title: The role of nephritis-associated plasmin receptor (NAPlr) in glomerulonephritis associated with streptococcal infection.
abstract: It is well known that glomerulonephritis can occur after streptococcal infection, which is classically referred to as acute poststreptococcal glomerulonephritis (APSGN). The pathogenic mechanism of APSGN has been described by so-called immune complex theory, which involves glomerular deposition of nephritogenic streptococcal antigen and subsequent formation of immune complexes in situ and/or the deposition of circulating antigen-antibody complexes. However, the exact entity of the causative antigen has remained a matter of debate. We isolated a nephritogenic antigen for APSGN from the cytoplasmic fractions of group A streptococcus (GAS) depending on the affinity for IgG of APSGN patients. The amino acid and the nucleotide sequences of the isolated protein revealed to be highly identical to those of reported plasmin(ogen) receptor of GAS. Thus, we termed this antigen nephritis-associated plasmin receptor (NAPlr). Immunofluorescence staining of the renal biopsy tissues with anti-NAPlr antibody revealed glomerular NAPlr deposition in essentially all patients with early-phase APSGN. Furthermore, glomerular plasmin activity was detected by in situ zymography in the distribution almost identical to NAPlr deposition in renal biopsy tissues of APSGN patients. These data suggest that NAPlr has a direct, nonimmunologic function as a plasmin receptor and may contribute to the pathogenesis of APSGN by maintaining plasmin activity.
authors.affiliation: Department of Nephrology, National Defense Medical College, Tokorozawa-shi, Saitama, Japan. takashio@ndmc.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Oda
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Yoshizawa
authors.forename: Kazuo
authors.initials: K
authors.lastname: Yamakami
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Sakurai
authors.forename: Hanako
authors.initials: H
authors.lastname: Takechi
authors.forename: Kojiro
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Naoki
authors.initials: N
authors.lastname: Oshima
authors.forename: Hiroo
authors.initials: H
authors.lastname: Kumagai
mesh_terms: D000907:Antibodies, Bacterial / Q000276:immunology; D000917:Antibody Formation / Q000276:immunology; D000942:Antigens, Bacterial / Q000302:isolation & purification / Q000378:metabolism*; D005921:Glomerulonephritis / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology*; D006801:Humans; D007678:Kidney Glomerulus / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D011956:Receptors, Cell Surface / Q000302:isolation & purification / Q000378:metabolism*; D013290:Streptococcal Infections / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D011956:Receptors, Cell Surface; C517776:nephritis-associated plasminogen receptor, Streptococcus