The immune response to human type III and type V (AB2) collagen: antigenic determinants and genetic control in mice

Collagen V oral administration decreases inflammation and remodeling of synovial membrane in experimental arthritis

Because collagen type V (Col V) can be exposed in tissue injury, we hypothesized that oral administration of this collagen species modulates the inflammation and remodeling of experimental synovitis, avoiding joint destruction, and that the modulation may differ according to the temporal administration. Arthritis (IA, n = 20) was induced in Lewis rats by intraarticular (ia) injection of 500 μg of methylated bovine serum albumin (mBSA) emulsified in complete Freund’s adjuvant (CFA) (10 μl) followed by an intraarticular booster of mBSA (50 μg) in saline (50 μl) administered at 7 and 14 days. The control group received saline (50 μl, ia). After the first intraarticular injection, ten IA animals were supplemented via gavage with Col V (500 μg/300 μl) daily for 30 days (IA/Suppl). The control group received saline (50 μL) and Col V supplement in the same way (Suppl). Col V oral administration in IA/Suppl led to 1) inhibited edema and severe inflammatory cell infiltration, 2) decreased collagen fiber content, 3) decreased collagen type I, 4) inhibited lymphocyte subpopulations and macrophages, 5) inhibited IL-1β, IL-10, IL-17 and TNF-α production and 6) increased expression of caspase-9 in the synovial tissue. In conclusion, Col V supplementation decreased synovial inflammation and the fibrotic response, possibly by increased the apoptosis of inflammatory cells.

Distribution of collagen types I, III, and V in pregnant mouse endometrium

Decidualization in mice comprises a deep remodeling of extracellular matrix (ECM) components of the endometrium. In a previous biochemical study we showed that collagen types I and III are present in both pregnant and nonpregnant mouse endometrium, whereas collagen type V is expressed exclusively after the onset of decidualization. The distribution of collagen types in the pregnant mouse endometrium and possible changes of these molecular types in the different regions of the decidua is, however, not known. Using immunofluorescence and confocal microscopy we showed the presence of collagen types I, III, and V in the endometrial stroma of implantation and interimplantation sites from days 5 to 8 of pregnancy in the mouse. Collagen type III was chiefly expressed in the implantation sites and was the only collagen type to be present in the materno-fetal interface on the day of the embryo implantation. However, collagen type I was the predominant collagen in the interimplantation sites. Collagen type V was weakly expressed in the nondecidualized stroma during all periods but was expressed in larger amounts in the decidualized areas on day 7 of pregnancy, simultaneously with the accumulation of thick collagen fibrils in the same region. The highest immunofluorescence labeling for the three types of collagen was observed on day 7 when the antimesometrial decidual tissue achieved its greatest development. These data support previous studies that showed an intense ECM remodeling of the mouse endometrial stroma during the beginning of pregnancy. This outstanding remodeling may be important to stabilize placental anchorage.

Architectural remodelling in lungs of rabbits induced by type V collagen immunization: a preliminary morphologic model to study diffuse connective tissue diseases

The pathogenesis of diffuse connective tissue diseases (DCTD) is still unknown and has been extensively studied regarding its autoimmunity aspects related to extracellular matrix (ECM) remodelling, with an emphasis on the collagens at the inflammatory site. The present paper describes the pulmonary architectural and repair/remodelling responses to injury after immunization of rabbits with human type V collagen. The animal model consisted of rabbits immunized with collagen mixed with Freund's adjuvant and sacrificed 7, 15, 30, 75, and 120 days after the first of four doses of antigen. Pulmonary architecture remodelling response was evaluated by histology, morphometry, and the immunofluorescence method, according to compartments of reference (parenchyma and interstitium) and injury: 1 inflammation (polymorphonuclear and mononuclear cells); 2-repair (fibrosis) and 3-ECM remodelling (collagen system). The results showed an intense inflammatory involvement of the pulmonary vascular and bronchiolar parenchyma, characterized by increased wall thickness in small arteries, infiltrations by pseudoeosinophils, and mononuclear cells. Progressive remodelling of the pulmonary ECM was characterized by collagen deposition in the septal and bronchovascular interstitium, especially in rabbits sacrifices at 75 and 120 days. The ECM remodelling process was not reproduced when rabbits were inoculated with collagen types I and III. We conclude that the model reproduces morphologic changes similar to those observed in many DCTD, encouraging realization of other experiments to gain a better understanding of the pathogenesis of these diseases.

Germline-encoded IgG antibodies bind mouse cartilage in vivo: epitope- and idiotype-specific binding and inhibition

Autoantibodies specific for type-II collagen (CII) occur in mice and rats with collagen-induced arthritis (CIA). The binding in vitro and in vivo of mouse monoclonal antibodies (MoAbs) specific for separate epitopes in CII have been investigated. Two-day-old mice were injected intraperitoneally (i.p.) with the anti-CII antibody CIID3 in both unlabelled and biotinylated form. It was found that antibodies binding to the same epitope in CII in vivo can inhibit others from binding in an epitope-specific fashion. The binding in vivo and in vitro of anti-CII antibodies could be inhibited also by an anti-idiotypic rat antiserum produced against the D3 antibody. The anti-idiotypic antiserum inhibited the binding of the antibody D3 and the idiotypically related antibody C2. The cDNA's of anti-CII antibodies D3, C2, and F4 were sequenced and found to contain germline encoded V-genes, apparently without somatic mutations. The variable heavy chain of D3 and C2 both expressed the same VH rearrangement, confirming that they share idiotypes. This report demonstrates that CII-specific germline-encoded IgG autoantibodies bind specifically to normal cartilage in vivo via their combining site.

Autoimmune recognition of cartilage collagens

Recent advances in basic research on the immune system and molecular biology of cartilage components have greatly increased our understanding of the role of autoimmunity in inflammatory diseases affecting joints, particularly rheumatoid arthritis. Many of these diseases are common and their complex pathogenesis probably involves a large number of genes polymorphic in the population as well as environmental factors. Characteristic features of inflammatory arthritis include expansion of the synovial tissue into a pannus containing lymphocytes and macrophages, autoimmune reactions against cartilage antigens, and erosion of cartilage. Since hyaline cartilage of the articular surfaces is the only structure within the joint known to contain joint-specific antigens this tissue is the prime suspect as the target of the autoimmune This review will first present the capacity of the immune system to discriminate between self and non-self structures, and then summarize our current understanding of the structures of cartilage collagens. Subsequently we will discuss how the immune system normally interacts with cartilage and how such interactions can lead to arthritis. We propose that collagen-induced arthritis (CIA) is valuable for understanding the autoimmune recognition of cartilage collagen which precedes the outbreak of arthritis and may perpetuate its chronicity, and serves as an animal model of rheumatoid arthritis.

A quantitative analysis of H-2 linked effects on hepatic ganglioside composition

We have conducted a quantitative analysis of the gangliosides extracted from brain, spleen, thymus, and liver tissue of 8-week-old male mice from H-2 congenic mouse strains on the B10 background, using high performance thin-layer chromatography (HPTLC). An analysis of variance of replicate samples of liver from strains B10, B10.A, and B10.G revealed that the time of sample and colony of origin were not sources of significant variance but that for N-glycolylated gangliosides GM2, GM1, and GD1a, the differences detected between strains were significant. Particularly important were the differences for GM1: the values of 0.0% for B10, 19.0% for B10.A, and 36.0% for B10.G were each significantly different from the others (P less than 0.0005). Further studies with liver tissue from B10/A H-2 recombinant strains also revealed three significantly different levels of GD1a: less than or equal to 4.0% [B10, B10.A (3R), B10.A (5R), B10.A (18R)], 11.0% (B10.A), and 33% [B10.A (1R), B10.A (2R), B10.A (4R)]. Our findings support prior studies which indicate that a gene linked to the H-2 complex affects hepatic GM2 galactosyltransferase activity. However, they also indicate that the current model, which classifies all strains as possessing either an allele for "high" enzyme activity or a single alternative allele for "low" enzyme activity, is probably oversimplified, since at least three levels of enzyme activity appear to exist as stable phenotypic markers. Moreover, the current model cannot readily account for the three different levels of GD1a observed with B10/A H-2 recombinants. Alternative models are proposed, including the novel suggestion that a distinct H-2 linked gene may affect hepatic GM1 sialyltransferase activity. These findings demonstrate that further study of H-2 linked genes affecting the activities of glycosyltransferases is indicated.

Determinant-specific regulation of T helper cell responses to murine lambda light chains by both H-2 and non-H-2 genes

Previous work has revealed that the T helper cell (Th) responses to an antigenic determinant of V lambda 2(315) (called lambda 2.1) is regulated by both H-2 and non-H-2 genes. In the present study this was confirmed and extended to two other determinants, one shared between free lambda 2(315) and lambda 1(J558) (called lambda 2.2) and one unique for free lambda 1(J558) (called lambda 1.1). H-2 genes regulate the responses to the latter determinants, because BALB.B (H-2b) mice were low responders and BALB/c (H-2d) mice were high responders. Thus, the H-2d haplotype on BALB/c background was associated with high responder status. However, when the H-2d haplotype was examined on other genetic backgrounds than BALB/c, the animals could be classified as either intermediate or low responders, depending upon the non-H-2 background. This demonstrated that non-H-2 genes also influenced Th responses. Furthermore, C3H-H-2o, DBA/2 and B10.D2 mice (all H-2d) responded to only one (lambda 2.1) but not the other (lambda 2.2) of two determinants physically linked on the same polypeptide chain (lambda 2(315)). This indicated that the non-H-2 gene effect is capable of fine discrimination, i.e. the non-H-2 gene-mediated low responder phenotype may at least in part be due to failure of recognition of certain antigenic sites, like the H-2-linked Ir-gene defect. F1 hybrids responded to the same determinants as their parental strains; e.g., the BALB/c non-H-2 background exerted a dominant influence over the low responder background of C3H, B10 and DBA/2 strains.

Immune response to connective tissue components of the basement membrane

The immune response to connective tissue components of basement membrane (type IV collagen and laminin) and to interstitial collagen (type I) has been examined in human and murine systems. We also examined the role that immunologic sensitization to autologous connective tissue components might play in inducing an inflammatory response resulting in pathologic sequelae. Mice receiving a single subcutaneous injection of 5 micrograms type IV or type I murine collagens, or murine laminin in complete Freund's adjuvant mount a delayed-type hypersensitivity response characterized by a mononuclear cell infiltrate when challenged in the footpad with the sensitizing antigen. Cell-mediated immunity to these connective tissue antigens can be transferred to normal syngeneic mice with sensitized T-lymphocytes. In addition, repeated immunizations with these homologous connective tissue components elicit antibody responses in mice. Our data demonstrate the immunogenic nature of types IV and I collagen, and of laminin in a syngeneic murine model. We have demonstrated autoantibodies to the basement membrane and interstitial collagens in the sera of patients with scleroderma (systemic sclerosis); ELISA ratios correlate directly with the extent of pulmonary fibrosis in these patients. Anti-type IV collagen autoantibodies were found to be primarily IgM and anti-type I collagen antibodies, primarily IgG. An antibody response to autologous connective tissue antigens could lead to complement activation, immune complex formation, and deposition of the complexes along vascular endothelium with recruitment of blood monocytes in situ, mirroring the early scleroderma lesion (perivascular mononuclear cell filtrates). In vitro we examined the role of human peripheral blood mononuclear cells in the activation of fibroblasts. Adherent human blood monocytes release mediators which stimulate fibroblast proliferation and collagen deposition. A model is presented for the induction of immunity to autologous connective tissue components, leading to mononuclear cell inflammation, fibroblast activation and fibrosis. Selective immunity to basement membrane collagens may influence the clinical expression of diffuse connective tissue syndromes such as scleroderma (systemic sclerosis).