[Isolation of glomerular IgA deposits from biopsied kidney tissues of patients with IgA nephritis and analysis of the antibody specificity of IgA].
Glomerular IgA deposits were eluted from biopsied kidney tissues of patients with IgA nephritis and the antibody specificity was analyzed. The IgA was successfully eluted with combined use of citrate buffer and collagenase. The elution procedure did not attenuate antibody activity which was confirmed by the preliminary experiment that mouse IgA monoclonal anti-DNP antibody similarly treated did not cause any decline of antigen-binding ability. Because of the limited amounts ranging from 80-800 ng/ml, the eluted IgA did not react with respective lysates of the kidney tissues from which the IgA had derived. Moreover, kidney tissues from 9 biopsies yielded 5 micrograms/ml of IgA, when mixed together as source of IgA; nevertheless, the eluted IgA did not react with the kidney lysates, either. The eluted IgA, however, did react with several bacterial antigens, among which the 34-kDa antigen from Haemophilus influenzae (34-kDa H. influenzae) was most clearly detected with IgA eluted from pooled 10 kidney samples of IgA nephritis, which was confirming by Western blot analysis. The reactivity of the eluted IgA with the 34-kDa H. influenzae antigen was seen in 3/5 of IgA nephritis and 3/9 of non IgA nephritis patients with glomerular IgA deposits, respectively. The reactivity of serum IgA with the bacterial antigen was also investigated, which revealed that the serum IgA reacted with the 34-kDa antigen in 2/12 of IgA nephritis, 4/10 of liver cirrhosis patients and 3/10 of healthy control individuals, respectively. The surerum IgA from the IgA nephritis patients appeared to react with 34-kDa antigen more intensively than did healthy control IgAs. These results suggest that the 34-kDa H. influenzae plays an important role in the pathogenesis of at least certain IgA nephritis cases.
Ogawa
Y
Y
First Department of Pathology, Hokkaido University School of Medicine, Sapporo, Japan.
D000818:Animals; D000918:Antibody Specificity; D000942:Antigens, Bacterial / Q000276:immunology; D005260:Female; D005922:Glomerulonephritis, IGA / Q000276:immunology*; D006193:Haemophilus influenzae / Q000276:immunology; D006801:Humans; D007070:Immunoglobulin A / Q000302:isolation & purification*; D007678:Kidney Glomerulus / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight
D000942:Antigens, Bacterial; D007070:Immunoglobulin A