TIRC7 deficiency causes in vitro and in vivo augmentation of T and B cell activation and cytokine response

SMRT and NCoR1 fine-tune inflammatory versus tolerogenic balance in dendritic cells by differentially regulating STAT3 signaling

Dendritic cell (DC) fine-tunes inflammatory versus tolerogenic responses to protect from immune-pathology. However, the role of co-regulators in maintaining this balance is unexplored. NCoR1-mediated repression of DC immune-tolerance has been recently reported. Here we found that depletion of NCoR1 paralog SMRT (NCoR2) enhanced cDC1 activation and expression of IL-6, IL-12 and IL-23 while concomitantly decreasing IL-10 expression/secretion. Consequently, co-cultured CD4+ and CD8+ T-cells depicted enhanced Th1/Th17 frequency and cytotoxicity, respectively. Comparative genomic and transcriptomic analysis demonstrated differential regulation of IL-10 by SMRT and NCoR1. SMRT depletion represses mTOR-STAT3-IL10 signaling in cDC1 by down-regulating NR4A1. Besides, Nfkbia and Socs3 were down-regulated in Ncor2 (Smrt) depleted cDC1, supporting increased production of inflammatory cytokines. Moreover, studies in mice showed, adoptive transfer of SMRT depleted cDC1 in OVA-DTH induced footpad inflammation led to increased Th1/Th17 and reduced tumor burden after B16 melanoma injection by enhancing oncolytic CD8+ T-cell frequency, respectively. We also depicted decreased Ncor2 expression in Rheumatoid Arthritis, a Th1/Th17 disease.

Immune Regulatory 1 Cells: A Novel and Potent Subset of Human T Regulatory Cells

A subset of T regulatory cells (Tregs), identified by TIRC7 (T cell immune response cDNA 7) expression is designated as Immune Regulatory 1 Cells (IR1 cells). TIRC7 is an immune checkpoint inhibitor, co-localized with the T- cell receptor, HLA-DR and CTLA-4 during T-cell activation, which delivers regulatory signals via binding to its ligand, HLA-DR α2 domain. IR1 cells express FOXP3, and multiple other markers associated with immune suppression. They constitute as much as 10% of Tregs. IR1 cells strongly inhibit proliferation in mixed lymphocyte reactions, where they express high levels of IL-10. Ex vivo expansion of Tregs over 2 weeks in the presence of an agonist TIRC7 antibody disproportionately expands the IR1 Treg subset, while maintaining high expression of suppressive markers including CD39, IL-10, LAP and GARP. Ex vivo expanded IR1 cells are a potent, homogeneous, stable set of suppressor Tregs with the potential to modulate immune dysregulation. The characteristics of IR1 cells suggest a therapeutic advantage over polyclonal Tregs for therapeutic interventions. Early restoration of immune homeostasis using IR1 cells has the potential to fundamentally alter the natural history of conditions characterized by abnormalities in the T regulatory cell compartment.

The Transmembrane Receptor TIRC7 Identifies a Distinct Subset of Immune Cells with Prognostic Implications in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a heterogeneous malignancy with a dismal prognosis. Therapeutic options are largely limited to surgery and conventional chemotherapy offers limited benefit. As immunotherapy has proven highly effective in various cancer types, we have undertaken a quantitative immunohistopathological assessment of immune cells expressing the immunoinhibitory T cell immune response cDNA 7 receptor (TIRC7), an emerging immunoinhibitory receptor, in a cohort of 135 CCA patients. TIRC7+ immune cells were present in both the tumor epithelia and stroma in the majority of CCA cases with the highest levels found in intrahepatic CCA. While intraepithelial density of TIRC7+ immune cells was decreased compared to matched non-neoplastic bile ducts, stromal quantity was higher in the tumor samples. Tumors exhibiting signet ring cell or adenosquamous morphology were exclusively associated with an intraepithelial TIRC7+ phenotype. Survival analysis showed intraepithelial TIRC7+ immune cell density to be a highly significant favorable prognosticator in intrahepatic but not proximal or distal CCA. Furthermore, intraepithelial TIRC7+ immune cell density correlated with the number of intraepithelial CD8+ immune cells and with the total number of CD4+ immune cells. Our results suggest the presence and prognostic relevance of TIRC7+ immune cells in CCA and warrant further functional studies on its pharmacological modulation.

Immunomodulation in the Treatment of Periodontitis: Progress and Perspectives

Periodontitis is one of the most common dental diseases. Compared with healthy periodontal tissues, the immune microenvironment plays the key role in periodontitis by allowing the invasion of pathogens. It is possible that modulating the immune microenvironment can supplement traditional treatments and may even promote periodontal regeneration by using stem cells, bacteria, etc. New anti-inflammatory therapies can enhance the generation of a viable local immune microenvironment and promote cell homing and tissue formation, thereby achieving higher levels of immune regulation and tissue repair. We screened recent studies to summarize the advances of the immunomodulatory treatments for periodontitis in the aspects of drug therapy, microbial therapy, stem cell therapy, gene therapy and other therapies. In addition, we included the changes of immune cells and cytokines in the immune microenvironment of periodontitis in the section of drug therapy so as to make it clearer how the treatments took effects accordingly. In the future, more research needs to be done to improve immunotherapy methods and understand the risks and long-term efficacy of these methods in periodontitis.

Identification of contributing genes of Huntington's disease by machine learning

Background

Huntington’s disease (HD) is an inherited disorder caused by the polyglutamine (poly-Q) mutations of the HTT gene results in neurodegeneration characterized by chorea, loss of coordination, cognitive decline. However, HD pathogenesis is still elusive. Despite the availability of a wide range of biological data, a comprehensive understanding of HD’s mechanism from machine learning is so far unrealized, majorly due to the lack of needed data density.

Methods

To harness the knowledge of the HD pathogenesis from the expression profiles of postmortem prefrontal cortex samples of 157 HD and 157 controls, we used gene profiling ranking as the criteria to reduce the dimension to the order of magnitude of the sample size, followed by machine learning using the decision tree, rule induction, random forest, and generalized linear model.

Results

These four Machine learning models identified 66 potential HD-contributing genes, with the cross-validated accuracy of 90.79 ± 4.57%, 89.49 ± 5.20%, 90.45 ± 4.24%, and 97.46 ± 3.26%, respectively. The identified genes enriched the gene ontology of transcriptional regulation, inflammatory response, neuron projection, and the cytoskeleton. Moreover, three genes in the cognitive, sensory, and perceptual systems were also identified.

Conclusions

The mutant HTT may interfere with both the expression and transport of these identified genes to promote the HD pathogenesis.

Role of T cell immune response cDNA 7 on the pathology of acute graft-versus-host disease

Activation of T lymphocytes is the initiating factor of the occurrence of acute graft-versus-host disease (aGVHD), and cytotoxic T lymphocyte antigen-4 (CTLA-4) is the inhibitory receptor for activating T cells. T cell immune response cDNA 7 (TIRC7) is considered an upstream regulator of CTLA-4; however, little is understood regarding the effects of TIRC7 on the regulation of CTLA-4 in aGVHD. The purpose of the present study was to evaluate the regulatory effects of TIRC7 on aGVHD, mainly in the pathology. Recipient mice were exposed to a preconditioning dose of 7.5 Gy irradiation on the day of the transplantation and were divided into the following groups: Blank control group, bone marrow transplantation control group, total body irradiation group, mild-moderate aGVHD group and severe aGVHD group. According to the different administration of CTLA-4 and TIRC7 monoclonal antibodies, the mild-moderate and severe aGVHD groups were randomly divided into the hematopoietic stem cell transplantation (HSCT) and HSCT + CTLA-4/TIRC7 groups. Recipient mice were sacrificed at different time points post-HSCT for histopathological analysis by hematoxylin and eosin staining. Compared with the control and other experimental groups, the mice in the combined CTLA-4 and TIRC7 group exhibited ameliorated pathological injury, and lower pathology scores of the liver, lung and intestine. These data revealed that intraperitoneal injection of anti-TIRC7 and/or anti-CTLA-4 monoclonal antibody into mice could effectively alleviate the severity of aGVHD.

TIRC7 inhibits Th1 cells by upregulating the expression of CTLA‑4 and STAT3 in mice with acute graft‑versus‑host disease

In a previous study, it was demonstrated that T‑cell immune response cDNA 7 (TIRC7) levels reflect the efficacy of treatment of patients with acute graft‑versus‑host disease (GVHD). However, the pathogenesis of TIRC7 in acute GVHD remains poorly understood. Lymphocytes from patients with acute GVHD were selected as targeT cells, and the effects of TIRC7 on cytotoxic T lymphocyte antigen‑4 (CTLA‑4), T cell activation and cytokine secretion were observed by electroporation. A mouse model of acute GVHD was established; anti‑TIRC7 and anti‑CTLA‑4 monoclonal antibodies were intraperitoneally injected into recipient mice. Then, the effects of TIRC7 and CTLA‑4 on T cell activation and acute GVHD were monitored. After TIRC7 expression was downregulated, CTLA‑4 levels were decreased and STAT3 phosphorylation was reduced; conversely, the activation capacity of T lymphocytes was elevated, and the secretion of interferon‑γ and other cytokines was increased. The mice in the TIRC7 + CTLA‑4 co‑administration group exhibited the lowest acute GVHD scores, with the longest average survival time and shortest recovery time of hematopoietic reconstitution. In conclusion, the results indicated that TIRC7 may positively regulate the function of CTLA‑4 and inhibit T cell activation, thus suppressing the development and progression of acute GVHD.

RNA interference-mediated silencing of Atp6i prevents both periapical bone erosion and inflammation in the mouse model of endodontic disease

Dental caries is one of the most prevalent infectious diseases in the United States, affecting approximately 80% of children and the majority of adults. Dental caries may lead to endodontic disease, where the bacterial infection progresses to the root canal system of the tooth, leading to periapical inflammation, bone erosion, severe pain, and tooth loss. Periapical inflammation may also exacerbate inflammation in other parts of the body. Although conventional clinical therapies for this disease are successful in approximately 80% of cases, there is still an urgent need for increased efficacy of treatment. In this study, we applied a novel gene-therapeutic approach using recombinant adeno-associated virus (AAV)-mediated Atp6i RNA interference (RNAi) knockdown of Atp6i/TIRC7 gene expression to simultaneously target periapical bone resorption and periapical inflammation. We found that Atp6i inhibition impaired osteoclast function in vitro and in vivo and decreased the number of T cells in the periapical lesion. Notably, AAV-mediated Atp6i/TIRC7 knockdown gene therapy reduced bacterial infection-stimulated bone resorption by 80% in the mouse model of endodontic disease. Importantly, Atp6i(+/-) mice with haploinsufficiency of Atp6i exhibited protection similar to that in mice with bacterial infection-stimulated bone erosion and periapical inflammation, which confirms the potential therapeutic effect of AAV-small hairpin RNA (shRNA)-Atp6i/TIRC7. Our results demonstrate that AAV-mediated Atp6i/TIRC7 knockdown in periapical tissues can inhibit endodontic disease development, bone resorption, and inflammation, indicating for the first time that this potential gene therapy may significantly improve the health of those who suffer from endodontic disease.

RNAi-mediated silencing of Atp6i and Atp6i haploinsufficiency prevents both bone loss and inflammation in a mouse model of periodontal disease

Periodontal disease affects about 80% of adults in America, and is characterized by oral bacterial infection-induced gingival inflammation, oral bone resorption, and tooth loss. Periodontitis is also associated with other diseases such as rheumatoid arthritis, diabetes, and heart disease. Although many efforts have been made to develop effective therapies for this disease, none have been very effective and there is still an urgent need for better treatments and preventative strategies. Herein we explored for the first time the possibility that adeno-associated virus (AAV)-mediated RNAi knockdown could be used to treat periodontal disease with improved efficacy. For this purpose, we used AAV-mediated RNAi knockdown of Atp6i/TIRC7 gene expression to target bone resorption and gingival inflammation simultaneously. Mice were infected with the oral pathogen Porphyromonas gingivalis W50 (P. gingivalis) in the maxillary periodontium to induce periodontitis. We found that Atp6i depletion impaired extracellular acidification and osteoclast-mediated bone resorption. Furthermore, local injection of AAV-shRNA-Atp6i/TIRC7 into the periodontal tissues in vivo protected mice from P. gingivalis infection-stimulated bone resorption by >85% and decreased the T-cell number in periodontal tissues. Notably, AAV-mediated Atp6i/TIRC7 knockdown also reduced the expression of osteoclast marker genes and inflammation-induced cytokine genes. Atp6i(+/-) mice with haploinsufficiency were similarly protected from P. gingivalis infection-stimulated bone loss and gingival inflammation. This suggests that AAV-shRNA-Atp6i/TIRC7 therapeutic treatment may significantly improve the health of millions who suffer from P. gingivalis-mediated periodontal disease.

FOXP3, CBLB and ITCH gene expression and cytotoxic T lymphocyte antigen 4 expression on CD4(+) CD25(high) T cells in multiple sclerosis

Expression of the forkhead box protein 3 (FoxP3) transcription factor is regulated by the E3 ubiquitin ligases Itch and Cbl-b and induces regulatory activity CD4(+) CD25(high) T cells. Treatment with interferon (IFN)-β enhances regulatory T cell activity in multiple sclerosis (MS). We studied the phenotype of CD4(+) CD25(high) T cells in MS by flow cytometry and its relationship with expression of the FOXP3, ITCH and CBLB genes. We found that untreated MS patients had lower cell surface expression of cytotoxic T lymphocyte antigen 4 (CTLA-4) on CD4(+) CD25(high) T cells and higher intracellular CTLA-4 expression than healthy controls. Cell surface expression of CTLA-4 on CD4(+) CD25(high) T cells correlated with expression of FOXP3 mRNA in untreated patients and increased significantly with time from most recent injection in patients treated with IFN-β. FOXP3 mRNA expression correlated with CBLB and ITCH and T helper type 2 cytokine mRNA expression in MS patients. These data link expression of FOXP3, CBLB and ITCH mRNA and CTLA-4 expression on the surface of CD4(+) CD25(high) T cell in MS. We hypothesize that this may reflect alterations in the inhibitory effect of CTLA-4 or in regulatory T cell function.

Monocytes differentiation upon treatment with a peptide corresponding to the C-terminus of activated T cell-expressed Tirc7 protein

Atp6v0a3 gene encodes for two alternative products, Tirc7 and a3 proteins, which are differentially expressed in activated T cells and resorbing osteoclasts, respectively. Tirc7 plays a central role in T cell activation, while a3 protein is critical for osteoclast-mediated bone matrix resorption. Based on the large body of evidences documenting the relationships between T cells and osteoclasts, we hypothesized that the extracellular C-terminus of Tirc7 protein could directly interact with osteoclast precursor cells. To address this issue, we performed the molecular cloning of a mouse Atp6v0a3 cDNA segment encoding the last 40 amino acids of Tirc7 protein, and we used this peptide as a ligand added to mouse osteoclast precursor cells. We evidenced that Tirc7-Cter peptide induced the differentiation of RAW264.7 cells into osteoclast-like cells, stimulated an autocrine/paracrine regulatory loop potentially involved in osteoclastic differentiation control, and strongly up-regulated F4/80 protein expression within multinucleated osteoclast-like cells. Using a mouse bone marrow-derived CD11b(+) cell line, or total bone marrow primary cells, we observed that similarly to Rankl, Tirc7-Cter peptide induced the formation of TRACP-positive large multinucleated cells. At last, using mouse primary monocytes purified from total bone marrow, we determined that Tirc7-Cter peptide induced the appearance of small multinucleated cells (3-4 nuclei), devoid of resorbing activity, and which displayed modulations of dendritic cell marker genes expression. In conclusion, we report for the first time on biological effects mediated by a peptide corresponding to the C-terminus of Tirc7 protein, which interfere with monocytic differentiation pathways.

A single-center experience in 20 patients with infantile malignant osteopetrosis

Infantile malignant osteopetrosis (IMO) includes various genetic disorders that affect osteoclast development and/or function. Genotype-phenotype correlation studies in IMO have been hampered by the rarity and heterogeneity of the disease and by the severity of the clinical course, which often leads to death early in life. We report on the clinical and molecular findings and treatment in 20 consecutive patients (11 males, nine females) with IMO, diagnosed at a single center in the period 1991-2008. Mean age at diagnosis was 3.9 months, and mean follow-up was 66.75 months. Mutations in TCIRG1, OSTM1, ClCN7, and TNFRSF11A genes were detected in nine, three, one, and one patients, respectively. Six patients remain genetically undefined. OSTM1 and ClCN7 mutations were associated with poor neurologic outcome. Among nine patients with TCIRG1 defects, six presented with hypogammaglobulinemia, and one showed primary pulmonary hypertension. Fourteen patients received hematopoietic cell transplantation; of these, nine are alive and eight of them have evidence of osteoclast function. These data may provide a basis for informed decisions regarding the care of patients with IMO.

Direct recruitment of H+-ATPase from lysosomes for phagosomal acidification

The nascent phagosome progressively establishes an acidic milieu by acquiring a proton pump, the vacuolar-type ATPase (V-ATPase). However, the origin of phagosomal V-ATPase remains poorly understood. We found that phagosomes were enriched with the V-ATPase a3 subunit, which also accumulated in late endosomes and lysosomes. We modified the mouse Tcirg1 locus encoding subunit a3, to express an a3-GFP fusion protein. Live-cell imaging and immunofluorescence microscopy revealed that nascent phagosomes received the a3-GFP from tubular structures extending from lysosomes located in the perinuclear region. Macrophages from a3-deficient mice exhibited impaired acidification of phagosomes and delayed digestion of bacteria. These results show that lysosomal V-ATPase is recruited directly to the phagosomes via tubular lysosomes to establish the acidic environment hostile to pathogens.

CTLA-4 trafficking and surface expression

The T-cell co-receptor cytotoxic T-cell antigen 4 (CTLA-4) has a strong inhibitory role as shown by the lymphoproliferative phenotype of CTLA-4-deficient mice. Despite its potent effects on T-cell function, CTLA-4 is primarily an intracellular antigen whose surface expression is tightly regulated by restricted trafficking to the cell surface and rapid internalisation. Recently, several signalling molecules such as Trim, PLD, ARF-1 and TIRC7 have been described to be involved in the transport of CTLA-4 to the cell surface. Minor changes in surface expression levels have major effects on the outcome of T-cell activation. Optimal regulation of CTLA-4 surface expression is crucial for the balance of stimulatory and inhibitory signals to maximize protective immune responses while maintaining immunological tolerance and preventing autoimmunity.

Towards a better understanding and new therapeutics of osteopetrosis

Lack of or dysfunction in osteoclasts result in osteopetrosis, a group of rare but often severe, genetic disorders affecting skeletal tissue. Increase in bone mass results in skeletal malformation and bone marrow failure that may be fatal. Many of the underlying defects have lately been characterized in humans and in animal models of the disease. In humans, these defects often involve mutations in genes expressing proteins involved in the acidification of the osteoclast resorption compartment, a process necessary for proper bone degradation. So far, the only cure for children with severe osteopetrosis is allogeneic hematopoietic stem cell (HSC) transplantation but without a matching donor this form of therapy is far from optimal. The characterization of the genetic defects opens up the possibility for gene replacement therapy as an alternative. Accordingly, HSC-targeted gene therapy in a mouse model of infantile malignant osteopetrosis was recently shown to correct many aspects of the disease.

Molecular profile of peripheral blood mononuclear cells from patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory arthritis. Currently, diagnosis of RA may take several weeks, and factors used to predict a poor prognosis are not always reliable. Gene expression in RA may consist of a unique signature. Gene expression analysis has been applied to synovial tissue to define molecularly distinct forms of RA; however, expression analysis of tissue taken from a synovial joint is invasive and clinically impractical. Recent studies have demonstrated that unique gene expression changes can be identified in peripheral blood mononuclear cells (PBMCs) from patients with cancer, multiple sclerosis, and lupus. To identify RA disease-related genes, we performed a global gene expression analysis. RNA from PBMCs of 9 RA patients and 13 normal volunteers was analyzed on an oligonucleotide array. Compared with normal PBMCs, 330 transcripts were differentially expressed in RA. The differentially regulated genes belong to diverse functional classes and include genes involved in calcium binding, chaperones, cytokines, transcription, translation, signal transduction, extracellular matrix, integral to plasma membrane, integral to intracellular membrane, mitochondrial, ribosomal, structural, enzymes, and proteases. A k-nearest neighbor analysis identified 29 transcripts that were preferentially expressed in RA. Ten genes with increased expression in RA PBMCs compared with controls mapped to a RA susceptibility locus, 6p21.3. These results suggest that analysis of RA PBMCs at the molecular level may provide a set of candidate genes that could yield an easily accessible gene signature to aid in early diagnosis and treatment.

TIRC7 inhibits T cell proliferation by modulation of CTLA-4 expression

Ab targeting of TIRC7 has been shown previously to inhibit T cell proliferation and Th1 lymphocyte-associated cytokine production. In this study, we demonstrate that Ab targeting of TIRC7 induces early cell surface expression of CTLA-4. The majority of stimulated CD4+ and CD8+ human T cells coexpress CTLA-4 and TIRC7. Similar to CTLA-4, TIRC7 rapidly accumulates at the site of Ag adhesion upon T cell activation. TIRC7 seems to colocalize with CTLA-4 in human T cells, and both molecules are associated with clathrin-coated vesicles, indicating they share intracellular transport systems. Moreover, Ab targeting of TIRC7 results in an early activation of CTLA-4 transcription. The inhibition of cell proliferation mediated by TIRC7 is dependent on CTLA-4 expression because the TIRC7-mediated inhibitory effects on cell proliferation and cytokine expression are abolished by Ab blockade of CTLA-4. Splenocytes obtained from CTLA-4-deficient mice are not responsive to TIRC7 Ab targeting. Thus, TIRC7 acts as an upstream regulatory molecule of CTLA-4 expression.

Prediction of graft-versus-host disease in humans by donor gene-expression profiling

BACKGROUND

Graft-versus-host disease (GVHD) results from recognition of host antigens by donor T cells following allogeneic hematopoietic cell transplantation (AHCT). Notably, histoincompatibility between donor and recipient is necessary but not sufficient to elicit GVHD. Therefore, we tested the hypothesis that some donors may be "stronger alloresponders" than others, and consequently more likely to elicit GVHD.

METHODS AND FINDINGS

To this end, we measured the gene-expression profiles of CD4(+) and CD8(+) T cells from 50 AHCT donors with microarrays. We report that pre-AHCT gene-expression profiling segregates donors whose recipient suffered from GVHD or not. Using quantitative PCR, established statistical tests, and analysis of multiple independent training-test datasets, we found that for chronic GVHD the "dangerous donor" trait (occurrence of GVHD in the recipient) is under polygenic control and is shaped by the activity of genes that regulate transforming growth factor-beta signaling and cell proliferation.

CONCLUSIONS

These findings strongly suggest that the donor gene-expression profile has a dominant influence on the occurrence of GVHD in the recipient. The ability to discriminate strong and weak alloresponders using gene-expression profiling could pave the way to personalized transplantation medicine.

TIRC7 is induced in rejected human kidneys and anti-TIRC7 mAb with FK506 prolongs survival of kidney allografts in rats

TIRC7 delivers essential signals during immune activation as antibodies targeting TIRC7 inhibit lymphocyte proliferation and Th1 cytokine expression in vitro and prolonged kidney and heart allograft survival in vivo. Immunohistochemical analysis of biopsy specimens from human renal allografts undergoing rejection despite treatment with Calcineurin inhibitors (CI) showed elevated TIRC7 expression. Accordingly, with a view to clinical application, we evaluated the therapeutic effect of a chimerized anti-TIRC7 mAb in combination with Tacrolimus (FK506) using a rat kidney transplantation model (DA to Lewis). The combination of sub-therapeutic doses of both compounds significantly (p<0.05) prolonged the median graft survival to 19.5 days compared to monotherapy with FK506 (median survival, 7d) or mAb against TIRC7 (7d). These results suggest a potential synergism of anti-TIRC7 mAb and FK506 action, which could be developed into a novel combination therapy in the clinic by lowering side effects of present CI treatment. Moreover, the identification of TIRC7 in graft infiltrating lymphocytes might serve as a diagnostic marker to detect allograft rejection.

Antibody targeting of TIRC7 results in significant therapeutic effects on collagen-induced arthritis in mice

TIRC7 is a cell surface molecule which is expressed in T and B lymphocytes and negatively regulates their function. Anti-TIRC7 specific monoclonal antibody (mAb) inhibited T cell memory response to recall antigens. Up-regulation of TIRC7 on lymphocytes from joint tissue of patients with Rheumatoid Arthritis (RA) and mice with collagen induced arthritis (CIA) suggested TIRC7 as a novel target to promote anti-inflammatory reaction. Anti-TIRC7 mAb administration significantly inhibited the induction and progression of CIA and the anti-collagen IgG1 and IgG2a antibody response. Combination therapy of anti-TIRC7 mAb and soluble TNF-alpha receptor demonstrated an increased inhibitory effect over the single compounds on CIA. The results demonstrate the therapeutic potential of TIRC7 targeting with mAb in diseases associated with exaggerated T and B cell responses.

Identification of new alternative splice events in the TCIRG1 gene in different human tissues

Two transcript variants (TV) of the T cell immune regulator gene 1 (TCIRG1) have already been characterized. TV1 encodes a subunit of the osteoclast vacuolar proton pump and TV2 encodes a T cell inhibitory receptor. Based on the search in dbEST, we validated by RT-PCR six new alternative splice events in TCIRG1 in most of the 28 human tissues studied. In addition, we observed that transcripts using the TV1 transcription start site and two splice forms previously described in a patient with infantile malignant osteopetrosis are also expressed in various tissues of healthy individuals. Studies of these nine splice forms in cytoplasmic RNA of peripheral blood mononuclear cells showed that at least six of them could be efficiently exported from the nucleus. Since various products with nearly ubiquitous tissue distribution are generated from TCIRG1, this gene may be involved in other processes besides immune response and bone resorption.