Search tips
Search criteria

Results 1-12 (12)

Clipboard (0)

Select a Filter Below

Year of Publication
Document Types
1.  Preserving Sialic Acid-dependent Pattern Recognition by CD24-Siglec G Interaction for Therapy of Polybacterial Sepsis 
Nature biotechnology  2011;29(5):428-435.
Control of inflammation is critical for therapy of infectious diseases. Pathogen-associated and/or danger-associated molecular patterns (PAMPs and DAMPs, respectively) are the two major inducers of inflammation. Because the CD24-Siglec G/10 interactions selectively repress inflammatory response to DAMPs, microbial disruption of the negative regulation would provide a general mechanism to exacerbate inflammation. Here we show that the sialic acid-based pattern recognitions of CD24 by Siglec G/10 are targeted by sialidases in polybacterial sepsis. Sialidase inhibitors protect mice against sepsis by a CD24-Siglecg-dependent mechanism, whereas a targeted mutation of either CD24 or Siglecg exacerbates sepsis. Bacterial sialidase and host CD24 and Siglecg genes interact to determine pathogen virulence. Our data demonstrate a critical role for disrupting sialic acid-based pattern recognitions in microbial virulence and suggest a therapeutic approach to dampen harmful inflammatory response during infection.
PMCID: PMC4090080  PMID: 21478876
2.  Tumor-derived IL-35 promotes tumor growth by enhancing myeloid cell accumulation and angiogenesis 
IL-35 is a member of the IL-12 family of cytokines consisting of IL-12 p35 subunit and IL-12 p40-related protein subunit, EBV-induced gene 3 (EBI3). IL-35 functions through IL-35R and has a potent immune suppressive activity. Although IL-35 has been demonstrated to be produced by regulatory T cells, gene expression analysis has revealed that IL-35 is likely to have wider distribution including expression in cancer cells. In this study we have demonstrated that IL-35 is produced in human cancer tissues such as large B cell lymphoma, nasopharyngeal carcinoma and melanoma. In order to determine the roles of tumor-derived IL-35 in tumorigenesis and tumor immunity, we generated IL-35 producing plasmacytoma J558 and B16 melanoma cells, and observed that the expression of IL-35 in cancer cells does not affect their growth and survival in vitro, but stimulates tumorigenesis in both immune competent and Rag1/2 deficient mice. Tumor-derived IL-35 increases CD11b+Gr1+ myeloid cell accumulation in tumor microenvironment, and thereby promotes tumor angiogenesis. In immune competent mice, spontaneous CTL responses to tumors are diminished. IL-35 does not directly inhibit tumor antigen specific CD8+ T cell activation, differentiation and effector functions. However, IL-35-treated cancer cells had increased expression of gp130 and reduced sensitivity to CTL destruction. Thus, our study indicates novel functions of IL-35 in promoting tumor growth via enhancing myeloid cell accumulation, tumor angiogenesis and suppression of tumor immunity.
PMCID: PMC3578001  PMID: 23345334
3.  IL-27 enhances the survival of tumor antigen-specific CD8+ T cells and programs them into IL-10-producing, memory precursor-like effector cells 
European journal of immunology  2013;43(2):468-479.
IL-27 is a member of the IL-12 family of cytokines that is comprised of an IL-12 p40-related protein subunit, EBV-induced gene 3 (EBI3), and a p35-related subunit, p28. IL-27 functions through IL-27R and has been shown to have potent anti-tumor activity via activation of a variety of cellular components, including anti-tumor CD8+ T-cell responses. However, the exact mechanisms of how IL-27 enhances anti-tumor CD8+ T-cell responses remain unclear. Here we show that IL-27 significantly enhances the survival of activated tumor antigen specific CD8+ T cells in vitro and in vivo, and programs tumor antigen-specific CD8+ T cells into memory precursor (MPC)-like effector cells, characterized by upregulation of Bcl-6, SOCS3, Sca-1, and IL-10. While STAT3 activation and the CTL survival-enhancing effects can be independent of CTL IL-10 production, we show here that IL-27-induced CTL IL-10 production contributes to MPC phenotype induction, CTL memory, and tumor rejection. Thus, IL-27 enhances anti-tumor CTL responses via programming tumor antigen-specific CD8+ T cells into a unique memory precursor-type of effector cells characterized by a greater survival advantage. Our results have important implications for designing immunotherapy against human cancer.
PMCID: PMC3625660  PMID: 23225163
4.  Enhanced Th17 and Treg responses in EBI3-deficient mice lead to marginally enhanced development of autoimmune encephalomyelitis 
Epstein-Barr virus-induced gene 3 (EBI3) encoded protein can form heterodimers with IL-27P28 and IL-12P35 to form IL-27 and IL-35. IL-27 and IL-35 may influence autoimmunity through inhibiting Th17 differentiation, and facilitating the inhibitory roles of Foxp3+ Treg cells, respectively. In this study we have evaluated the development of experimental autoimmune encephalomyelitis (EAE) in EBI3-deficient mice that lack both IL-27 and IL-35. We found that MOG peptide immunization resulted in marginally enhanced EAE development in EBI3-deficient C57BL6 and 2D2 TCR transgenic mice. EBI3-deficiency resulted in significantly increased Th17 and Th1 responses in the central nervous system (CNS) and increased T cell production of IL-2 and IL-17 in the peripheral lymphoid organs. EBI3-deficient and -sufficient 2D2 T cells had equal ability in inducing EAE in Rag1−/− mice, however more severe disease was induced in EBI3−/−Rag1−/− mice than in Rag1−/− mice by 2D2 T cells. EBI3-deficient mice had increased numbers of CD4+FoxP3+ Treg cells in peripheral lymphoid organs. More strikingly, EBI3-deficient Treg cells had more potent suppressive functions in vitro and in vivo. Thus, our data support an inhibitory role for EBI3 in Th17, Th1, IL-2 and Treg responses. While these observations are consistent with the known functions of IL-27, the IL-35 contribution to the suppressive functions of Treg cells is not evident in this model. Enhanced Treg responses in EBI3−/− mice may explain why the EAE development is only modestly enhanced compared to WT mice.
PMCID: PMC3311737  PMID: 22387555
5.  CD24 on thymic antigen presenting cells regulates negative selection of myelin antigen specific T lymphocytes 
European Journal of Immunology  2012;42(4):924-935.
Negative selection plays a key role in the clonal deletion of autoreactive T cells in the thymus. However, negative selection is incomplete; as high numbers of autoreactive T cells can be detected in normal individuals, mechanisms that regulate negative selection must exist. In this regard, we previously reported that CD24, a GPI-anchored glycoprotein, is required for thymic generation of autoreactive T lymphocytes. The CD24-deficient 2D2 TCR transgenic mice (2D2+CD24-/-), whose TCR recognizes myelin oligodendrocyte glycoprotein (MOG), fail to generate functional 2D2 T cells. However, it was unclear if the CD24 function involved regulation of negative selection, and if so, what cellular mechanisms were involved. Here we show that elimination of MOG or Aire gene expression in 2D2+CD24-/- mice - through the creation of 2D2+CD24-/-MOG-/- or 2D2+CD24-/-Aire-/-mice - completely restores thymic cellularity and function of 2D2 T cells. Restoration of CD24 expression on dendritic cells (DCs), but not on thymocytes also partially restores 2D2 T-cell generation in 2D2+CD24-/- mice. Taken together, we propose that CD24 expression on thymic antigen presenting cells (mTECs, DCs) down-regulates autoantigen-mediated clonal deletion of autoreactive thymocytes.
PMCID: PMC3359065  PMID: 22213356
6.  IL-10 Contributes to the Suppressive Function of Tumor Associated Myeloid Cells and Enhances Myeloid Cell Accumulation in Tumors 
Studies have revealed that tumor associated myeloid cells (TAMC) are one of the major sources of IL-10 in tumor-bearing mice. However, the significance of TAMC-derived IL-10 in tumor 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 tumor burdens have similar TAMC populations. The tumors from IL-10-deficient mice however, have reduced numbers of TAMC compared with tumors from their WT counterparts. IL-10−/−RAG-2−/− mice also had reduced numbers of TAMC compared with tumors from IL-10+/+RAG-2−/− mice; therefore the reduction of TAMC in IL-10-deficient tumors was not due to adaptive immune response in tumors. Adoptively transferred tumor antigen specific CD8 T cells expanded more efficiently within tumors in IL-10−/−RAG-2−/− mice than in tumors from IL-10+/+RAG-2−/− mice. CTL adoptive transfer therapy prevented tumor evasion in IL-10−/−RAG-2−/− mice more efficiently than in IL-10+/+RAG-2−/− mice. Thus, IL-10 enhances accumulation of myeloid cells in tumors and TAMC-derived IL-10 suppresses activation and expansion of tumor antigen specific T cells.
PMCID: PMC3279616  PMID: 22050574
7.  Melanoma Cell Expression of CD200 Inhibits Tumor Formation and Lung Metastasis via Inhibition of Myeloid Cell Functions 
PLoS ONE  2012;7(2):e31442.
CD200 is a cell surface glycoprotein that functions through engaging CD200 receptor on cells of the myeloid lineage and inhibits their functions. Expression of CD200 has been implicated in a variety of human cancer cells including melanoma cells and has been thought to play a protumor role. To investigate the role of cancer cell expression of CD200 in tumor formation and metastasis, we generated CD200-positive and CD200-negative B16 melanoma cells. Subcutaneous injection of CD200-positive B16 melanoma cells inhibited tumor formation and growth in C57BL/6 mice but not in Rag1−/−C57BL/6 mice. However, i.v. injection of CD200-positive B16 melanoma cells dramatically inhibited tumor foci formation in the lungs of both C57BL/6 and Rag1−/−C57BL6 mice. Flow cytometry analysis revealed higher expression of CD200R in Gr1+ myeloid cells in the lung than in peripheral myeloid cells. Depletion of Gr1+ cells or stimulation of CD200R with an agonistic antibody in vivo dramatically inhibited tumor foci formation in the lungs. In addition, treatment with tumor antigen specific CD4 or CD8 T cells or their combination yielded a survival advantage for CD200 positive tumor bearing mice over mice bearing CD200-negative tumors. Taken together, we have revealed a novel role for CD200-CD200R interaction in inhibiting tumor formation and metastasis. Targeting CD200R may represent a novel approach for cancer immunotherapy.
PMCID: PMC3272017  PMID: 22319630
8.  Tumor Expression of CD200 Inhibits IL-10 Production by Tumor-Associated Myeloid Cells and Prevents Tumor Immune Evasion of CTL Therapy 
European journal of immunology  2010;40(9):2569-2579.
CD200 is a cell-surface glycoprotein that functions through interaction with the CD200 receptor (CD200R) on myeloid lineage cells to regulate myeloid cell functions. Expression of CD200 has been implicated in multiple types of human cancer, however the impact of tumor expression of CD200 on tumor immunity remains poorly understood. To evaluate this issue, we generated CD200-positive mouse plasmacytoma J558 and mastocytoma P815 cells. We found that established CD200-positive tumors were often completely rejected by adoptively transferred CTL without tumor recurrence; in contrast, CD200-negative tumors were initially rejected by adoptively transferred CTL but the majority of tumors recurred. Tumor expression of CD200 significantly inhibited suppressive activity and IL-10 production by tumor-associated myeloid cells (TAMC), and as a result, more CTL accumulated in the tumor and exhibited a greater capacity to produce IFN-γ in CD200-positive tumors than in CD200-negative tumors. Neutralization of IL-10 significantly inhibited the suppressor activity of TAMC, and IL-10-deficiency allowed TAMC to kill cancer cells and their antigenic variants, which prevented tumor recurrence during CTL therapy. Thus, tumor expression of CD200 prevents tumor recurrence via inhibiting IL-10 production by TAMC.
PMCID: PMC3003298  PMID: 20662098
CD200; Tumor associated myeloid cells; Cytotoxic T Lymphocytes; Immune evasion
9.  Targeting Activation Induced Cytidine Deaminase Overcome Tumor Evasion of Immunotherapy by Cytotoxic T Lymphocytes 
Activation induced cytidine deaminase (AID) is an enzyme essential for the generation of antibody diversity in B cells and is considered to be a general gene mutator. In addition, AID expression was also implicated in the pathogenesis of human B cell malignancies and associated with poor prognosis. Here we report that siRNA silencing of AID in plasmacytoma dramatically increased its susceptibility to immunotherapy by cytotoxic T lymphocytes. AID silencing did not decrease the mutation frequencies of tumor antigen gene P1A. Gene-array analysis showed dramatically altered expression of a number of genes in AID-silenced plasmacytoma cells and upregulation of CD200 was shown to be in favor of tumor eradication by CTL. Taken together, we demonstrate a novel function of AID in tumor evasion of CTL therapy and that targeting AID should be beneficial in the immunotherapy of AID positive tumors.
PMCID: PMC2874093  PMID: 20404277
Activation induced cytidine deaminase; Plasmacytoma; Cytotoxic T Lymphocytes; Immune evasion
10.  FOXP3 is an X-linked breast cancer suppressor gene and an important repressor of the HER-2/ErbB2 oncogene 
Cell  2007;129(7):1275-1286.
The X-linked Foxp3 is a member of the forkhead/winged helix transcription factor family. Germ-line mutations cause lethal autoimmune diseases in males. Serendipitously, we observed that Foxp3sf/+ heterozygous mice developed cancer at a high rate. The majority of the cancers were mammary carcinomas in which the wild-type Foxp3 allele was inactivated and ErbB2 was over-expressed. Foxp3 bound and repressed the ErbB2 promoter. Deletion, functionally significant somatic mutations and down-regulation of the FOXP3 gene were commonly found in human breast cancer samples and correlated significantly with HER-2 over-expression, regardless of the status of HER-2 amplification. In toto, the data demonstrate that FOXP3 is an X-linked breast cancer suppressor gene and an important regulator of the HER-2/ErbB2 oncogene.
PMCID: PMC1974845  PMID: 17570480
11.  A Dinucleotide Deletion in CD24 Confers Protection against Autoimmune Diseases 
PLoS Genetics  2007;3(4):e49.
It is generally believed that susceptibility to both organ-specific and systemic autoimmune diseases is under polygenic control. Although multiple genes have been implicated in each type of autoimmune disease, few are known to have a significant impact on both. Here, we investigated the significance of polymorphisms in the human gene CD24 and the susceptibility to multiple sclerosis (MS) and systemic lupus erythematosus (SLE). We used cases/control studies to determine the association between CD24 polymorphism and the risk of MS and SLE. In addition, we also considered transmission disequilibrium tests using family data from two cohorts consisting of a total of 150 pedigrees of MS families and 187 pedigrees of SLE families. Our analyses revealed that a dinucleotide deletion at position 1527∼1528 (P1527del) from the CD24 mRNA translation start site is associated with a significantly reduced risk (odds ratio = 0.54 with 95% confidence interval = 0.34–0.82) and delayed progression (p = 0.0188) of MS. Among the SLE cohort, we found a similar reduction of risk with the same polymorphism (odds ratio = 0.38, confidence interval = 0.22–0.62). More importantly, using 150 pedigrees of MS families from two independent cohorts and the TRANSMIT software, we found that the P1527del allele was preferentially transmitted to unaffected individuals (p = 0.002). Likewise, an analysis of 187 SLE families revealed the dinucleotide-deleted allele was preferentially transmitted to unaffected individuals (p = 0.002). The mRNA levels for the dinucleotide-deletion allele were 2.5-fold less than that of the wild-type allele. The dinucleotide deletion significantly reduced the stability of CD24 mRNA. Our results demonstrate that a destabilizing dinucleotide deletion in the 3′ UTR of CD24 mRNA conveys significant protection against both MS and SLE.
Author Summary
When an individual's immune system attacks self tissues or organs, he/she develops autoimmune diseases. Although it is well established that multiple genes control susceptibility to autoimmune diseases, most of the genes remain unidentified. In addition, although different autoimmune diseases have a common immunological basis, a very small number of genes have been identified that affect multiple autoimmune diseases. Here we show that a variation in CD24 is a likely genetic factor for the risk and progression of two types of autoimmune diseases, including multiple sclerosis (MS), an organ-specific autoimmune disease affecting the central nervous system, and systemic lupus erythematosus, a systemic autoimmune disease. Our data indicated that if an individual's CD24 gene has a specific two-nucleotide deletion in the noncoding region of CD24 mRNA, his/her risk of developing MS or SLE is reduced by 2- to 3-fold. As a group, MS patients with the two-nucleotide deletion will likely have a slower disease progression. Biochemical analysis indicated that the deletion leads to rapid decay of CD24 mRNA, which should result in reduced synthesis of the CD24 protein. Our data may be useful for the treatment and diagnosis of autoimmune diseases.
PMCID: PMC1847692  PMID: 17411341
12.  The heat-stable antigen determines pathogenicity of self-reactive T cells in experimental autoimmune encephalomyelitis 
Journal of Clinical Investigation  2000;105(9):1227-1232.
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.
PMCID: PMC315444  PMID: 10791997

Results 1-12 (12)