Wk. Bolton et al., STUDY OF EHS TYPE-IV COLLAGEN LACKING GOODPASTURES EPITOPE IN GLOMERULONEPHRITIS IN RATS, Kidney international, 47(2), 1995, pp. 404-410
The Goodpasture's epitope has been mapped to the alpha(3) non-collagen
ous chain (NC1) of type (IV) collagen [alpha(3)col(IV)]. We have devel
oped a model of experimental autoimmune glomerulonephritis (EAG) in ra
ts immunized once with collagenase solubilized GBM (csGBM). Engelbreth
-Holm-Swarm (EHS) tumor contains abundant col(IV) with little or no al
pha(3)col(IV). To test the hypothesis that antigens related to Goodpas
ture epitope are required to produce EAG in our model, we immunized ra
ts once with 40 mu g csEHS. Positive controls immunized with csGBM dev
eloped typical EAG with GBM bound antibody, proteinuria, and glomerulo
nephritis. EHS rats developed circulating and bound antibody to mesang
ium and tubular basement membrane with minimal GBM deposits, but did n
ot develop proteinuria or glomerulonephritis. Although circulating ant
ibody in EHS rats bound to csGBM by ELISA, there was no binding in ELI
SA to M2 antigen containing the Goodpasture epitope while EAG rat's se
rum did bind. By Western blot with antisera to Goodpasture epitope, EH
S antigen was less complex than GBM in the monomer/dimer regions and a
ppeared to lack NCI corresponding to alpha(3)col(IV). Blotting with se
ra from EHS rats demonstrated reactivity to various components of GBM
but not to alpha(3)col(IV). EAG sera and renal eluates bound to alpha(
3)col(IV). EAG rats evidenced cell mediated immunity while EHS rats di
d not (stimulation index EHS 1.1, EAG rats 8.0). These studies show th
at the development of antibody to col(nr) in a setting conducive to EA
G does not cause EAG in the absence of alpha(3)col(TV) NC1, that the a
ntibody response in EHS rats was not associated with a cellular respon
se to the antigen and that an epitope on the same NC1 alpha(3)col(IV)
which contains the Goodpasture epitope appears necessary to induce EAG
in this model These studies further implicate the alpha(3)col(IV) as
a pathogenetic factor in the development of Goodpasture syndrome in hu
mans as well as a marker of disease.