Idiotype usage by polyclonally activated B cells in experimental autoimmunity and infection.

Both in animal models and in human systemic lupus erythematosus (SLE) the occurrence of nephritogenic autoantibodies bearing dominant idiotypes has been described. In this study we investigate the relation between the induction pathway of polyclonal B cell activation and the production and glomerular deposition of nephritogenic antibodies with shared dominant idiotype(s). Polyclonal B cell activation was induced in several experimental models characterized by glomerular immune deposit formation. We monitored the occurrence of dominant idiotypes among immunoglobulins deposited in the glomeruli. In addition, we studied the species specificity of the dominant idiotypes, by monitoring their presence in kidney sections of patients with an immunologically mediated kidney disease. Anti-idiotype antisera against two monoclonal anti-DNA autoantibodies were used, derived from MRL-lpr/lpr mice, i. e. clone H241 and clone H130. Autoantibodies with the H241 idiotype were present in immune complex depositions in all experimental models but not in humans. We therefore conclude that the presence of this dominant idiotype is independent of the induction pathway of polyclonal B cell activation. However, autoantibodies bearing the H130 idiotype were only detected in kidney sections of mice with spontaneous lupus.

T-cell receptor Vbeta gene expression in experimental lupus nephritis.

A limited T-cell receptor (TCR) Vbeta repertoire employed by autoreactive T cells may be related to the development and course of autoimmune diseases. Vbeta repertoire skewing has been observed not only in man, but also in animal models of several human autoimmune diseases, such as MRL-lpr mice, which spontaneously develop a systemic lupus erythematosus (SLE)-like disease. Murine chronic graft-versus-host disease (GVHD) is an inducible model for SLE, involving direct interaction between donor T cells and recipient B cells. It is not known whether Vbeta-specific T-cell subsets are pathogenically involved in this model. Retroviral superantigens such as Mls-1 are known to have a profound impact on the TCR Vbeta repertoire in mice. Restriction of the peripheral TCR repertoire may result from intrathymic expression of Mls-1, which causes deletion of T cells expressing Vbeta6, -7, -8.1, or -9. Mls-1 incompatibility between donor and recipient can be used to determine the involvement of these TCR Vbeta families in GVHD. In the present study we induced GVHD in several strain combinations to investigate TCR Vbeta gene expression during GVHD, and the effect of Mls-1 incompatibility on the TCR Vbeta repertoire. TCR Vbeta gene expression was determined using an RNase protection assay. Our results indicate that T cells expressing the Vbeta2 or Vbeta16 chain play an important pathogenetic role, while T cells bearing the Vbeta1 or Vbeta6 chain may be related to self-limitation of the lupus-like disease in this model.

Experimental glomerulonephritis is attenuated by CD8+ T cell chimerism and prevented by Mls-1-incompatible thymocytes.

Chronic graft-versus-host disease (GvHD) in mice is a model resembling glomerulonephritis in human systemic lupus erythematosus. In the present study congenic mouse strains were used to investigate the pathogenetic role of (1) donor T cell subset chimerism and (2) donor thymocytes in this model. In GvHD employing minor lymphocyte-stimulating-1 (Mls-1)-compatible donors and recipients, full-blown immune complex glomerulonephritis was associated with a low-donor CD8(+) T cell chimerism. Injection of lymphocytes from Mls-1-negative donors (Mls-1(b)) into Mls-1-positive recipients (Mls-1(a)) induces a type of GvHD characterized by rapid self-limitation accompanied by the immediate inhibition of donor T cell chimerism and the absence of glomerulonephritis. However, omission of thymocytes from the donor inoculate does result in glomerular depositions containing immunoglobulins. These results suggest that donor CD8(+) T cell chimerism is associated with attenuation of immune complex glomerulonephritis, whereas Mls-1-incompatible donor T cell precursors prevent the disease.

Association between leukocyte infiltration and development of glomerulosclerosis in experimental lupus nephritis.

Mice with chronic graft-versus-host disease (GvHD) induced by injection of DBA/2 lymphocytes into (DBA/2 x C57BL/10) F1 hybrids (DBA/2 GvHD) develop a lupus-like glomerulonephritis with global glomerulosclerosis 12 weeks after induction of the disease. In two other strain combinations with similar H-2 incompatibilities [BALB/c into BALB/c x BL10 (BALB/c GvHD) and BALB.D2 into BALB.D2 x BL10 (BALB.D2 GvHD)], GvHD induction leads to lupus nephritis without global glomerulosclerosis. This study investigated the identity of kidney-infiltrating leukocytes and their involvement in the development of glomerulosclerosis in these three strain combinations. In mice with DBA/2 GvHD, a significant increase in glomerular CD11a-positive cells was found 4 weeks after disease induction. Mice with BALB/c or BALB.D2 GvHD did not show an increase in glomerular CD11a-positive cells at any time point. In the interstitium, CD11a-positive cells were observed 4 weeks after disease induction only in mice with DBA/2 GvHD. In mice with BALB.D2 GvHD, no increase was found in interstitial CD11a-positive cells. In mice with BALB/c GvHD, interstitial CD11a-positive cells were found from week 4 onward. Further immunohistochemical analysis of the glomerular CD11a-positive cells in mice with DBA/2 GvHD showed that these cells were neither polymorphonuclear leukocytes (PMN), nor CD3-positive (T cells), B220-positive (B cells), or F4/80-positive (macrophages). They were all CD45-positive (leukocytes) and MHC class II-positive. In conclusion, we have shown in this model of chronic lupus nephritis that glomerular influx of as yet unidentified CD11a-positive leukocytes is associated with the development of glomerulosclerosis.

Matrix and adhesion molecules in kidney pathology: recent observations.

The purpose of this article is to review a set of recently obtained data concerning matrix and matrix adhesion molecules in renal disease. Our goal is not to cover the entire topic, but rather to focus on findings obtained with an experimental model for chronic lupus nephritis, evoked in mice by inducing graft-versus-host disease (GVHD). The overall aim of these studies was to investigate the role of adhesion molecules as targets for autoantibodies, in the recruitment of inflammatory cells, and in the accumulation of matrix in kidney disorders. In addition, we set out to discover how matrix proteins in renal diseases differ from normal matrix molecules both quantitatively, in their increased frequency, and qualitatively, in their intramolecular structure. The advances in understanding and methodology described in this review imply a substantial capability for greater insight into the pathogenesis of kidney disease; for making better use of renal biopsies, such as in applying competitive reverse-transcriptase-polymerase chain reaction (RT-PCR) in RNA analysis for matrix; and in developing more effective treatment strategies for patients with kidney disease.

Collagen types VIII and X, two non-fibrillar, short-chain collagens. Structure homologies, functions and involvement in pathology.

Collagens can be divided into two groups, i.e., fibrillar and non-fibrillar collagens. Short-chain collagens, a subgroup of non-fibrillar collagens, comprises collagen type VIII and type X. These two collagen types show several similarities in structure and possibly also in function. Type VIII collagen appears to be secreted by rapidly proliferating cells. It can be found in basement membranes and may serve as a molecular bridge between different types of matrix molecules. In different tissues this collagen type may serve different functions. Stabilization of membranes, angiogenesis, and interactions with other extracellular matrix molecules. Since collagen type X is produced by hypertrophic chondrocytes, this collagen type can only be found in matrix of the hypertrophic zone of the epiphyseal growth plate cartilage. Collagen type X is probably involved in the process of mineralization, endochondral ossification, and is also proposed to play a role in angiogenesis. Collagen types VII and X may be involved in matrix and bone disorders. Their structure, function, and involvement in pathology are discussed in this review.

Non-MHC genes determine the development of lupus nephritis in H-2 identical mouse strains.

Susceptibility to systemic lupus erythematosus (SLE) and, in particular, lupus nephritis is strongly influenced by genetic factors. Previous studies have shown that MHC-related antigens influence the development of SLE. In the current study, we set out to investigate how non-MHC genes influence the pathogenesis of glomerulonephritis in chronic graft-versus-host disease (GVHD) in mice, a model for lupus nephritis. For the induction of GVHD we used parent-to-F1 hybrid mouse strain combinations. DBA/2, BALB/c, BALB.D2 and C57B1/10.D2 (BL10.D2) donor lymphocytes carrying an H-2d haplotype were injected into H-2b/d F1 hybrids of BL10 mice, which differed only at non-MHC loci. Within these hybrid strains the development of immune complex glomerulonephritis was investigated by monitoring the occurrence of autoantibodies in the circulation, deposition of immunoglobulins in the glomeruli, development of albuminuria, and glomerulosclerosis. In diseased DBA/2 mice albuminuria developed 6 weeks after induction of the disease. Mice with a BALB background developed a lupus-like syndrome characterized by albuminuria starting 8 weeks after induction of the GVHD. During the development of the GVHD, polyclonal B cell activation occurred in both the DBA/2 and BALB/c strains, resulting in the formation of autoantibodies. Only the strain combination using DBA/2 mice developed anti-GBM antibodies. In DBA/2 and BALB strain combinations immune complexes were detected in a granular pattern along the glomerular capillary walls. In the DBA/2 recipients a linear pattern of immunoglobulin depositions preceded the granular phase. This study demonstrates that: (i) non-MHC genes govern the pathogenesis of immune complex nephritis in this model by influencing the autoantibody profile; and (ii) the presence of anti-GBM antibodies in the early stages of the disease is a conditio sine qua non for the development of full-blown glomerulonephritis and glomerulosclerosis in this model.