declined as the number of viable mycobacteria within the spleen fell below an arbitrary threshold level. Mice infected with either M. kansasii 1203 or 1214 could be immunized with sheep red blood cells (SRBCs), an unrelated T cell-dependent antigen. The humoral (PFC) response was not affected by the mycobacterial load within the spleen. However, the delayed footpad swelling reaction was severely depressed. The latter could be restored merely by increasing the size of the intravenous sensitizing inoculum 100-fold. The present study indicates that mice chronically infected with M. kansasii are not severely immunosuppressed (as had been inferred from earlier in vitro lymphoproliferation studies) but are fully capable of responding to appropriate in vivo stimuli.     

Immune complex glomerulonephritis is induced in rats immunized with heterologous myeloperoxidase.

Anti-neutrophil cytoplasmic antibodies (ANCA), including anti-myeloperoxidase (MPO) antibodies, are associated with pauci-immune necrotizing small vessel vasculitis or glomerulonephritis. In order to substantiate a pathogenic role for ANCA, an animal model of pauci-immune ANCA-induced glomerulonephritis or vasculitis is required. Brouwer et al. reported pauci-immune glomerulonephritis in rats immunized with human MPO followed by perfusion of kidneys with lysosomal enzyme extract combined with H2O2, and suggested that this could serve as a model of ANCA-induced disease. We repeated these studies in spontaneously hypertensive rats (SHR) and Brown Norway rats (BNR). We immunized rats with human MPO. When circulating anti-MPO antibodies were detectable by indirect immunofluorescence microscopy and ELISA, blood pressure was measured, then perfusion of the left kidney of each rat was done via the renal artery in a closed, blood-free circuit with either MPO + H2O2, MPO, H2O2 alone or MPO + H2O2 + neutral protease. Rats were killed on day 4 or day 10 after perfusion, and specimens were examined by light and immunofluorescence microscopy. Pathological lesions and deposits of IgG, C3, and MPO were found in immunized rats perfused with MPO + H2O2 with or without neutral protease, or MPO alone, in both rat strains and on both day 4 and day 10. The degree of histologic injury was proportional in intensity to the amount of IgG immune deposits. Spontaneously hypertensive rats sustained more damage and higher blood pressure than Brown Norway rats. No lesion was observed in immunized rats perfused with H2O2 or in the non-perfused right kidneys. Some of the non-immunized rats perfused with MPO + H2O2 developed pathological lesions. In conclusion, these rat models are examples of immune complex-mediated glomerulonephritis, and therefore are not similar to human ANCA-associated disease.     

Immune complex type glomerulonephritis in cirrhosis of the liver.

Glomerular lesions were detected in 9 of 10 patients with liver cirrhosis: these lesions consisted of a) thickening of basement-membrane-like material, b) electron-dense deposits in mesangial areas and in capillary walls, c) round areas of rarefaction in the membrane-like material and in some deposits, and d) presence of IgA, with IgG and/or IgM and/or C3, in the deposits. The association of these four abnormalities seems to be characteristic of "cirrhotic glomerulonephritis." The deposits could be the result of precipitation in the glomeruli of either aggregated immunoglobulins or circulating immune complexes.     

Fecal leukocytes in children infected with diarrheagenic Escherichia coli

The purpose of this study was to determine the presence and quantity of fecal leukocytes in children infected with diarrheagenic Escherichia coli and to compare these levels between diarrhea and control cases. We analyzed 1,474 stool samples from 935 diarrhea episodes and 539 from healthy controls of a cohort study of children younger than 2 years of age in Lima, Peru. Stools were analyzed for common enteric pathogens, and diarrheagenic E. coli isolates were studied by a multiplex real-time PCR. Stool smears were stained with methylene blue and read by a blinded observer to determine the number of polymorphonuclear leukocytes per high-power field (L/hpf). Fecal leukocytes at >10 L/hpf were present in 11.8% (110/935) of all diarrheal episodes versus 1.1% (6/539) in controls (P < 0.001). Among stool samples with diarrheagenic E. coli as the only pathogen isolated (excluding coinfection), fecal leukocytes at >10 L/hpf were present in 8.5% (18/212) of diarrhea versus 1.3% (2/157) of control samples (P < 0.01). Ninety-five percent of 99 diarrheagenic E. coli diarrhea samples were positive for fecal lactoferrin. Adjusting for the presence of blood in stools, age, sex, undernutrition, and breastfeeding, enterotoxigenic E. coli (ETEC) isolation as a single pathogen, excluding coinfections, was highly associated with the presence of fecal leukocytes (>10 L/hpf) with an odds ratio (OR) of 4.1 (95% confidence interval [CI], 1.08 to 15.51; P < 0.05). Although diarrheagenic E. coli was isolated with similar frequencies in diarrhea and control samples, clearly it was associated with a more inflammatory response during symptomatic infection; however, in general, these pathogens elicited a mild inflammatory response.     

Immune complex disease. VII. Experimental mesangiopathic glomerulonephritis produced by chronic immunization with thyroglobulin.

Immunohistologic and electron microscipic studies were performed on the kidneys of rabbits given daily intravenous injections of porcine thyroglobulin in amounts adjusted to the immune response of the individual rabbits. Glomerular lesions were restricted to the mesangium, were characterized by varying degrees of proliferation of mesangial cells and increase of mesangial matrix, and were accompanied by accumulations of rabbit immunoglobulins, C3, and porcine thyroglobulin. Electron-dense deposits were localized to the mesangium and the adjacent subendothelial space. Less than 10 per cent of the animals with mesangila lesions developed obvious impairment of glomerular function. Thyroglobulin-containing immune complexes were found to be rapidly removed from the mesangium, so that overloading of the mesangium and consequent accumulation of complexes in the adjacent capillary loops could not occur. Thus, the results provide further evidence that when immune complex deposition is restricted to the mesangium, relatively little interference with glomerular function results. This situation is paralleled in man by the lesions of subclinical lupus nephritis, chance proteinuria and hematuria, and the early lesions of Berger's disease.     

Immune complex acute necrotizing glomerulonephritis with progression to diffuse glomerulosclerosis. A murine model

Male BALB/c mice given daily intraperitoneal injections of 4 mg of horse-spleen apoferritin develop, in the majority of cases, a proliferative and necrotizing glomerulonephritis with leukocytic infiltration and extensive intraglomerular thrombosis within 10 to 14 days, as previously reported. We now show that if injection of the antigen is discontinued, surviving animals develop extensive glomerulosclerosis (GS). Ten of 13 mice treated as indicated above and sacrificed 4 months after the last horse-spleen apoferritin injection developed segmental GS involving over 40% of their glomeruli. Tubulointerstitial damage of proportionate severity also developed. Ultrastructurally, pronounced mesangial expansion due to matrix deposition obliterated the glomerular architecture. We offer this as a reproducible model of immune complex-mediated GS particularly suited to the study of cellular interactions involved in the pathogenesis of GS.     

Effect of trimethoprim-sulfamethoxazole on recurrent bacteriuria and bacterial persistence in mice infected with uropathogenic Escherichia coli

One of the more perplexing aspects of urinary tract infections (UTIs) is their high propensity to recur. It has been proposed that recurrent infections are a result of the reintroduction of bacteria from the gastrointestinal tract (GIT) to the urinary tract (UT); however, since a significant subset of recurrent UTIs are caused by an identical bacterial strain, it has been challenging to formally prove this hypothesis for same-strain recurrences by using epidemiologic approaches. We present data here obtained by using a mouse model of UTIs in which it was shown that 36% (5 of 14) of mice infected with uropathogenic Escherichia coli (UPEC) will have at least one bacteriuric recurrence, with 21% (3 of 14) having more than one recurrence during a 6-week period after an acute UTI. Intraurethrally infected mice develop UPEC reservoirs in both their feces and their bladders. Ten days of trimethoprim-sulfamethoxazole (SXT) therapy reduces urinary recurrences and eradicates fecal colonization, whereas 3 days of SXT treatment has no effect over a twenty-eight-day observation period despite clearing fecal colonization acutely. Interestingly, SXT is unable to eradicate bacteria from the bladder reservoir even after a 10-day treatment regimen, thus demonstrating that the bladder reservoir can persist even in the face of long-term antibiotic therapy.     

Nonspecific resistance to Escherichia coli in mice.

Nonspecific cell-mediated immunity to a relatively virulent strain of Escherichia coli was studied in mice infected with Staphylococcus aureus and elicited with specific antigens. The infected and elicited mice were protected against as intraperitoneal challenge by E. coli for an observation period of 7 days, whereas normal mice, given the same number of bacteria, died within 18 to 24 h. However, the amount of time elapsing between elicitation and challenge greatly affected the rate of protection. Little or no protection was observed in mice injected with S. aureus but not elicited or in mice injected with staphylococcal antigens but not infected with staphylococci.     

Immune response to Escherichia coli B surface antigens.

The cell surface antigens of Escherichia coli B were investigated. We found that mice immunized with live bacteria responded with an immune response directed mainly against the protein structure of the cell surface. The lipopolysaccharide component of the bacterium was immunogenic, but its contribution to the overall response was only secondary. It is suggested that when considering the immune response to gram-negative bacteria, more attention should be given to the protein antigens.     

Shiga toxin-mediated disease in MyD88-deficient mice infected with Escherichia coli O157:H7

Toll-like receptors (TLRs) are key factors of innate immunity that detect pathogen invasion and trigger a host response. TLR4 can mediate a response through adaptor molecules, MyD88 or TRIF. In the present study, streptomycin-treated MyD88^−/−, Tlr4^−/−, Trif ^Lps2/Lps2, and C57BL/6 wild-type (WT) mice were infected with either Shiga toxin (Stx)-producing or non-producing Escherichia coli O157:H7. Moderate to severe clinical signs of disease developed in MyD88^−/− (n = 21/21), Tlr4^−/− (n = 12/16), Trif ^Lps2/Lps2 (n = 7/15) and WT mice (n = 6/20) infected with Stx-producing E. coli O157:H7 but not in mice inoculated with the Stx non-producing strain (n = 0/54, P < 0.001). MyD88^−/− mice infected with Stx-producing E. coli O157:H7 developed the most severe disease and had the highest bacterial burden. Hematological analysis of sick MyD88^−/− mice showed reduced red blood cell counts and reticulocytosis, suggesting hemolysis. Thrombocytopenia developed in MyD88^−/−, Trif ^Lps2/Lps2, and WT mice, and creatinine levels were elevated in both MyD88^−/− and WT mice infected with the Stx-producing strain. Renal histopathology showed evidence of glomerular capillary congestion, tubular desquamation, and fibrinogen deposition, and intestinal histopathology showed mucosal injury, edema, and inflammation in sick mice. Administration of purified Stx2 to MyD88^−/− and WT mice led to severe disease in both groups, suggesting that MyD88^−/− mice are not more sensitive to Stx than WT mice. As MyD88^−/− mice developed the most severe disease hematological and pathological changes, the results suggest that dysfunctional innate immune responses via MyD88 enhanced Stx-induced disease.     

Clinical manifestations of diarrhea in calves infected with rotavirus and enterotoxigenic Escherichia coli.

The susceptibility of gnotobiotic, colostrum-derived, or suckling calves to four bovine rotavirus isolates was found to be age dependent. Calves older than 7 days remained clinically normal, although they excreted virus in their feces and subsequently developed antibody against the virus, Enterotoxigenic Escherichia coli, fed to gnotobiotic, colostrum-deprived, or suckling calves ranging in age from a few hours to 26 days old, only caused diarrhea in animals younger than 24 h old. In contrast, diarrhea was consistently induced in 1- and 2-week-old calves infected with both enterotoxigenic E. coli and rotavirus. In general, diarrhea appeared after a rotavirus incubation period of approximately 3 days and was independent of the order in which the two microbial agents were given, the age of the calf, or the level of circulating rotavirus antibodies. The disease episode coincided with the excretion of rotavirus, rather than enterotoxigenic E. coli, in the feces. Infection with enterotoxigenic E. coli became established within 24 h of inoculation, and in older calves enterotoxigenic E. coli was often excreted in very small numbers and for a longer period than rotavirus.     

Immune response to Escherichia coli alpha-hemolysin in patients

The serum antibody response of patients infected with alpha-hemolysin (AH)-producing Escherichia coli was measured by three immunoassays: tube neutralization, microneutralization, and enzyme-linked immunosorbent assay. All three assay results showed good correlation with each other. The mean anti-AH titer in patients with E. coli infection was higher than the mean titer in noninfected patients. The hemolysin-neutralizing activity was immunoglobulin G. The amount of lipopolysaccharide (LPS) antibody did not correlate with the amount of AH antibody. LPS antibody measured by enzyme-linked immunosorbent assay was predominantly of the immunoglobulin G class. Adsorption of LPS antibody by E. coli H79 LPS did not affect anti-AH titers, indicating that LPS and AH have different antigenic determinants. AHs prepared from several different E. coli strains had identical or similar antigenic determinants at the active site. Hemolysin proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were stained identically by human sera with AH antibody and by a mouse monoclonal AH antibody.     

Treatment of experimental Escherichia coli infection in mice with colicine V.

Concentrated non-toxic preparations of colicine V were obtained by filtering centrifugates of soft-agar cultures of a Col V+ K12 strain of E. coli through Millipore filters in which the colicine V was retained. These preparations, given subcutaneously, favourably influenced the course of disease in mice infected intraperitoneally with a pathogenic strain of E. coli that was very sensitive to colicine V in vitro. A beneficial effect was noted even when treatment was delayed until the mice were visibly ill.     

Plasmid-phage recombination in T7 infected Escherichia coli

Recombination between genetically marked T7 bacteriophage and plasmids containing inserts of T7 DNA has been studied in order to gain some insight into the phage recombination process. The results suggest that plasmid-phage recombination requires the products of T7 genes 3 (endonuclease), 4 (DNA primase), 5 (DNA polymerase), and 6 (exonuclease), as has been demonstrated previously for phage-phage recombination. Plasmid replication does not compensate for a complete block in phage polymerase synthesis, suggesting a direct role for this enzyme in recombination, rather than an indirect role, by means of producing replicative structures that are recombinogenic. In most respects, plasmid-phage recombination appears to be similar to phage-phage recombination. The participation of two autonomous, structurally dissimilar, homologues, however, might render certain aspects of the recombination process more amenable to analysis. As examples, the characterization of an apparent marker effect and the demonstration of genetic heterozygotes among the products of plasmid-phage recombination are presented.