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1.  T Cells Stimulated by an Analog Peptide of Type II Collagen Require FcRγ to Secrete IL-4 and Suppress Autoimmune Arthritis 
Arthritis and rheumatism  2011;63(9):2661-2670.
Using the collagen-induced arthritis (CIA) model, we explored the characteristics of the T cell population which responds to an analog peptide (A9) of type II collagen (CII) and regulates autoimmunity.
A9 is a 26 amino acid peptide analogous to the sequence of a segment of CII (CII 245-270) but with substitutions made at amino acid positions 260 (alanine for isoleucine), 261 (hydroxyproline for alanine), and 263 (asparagine for phenylalanine). We have previously shown that A9 profoundly suppresses immunity to CII and CIA. In order to determine the mechanism of suppression, we used a transgenic mouse whose T cells express a CII specific receptor (TCR) and performed passive cell transfer experiments.
The results demonstrate that suppression of CIA by the A9 is dependent upon T cells. Using multiparameter flow cytometry, we determined that the cells responsible for suppression were CD4+ and expressed high levels of FcεRIγ(FcRγ). To establish the significance of this finding, we obtained mice genetically deficient in FcRγ to perform passive transfer experiments. The resulting FcRγ-/- CD4+ T cells when primed by culture with A9 could not transfer the suppression of arthritis nor secrete cytokines in response to A9.
Taken together, these data suggest that the suppression of arthritis and the Th2 cytokine profile elicited by A9 is dependent upon the presence of FcRγ in the T cells. These findings are novel and may have therapeutic potential for patients with autoimmune arthritis.
PMCID: PMC3575180  PMID: 21590683
2.  Genetic and Molecular Basis of Quantitative Trait Loci of Arthritis in Rat: Genes and Polymorphisms1 
Rheumatoid arthritis (RA) is an autoimmune disease, the pathogenesis of which is affected by multiple genetic and environmental factors. To understand the genetic and molecular basis of RA, a large number of quantitative trait loci (QTL) that regulate experimental autoimmune arthritis have been identified using various rat models for RA. However, identifying the particular responsible genes within these QTL remains a major challenge. Using currently available genome data and gene annotation information, we systematically examined RA-associated genes and polymorphisms within and outside QTL over the whole rat genome. By the whole genome analysis of genes and polymorphisms, we found that there are significantly more RA-associated genes in QTL regions as contrasted with non-QTL regions. Further experimental studies are necessary to determine whether these known RA-associated genes or polymorphisms are genetic components causing the QTL effect.
PMCID: PMC3466165  PMID: 18606636
3.  T Cell Receptor-Signaling Induced by an Analog Peptide of type II Collagen Requires Activation of Syk 
Clinical immunology (Orlando, Fla.)  2009;133(1):145-153.
We have previously described an analog peptide of type II collagen (CII) that can suppress collagen-induced arthritis (CIA). This analog peptide represents CII245-270, the immunodominant epitope of CII, but with substitutions at 260, 261, and 263 - CII245-270 (A260, B261, and N263) (A9). To elucidate the mechanisms responsible for suppression, we used mice transgenic for a collagen-specific T cell receptor (TCR). When we found that APCs pulsed with A9 failed to induce T cell phosphorylation of TCR-? and ZAP-70, we explored alternative signaling pathways. We determined that A9 instead induced phosphorylation of spleen tyrosine kinase (Syk). The importance of Syk was confirmed by the use of chemical Syk inhibitors, which blocked both cytokine secretion and activation of GATA-3 mediated by peptide A9. In summary, T cells use an alternative pathway in response to A9 that involves Syk. This novel T cell pathway may represent an important means for altering T cell phenotypes.
PMCID: PMC2756788  PMID: 19596610
Collagen II; T cells; altered peptide ligands; T cell signaling; Syk (spleen tyrosine kinase); autoimmunity
4.  Characterization of T cell phenotype and function in a double transgenic (collagen-specific TCR/HLA-DR1) humanized model of arthritis 
T cells orchestrate joint inflammation in rheumatoid arthritis (RA), yet they are difficult to study due to the small numbers of antigen-specific cells. The goal of this study was to characterize a new humanized model of autoimmune arthritis and to describe the phenotypic and functional changes that occur in autoimmune T cells following the induction of pathological events.
We developed a double transgenic mouse containing both the HLA-DR1 transgene and an HLA-DR1-restricted collagen-specific TCR in order to obtain large numbers of antigen-specific T cells that can be used for immunologic studies.
In vitro, CII-specific T cells from this mouse proliferated vigorously in response to the CII immunodominant peptide A2 and the cells altered their phenotype to become predominately CD62Llow and CD44high “activated” T cells. The response was accompanied by the production of Th1, Th2, and Th17-type cytokines. Following immunization with bovine CII/CFA, these mice develop an accelerated arthritis compared to single transgenic HLA-DR1 mice. On the other hand, when the mice were treated orally with the analog peptide A12, (a suppressive analog of collagen we have previously described), arthritis was significantly suppressed, despite the fact that >90% of the CD4+ T cells express the TCR Tg. In GALT tissues taken from the A12-treated mice, IL-2, IFN-γ, and IL-17 production to the autoimmune collagen determinant dropped while high levels of IL-10 and IL-4 were produced.
We have developed a humanized model of autoimmune arthritis that will be useful for the study of T cell directed therapies as well as T cell mediated mechanisms of autoimmune diseases.
PMCID: PMC3978884  PMID: 24405551
5.  Analog peptides of type II collagen can suppress arthritis in HLA-DR4 (DRB1*0401) transgenic mice 
Rheumatoid arthritis (RA) is an autoimmune disease associated with the recognition of self proteins secluded in diarthrodial joints. We have previously established that mice transgenic for the human DR genes associated with RA are susceptible to collagen-induced arthritis (CIA) and we have identified a determinant of type II collagen (CII263–270) that triggers T-cell immune responses in these mice. We have also determined that an analog of CII263–270 would suppress disease in DR1 transgenic mice. Because the immunodominant determinant is the same for both DR1 transgenic and DR4 transgenic mice, we attempted to determine whether the analog peptide that was suppressive in DR1 transgenic mice would also be effective in suppressing CIA in DR4 transgenic mice. We treated DR4 transgenic mice with two analog peptides of CII that contained substitutions in the core of the immunodominant determinant: CII256–276 (F263N, E266D) and CII256–270 (F263N, E266A). Mice were observed for CIA, and T-cell proliferative responses were determined. Either peptide administered at the time of immunization with CII significantly downregulated arthritis. Binding studies demonstrated that replacement of the phenylalanine residue in position 263 of the CII peptide with asparagine significantly decreased the affinity of the peptide for the DR4 molecule. In contrast, replacement of the glutamic acid residue in position 266 with aspartic acid or with alanine had differing results. Aspartic acid reduced the affinity (35-fold) whereas alanine did not. Both peptides were capable of suppressing CIA. With the use of either peptide, CII256–276 (F263N, E266D) or CII256–270 (F263N, E266A), the modulation of CIA was associated with an increase in T-cell secretion of IL-4 together with a decrease in IFN-γ. We have identified two analog peptides that are potent suppressors of CIA in DR4 transgenic mice. These experiments represent the first description of an analog peptide of CII recognized by T cells in the context of HLA-DR4 that can suppress autoimmune arthritis.
PMCID: PMC1779432  PMID: 16982003
6.  Characterisation of the immune response to type I collagen in scleroderma 
This study was conducted to examine the frequency, phenotype, and functional profile of T lymphocytes that proliferate in response to type I collagen (CI) in patients with scleroderma (SSc). Peripheral blood mononuclear cells (PBMCs) from SSc patients, healthy controls, and rheumatoid arthritis disease controls were labeled with carboxy-fluorescein diacetate, succinimidyl ester (CFSE), cultured with or without antigen (bovine CI) for 14 days, and analysed by flow cytometry. Surface markers of proliferating cells were identified by multi-color flow cytometry. T-cell lines were derived after sorting for proliferating T cells (CFSElow). Cytokine expression in CI-responsive T cells was detected by intracellular staining/flow cytometry and by multiplex cytokine bead assay (Bio-Plex). A T-cell proliferative response to CI was detected in 8 of 25 (32%) SSc patients, but was infrequent in healthy or disease controls (3.6%; p = 0.009). The proliferating T cells expressed a CD4+, activated (CD25+), memory (CD45RO+) phenotype. Proliferation to CI did not correlate with disease duration or extent of skin involvement. T-cell lines were generated using in vitro CI stimulation to study the functional profile of these cells. Following activation of CI-reactive T cells, we detected intracellular interferon (IFN)-γ but not interleukin (IL)-4 by flow cytometry. Supernatants from the T-cell lines generated in vitro contained IL-2, IFN-γ, GM-CSF (granulocyte macrophage-colony-stimulating factor), and tumour necrosis factor-α, but little or no IL-4 and IL-10, suggesting that CI-responsive T cells express a predominantly Th1 cytokine pattern. In conclusion, circulating memory CD4 T cells that proliferate to CI are present in a subset of patients with SSc, but are infrequent in healthy or disease controls.
PMCID: PMC1779396  PMID: 16879746
7.  An HLA-DR1 Transgene Confers Susceptibility to Collagen-induced Arthritis Elicited with Human Type II Collagen 
The Journal of Experimental Medicine  1997;185(6):1113-1122.
Rheumatoid arthritis (RA) is an autoimmune disease that is strongly associated with the expression of several HLA-DR haplotypes, including DR1 (DRB1*0101). Although the antigen that initiates RA remains elusive, it has been shown that many patients have autoimmunity directed to type II collagen (CII). To test the hypothesis that HLA-DR1 is capable of mediating an immune response to CII, we have generated transgenic mice expressing chimeric (human/ mouse) HLA-DR1. When the DR1 transgenic mice were immunized with human CII (hCII), they developed a severe autoimmune arthritis, evidenced by severe swelling and erythema of the limbs and marked inflammation and erosion of articular joints. The development of the autoimmune arthritis was accompanied by strong DR1-restricted T and B cell responses to hCII. The T cell response was focused on a dominant determinant contained within CII(259–273) from which an eight amino acid core was defined. The B cell response was characterized by high titers of antibody specific for hCII, and a high degree of cross-reactivity with murine type II collagen. These data demonstrate that HLA-DR1 is capable of presenting peptides derived from hCII, and suggest that this DR1 transgenic model will be useful in the development of DR1-specific therapies for RA.
PMCID: PMC2196244  PMID: 9091584
8.  Binding of Chemotactic Collagen-Derived Peptides to Fibroblasts 
Journal of Clinical Investigation  1978;62(5):916-922.
We previously showed that collagen, α-chains, and collagen-derived peptide fragments induce chemotactic migration of human fibroblasts in vitro. We now describe biochemical and immunological evidence showing there are binding sites for collagen peptides on fibroblast membranes.
By the use of 14C-labeled α1(I) chain, binding to intact fibroblasts was demonstrated. The process was reversible, and time- and fibroblast concentration-dependent. Scatchard plot analyses of the data obtained for the binding of α1(I) suggested that there are ≅ 16 × 106 binding sites per fibroblast with an association constant of 1.1 × 107/M for α1(I). Dissociation of the bound radioactivity and subsequent chromatographic analysis on agarose A-1.5 m revealed that the α1 was unaltered. The binding of 14C-labeled α1 was inhibited by each of the CNBr peptides derived from α1 chain of chick skin collagen and CNBr peptide mixtures of various genetic types of collagen chains.
Immunofluorescence studies with anti-α1 antibody showed that α1-treated fibroblasts exhibited strong immunofluorescence. The intensity of fluorescence was markedly diminished by prior absorption of the antibody with α1. The α1-treated cells stained with preimmune sera did not show significant fluorescence.
Dose-response curves of fibroblast chemotaxis induced by α1 and the binding of α1 by fibroblasts correlate closely. Furthermore, the potency of α1-CNBr peptides as chemotactic agents correlates with their ability to inhibit the binding of labeled α1(I). These data suggest the hypothesis that collagenderived peptides cause fibroblast chemotactic migration by acting on fibroblast membranes.
PMCID: PMC371848  PMID: 711857
9.  Humoral and Cellular Sensitivity to Collagen in Type II Collagen-Induced Arthritis in Rats 
We have recently described a new animal model of arthritis induced by intradermal injection of a distinct type of collagen found in cartilage (type II collagen). Since immunologic sensitivity to collagen could play a role in the pathogenesis of this type II collagen-induced arthritis in rats, the ability of purified types of native collagens to induce cellular and humoral responses was quantified by antigeninduced tritiated thymidine incorporation into lymphocytes by collagen and passive hemagglutination, respectively. Rats injected intradermally with native heterologous or homologous type II collagens in adjuvant developed type-specific cellular as well as humoral reactivity. Types I and III collagens were less immunogenic than was type II. The latter collagen induced brisk cellular and humoral responses that were equivalent whether complete Freund's adjuvant or incomplete Freund's adjuvant were employed. Both responses could be induced by native type II collagens modified by limited pepsin digestion, indicating that they are not attributable to determinants in the telopeptide regions of the molecule. Thus, these studies demonstrate the unique immunogenic as well as arthritogenic properties of the type II collagen molecule and indicate that both result from a helical conformation of its structurally distinct α-chains. Further, they suggest that type II collagen may, by humoral or cellular mechanisms, provoke or perpetuate inflammation in other arthritic diseases.
PMCID: PMC372517  PMID: 618915
10.  A Collagen Defect in Homocystinuria 
Journal of Clinical Investigation  1973;52(10):2571-2578.
The biochemical mechanism accounting for the connective tissue abnormalities in homocystinuria was explored by examining the effects of various amino acids known to accumulate in the plasma of patients with this disease on cross-link formation in collagen. Neutral salt solutions of purified, rat skin collagen, rich in cross-link precursor aldehydes, were polymerized to native type fibrils by incubating at 37°C in the presence of homocysteine, homocystine, or methionine. After the polymerization was completed, each sample was examined for the formation of covalent intermolecular cross-links, assessed indirectly by solubility tests and directly by measuring the cross-link compounds after reduction with tritiated sodium borohydride and hydrolysis.
Collagen solutions containing homocysteine (0.01 M-0.1 M) failed to form insoluble fibrils. Furthermore, much less of the reducible cross-links, Δ6,7 dehydrohydroxylysinonorleucine, Δ6,7 dehydrohydroxylysinohydroxynorleucine, and histidino-dehydrohydroxymerodesmosine were formed in the preparations containing homocysteine as compared with the control and the samples containing methionine or homocystine. The content of the precursor aldehydes, α-aminoadipic-δ-semialdehyde (allysine) and the aldol condensation product, was also markedly diminished in tropocollagen incubated with homocysteine. It is concluded that homocysteine interferes with the formation of intermolecular cross-links that help stabilize the collagen macromolecular network via its reversible binding to the aldehydic functional groups.
Analysis of the collagen cross-links in skin biopsy samples obtained from three patients with documented homocystinuria showed that the cross-links were significantly decreased as compared with the age-matched controls, supporting the tentative conclusions reached from the in vitro model studies. In addition, the solubility of dermal collagen in non-denaturing solvents was significantly increased in the two patients examined, reflecting a functional defect in collagen cross-linking. Although the concentration of homocysteine used in this study to demonstrate these effects in vitro is clearly higher than that which is observed in homocystinuric's plasma, the data do suggest a possible pathogenetic mechanism of connective tissue defect in homocystinuria.
PMCID: PMC302517  PMID: 4729050
11.  Characterization of inhibitory T cells induced by an analog of type II collagen in an HLA-DR1 humanized mouse model of autoimmune arthritis 
Arthritis Research & Therapy  2012;14(3):R107.
We used DR1 transgenic mice and covalently linked DR1 multimers to characterize analog-specific inhibitory T cells in collagen-induced arthritis (CIA). Because of the low numbers of antigen-specific T cells in wild-type mice, functional T-cell studies in autoimmune arthritis have been challenging. The use of T-cell receptor (TCR) transgenic mice has provided useful information, but such T cells may not represent the heterogeneous T-cell response that occurs in natural settings. Our focus was to develop tools to identify and characterize the population of immunoregulatory T cells induced in wild-type mice by an analog peptide of CII259-273, which contains amino acid substitutions at positions 263 (N) and 266 (D) (analog peptide A12).
DR1 multimers, developed by loading empty class II molecules with exogenous peptide, provide a method for visualizing antigen-specific T cells with flow cytometry. However, the low binding avidity of A12 for the major histocompatibility complex (MHC) made this strategy untenable. To overcome this problem, we generated DR1 multimers in which the analog peptide A12 was covalently linked, hoping that the low-avidity analog would occupy enough binding clefts to allow detection of the responsive T cells.
Staining with the tetramer revealed that A12-specific T cells were readily detectable at 10 days after immunization. These CD4(+) T cells are a highly selective subset of the TCR repertoire and have a limited clonality. Analysis of cytokine expression showed that cells detected by tetramer (A12) expressed primarily suppressive cytokines (interleukin-4 (IL-4) and IL-10) in response to collagen, compared with control cells. Although they did not express Fox-p3, they were extremely effective in preventing and suppressing inflammatory arthritis.
In summary, our studies showed that the use of covalently linked multimers allows characterization of analog-specific T cells that are otherwise difficult to detect. The suppressive character of the analog-specific T-cell response suggests that these cells attenuate autoimmunity and differ significantly in phenotype from the inflammatory T cells predominantly found in arthritic joints. Such reagents will become powerful tools to study T-cell responses in RA patients in upcoming clinical trials.
PMCID: PMC3446484  PMID: 22569209
12.  Modulation of collagen-induced arthritis by adenovirus-mediated intra-articular expression of modified collagen type II 
Arthritis Research & Therapy  2010;12(4):R136.
Rheumatoid arthritis (RA) is a systemic disease manifested by chronic inflammation in multiple articular joints, including the knees and small joints of the hands and feet. We have developed a unique modification to a clinically accepted method for delivering therapies directly to the synovium. Our therapy is based on our previous discovery of an analog peptide (A9) with amino acid substitutions made at positions 260 (I to A), 261 (A to B), and 263 (F to N) that could profoundly suppress immunity to type II collagen (CII) and arthritis in the collagen-induced arthritis model (CIA).
We engineered an adenoviral vector to contain the CB11 portion of recombinant type II collagen and used PCR to introduce point mutations at three sites within (CII124-402, 260A, 261B, 263D), (rCB11-A9) so that the resulting molecule contained the A9 sequence at the exact site of the wild-type sequence.
We used this construct to target intra-articular tissues of mice and utilized the collagen-induced arthritis model to show that this treatment strategy provided a sustained, local therapy for individual arthritic joints, effective whether given to prevent arthritis or as a treatment. We also developed a novel system for in vivo bioimaging, using the firefly luciferase reporter gene to allow serial bioluminescence imaging to show that luciferase can be detected as late as 18 days post injection into the joint.
Our therapy is unique in that we target synovial cells to ultimately shut down T cell-mediated inflammation. Its effectiveness is based on its ability to transform potential inflammatory T cells and/or bystander T cells into therapeutic (regulatory-like) T cells which secrete interleukin (IL)-4. We believe this approach has potential to effectively suppress RA with minimal side effects.
PMCID: PMC2945026  PMID: 20615221

Results 1-12 (12)