deoxycholic-acid and Nephritis

This study describes biochemical comparison of proximal tubule antigens from the brush border membrane (BBM) of dog and rat kidney. The purpose was to determine if a difference in BBM composition could explain the inability to produce either active or passive Heymann Nephritis in the dog. Although the membrane composition as revealed by coomassie blue staining on 4 to 11 per cent polyacrylamide electrophoresis varied considerably between rats and dogs, polyclonal antibodies (rabbit anti-rat, rabbit anti-dog) against purified BBM from both species immunoprecipitated five identical polypeptides. Four bands were visualized between 70 kd and 170 kd; but the major polypeptide had an apparent molecular wt of approximately 460 kd. This high molecular wt constituent and three of the other peptides were bound specifically to lentil lectin column, confirming their glycoprotein nature. Only the 460 kd polypeptide was immunoprecipitated by monoclonal antibody against gp 330. Since both rat and dog BBM contain gp 330, believed to be the sole pathogenic antigen in Heymann Nephritis, we conclude that failure to produce active or passive Heymann Nephritis in the dog using the same protocol that is successful in rats cannot be attributed to differences in antigenic make-up of the brush border membrane.

Topics: Animals; Antibodies, Monoclonal; Antigens; Autoantigens; Chemical Precipitation; Deoxycholic Acid; Dogs; Kidney Tubules, Proximal; Microvilli; Molecular Weight; Nephritis; Rats; Species Specificity

The present study was conducted to determine if Fx1A, a renal cortical extract used to induce Heymann nephritis, contains nephritogenic antigens in addition to the brush border-derived glycoprotein gp 330. Of 26 Lewis rats immunized with Fx1A, 24 developed abnormal proteinuria (greater than 20 mg/24 hr) by wk 10, whereas of 15 rats immunized with a partially purified gp 330 preparation (MVH), only one developed proteinuria. Immunofluorescence studies showed that all Fx1A rats developed large, diffuse, granular deposits along the glomerular basement membrane which stained brightly for IgG and C3; only 11 of the 15 MVH rats had definite deposits; in most rats, they were small and stained only moderately for IgG and faintly or not at all for C3. The Fx1A and MVH rats developed comparable levels of antibodies to MVH (gp 330) before the onset of proteinuria in Fx1A rats, after which serum IgG and antibody levels declined. In contrast, antibodies against soluble Fx1A antigens appeared earlier and rose more rapidly in Fx1A than in MVH rats. Larger amounts of IgG could be eluted from the glomeruli of Fx1A rats than from MVH rats. Eluates from the Fx1A rats contained antibodies that reacted with gp 330 and also a 95 kd antigen; the latter reactivity was not demonstrated in eluates of MVH rats. Immunoprecipitation studies showed that both gp 330 and the 95 kd antigen are components of normal glomeruli. The results show that immunization with Fx1A produces a more severe form of Heymann nephritis than does gp 330, and that Fx1A contains at least one nephritogenic antigen in addition to gp 330.

Topics: Animals; Antibody Specificity; Antigens; Autoantibodies; Autoantigens; Chromatography, Gel; Deoxycholic Acid; Epitopes; Female; Fluorescent Antibody Technique; Kidney Cortex; Microvilli; Nephritis; Precipitin Tests; Proteinuria; Radioimmunoassay; Rats; Rats, Inbred Lew; Rats, Inbred Strains

A ubiquitous tissue antigen (UTA), associated with chronic renal diseases was partially purified and characterized. The antigen was extracted by solubilization in 0.5% sodium deoxycholate (DOC) of various organs of human and animal origin. UTA was soluble in ammonium sulfate at 50% concentration and precipitable in 71% ethanol. Considerable purification of UTA was achieved by fractional ammunium sulfate precipitation, zone electrophoresis and gel filtration. Gel filtration on Sephadex G-200 and velocity gradient centrifugation through 10-40% sucrose gradients suggested that the main antigenic component is a macromolecule, although aggregability of DOC-extracted proteins upon removal of the solubilizer prevented more accurate determinations. UTA appeared to be a heat-stable glycoprotein which did not contain lipids detectable by Sudan black B staining. The yield of purest UTA preparations, which did not contain components of homologous serum as tested by double diffusion gel precipitation or immunoelectrophoresis, was 0.1-0.2 mg/100 g of starting tissue. Immunization of rabbits with homologous UTA-containing preparations resulted in anti-UTA antibody formation.

Topics: Ammonium Sulfate; Antibody Formation; Antigens; Chromatography, Gel; Complement Fixation Tests; Deoxycholic Acid; Ethanol; Glycoproteins; Humans; Kidney; Liver; Nephritis; Solubility