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To identify and characterize anti-citrullinated glucose-6-phosphate isomerase ( GPI) peptide antibodies in patients with rheumatoid arthritis ( RA). Nine GPI arginine-bearing peptides in human GPI protein were selected and cyclic citrullinated GPI peptides ( CCG-1-9) were constructed. Samples were obtained from RA ( n = 208), systemic lupus erythematosus ( SLE) ( n = 101), Sjögren's syndrome ( SS; n = 101) and healthy controls ( n = 174). Antibodies against CCG-1-9 were measured, and anti-citrullinated α-enolase-1 ( CEP-1), -cyclic citrullinated peptides ( CCP) and - GPI proteins antibodies were also examined. Patients with RA were genotyped for HLA- DRB1. The numbers of shared epitope ( SE) alleles were counted and compared with those of the autoantibodies. Rabbit GPI was citrullinated with rabbit peptidylarginine deiminase and immunoblot analysis of RA sera performed. The levels of autoantibodies were compared before and after treatment with TNF antagonists in 58 RA patients. Anti- CCG-2, -4 and -7 antibodies were detected in 25·5, 33·2 and 37·0% patients with RA, respectively, and these antibodies were very specific for RA (specificity, 98·1-99·7%). Altogether, 44·2, 86·1 and 13·9% of RA sera were positive for anti- CEP-1, - CCP and - GPI protein antibodies, respectively. Anti- CCG-2, -4 and -7 antibodies were correlated with anti- CCP and anti- CEP-1 antibodies and with the presence of HLA- DRB1 SE alleles. Citrullinated GPI protein was detected using RA sera. Treatment with tumour necrosis factor antagonists reduced significantly the levels of anti- CCG-2 and -7 but not of anti- CEP-1 antibodies. This is the first report documenting the presence of anti- CCG antibodies in RA. Anti- CCG-2 and -7 antibodies could be considered as markers for the diagnosis of RA and its disease activity. [ABSTRACT FROM AUTHOR]

Alpha-carba-GalCer (RCAI-56), a novel synthetic analogue of α-galactosylceramide (α-GalCer), stimulates invariant natural killer T (NK T) cells to produce interferon (IFN)-γ. IFN-γ exhibits immunoregulatory properties in autoimmune diseases by suppressing T helper (Th)-17 cell differentiation and inducing regulatory T cells and apoptosis of autoreactive T cells. Here, we investigated the protective effects of α-carba-GalCer on collagen-induced arthritis (CIA) in mice. First, we confirmed that α-carba-GalCer selectively induced IFN-γ in CIA-susceptible DBA/1 mice in vivo. Then, DBA/1 mice were immunized with bovine type II collagen (CII) and α-carba-GalCer. The incidence and clinical score of CIA were significantly lower in α-carba-GalCer-treated mice. Anti-IFN-γ antibodies abolished the beneficial effects of α-carba-GalCer, suggesting that α-carba-GalCer ameliorated CIA in an IFN-γ-dependent manner. Treatment with α-carba-GalCer reduced anti-CII antibody production [immunoglobulin (Ig)G and IgG2a] and CII-reactive interleukin (IL)-17 production by draining lymph node (DLN) cells, did not induce apoptosis or regulatory T cells, and significantly increased the ratio of the percentage of IFN-γ-producing T cells to IL-17-producing T cells (Th1/Th17 ratio). Moreover, the gene expression levels of IL-6 and IL-23p19, Th17-related cytokines, were reduced significantly in mice treated with α-carba-GalCer. In addition, we observed higher IFN-γ production by NK T cells in α-carba-GalCer-treated mice in the initial phase of CIA. These findings indicate that α-carba-GalCer polarizes the T cell response toward Th1 and suppresses Th17 differentiation or activation, suggesting that α-carba-GalCer, a novel NK T cell ligand, can potentially provide protection against Th17-mediated autoimmune arthritis by enhancing the Th1 response. [ABSTRACT FROM AUTHOR]

M3 muscarinic acetylcholine receptor (M3R) plays a crucial role in the secretion of saliva from salivary glands. It is reported that some patients with Sjögren's syndrome (SS) carried inhibitory autoantibodies against M3R. The purpose of this study is to clarify the epitopes and function of anti-M3R antibodies in SS. We synthesized peptides encoding the extracellular domains of human-M3R including the N-terminal region and the first, second and third extracellular loops. Antibodies against these regions were examined by enzyme-linked immunosorbent assay in sera from 42 SS and 42 healthy controls. For functional analysis, human salivary gland (HSG) cells were preincubated with immunoglobulin G (IgG) separated from sera of anti-M3R antibody-positive SS, -negative SS and controls for 12 h. After loading with Fluo-3, HSG cells were stimulated with cevimeline hydrochloride, and intracellular Ca2+ concentrations [(Ca2+)i] were measured. Antibodies to the N-terminal, first, second and third loops were detected in 42·9% (18 of 42), 47·6% (20 of 42), 54·8% (23 of 42) and 45·2% (19 of 42) of SS, while in 4·8% (two of 42), 7·1% (three of 42), 2·4% (one of 42) and 2·4% (one of 42) of controls, respectively. Antibodies to the second loop positive SS-IgG inhibited the increase of (Ca2+)i induced by cevimeline hydrochloride. Antibodies to the N-terminal positive SS-IgG and antibodies to the first loop positive SS-IgG enhanced it, while antibodies to the third loop positive SS-IgG showed no effect on (Ca2+)i as well as anti-M3R antibody-negative SS-IgG. Our results indicated the presence of several B cell epitopes on M3R in SS. The influence of anti-M3R antibodies on salivary secretion might differ based on these epitopes. [ABSTRACT FROM AUTHOR]

Interstitial lung disease (ILD) is an intractable disease induced by various factors in humans. However, there is no universally effective treatment for ILD. In this study, we investigated the role of transforming growth factor (TGF)-β signalling in the pathogenesis of ILD by using model mice. Injection of interleukin (IL)-18 plus IL-2 in C57BL6 (B6) mice resulted in acute ILD by infiltration of natural killer (NK) cells and a significant increase of TGF-β mRNA in the lung. To examine the pathogenetic role of TGF-β in ILD mice, we used SB-431542 (4-[4-(1,3-benzodioxol-5-yl)-5-(2-pyridinyl)-1H-imidazol-2-yl]-benzamide), which is a potent and selective inhibitor of TGF-β receptor I (TβRI), also known as activin receptor-like kinase 5 (ALK5). Treatment of B6-ILD mice with SB-431542 resulted in improvement of ILD, delay in mortality, reduction of the expression of interferon (IFN)-γ and IL-6 in the lungs. The same treatment also decreased significantly the percentage of natural killer (NK) cells in the lungs ( P < 0·05) and mRNA expression levels of certain chemokines such as CCL2, CCL3, CCL4, CCL5 and CXCL10 in B6-ILD. These findings were confirmed by IL-18 plus IL-2 treatment of Smad3-deficient (Smad3–/–) mice ( P < 0·05). Our results showed that inhibition of TGF-β signalling reduced the percentage of NK cells and the expression of certain chemokines in the lungs, resulting in improvement of ILD. The findings suggest that TGF-β signalling may play an important role in the pathogenesis of IL-18 plus IL-2-induced ILD in mice. [ABSTRACT FROM AUTHOR]

To determine the cytokine balance in patients with lupus nephritis (LN), we analysed kidney-infiltrating T cells. Renal biopsy samples from 15 systemic lupus erythematosus (SLE) patients were used. In accordance with the classification of International Society of Nephrology/Renal Pathology Society, they were categorized into Class III, Class III+V (Class III-predominant group, n = 4), Class IV, Class IV+V (Class IV-predominant group, n = 7) and Class V ( n = 4) groups. The single-cell samples of both the glomelular and interstitial infiltrating cells were captured by laser-microdissection. The glomerular and interstitial infiltrating T cells produced interleukin (IL)-2, IL-4, IL-10, IL-13 and IL-17 cytokines in the Class III-predominant, Class IV-predominant and Class V groups. Interferon-gamma was detected only in the glomeruli of the Class III-predominant and Class V group samples. The expression level of IL-17 was correlated closely with clinical parameters such as haematuria, blood urea nitrogen level, SLE Disease Activity Index scores in both glomeruli and interstitium, urine protein level in glomeruli and serum creatinine and creatinine clearance levels in interstitium. This suggests that the glomerular infiltrating T cells might act as T helper type 1 (Th1), Th2 and Th17 cells while the interstitial infiltrating T cells, act as Th2 and Th17 cells in the Class III-predominant and Class V groups. In contrast, both the glomerular and interstitial infiltrating T cells might act as Th2 and Th17 cells in the Class IV-predominant group. The cytokine balances may be dependent upon the classification of renal pathology, and IL-17 might play a critical role in SLE development. [ABSTRACT FROM AUTHOR]

We have reported previously that the LAD-4 monoclonal antibody (mAb) directed against a fibronectin receptor (FNR) on RL-male-1 T lymphoma cells in BALB/c mice partially inhibited their migration to the liver. In the present study, we examined the mechanism by which another anti-FNR mAb, LAD-1, exerts its antitumourigenic effects. Administration of LAD-1 significantly prolonged survival of BALB/c mice challenged previously with RL-male-1 cells. LAD-1 enhanced phagocytosis of RL-male-1 cells by hepatic macrophages and clodronate-mediated macrophage depletion abrogated the antitumour activity of LAD-1. In vitro experiments revealed that a pan-caspase inhibitor, zVAD-fmk, did not affect the ability of LAD-1 to inhibit the proliferation of RL-male-1 cells. These data suggest that the antitumour effects of LAD-1 may be dependent on stimulation of tumour cell phagocytosis and are apoptosis-independent. Thus, LAD-1-induced phagocytosis of lymphoma cells by hepatic macrophages in mice may, at least in part, be responsible for the prolonged survival of the mice. [ABSTRACT FROM AUTHOR]