[Placental mesenchymal stem cell exosome-derived miR-139-5p regulates PTEN gene and influences chemotherapeutic-induced ovarian dysfunction].

Objective: To investigate the impact of exosomes and microRNA (miRNA) from placental mesenchymal stem cells on chemotherapy-damaged ovarian granulosa cells. Methods: Various public databases were searched for miRNA targeting phosphatase and tensin homologue deleted on chromosome 10 (PTEN) gene. After miRNA transfection into human ovarian granulosa cells, cell growth and expressions of the target miRNA and PTEN were detected. Cisplatin was utilized to induce damage to human ovarian granulosa cells, which were subsequently co-cultured with human placental mesenchymal stem cells and exosomes generated from mesenchymal stem cells, then apoptosis and expressions of PTEN and the target miRNA were detected. Results: After analyzing several databases, miRNA 139-5p (miR-139-5p) was chosen as the target miRNA for this research. Transfection of miR-139-5p mimics into human ovarian granulosa cells elevated miR-139-5p expression level (9 882.080±1 049.130), reduced PTEN protein expression level (0.78±0.11), and increased cell proliferation absorbance (0.85±0.07). Cisplatin treatment severely damaged human ovarian granulosa cells and increased apoptosis, cisplatin-treated cells had a higher apoptosis ratio compared to untreated cells [ (41.9±1.0)% vs (5.0±0.3)%, P<0.001]. In damaged human ovarian granulosa cells, co-cultured with human placental mesenchymal stem cells and exosomes increased miR-139-5p expression levels (1.31±0.04 and 1.20±0.03, respectively) and decreased apoptosis ratios [(20.0±0.4)% and (22.3±1.1)%, respectively]. Conclusion: Placental mesenchymal stem cell-derived exosomes repair damages of cisplatin-induced ovarian granulosa cell and could target PTEN gene through miR-139-5p, which might be a potential option for the treatment of chemotherapy-induced ovarian dysfunction.

Review of research pertaining to the effect of tumor-derived exosomes on natural killer cells.

Tumor-derived exosomes (TDEs) play critical roles in many aspects of cancer progression. There have been several advances in cancer immunotherapy in recent years. A major challenge, however, has been addressed to the role of TDEs in tumor cell immune escape through their influence on the antitumor immunity of natural killer (NK) cells, a key type of immune cell. In this review, we present our overview of the effects of different TDEs on NK cell activation and NK cell toxicity. Studies on mechanism suggest that TDEs mainly affect the immune response of NK cells by inhibiting activated receptors on the surface of NK cells and downregulating the NK recognition ligand MICA/B on the tumor cell surface. In addition, a summary was documented on how to restore the cytotoxicity of NK cells and improve the drug's ability to recognize tumor cells, and a detailed explanation was also provided on the mechanism of action of the drug.

Knockdown of lncRNA XIST inhibits hypoxia-induced glycolysis, migration and invasion through regulating miR-381-3p/NEK5 axis in nasopharyngeal carcinoma.

OBJECTIVE: Hypoxia is an important feature of nasopharyngeal carcinoma (NPC). Growing evidence demonstrated that long non-coding RNAs (lncRNAs) could participate in cancer progression and hypoxia regulation. However, the exact roles and underlying mechanism of lncRNA X-inactive specific transcript (XIST) in NPC under hypoxia are still unclear. MATERIALS AND METHODS: The expressions of XIST, microRNA-381-3p (miR-381-3p) and NIMA related kinase 5 (NEK5) were detected by quantitative Real-time polymerase chain reaction (qRT-PCR). The glucose consumption and lactate production were measured using the glucose assay kit and lactate assay kit, respectively. Western blot assay was used to determine the protein levels of hexokinase II (HK2) and NEK5. Transwell assay was employed to evaluate cell migration and invasion. The interaction between miR-381-3p and XIST or NEK5 was predicted by bioinformatics analysis and verified by dual-luciferase reporter assay. The mice xenograft model was established to investigate the roles of XIST in NPC progression in vivo. RESULTS: XIST and NEK5 were highly expressed while miR-381-3p was lowly expressed in NPC (tissues and cells) and hypoxia-induced NPC cells. Deficiency of XIST or NEK5 suppressed hypoxia-induced glycolysis and metastasis in NPC cells. Moreover, miR-381-3p could directly bind to XIST and its inhibition reversed the inhibitory effects of XIST knockdown on glycolysis and metastasis under hypoxia. NEK5 was a direct target of miR-381-3p and its interference attenuated the promotive effects of miR-381-3p downregulation on glycolysis and metastasis under hypoxic conditions. Besides, interference of XIST decreased tumor growth by upregulating miR-381-3p and downregulating NEK5. CONCLUSIONS: XIST knockdown inhibited glycolysis and metastasis in hypoxia-induced NPC cells through regulating miR-381-3p/NEK5 axis, providing new insights into the pathogenesis of NPC.

[Clinical research of extensive alveolar cleft treatment with computer assistant distraction osteogenesis].

Objective: To evaluate the feasibility and outcome of computer assisted distraction osteogenesis in the treatment of extensive alveolar cleft. Methods: Four patients [1 male and 3 females, aged (15.5±3.7) years] received treatment in the Department of Oral-Maxillofacial Surgery and Plastic Surgery, School of Stomatology, China Medical University from June 2016 to April 2018 were involved in this study. All the patients with extensive alveolar cleft [cleft width (7.64±1.29) mm] were performed orthodontic treatment to expand the dental arch and interdental space between the first molar and premolars. Three-dimensional (3D) model of the maxilla and the osteotomy guider were printed according to the CT data. The fix wings of the distractor were pre-shaped according to the 3D model. The osteotomy was performed at the interdental space and horizontal plate of palate to dissociate the alveolar bone segment. The distractor was fixed on the predetermined position. Distraction (0.4-0.8 mm/day) was performed in 7 days later and stopped when the incision connected with the canine. The distractor was removed after six months. Results: The distraction period was (10.8±2.5) d in four cases. The cleft was completely closed with interdental bone anchored distraction in four cases. The imaging examination in six months showed good new bone structure in the distraction zone and bone connection of the cleft. Conclusions: Computer assisted distraction osteogenesis was effective and feasible to close the extensive alveolar cleft and provide sufficient new bone tissue.

Integrative analyses of transcriptome sequencing identify novel functional lncRNAs in esophageal squamous cell carcinoma.

Long non-coding RNAs (lncRNAs) have a critical role in cancer initiation and progression, and thus may mediate oncogenic or tumor suppressing effects, as well as be a new class of cancer therapeutic targets. We performed high-throughput sequencing of RNA (RNA-seq) to investigate the expression level of lncRNAs and protein-coding genes in 30 esophageal samples, comprised of 15 esophageal squamous cell carcinoma (ESCC) samples and their 15 paired non-tumor tissues. We further developed an integrative bioinformatics method, denoted URW-LPE, to identify key functional lncRNAs that regulate expression of downstream protein-coding genes in ESCC. A number of known onco-lncRNA and many putative novel ones were effectively identified by URW-LPE. Importantly, we identified lncRNA625 as a novel regulator of ESCC cell proliferation, invasion and migration. ESCC patients with high lncRNA625 expression had significantly shorter survival time than those with low expression. LncRNA625 also showed specific prognostic value for patients with metastatic ESCC. Finally, we identified E1A-binding protein p300 (EP300) as a downstream executor of lncRNA625-induced transcriptional responses. These findings establish a catalog of novel cancer-associated functional lncRNAs, which will promote our understanding of lncRNA-mediated regulation in this malignancy.

Dysregulation of TFDP1 and of the cell cycle pathway in high-grade glioblastoma multiforme: a bioinformatic analysis.

Despite extensive research, the prognosis of high-grade glioblastoma multiforme (GBM) has improved only slightly because of the limited response to standard treatments. Recent advances (discoveries of molecular biomarkers) provide new opportunities for the treatment of GBM. The aim of the present study was to identify diagnostic biomarkers of high-grade GBM. First, we combined 3 microarray expression datasets to screen them for genes differentially expressed in patients with high-grade GBM relative to healthy subjects. Next, the target network was constructed via the empirical Bayesian coexpression approach, and centrality analysis and a molecular complex detection (MCODE) algorithm were performed to explore hub genes and functional modules. Finally, a validation test was conducted to verify the bioinformatic results. A total of 277 differentially expressed genes were identified according to the criteria P < 0.05 and |log2(fold change)| ≥ 1.5. These genes were most significantly enriched in the cell cycle pathway. Centrality analysis uncovered 9 hub genes; among them, TFDP1 showed the highest degree of connectivity (43) and is a known participant in the cell cycle pathway; this finding pointed to the important role of TFDP1 in the progression of high-grade GBM. Experimental validation mostly supported the bioinformatic results. According to our study results, the gene TFDP1 and the cell cycle pathway are strongly associated with high-grade GBM; this result may provide new insights into the pathogenesis of GBM.

RNAi-mediated knockdown of FANCF suppresses cell proliferation, migration, invasion, and drug resistance potential of breast cancer cells

Fanconi anemia complementation group F protein (FANCF) is a key factor, which maintains the function of FA/BRCA, a DNA damage response pathway. However, the functional role of FANCF in breast cancer has not been elucidated. We performed a specific FANCF-shRNA knockdown of endogenous FANCF in vitro. Cell viability was measured with a CCK-8 assay. DNA damage was assessed with an alkaline comet assay. Apoptosis, cell cycle, and drug accumulation were measured by flow cytometry. The expression levels of protein were determined by Western blot using specific antibodies. Based on these results, we used cell migration and invasion assays to demonstrate a crucial role for FANCF in those processes. FANCF shRNA effectively inhibited expression of FANCF. We found that proliferation of FANCF knockdown breast cancer cells (MCF-7 and MDA-MB-435S) was significantly inhibited, with cell cycle arrest in the S phase, induction of apoptosis, and DNA fragmentation. Inhibition of FANCF also resulted in decreased cell migration and invasion. In addition, FANCF knockdown enhanced sensitivity to doxorubicin in breast cancer cells. These results suggest that FANCF may be a potential target for molecular, therapeutic intervention in breast cancer.

RNAi-mediated knockdown of FANCF suppresses cell proliferation, migration, invasion, and drug resistance potential of breast cancer cells.

Fanconi anemia complementation group F protein (FANCF) is a key factor, which maintains the function of FA/BRCA, a DNA damage response pathway. However, the functional role of FANCF in breast cancer has not been elucidated. We performed a specific FANCF-shRNA knockdown of endogenous FANCF in vitro. Cell viability was measured with a CCK-8 assay. DNA damage was assessed with an alkaline comet assay. Apoptosis, cell cycle, and drug accumulation were measured by flow cytometry. The expression levels of protein were determined by Western blot using specific antibodies. Based on these results, we used cell migration and invasion assays to demonstrate a crucial role for FANCF in those processes. FANCF shRNA effectively inhibited expression of FANCF. We found that proliferation of FANCF knockdown breast cancer cells (MCF-7 and MDA-MB-435S) was significantly inhibited, with cell cycle arrest in the S phase, induction of apoptosis, and DNA fragmentation. Inhibition of FANCF also resulted in decreased cell migration and invasion. In addition, FANCF knockdown enhanced sensitivity to doxorubicin in breast cancer cells. These results suggest that FANCF may be a potential target for molecular, therapeutic intervention in breast cancer.

Elevated vascular endothelial growth factor levels induce hyperpermeability of endothelial cells in hantavirus infection.

OBJECTIVE: To investigate the role of vascular endothelial growth factor (VEGF) in haemorrhagic fever with renal syndrome (HFRS). METHODS: VEGF, soluble VEGF receptor (sVEGFR)-2, angiopoietin (Ang)-1, tumour necrosis factor (TNF)-α and interferon (IFN)-γ levels were measured in serum samples from 68 patients with HFRS. Cultured human umbilical vein endothelial cells (HUEVCs) were infected by Hantaan virus (HTNV) and/or stimulated with recombinant VEGF; dextran permeability of the cells was determined. Claudin-1 and vascular endothelial (VE)-cadherin levels were determined by real-time reverse transcription-polymerase chain reaction and Western blot analyses. RESULTS: Serum VEGF, TNF-α and IFN-γ levels were significantly elevated, whereas sVEGFR2 and Ang-1 levels were reduced, during the acute phase of HFRS. In vitro cell permeability was unaffected by HTNV infection or VEGF stimulation alone, but the combination of HTNV infection and VEGF treatment significantly increased the permeability of endothelial cell monolayers in a time-dependent manner. Claudin-1 and VE-cadherin were downregulated at both the mRNA and protein level by combined HTNV infection and VEGF stimulation. CONCLUSIONS: Elevated VEGF induced by HTNV infection may play an important role in the vascular hyperpermeability that is characteristic of HFRS.

Elevated serum concentrations of inflammatory cytokines and chemokines in patients with haemorrhagic fever with renal syndrome.

OBJECTIVE: Prospective case-control study, undertaken to investigate serum cytokine and chemokine concentrations during all clinical phases and in different clinical types of haemorrhagic fever with renal syndrome (HFRS). METHODS: Serum was collected at various disease phases from patients with HFRS (n = 35) and healthy control subjects (n = 10). Tumour necrosis factor (TNF)-α, interleukin (IL)-6, IL-4, interferon (IFN)-γ, IL-8, interferon inducible protein-10 (IP-10) and chemokine (C-C motif) ligand 5 (also known as 'regulated upon activation, normal T-cell expressed and secreted' [RANTES]) were quantified using commercial enzyme-linked immunosorbent assay kits. RESULTS: Serum concentrations of TNF-α, IL-6, IFN-γ, IL-8, IP-10 and RANTES (but not IL-4) were significantly higher in patients compared with controls. Highest concentrations were generally found during the febrile, hypotensive and oliguric disease phases, as well as in clinically severe and critical cases. CONCLUSION: Serum concentrations of proinflammatory cytokines and chemokines increased in line with disease severity in HFRS patients.

IL-10 contributes to the suppressive function of tumour-associated myeloid cells and enhances myeloid cell accumulation in tumours.

Studies have revealed that tumour-associated myeloid cells (TAMC) are one of the major sources of IL-10 in tumour-bearing mice. However, the significance of TAMC-derived IL-10 in tumour immunity is poorly understood. Here, we show that IL-10 blockade or IL-10 deficiency reduces the capacity of TAMC in suppressing the proliferation of P1A-specific CD8 T cells. In the spleen, IL-10-deficient and wild-type (WT) mice bearing large tumour burdens have similar TAMC populations. The tumours from IL-10-deficient mice, however, have reduced numbers of TAMC compared with tumours from their WT counterparts. IL-10⁻/⁻ RAG-2⁻/⁻ mice also had reduced numbers of TAMC compared with tumours from IL-10⁺/⁺ RAG-2⁻/⁻ mice; therefore, the reduction in TAMC in IL-10-deficient tumours was not because of adaptive immune response in tumours. Adoptively transferred tumour antigen-specific CD8 T cells expanded more efficiently within tumours in IL-10⁻/⁻ RAG-2⁻/⁻ mice than in tumours from IL-10⁺/⁺ RAG-2⁻/⁻ mice. Cytotoxic T lymphocyte adoptive transfer therapy prevented tumour evasion in IL-10⁻/⁻ RAG-2⁻/⁻ mice more efficiently than in IL-10⁺/⁺ RAG-2⁻/⁻ mice. Thus, IL-10 enhances the accumulation of myeloid cells in tumours, and TAMC-derived IL-10 suppresses the activation and expansion of tumour antigen-specific T cells.

The diagnostic value of ultrasound elastography in patients with hepatitis B virus infection: a prospective study.

The aim of this prospective study was to investigate the diagnostic value of ultrasound elastography for evaluating liver stiffness measurement (LSM) in 74 patients with hepatitis B virus (HBV) infection, treated with telbivudine (22 with chronic HBV infection, 32 with compensated cirrhosis and 20 with decompensated cirrhosis). Each patient underwent ultrasound elastography measurements and serum liver marker assays before and after 6 months' treatment with 600 mg telbivudine, orally, once daily. In the 22 patients with chronic HBV infection, LSM values measured by ultrasound elastography decreased significantly following the treatment period compared with baseline. The LSM values were significantly higher in the 20 patients with decompensated cirrhosis than in the 32 patients with compensated cirrhosis after treatment. Significant decreases in serum hepatic fibrosis indices occurred in all patients following treatment. The correlation between fibrosis index, hyaluronic acid level and LSM was statistically significant in all patients, whereas the correlation between alanine aminotransferase and LSM was not. The findings suggest that liver stiffness in patients with HBV can be measured simply with ultrasound elastography and that it is reduced within 6 months by treatment with telbivudine. The main adverse events noted during the study period were that creatine kinase levels were increased in seven patients and that seven patients had influenza-like symptoms.

In vitro hepatic differentiation of mesenchymal stem cells from human fetal bone marrow.

We examined whether human fetal mesenchymal stem cells (FMSCs) derived from fetal bone marrow were able to differentiate into functional hepatocyte-like cells in vitro. The surface phenotype of FMSCs was characterized by flow cytometry. To induce hepatic differentiation of FMSCs, we added hepatocyte growth factor, basic fibroblast growth factor and oncostatin M into the cell culture medium. After 21 days of hepatocyte induction, FMSCs expressed the hepatocyte-specific markers, alpha-fetoprotein and cytokeratin 18, as demonstrated by immunofluorescence staining. Differentiated FMSCs also demonstrated in vitro functions characteristic of liver cells, including albumin production, urea secretion and glycogen storage. In conclusion, fetal bone marrow-derived FMSCs are able to differentiate into functional hepatocytelike cells and may serve as a source of cells for liver disease therapy.

CD4(+)CD25(+) regulatory T cells contribute to the therapeutic effects of glatiramer acetate in experimental autoimmune encephalomyelitis.

CD4(+)CD25(+) regulatory T cells (Tregs) are potent immunosuppressors that are pivotal in the maintenance of self-tolerance. The involvement of Tregs in therapies for immune-mediated diseases has been proposed, but direct supporting evidence is still lacking. While investigating mechanisms underlying the clinical benefits of glatiramer acetate (GA) in an animal model of multiple sclerosis (MS), i.e., experimental autoimmune encephalomyelitis (EAE), we recently demonstrated that GA can protect mice deficient in the Th(2) cytokines IL-4, IL-10 and IL-4/IL-10 from acquiring EAE, suggesting that mechanisms other than Th(2) cells may be responsible for the therapeutic effects of GA. Here we demonstrate that GA treatment boosts the expression of Foxp3 on Tregs during EAE. Furthermore, adoptive transfer of purified Tregs from GA-treated EAE mice is more effective in preventing EAE development than Tregs from untreated EAE controls. Thus, our current data provide evidence that Tregs may be the major contributor to GA's therapeutic action in EAE and, possibly, MS. Further mechanistic studies to reveal the molecular events linking GA with Tregs may optimize GA treatment and lead to the development of new, even more effective therapies that utilize this mechanism of action.

The clinical value of serum CEA, CA19-9, and CA242 in the diagnosis and prognosis of pancreatic cancer.

AIM: Serum tumour markers carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9) and CA242 were investigated to evaluate the values of single and combined test in the diagnosis and prognosis of pancreatic cancer. METHODS: Pre-operative serum CEA, CA19-9 and CA242 were measured in 105 pancreatic cancers, 70 non-pancreatic malignancies and 30 benign pancreatic diseases. RESULTS: The sensitivity of CA19-9 alone was the highest in pancreatic cancer patients (80%), but the specificity was significantly lower than that of CEA and CA242 (P<0.01). The combination of CEA and CA242 could increase the specificity to 92%. In serum CA242 positive patients, the survival time was remarkably shorter than that of patients with negative result (P<0.01). The survival time in patients with more than two markers positive expression of CEA, CA19-9 and CA242 was obviously shorter than that of only one or no marker positive expression (P<0.05). CONCLUSION: The diagnostic rate of CA19-9 in pancreatic cancer is better than that of CEA and CA242. Combined detection of CEA and CA242 can improve the diagnostic specificity obviously. High levels of serum markers are associated with advanced stage of the disease. Patients with two or three markers positive expression of CEA, CA19-9, and CA242 simultaneously had a shorter survival time.

B7H costimulates clonal expansion of, and cognate destruction of tumor cells by, CD8(+) T lymphocytes in vivo.

B7H/B7RP (hereby called B7H) is a new member of the B7 family of costimulatory molecules and interacts with inducible costimulatory molecule (ICOS). Its function for CD8 T cells has not been reported. We report here that expression of B7H on the tumor cells reduced tumorigenicity and induced immunity to subsequent challenge with parental tumor cells. The immune protection correlates with an enhanced cytotoxic T lymphocyte (CTL) response against P1A, the major tumor antigen expressed in the J558 tumor. To understand the mechanism of immune protection, we adoptively transferred transgenic T cells specific for tumor antigen P1A into mice that bore P1A-expressing tumors. We found that while the transgenic T cells divided faster in mice bearing the B7H(+) tumors, optimal B7H-induced clonal expansion of P1CTL required costimulation by B7-1 and B7-2 on the endogenous host antigen-presenting cells (APCs). Interestingly, when B7H(+) and B7H(-) tumors were coinjected, P1CTL selectively eliminated the B7H(+) tumor cells. Moreover, B7H expressed on the tumor cells made them highly susceptible to destruction by CTL in vivo, even if the CTL was administrated into mice with large tumor burdens. Tumors that recurred in the P1CTL-treated mice lost transfected B7H and/or H-2L(d), the class I molecule that presents the P1A peptide. Taken together, our results reveal that B7H costimulates clonal expansion of, and cognate destruction by CD8(+) T lymphocytes in vivo.

Local costimulation reinvigorates tumor-specific cytolytic T lymphocytes for experimental therapy in mice with large tumor burdens.

Cytotoxic T cells recognize tumor Ags and destroy cancer cells in vitro. Adoptive transfer studies with transgenic T cells specific for tumor Ags have demonstrated that CTL are effective only in mice with small tumor burdens and thus appear to have limited potential in cancer immunotherapy. Here we used transgenic mice that express the TCR specific for an unmutated tumor Ag P1A and multiple lineages of P1A-expressing tumors to address this critical issue. We found that local costimulation, either by expression of B7-1 on the tumor cells or by local administration of anti-CD28 mAb 37N, reinvigorated the function of CTL specific for the tumor Ag, as it substantially increased the efficacy of CTL therapy for mice with large tumor burdens. Our study suggests that CTL-based immunotherapy can be manipulated to deal with large tumors.

On the site and mode of antigen presentation for the initiation of clonal expansion of CD8 T cells specific for a natural tumor antigen.

Because of the low frequency of antigen-specific T cells, early events in the activation of tumor-specific T cells in vivo have not been well characterized. There is still no direct documentation on where the clonal expansion begins and how tumor antigens are presented to the host CD8 T cells to initiate it. Here we used transgenic T cells specific for a natural tumor antigen P1A to evaluate the kinetics, location, and modes of antigen presentation for initiating CTL response in vivo. Our results demonstrate that the initial activation of P1A-specific T cells takes place in the lymphoid organs. The activated T cells then migrate into tumors, where they undergo accelerated division and acquire distinct activation markers. The site of initiation cannot be altered by either local expression of costimulatory molecules or by intratumor injection of naïve T cells. Moreover, using genetic models that allow only one mode of antigen presentation, we show here that both cross-presentation of P1A by the host antigen-presenting cells, and direct antigen presentation and costimulation by the tumor cells are sufficient to initiate rapid T cell-clonal expansion in the lymphoid organ. These results provide direct evidence for two fundamental assumptions on the mechanisms of T-cell activation in vivo.

Optimal induction of effector but not memory antitumor cytotoxic T lymphocytes involves direct antigen presentation by the tumor cells.

MHC class I-restricted tumor antigen can be presented to CD8+ T cells by two distinct mechanisms. Direct presentation involves degradation of cytosolic proteins by the proteosome into peptides, transport of the peptides across the endoplasmic reticulum membrane, and expression of the MHC-peptide complex on the tumor cell surface. Cross-presentation, on the other hand, involves uptake and intracellular processing of the tumor antigen by host antigen-presenting cells. Whereas it is clear that cross-presentation is necessary and sufficient for the induction of memory CTLs, it has not been tested whether such presentation is sufficient to induce effector CTLs. Here we analyzed the requirements of direct antigen presentation for the induction of effector and memory antitumor CTLs using a MHC class I- mutant incapable of direct antigen presentation and its parent, the MHC class I+ J558 cell line. We report that in comparison with the MHC class I+ tumor cell, the MHC class I- mutant induces equal priming for recall CTL response but poor effector CTLs. Our results demonstrate that optimal induction of effector CTLs, but not memory CTLs, requires direct antigen presentation by the tumor cells.

The heat-stable antigen determines pathogenicity of self-reactive T cells in experimental autoimmune encephalomyelitis.

Induction of myelin-specific CD4 T cells is a pivotal event in the development of experimental autoimmune encephalomyelitis (EAE). Other checkpoints in EAE pathogenesis have not been clearly defined, although multiple genetic loci are known to influence EAE development. We report here that targeted mutation of the heat-stable antigen (HSA) abrogates development of EAE despite a complete lack of effect on induction of autoimmune T cells. To test whether T-cell expression of HSA is sufficient, we created transgenic mice in which HSA is expressed exclusively in the T-cell lineage. We found that these mice remain resistant to EAE induction. Adoptive transfer studies demonstrate that both T cells and non-T cells must express HSA in order for the pathogenic T cells to execute their effector function. Moreover, HSAIg, a fusion protein consisting of the extracellular domain of the HSA and the Fc portion of immunoglobulin, drastically ameliorates the clinical sign of EAE even when administrated after self-reactive T cells had been expanded. Thus, identification of HSA as a novel checkpoint, even after activation and expansion of self-reactive T cells, provides a novel approach for immunotherapy of autoimmune neurologic diseases, such as multiple sclerosis.