[Terminal complement complex (TTC) levels in plasma and urine from glomerular diseases: enzyme-linked immunosorbent assay (ELISA) using monoclonal antibody against neoantigens of TCC].
In order to get monoclonal antibodies (MoAbs) against neoantigens of terminal complement complex. MoAbs after immunization of mice with polymerized human C9 were screened for reactivities against native and polymerized C9. MoAb 1B4 reacted with tubular C9 polymer, but did not react with either native or sodium dodecyl sulfate-denatured monomeric C9 as revealed by enzyme-linked immunosorbent assay (ELISA) and Western blotting. Moreover, MoAb 1B4 reacted with the terminal complement complex (TCC), that is, membrane attack complex and the fluid-phase SC5b-9 complex. Thus, MoAb 1B4 recognized a neoantigen in the moiety of C9 polymer in the TCC. Thereafter, we measured TCC in plasma and urine with sandwich ELISA using 1B4 and antihuman C7 antibody to evaluate terminal complement activation in patients with glomerular diseases. TCC was detectable in plasma but not in urine from most of normal controls. In plasma, TCC was elevated in 5 of 23 with lupus nephritis and in 6 of 11 with membranoproliferative glomerulonephritis, but all patients with IgA nephritis, focal glomerulosclerosis, membranous glomerulonephritis and minimal change lesions (MC) showed normal levels. In urine, TCC was detectable in most of patients with severe proteinuria (greater than or equal to 100 mg/dl) except MC. The TCC present in urine was partially purified by gel filtration with Sepharose 6B and was found to contain C5, C6, C7, C8, C9, and S protein by ELISA. Although the molecular weight of SC5b-9 complex is similar to IgM, fractional excretion rate of TCC was about 100 times higher than that of IgM. These results suggest that urinary TCC contains SC5b-9 complex like plasma TCC and is mostly derived from renal origin.
Kusunoki
Y
Y
Department of Pediatrics, Hokkaido University School of Medicine, Sapporo, Japan.
D000293:Adolescent; D000328:Adult; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis; D002648:Child; D015938:Complement Membrane Attack Complex / Q000032:analysis* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008875:Middle Aged; D009393:Nephritis / Q000175:diagnosis*; D009401:Nephrosis / Q000175:diagnosis
D000911:Antibodies, Monoclonal; D015938:Complement Membrane Attack Complex