bluuebunny/crossref_metadata_2025 huggingface dataset:
CTL Adoptive Immunotherapy Concurrently Mediates Tumor Regression and Tumor Escape
Authors: Liu Kebin , Caldwell Sheila A. , Greeneltch Kristy M. , Yang Dafeng , Abrams Scott I.
Published: April 2014

Tumor escape and recurrence are major impediments for successful immunotherapy. It is well-documented that the emergence of Ag-loss variants, as well as regulatory mechanisms suppressing T cell function, have been linked to inadequate antitumor activity. However, little is known regarding the role of Fas-mediated cytotoxicity by tumor-specific CD8+ CTL in causing immune evasion of Fas resistant variants during adoptive immunotherapy. In this study, we made use of an adoptive transfer model of experimental lung metastasis using tumor-specific CTL as a relevant immune-based selective pressure, and wherein the Fas ligand pathway was involved in the antitumor response. Surviving tumor cells were recovered and examined for alterations in antigenic, functional, and biologic properties. We showed that diminished susceptibility to Fas-mediated cytotoxicity in vivo was an important determinant of tumor escape following CTL-based immunotherapy. Tumor escape variants (TEV) recovered from the lungs of CTL-treated mice exhibited more aggressive behavior in vivo. However, these TEV retained relevant MHC class I and tumor Ag expression and sensitivity to CTL via the perforin pathway but reduced susceptibility to Fas-mediated lysis. Moreover, TEV were significantly less responsive to eradication by CTL adoptive immunotherapy paradigms as a consequence of increased Fas resistance. Overall, we identified that Faslow-TEV emerged as a direct consequence of CTL-tumor interactions in vivo, and that such an altered neoplastic Fas phenotype compromised immunotherapy efficacy. Together, these findings may have important implications for both tumor progression and the design of immunotherapeutic interventions to confront these selective pressures or escape mechanisms.
Alloantigen Affinity and CD4 Help Determine Severity of Graft-versus-Host Disease Mediated by CD8 Donor T Cells
Authors: Yu Xue-Zhong , Albert Michael H. , Anasetti Claudio
Published: April 2014

TCR affinity dictates T cell selection in the thymus and also has a high impact on the fate of peripheral T cells. Graft-vs-host disease (GVHD) is a pathological process initiated by activation of donor T cells after adoptive transfer into an allogeneic recipient. How TCR affinity affects the potential of alloreactive T cells to induce GVHD is unclear. Using alloreactive CD4+ and CD8+ TCR transgenic (Tg) T cells, GVHD models are presented that allow for the visualization of how CD8+ alloreactive T cells behave in response to alloantigens with different TCR affinity in the absence or presence of CD4 help. In a nonmyeloablative transplant model where GVHD lethality is due to marrow aplasia, alloreactive CD8+ TCR Tg T cells induced significantly more severe GVHD in the recipients that express an intermediate-affinity alloantigen than in the recipients that express a high-affinity alloantigen. In a myeloablative transplant model where GVHD lethality is due to epithelium injury, CD8+ TCR Tg cells were also more pathogenic in the recipients with an intermediate-affinity alloantigen than in those with a high-affinity alloantigen. The presence of alloreactive CD4+ TCR Tg cells enhanced the potential of CD8+ TCR Tg cells to cause GVHD in recipients with an intermediate-, but not with a high-, affinity alloantigen. These findings underscore that alloantigen affinity and CD4 help control the fate and pathogenicity of alloreactive CD8+ T cells in vivo.
The BZLF1 Homolog of an Epstein-Barr-Related γ-Herpesvirus Is a Frequent Target of the CTL Response in Persistently Infected Rhesus Macaques
Authors: Fogg Mark H. , Garry Deirdre , Awad Amany , Wang Fred , Kaur Amitinder
Published: April 2014

Although CD8+ T lymphocytes targeting lytic infection proteins dominate the immune response to acute and persistent EBV infection, their role in immune control of EBV replication is not known. Rhesus lymphocryptovirus (rhLCV) is a γ-herpesvirus closely related to EBV, which establishes persistent infection in rhesus macaques. In this study, we investigated cellular immune responses to the rhLCV BZLF1 (rhBZLF1) homolog in a cohort of rhLCV-seropositive rhesus macaques. rhBZLF1-specific IFN-γ ELISPOT responses ranging between 56 and 3070 spot-forming cells/106 PBMC were detected in 36 of 57 (63%) rhesus macaques and were largely mediated by CD8+ T lymphocytes. The prevalence and magnitude of ELISPOT responses were greater in adult (5–15 years of age) rather than juvenile macaques (<5 years of age), suggesting that rhBZLF1-specific CTL increase over time following early primary infection. A highly immunogenic region in the carboxyl terminus of the rhBZLF1 protein containing overlapping CTL epitopes restricted by Mamu-A*01 and other as yet unidentified MHC class I alleles was identified. The presence of a robust CD8+ T lymphocyte response targeting this lytic infection protein in both rhesus macaques and humans suggests that these CTL may be important for immune control of EBV-related γ-herpesvirus infection. These data underscore the utility of the rhLCV-macaque model for studies of EBV pathogenesis.
Role of Antigen-Processing Machinery in the In Vitro Resistance of Squamous Cell Carcinoma of the Head and Neck Cells to Recognition by CTL
Authors: López-Albaitero Andrés , Nayak Jayakar V. , Ogino Takeshi , Machandia Avinash , Gooding William , DeLeo Albert B. , Ferrone Soldano , Ferris Robert L.
Published: April 2014

Squamous cell carcinoma of the head and neck (SCCHN) cells are poorly recognized in vitro by CTL despite expressing the restricting HLA class I allele and the targeted tumor Ag (TA). Several lines of evidence indicate that the lack of SCCHN cell recognition by CTL reflects defects in targeted TA peptide presentation by HLA class I Ag to CTL because of Ag-processing machinery (APM) dysfunction. First, lack of recognition of SCCHN cells by CTL is associated with marked down-regulation of the IFN-γ-inducible APM components low-m.w. protein 2, TAP1, TAP2, and tapasin. Second, SCCHN cell recognition by CTL is restored by pulsing cells with exogenous targeted TA peptide. Third, the restoration of CTL recognition following incubation of SCCHN cells with IFN-γ is associated with a significant (p = 0.001) up-regulation of the APM components TAP1, TAP2, and tapasin. Lastly, and most conclusively, SCCHN cell recognition by CTL is restored by transfection with wild-type TAP1 cDNA. Our findings may explain the association between APM component down-regulation and poor clinical course of the disease in SCCHN. Furthermore, the regulatory nature of the APM defects in SCCHN cells suggests that intralesional administration of IFN-γ may have a beneficial effect on the clinical course of the disease and on T cell-based immunotherapy of SCCHN by restoring SCCHN cell recognition by CTL.
Induction of Alloreactive CD4 T Cell Tolerance in Molecular Chimeras: A Possible Role for Regulatory T Cells
Authors: Forman Daron , Kang Eun-Suk , Tian Chaorui , Paez-Cortez Jesus , Iacomini John
Published: April 2014

Induction of molecular chimerism following reconstitution of mice with autologous bone marrow cells expressing a retrovirally encoded allogeneic MHC class I Ag results in donor-specific tolerance. To investigate the mechanism by which CD4 T cells that recognize allogeneic MHC class I through the indirect pathway of Ag presentation are rendered tolerant in molecular chimeras, transgenic mice expressing a TCR on CD4 T cells specific for peptides derived from Kb were used. CD4 T cells expressing the transgenic TCR were detected in mice reconstituted with bone marrow cells transduced with retroviruses carrying the gene encoding H-2Kb, albeit detection was at lower levels than in mice receiving mock-transduced bone marrow. Despite the presence of CD4 T cells expressing an alloreactive TCR, mice receiving H-2Kb-transduced bone marrow permanently accepted Kb disparate skin grafts. CD4+CD25+ T cells from mice reconstituted with H-2Kb-transduced bone marrow prevented rejection of Kb disparate skin grafts when adoptively transferred into immunodeficient mice along with effector T cells, suggesting that induction of molecular chimerism leads to the generation of donor specific regulatory T cells, which may be involved in preventing alloreactive CD4 T cell responses that lead to rejection.
Combinations of CD45 Isoforms Are Crucial for Immune Function and Disease
Authors: Dawes Ritu , Petrova Svetla , Liu Zhe , Wraith David , Beverley Peter C. L. , Tchilian Elma Z.
Published: April 2014

Expression of the CD45 Ag in hemopoietic cells is essential for normal development and function of lymphocytes, and both mice and humans lacking expression exhibit SCID. Human genetic variants of CD45, the exon 4 C77G and exon 6 A138G alleles, which alter the pattern of CD45 isoform expression, are associated with autoimmune and infectious diseases. We constructed transgenic mice expressing either an altered level or combination of CD45 isoforms. We show that the total level of CD45 expressed is crucial for normal TCR signaling, lymphocyte proliferation, and cytokine production. Most importantly, transgenic lines with a normal level, but altered combinations of CD45 isoforms, CD45RABC/+ and CD45RO/+ mice, which mimic variant CD45 expression in C77G and A138G humans, show more rapid onset and increased severity of experimental autoimmune encephalomyelitis. CD45RO/+ cells produce more TNF-α and IFN-γ. Thus, for the first time, we have shown experimentally that it is the combination of CD45 isoforms that affects immune function and disease.
Immunization with Murine Breast Cancer Cells Treated with Antisense Oligodeoxynucleotides to Type I Insulin-Like Growth Factor Receptor Induced an Antitumoral Effect Mediated by a CD8+ Response Involving Fas/Fas Ligand Cytotoxic Pathway
Authors: Schillaci Roxana , Salatino Mariana , Cassataro Juliana , Proietti Cecilia J. , Giambartolomei Guillermo H. , Rivas Martín A. , Carnevale Romina P. , Charreau Eduardo H. , Elizalde Patricia V.
Published: April 2014

We have demonstrated that in vivo administration of phosphorothioate antisense oligodeoxynucleotides (AS[S]ODNs) to type I insulin-like growth factor receptor (IGF-IR) mRNA resulted in inhibition of C4HD breast cancer growth in BALB/c mice. The present study focused on whether in vivo administration of C4HD tumor cells pretreated with IGF-IR AS[S]ODN and irradiated could provide protection against C4HD wild-type tumor challenge and also on elucidating the mechanism mediating this effect. Our results showed that mice immunized with IGF-IR AS[S]ODN-treated C4HD cells experienced a growth inhibition of 53.4%, 61.6%, and 60.2% when compared with PBS-treated mice, wild-type C4HD cell-injected mice, or phosphorothioate sense oligodeoxynucleotide-treated C4HD cell-injected mice, respectively. The protective effect was C4HD-specific, because no cross-protection was observed against other syngeneic mammary tumor lines. The lack of protection against tumor formation in nude mice indicated that T cells were involved in the antitumoral response. Furthermore, cytotoxicity and splenocyte proliferation assays demonstrated that a cellular CD8+-dependent immune response, acting through the Fas/Fas ligand death pathway, could be mediating the antitumor effect induced by immunization with AS[S]ODN-treated cells. Immunization also induced splenocytes to produce Ag-dependent IFN-γ, indicating the presence of a type 1 response. We demonstrated for the first time that IGF-IR AS[S]ODN treatment of breast cancer cells induced expression of CD86 and heat shock protein 70 molecules, both involved in the induction of the immunogenic phenotype. Immunization with these tumor immunogens imparted protection against parental tumor growth through activation of a specific immune response.
Differential MHC Class II Presentation of a Pathogenic Autoantigen during Health and Disease
Authors: Shih Fei F. , Racz Jennifer , Allen Paul M.
Published: April 2014

Glucose-6-phosphate isomerase (GPI) is the target autoantigen recognized by KRN T cells in the K/BxN model of rheumatoid arthritis. T cell reactivity to this ubiquitous Ag results in the recruitment of anti-GPI B cells and subsequent immune complex-mediated arthritis. Because all APCs have the capacity to process and present this autoantigen, it is unclear why systemic autoimmunity with polyclonal B cell activation does not ensue. To this end, we examined how GPI is presented by B cells relative to other immunologically relevant APCs such as dendritic cells (DCs) and macrophages in the steady state, during different phases of arthritis development, and after TLR stimulation. Although all APCs can process and present the GPI:I-Ag7 complex, they do so with different efficiencies. DCs are the most potent at baseline and become progressively more potent with disease development correlating with immune complex uptake. Interestingly, in vivo and in vitro maturation of DCs did not enhance GPI presentation, suggesting that DCs use mechanisms to regulate the presentation of self-peptides. Non-GPI-specific B cells are the weakest APCs (100-fold less potent than DCs) and fail to productively engage KRN T cells at steady state and during arthritis. However, the ability to stimulate KRN T cells is strongly enhanced in B cells after TLR ligation and provides a mechanism whereby polyclonal B cells may be activated in the wake of an acute infection.
Regulatory T Cells Can Mediate Their Function through the Stimulation of APCs to Produce Immunosuppressive Nitric Oxide
Authors: Chen Cyndi , Lee Wen-hui , Zhong Lingwen , Liu Chih-Pin
Published: April 2014

Regulatory T cells (Tr cells) play a critical role in inducing immune tolerance. It remains largely unclear how various types of Tr cells perform their regulatory function. We have studied the underlying regulatory mechanism of a population of autoantigen-specific CD4+ Tr cells. These T cells are specific for the glutamic acid decarboxylase p206–220 peptide and are isolated from the diabetes-resistant nonobese-resistant mice. Although these T cells express T-bet and display a Th1 phenotype, they are able to inhibit diabetes. Their regulatory function is dependent on both IFN-γ and cell contact with target cells. These Tr cells can mediate their cell contact-dependent regulatory function by secreting IFN-γ which stimulates APCs to produce NO. NO is necessary for the Tr cells to inhibit the proliferation of pathogenic T cells and the development of diabetes. Therefore, we have identified a novel mechanism by which these Tr cells can exert their regulatory function. These results also provide an explanation as to why IFN-γ may play both pathogenic and immunomodulatory roles in autoimmune diseases.
Superior Protective and Therapeutic Effects of IL-12 and IL-18 Gene-Transduced Dendritic Neuroblastoma Fusion Cells on Liver Metastasis of Murine Neuroblastoma
Authors: Iinuma Hisae , Okinaga Kota , Fukushima Ryoji , Inaba Tsuyoshi , Iwasaki Kota , Okinaga Akira , Takahashi Ichiro , Kaneko Michio
Published: April 2014

Fusion vaccine of dendritic cells (DCs) and tumor cells has the advantage of inducing an immune response against multiple tumor Ags, including unknown tumor Ags. Using the liver metastasis model of C1300 neuroblastoma cells, we assessed the protective and therapeutic effects of fusion cells transduced with the IL-12 gene and/or the IL-18 gene. Improving the fusion method by combining polyethylene glycol and electroporation increased loading efficiency. In the A/J mice vaccinated with fusion cells modified with the LacZ gene (fusion/LacZ), IFN-γ production and CTL activity increased significantly compared with that of DCs/LacZ, C1300/LacZ, or a mixture of the two (mixture/LacZ). With the transduction of IL-12 and IL-18 genes into the fusion cells (fusion/IL-12/IL-18), the level of IFN-γ increased more than five times that of other fusion groups. In addition, NK cell activity and CTL activity increased significantly compared with that of mixture/LacZ, fusion/LacZ, DC/LacZ, or C1300/LacZ. In the protective and therapeutic studies of fusion cell vaccine, mice vaccinated with fusion/LacZ, fusion/IL-12, fusion/IL-18, or fusion/IL-12/IL-18 showed a significant decrease in liver metastasis and a significant increase in survival compared with mice given a mixture/LacZ, DCs/LacZ, or C1300/LacZ. In particular, the mice receiving fusion/IL-12/IL-18 vaccine showed a complete protective effect and the highest therapeutic effects. The present study investigates the improved loading efficiency of fusion cells and suggests that the introduction of IL-12 and IL-18 genes can induce extremely strong protective and therapeutic effects on liver metastasis of neuroblastoma.
GATA-3 Directly Remodels the IL-10 Locus Independently of IL-4 in CD4+ T Cells
Authors: Shoemaker John , Saraiva Margarida , O’Garra Anne
Published: April 2014

IL-10 is a major regulator in inflammatory responses. Although various transcription factors were defined to enhance IL-10, the molecular mechanism for the initiation of Il-10 transcription, remains unknown. mRNA profiling of six distinct primary CD4+ T cell populations showed differential expression of the transcription factor GATA-3 correlated with levels of IL-10 expression. We showed that ectopic expression of GATA-3 in naive primary CD4+ T cells enhanced expression of IL-10 by these cells and uncovered a possible mechanism for this effect. We found that GATA-3 induced changes of the chromatin structure at the Il-10 locus and that these changes occur even in the absence of IL-4. Furthermore we found that in the presence of GATA-3 the histones at the Il-10 locus become acetylated. Despite being recruited in vivo to two locations on the Il-10 locus, GATA-3 did not transactivate the IL-10 promoter. We therefore suggest a key role of GATA-3 in instructing Il-10 gene expression in primary CD4+ T cells, possibly by switching and stabilizing the Il-10 locus into a transcriptionally competent status.
Differential Role of Programmed Death-Ligand 1 and Programmed Death-Ligand 2 in Regulating the Susceptibility and Chronic Progression of Experimental Autoimmune Encephalomyelitis
Authors: Zhu Bing , Guleria Indira , Khosroshahi Arezou , Chitnis Tanuja , Imitola Jaime , Azuma Miyuki , Yagita Hideo , Sayegh Mohamed H. , Khoury Samia J.
Published: April 2014

Programmed death-1 (PD-1) is a negative costimulatory molecule, and blocking the interaction of PD-1 with its ligands, PD-L1 (B7-H1) and PD-L2 (B7-DC), enhances autoimmune disease in several animal models. We have studied the role of PD-1 ligands in disease susceptibility and chronic progression in experimental autoimmune encephalomyelitis (EAE). In BALB/c mice immunized with myelin oligodendrocyte glycoprotein (MOG) peptide 35–55, PD-L1 but not PD-L2 blockade significantly increased EAE incidence. In B10.S mice immunized with myelin proteolipid protein (PLP) peptide 139–151, both PD-L1 and PD-L2 blockade markedly enhanced EAE severity. In prediabetic NOD mice immunized with PLP48-70, PD-L2 blockade worsened EAE but did not induce diabetes, whereas PD-L1 blockade precipitated diabetes but did not worsen EAE, suggesting different regulatory roles of these two ligands in EAE and diabetes. B6 mice immunized with MOG35-55 developed chronic persistent EAE, and PD-L2 blockade in the chronic phase exacerbated EAE, whereas PD-L1 blockade did not. In contrast, SJL/J mice immunized with PLP139-151 developed chronic relapsing-remitting EAE, and only PD-L1 blockade during remission precipitated EAE relapse. The strain-specific effects of PD-1 ligand blockade did not correlate with the expression of PD-L1 and PD-L2 on dendritic cells and macrophages in lymphoid tissue, or on inflammatory cells in the CNS. However, EAE enhancement is correlated with less prominent Th2 cytokine induction after specific PD-1 ligand blockade. In conclusion, PD-L1 and PD-L2 differentially regulate the susceptibility and chronic progression of EAE in a strain-specific manner.
Overexpression of Cellular Prion Protein Induces an Antioxidant Environment Altering T Cell Development in the Thymus
Authors: Jouvin-Marche Evelyne , Attuil-Audenis Valérie , Aude-Garcia Catherine , Rachidi Walid , Zabel Mark , Podevin-Dimster Valérie , Siret Carole , Huber Christoph , Martinic Marianne , Riondel Jacqueline , Villiers Christian L. , Favier Alain , Naquet Philippe , Cesbron Jean-Yves , Marche Patrice N.
Published: April 2014

Cellular prion protein (PrPC) is an ubiquitously expressed glycoprotein whose roles are still widely discussed, particularly in the field of immunology. Using TgA20- and Tg33-transgenic mice overexpressing PrPC, we investigated the consequences of this overexpression on T cell development. In both models, overexpression of PrPC induces strong alterations at different steps of T cell maturation. On TgA20 mice, we observed that these alterations are cell autonomous and lead to a decrease of αβ T cells and a concomitant increase of γδ T cell numbers. PrPC has been shown to bind and chelate copper and, interestingly, under a copper supplementation diet, TgA20 mice presented a partial restoration of the αβ T cell development, suggesting that PrPC overexpression, by chelating copper, generates an antioxidant context differentially impacting on αβ and γδ T cell lineage.
Primary T Cell Expansion and Differentiation In Vivo Requires Antigen Presentation by B Cells
Authors: Crawford Alison , MacLeod Megan , Schumacher Ton , Corlett Louise , Gray David
Published: April 2014

B cells are well documented as APC; however, their role in supporting and programming the T cell response in vivo is still unclear. Studies using B cell-deficient mice have given rise to contradictory results. We have used mixed BM chimeric mice to define the contribution that B cells make as APC. When the B cell compartment is deficient in MHC class II, while other APC are largely normal, T cell clonal expansion is significantly reduced and the differentiation of T cells into cytokine-secreting effector cells is impaired (in particular, Th2 cells). The development of the memory T cell populations is also decreased. Although MHC class II-mediated presentation by B cells was crucial for an optimal T cell response, neither a B cell-specific lack of CD40 (influencing costimulation) nor lymphotoxin α (influencing lymphoid tissue architecture) had any effect on the T cell response. We conclude that in vivo B cells provide extra and essential Ag presentation capacity over and above that provided by dendritic cells, optimizing expansion and allowing the generation of memory and effector T cells.
Engagement of Glucocorticoid-Induced TNF Receptor Costimulates NKT Cell Activation In Vitro and In Vivo
Authors: Kim Hyun Jung , Kim Hye Young , Kim Byoung Kwon , Kim Sanghee , Chung Doo Hyun
Published: April 2014

Glucocorticoid-induced TNF receptor (GITR) is known to provide costimulatory signals to CD4+CD25− and CD4+CD25+ T cells during immune responses in vivo. However, the functional roles of GITR expressed on NKT cells have not been well characterized. In this study, we have explored the functions of GITR as a costimulatory factor on NKT cells. GITR was found to be constitutively expressed on NKT cells and its expression was enhanced by TCR signals. GITR engagement using DTA-1, an agonistic mAb against GITR, in the presence of TCR signals, augmented IL-2 production, the expression of activation markers, cell cycle progression, and the nuclear translocations of NF-κB p50 and p65. Furthermore, GITR engagement enhanced the production of IL-4, IL-10, IL-13, and IFN-γ by NKT cells and the expression level of phosphorylated p65 in NKT cells in the presence of TCR engagement, indicating that GITR provides costimulatory signals to NKT cells. The costimulatory effects of GITR on NKT cells were comparable to those of CD28 in terms of cytokine production. Moreover, the coinjection of DTA-1 and α-galactosylceramide into B6 mice induced more IL-4 and IFN-γ production than the coinjection of control mAbs and α-galactosylceramide. In addition, the adoptive transfer of DTA-1-pretreated NKT cells into CD1d−/− mice attenuated hypersensitivity pneumonitis more than control IgG pretreated NKT cells in these mice. These findings demonstrate that GITR engagement on NKT cells modulates immune responses in hypersensitivity pneumonitis in vivo. Taken together, our findings suggest that GITR engagement costimulates NKT cells and contributes to the regulation of immune-associated disease processes in vivo.
Complement Receptor 1 and 2 Deficiency Increases Coxsackievirus B3-Induced Myocarditis, Dilated Cardiomyopathy, and Heart Failure by Increasing Macrophages, IL-1β, and Immune Complex Deposition in the Heart
Authors: Fairweather DeLisa , Frisancho-Kiss Sylvia , Njoku Dolores B. , Nyland Jennifer F. , Kaya Ziya , Yusung Susy A. , Davis Sarah E. , Frisancho J. Augusto , Barrett Masheka A. , Rose Noel R.
Published: April 2014

Complement and complement receptors (CR) play a central role in immune defense by initiating the rapid destruction of invading microorganisms, amplifying the innate and adaptive immune responses, and mediating solubilization and clearance of immune complexes. Defects in the expression of C or CR have been associated with loss of tolerance to self proteins and the development of immune complex-mediated autoimmune diseases such as systemic lupus erythematosus. In this study, we examined the role of CR on coxsackievirus B3 (CVB3)-induced myocarditis using mice deficient in CR1/2. We found that CR1/2 deficiency significantly increased acute CVB3 myocarditis and pericardial fibrosis resulting in early progression to dilated cardiomyopathy and heart failure. The increase in inflammation was not due to increased viral replication, which was not significantly altered in the hearts of CR1/2-deficient mice, but was associated with increased numbers of macrophages, IL-1β levels, and immune complex deposition in the heart. The complement regulatory protein, CR1-related gene/protein Y (Crry), was increased on cardiac macrophage populations, while immature B220low B cells were increased in the spleen of CR1/2-deficient mice during acute CVB3-induced myocarditis. These results show that expression of CR1/2 is not necessary for effective clearance of CVB3 infection, but prevents immune-mediated damage to the heart.
Distinct Subsets of Dendritic Cells Regulate the Pattern of Acute Xenograft Rejection and Susceptibility to Cyclosporine Therapy
Authors: Wang Hao , Arp Jacqueline , Huang Xuyan , Liu Weihua , Ramcharran Siobhan , Jiang Jifu , Garcia Bertha , Kanai Nobuyuki , Min Weiping , O’Connell Peta J. , Zhong Robert
Published: April 2014

We determined whether distinct subclasses of dendritic cells (DC) could polarize cytokine production and regulate the pattern of xenograft rejection. C57BL/6 recipients, transplanted with Lewis rat hearts, exhibited a predominantly CD11c+CD8α+ splenic DC population and an intragraft cytokine profile characteristic of a Th1-dominant response. In contrast, BALB/c recipients of Lewis rat heart xenografts displayed a predominantly CD11c+CD8α− splenic DC population and IL-4 intragraft expression characteristic of a Th2 response. In addition, the CD11c+IL-12+ splenic DC population in C57BL/6 recipients was significantly higher than that in BALB/c recipients. Adoptive transfer of syngeneic CD8α− bone marrow-derived DC shifted a Th1-dominant, slow cell-mediated rejection to a Th2-dominant, aggressive acute vascular rejection (AVR) in C57BL/6 mice. This was associated with a cytokine shift from Th1 to Th2 in these mice. In contrast, transfer of CD8α+ bone marrow-derived DC shifted AVR to cell-mediated rejection in BALB/c mice and significantly prolonged graft survival time from 6.0 ± 0.6 days to 14.2 ± 0.8 days. CD8α+ DC transfer rendered BALB/c mice susceptible to cyclosporine therapy, thereby facilitating long-term graft survival. Furthermore, CD8α+ DC transfer in IL-12-deficient mice reconstituted IL-12 expression, induced Th1 response, and attenuated AVR. Our data suggest that the pattern of acute xenogeneic rejection can be regulated by distinct DC subsets.
Human Dendritic Cell Expression of HLA-DO Is Subset Specific and Regulated by Maturation
Authors: Hornell Tara M. C. , Burster Timo , Jahnsen Frode L. , Pashine Achal , Ochoa Maria T. , Harding James J. , Macaubas Claudia , Lee Andrew W. , Modlin Robert L. , Mellins Elizabeth D.
Published: April 2014

Expression of HLA-DO (DO) in cells that express HLA-DM (DM) results in an altered repertoire of MHC class II/peptide complexes, indicating that DO modulates DM function. Human and murine B cells and thymic epithelial cells express DO, while monocytes/macrophages do not. Monocyte-derived dendritic cells (DC) also have been found to be DO-negative, leading to the assumption that DC do not express DO. In this study, we report that, in fact, certain types of human primary DC express DO. These include Langerhans cells (LC) and some subtypes of circulating blood DC. Specifically, the majority of BDCA-3+ DC, a small subset of uncertain function, are DO+, while smaller proportions of CD11c+, BDCA-1+ (myeloid) DC, at most a minority of CD123+/BDCA-2+ (plasmacytoid) DC, and no detectable CD16+ (myeloid) DC, express DO. Immunohistochemistry of human tonsil sections demonstrates that tonsillar interdigitating DC are also DO+. In a subset of immature LC with higher DO expression, an increased fraction of surface DR molecules carry CLIP peptides, indicating that DO functions as a DM inhibitor in these cells. LC expression of DO is down-regulated by maturation stimuli. DM levels also decrease under these conditions, but the DM:DO ratio generally increases. In the myeloid cell types tested, DO expression correlates with levels of DOβ, but not DOα, implying that modulation of DOβ regulates DO dimer abundance in these cells. The range of APC types shown to express DO suggests a broader role for DO in immune function than previously appreciated.
H2-O Expression in Primary Dendritic Cells
Authors: Chen Xinjian , Reed-Loisel Lisa M. , Karlsson Lars , Jensen Peter E.
Published: April 2014

H2-O is a nonpolymorphic class II molecule whose biological role remains to be determined. H2-O modulates H2-M function, and it has been generally believed to be expressed only in B lymphocytes and thymic medullary epithelial cells, but not in dendritic cells (DCs). In this study, we report identification of H2-O expression in primary murine DCs. Similar to B cells, H2-O is associated with H2-M in DCs, and its expression is differentially regulated in DC subsets as well as during cell maturation and activation. Primary bone marrow DCs and plasmacytoid DCs in the spleen and lymph nodes express MHC class II and H2-M, but not the inhibitor H2-O. In contrast, myeloid DCs in secondary lymphoid organs express both H2-M and H2-O. In CD8αα+ DCs, the ratio of H2-O to H2-M is higher than in CD8αα− DCs. In DCs generated from GM-CSF- and IL-4-conditioned bone marrow cultures, H2-O expression is not detected regardless of the maturation status of the cells. Administration of LPS induces in vivo activation of myeloid DCs, and this activation is associated with down-regulation of H2-O expression. Primary splenic DCs from H2-O−/− and H2-O+/+ mice present exogenous protein Ags to T cell hybridomas similarly well, but H2-O−/− DCs induce stronger allogeneic CD4 T cell response than the H2-O+/+ DCs in mixed leukocyte reactions. Our results suggest that H2-O has a broader role than previously appreciated in regulating Ag presentation.
IL-4 and IL-13 Form a Negative Feedback Circuit with Surfactant Protein-D in the Allergic Airway Response
Authors: Haczku Angela , Cao Yang , Vass Geza , Kierstein Sonja , Nath Puneeta , Atochina-Vasserman Elena N. , Scanlon Seth T. , Li Lily , Griswold Don E. , Chung K. Fan , Poulain Francis R. , Hawgood Samuel , Beers Michael F. , Crouch Erika C.
Published: April 2014

The innate immune molecule surfactant protein-D (SP-D) plays an important regulatory role in the allergic airway response. In this study, we demonstrate that mice sensitized and challenged with either Aspergillus fumigatus (Af) or OVA have increased SP-D levels in their lung. SP-D mRNA and protein levels in the lung also increased in response to either rIL-4 or rIL-13 treatment. Type II alveolar epithelial cell expression of IL-4Rs in mice sensitized and challenged with Af, and in vitro induction of SP-D mRNA and protein by IL-4 and IL-13, but not IFN-γ, suggested a direct role of IL-4R-mediated events. The regulatory function of IL-4 and IL-13 was further supported in STAT-6-deficient mice as well as in IL-4/IL-13 double knockout mice that failed to increase SP-D production upon allergen challenge. Interestingly, addition of rSP-D significantly inhibited Af-driven Th2 cell activation in vitro whereas mice lacking SP-D had increased numbers of CD4+ cells with elevated IL-13 and thymus- and activation-regulated chemokine levels in the lung and showed exaggerated production of IgE and IgG1 following allergic sensitization. We propose that allergen exposure induces elevation in SP-D protein levels in an IL-4/IL-13-dependent manner, which in turn, prevents further activation of sensitized T cells. This negative feedback regulatory circuit could be essential in protecting the airways from inflammatory damage after allergen inhalation.
Fms-Like Tyrosine Kinase 3 Ligand Recruits Plasmacytoid Dendritic Cells to the Brain
Authors: Curtin James F. , King Gwendalyn D. , Barcia Carlos , Liu Chunyan , Hubert François X. , Guillonneau Carole , Josien Régis , Anegon Ignacio , Lowenstein Pedro R. , Castro Maria G.
Published: April 2014

The lack of professional afferent APCs in naive brain parenchyma contributes to the systemic immune ignorance to Ags localized exclusively within the brain. Dendritic cells (DCs) appear within the brain as a consequence of inflammation, but no molecular mechanisms accounting for this influx have been described. In this study we demonstrate that Fms-like tyrosine kinase 3 ligand (Flt3L) recruits plasmacytoid DCs (pDCs; >50-fold; p < 0.001) to the brain parenchyma. These pDCs expressed IFN-α, the hallmark cytokine produced by pDCs, indicating recruitment and activation in situ of bona fide pDCs within the brain parenchyma. Flt3L did not increase the numbers of conventional DCs, macrophages, or B, T, NK, NKT, or microglial cells within the brain. Our data demonstrate that Flt3L reconstitutes a crucial afferent component of the immune response, namely, professional APCs within the brain parenchyma, and this could counteract the intrinsic systemic immune ignorance to Ags localized exclusively within the brain.
Modulation of Dendritic Cell Trafficking to and from the Airways
Authors: Jakubzick Claudia , Tacke Frank , Llodra Jaime , van Rooijen Nico , Randolph Gwendalyn J.
Published: April 2014

We investigated the fate of latex (LX) particles that were introduced into mice intranasally. Macrophages acquired the vast majority of particles and outnumbered LX particle-bearing airway dendritic cells (DCs) by at least two orders of magnitude. Yet alveolar macrophages were refractory to migration to the draining lymph node (DLN), and all transport to the DLN could be ascribed to the few LX+ airway DCs. Upon macrophage depletion, markedly greater numbers of DCs were recruited into the alveolar space. Consequently, the number of DCs that carried particles to the DLN was boosted by 20-fold. Thus, a so far overlooked aspect of macrophage-mediated suppression of airway DC function stems from the modulation of DC recruitment into the airway. This increase in DC recruitment permitted the development of a robust assay to quantify the subsequent migration of DCs to the DLN. Therefore, we determined whether lung DCs use the same molecules that skin DCs use during migration to DLNs. Like skin DCs, lung DCs used CCR7 ligands and CCR8 for emigration to DLN, but the leukotriene C4 transporter multidrug resistance-related protein 1 did not mediate lung DC migration as it does in skin, indicating that pathways governing DC migration from different tissues partially differ in molecular regulation.
Placenta-Derived Soluble MHC Class I Chain-Related Molecules Down-Regulate NKG2D Receptor on Peripheral Blood Mononuclear Cells during Human Pregnancy: A Possible Novel Immune Escape Mechanism for Fetal Survival
Authors: Mincheva-Nilsson Lucia , Nagaeva Olga , Chen Ting , Stendahl Ulf , Antsiferova Julia , Mogren Ingrid , Hernestål Jenny , Baranov Vladimir
Published: April 2014

Mammalian pregnancy is an intriguing immunological phenomenon where the semiallogeneic fetus is not rejected. Tolerance toward the fetus involves a number of mechanisms associated with modifications of the immune status of the mother. In this study, we strongly suggest a novel mechanism for fetal evasion of maternal immune attack, based on the engagement and down-regulation of the activating NK cell receptor NKG2D on PBMC by soluble MHC class I chain-related proteins A and B (collectively termed MIC). A similar immune escape pathway was previously described in tumors. We found that MIC mRNA was constitutively expressed by human placenta and could be up-regulated upon heat shock treatment. Our immunomorphologic studies showed that the MIC expression in placenta was restricted to the syncytiotrophoblast. Immunoelectron microscopy revealed a dual MIC expression in the syncytiotrophoblast: on the apical and basal cell membrane and in cytoplasmic vacuoles as MIC-loaded microvesicles/exosomes. Soluble MIC molecules were present at elevated levels in maternal blood throughout normal pregnancy and were released by placental explants in vitro. Simultaneously, the cell surface NKG2D expression on maternal PBMC was down-regulated compared with nonpregnant controls. The soluble MIC molecules in pregnancy serum were able to interact with NKG2D and down-regulate the receptor on PBMC from healthy donors, with the consequent inhibition of the NKG2D-dependent cytotoxic response. These findings suggest a new physiological mechanism of silencing the maternal immune system that promotes fetal allograft immune escape and supports the view of the placenta as an immunoregulatory organ.
Molecular Mechanisms Underlying FOXP3 Induction in Human T Cells
Authors: Mantel Pierre-Yves , Ouaked Nadia , Rückert Beate , Karagiannidis Christian , Welz Roland , Blaser Kurt , Schmidt-Weber Carsten B.
Published: April 2014

FOXP3 is playing an essential role for T regulatory cells and is involved in the molecular mechanisms controlling immune tolerance. Although the biological relevance of this transcription factor is well documented, the pathways responsible for its induction are still unclear. The current study reveals structure and function of the human FOXP3 promoter, revealing essential molecular mechanisms of its induction. The FOXP3 promoter was defined by RACE, cloned, and functionally analyzed using reporter-gene constructs in primary human T cells. The analysis revealed the basal, T cell-specific promoter with a TATA and CAAT box 6000 bp upstream the translation start site. The basal promoter contains six NF-AT and AP-1 binding sites, which are positively regulating the trans activation of the FOXP3 promoter after triggering of the TCR. The chromatin region containing the FOXP3 promoter was bound by NF-ATc2 under these conditions. Furthermore, FOXP3 expression was observed following TCR engagement. Promoter activity, mRNA, and protein expression of T cells were suppressed by addition of cyclosporin A. Taken together, this study reveals the structure of the human FOXP3 promoter and provides new insights in mechanisms of addressing T regulatory cell-inducing signals useful for promoting immune tolerance. Furthermore, the study identifies essential, positive regulators of the FOXP3 gene and highlights cyclosporin A as an inhibitor of FOXP3 expression contrasting other immunosuppressants such as steroids or rapamycin.
Signaling through Mutants of the IgA Receptor CD89 and Consequences for Fc Receptor γ-Chain Interaction
Authors: Bakema Jantine E. , de Haij Simone , den Hartog-Jager Constance F. , Bakker Johanna , Vidarsson Gestur , van Egmond Marjolein , van de Winkel Jan G. J. , Leusen Jeanette H. W.
Published: April 2014

The prototypic receptor for IgA (FcαRI, CD89) is expressed on myeloid cells and can trigger phagocytosis, tumor cell lysis, and release of inflammatory mediators. The functions of FcαRI and activating receptors for IgG (FcγRI and FcγRIII) are dependent on the FcR γ-chain dimer. This study increases our understanding of the molecular basis of the FcαRI-FcR γ-chain transmembrane interaction, which is distinct from that of other activatory FcRs. FcαRI is unique in its interaction with the common FcR γ-chain, because it is based on a positively charged residue at position 209, which associates with a negatively charged amino acid of FcR γ-chain. We explored the importance of the position of this positive charge within human FcαRI for FcR γ-chain association and FcαRI functioning with the use of site-directed mutagenesis. In an FcαRI R209L/A213H mutant, which represents a vertical relocation of the positive charge, proximal and distal FcR γ-chain-dependent functions, such as calcium flux, MAPK phosphorylation, and IL-2 release, were similar to those of wild-type FcαRI. A lateral transfer of the positive charge, however, completely abrogated FcR γ-chain-dependent functions in an FcαRI R209L/M210R mutant. By coimmunoprecipitation, we have demonstrated the loss of a physical interaction between FcR γ-chain and FcαRI M210R mutant, thus explaining the loss of FcR γ-chain-dependent functions. In conclusion, not only the presence of a basic residue in the transmembrane region of FcαRI, but also the orientation of FcαRI toward the FcR γ-chain dimer is essential for FcR γ-chain association. This suggests the involvement of additional amino acids in the FcαRI-FcR γ-chain interaction.
The γ-Parvin-Integrin-Linked Kinase Complex Is Critically Involved in Leukocyte-Substrate Interaction
Authors: Yoshimi Ryusuke , Yamaji Satoshi , Suzuki Atsushi , Mishima Wataru , Okamura Mayumi , Obana Takashi , Matsuda Chie , Miwa Yoshihiro , Ohno Shigeo , Ishigatsubo Yoshiaki
Published: April 2014

Leukocyte extravasation is an important step of inflammation, in which integrins have been demonstrated to play an essential role by mediating the interaction of leukocytes with the vascular endothelium and the subendothelial extracellular matrix. Previously, we identified an integrin-linked kinase (ILK)-binding protein affixin (β-parvin), which links initial integrin signals to rapid actin reorganization, and thus plays critical roles in fibroblast migration. In this study, we demonstrate that γ-parvin, one of three mammalian parvin family members, is specifically expressed in several lymphoid and monocytic cell lines in a complementary manner to affixin. Like affixin, γ-parvin directly associates with ILK through its CH2 domain and colocalizes with ILK at focal adhesions as well as the leading edge of PMA-stimulated U937 cells plated on fibronectin. The overexpression of the C-terminal fragment containing CH2 domain or the depletion of γ-parvin by RNA interference inhibits the substrate adhesion of MCP-1-stimulated U937 cells and the spreading of PMA-stimulated U937 cells on fibronectin. Interestingly, the overexpression of the CH2 fragment or the γ-parvin RNA interference also disrupts the asymmetric distribution of PTEN and F-actin observed at the very early stage of cell spreading, suggesting that the ILK-γ-parvin complex is essential for the establishment of cell polarity required for leukocyte migration. Taken together with the results that γ-parvin could form a complex with some important cytoskeletal proteins, such as αPIX, α-actinin, and paxillin as demonstrated for affixin and actopaxin (α-parvin), the results in this study suggest that the ILK-γ-parvin complex is critically involved in the initial integrin signaling for leukocyte migration.
Conserved and Heterogeneous Lipid Antigen Specificities of CD1d-Restricted NKT Cell Receptors
Authors: Brigl Manfred , van den Elzen Peter , Chen Xiuxu , Meyers Jennifer Hartt , Wu Douglass , Wong Chi-Huey , Reddington Faye , Illarianov Petr A. , Besra Gurdyal S. , Brenner Michael B. , Gumperz Jenny E.
Published: April 2014

CD1d-restricted NKT cells use structurally conserved TCRs and recognize both self and foreign glycolipids, but the TCR features that determine these Ag specificities remain unclear. We investigated the TCR structures and lipid Ag recognition properties of five novel Vα24-negative and 13 canonical Vα24-positive/Vβ11-positive human NKT cell clones generated using α-galactosylceramide (α-GalCer)-loaded CD1d tetramers. The Vα24-negative clones expressed Vβ11 paired with Vα10, Vα2, or Vα3. Strikingly, their Vα-chains had highly conserved rearrangements to Jα18, resulting in CDR3α loop sequences that are nearly identical to those of canonical TCRs. Vα24-positive and Vα24-negative clones responded similarly to α-GalCer and a closely related bacterial analog, suggesting that conservation of the CDR3α loop is sufficient for recognition of α-GalCer despite CDR1α and CDR2α sequence variation. Unlike Vα24-positive clones, the Vα24-negative clones responded poorly to a glucose-linked glycolipid (α-glucosylceramide), which correlated with their lack of a conserved CDR1α amino acid motif, suggesting that fine specificity for α-linked glycosphingolipids is influenced by Vα-encoded TCR regions. Vα24-negative clones showed no response to isoglobotrihexosylceramide, indicating that recognition of this mammalian lipid is not required for selection of Jα18-positive TCRs that can recognize α-GalCer. One α-GalCer-reactive, Vα24-positive clone differed from the others in responding specifically to mammalian phospholipids, demonstrating that semi-invariant NKT TCRs have a capacity for private Ag specificities that are likely conferred by individual TCR β-chain rearrangements. These results highlight the variation in Ag recognition among CD1d-restricted TCRs and suggest that TCR α-chain elements contribute to α-linked glycosphingolipid specificity, whereas TCR β-chains can confer heterogeneous additional reactivities.
Bruton’s Tyrosine Kinase Is Required for TLR2 and TLR4-Induced TNF, but Not IL-6, Production
Authors: Horwood Nicole J. , Page Theresa H. , McDaid John P. , Palmer Christine D. , Campbell Jamie , Mahon Tara , Brennan Fionula M. , Webster David , Foxwell Brian M. J.
Published: April 2014

Bruton’s tyrosine kinase (Btk), the gene mutated in the human immunodeficiency X-linked agammaglobulinemia, is activated by LPS and is required for LPS-induced TNF production. In this study, we have investigated the role of Btk both in signaling via another TLR (TLR2) and in the production of other proinflammatory cytokines such as IL-1β, IL-6, and IL-8. Our data show that in X-linked agammaglobulinemia PBMCs, stimulation with TLR4 (LPS) or TLR2 (N-palmitoyl-S-[2, 3-bis(palmitoyloxy)-(2R)-propyl]-(R)-cysteine) ligands produces significantly less TNF and IL-1β than in normal controls. In contrast, a lack of Btk has no impact on the production of IL-6, IL-8, or the anti-inflammatory cytokine, IL-10. Our previous data suggested that Btk lies within a p38-dependent pathway that stabilizes TNF mRNA. Accordingly, TaqMan quantitative PCR analysis of actinomycin D time courses presented in this work shows that overexpression of Btk is able to stabilize TNF, but not IL-6 mRNA. Furthermore, using the p38 inhibitor SB203580, we show that the TLR4-induced production of TNF, but not IL-6, requires the activity of p38 MAPK. These data provide evidence for a common requirement for Btk in TLR2- and TLR4-mediated induction of two important proinflammatory cytokines, TNF and IL-1β, and reveal important differences in the TLR-mediated signals required for the production of IL-6, IL-8, and IL-10.