bluuebunny/crossref_metadata_2025 huggingface dataset:
Antibody Targeting of the CC Chemokine Ligand 5 Results in Diminished Leukocyte Infiltration into the Central Nervous System and Reduced Neurologic Disease in a Viral Model of Multiple Sclerosis
Authors: Glass William G. , Hickey Michelle J. , Hardison Jenny L. , Liu Michael T. , Manning Jerry E. , Lane Thomas E.
Published: April 2014

Intracerebral infection of mice with mouse hepatitis virus, a member of the Coronaviridae family, reproducibly results in an acute encephalomyelitis that progresses to a chronic demyelinating disease. The ensuing neuropathology during the chronic stage of disease is primarily immune mediated and similar to that of the human demyelinating disease multiple sclerosis. Secretion of chemokines within the CNS signals the infiltration of leukocytes, which results in destruction of white matter and neurological impairment. The CC chemokine ligand (CCL)5 is localized in white matter tracts undergoing demyelination, suggesting that this chemokine participates in the pathogenesis of disease by attracting inflammatory cells into the CNS. In this study, we administer a mAb directed against CCL5 to mice with established mouse hepatitis virus-induced demyelination and impaired motor skills. Anti-CCL5 treatment decreased T cell accumulation within the CNS based, in part, on viral Ag specificity, indicating the ability to differentially target select populations of T cells. In addition, administration of anti-CCL5 improved neurological function and significantly (p ≤ 0.005) reduced the severity of demyelination and macrophage accumulation within the CNS. These results demonstrate that the severity of CNS disease can be reduced through the use of a neutralizing mAb directed against CCL5 in a viral model of demyelination.
Intralesional Injection of Adenovirus Encoding CC Chemokine Ligand 16 Inhibits Mammary Tumor Growth and Prevents Metastatic-Induced Death after Surgical Removal of the Treated Primary Tumor
Authors: Guiducci Cristiana , Di Carlo Emma , Parenza Mariella , Hitt Mary , Giovarelli Mirella , Musiani Piero , Colombo Mario P.
Published: April 2014

The CC chemokine ligand (CCL)16 exerts chemotactic activity on human monocytes and lymphocytes. Although no murine homologous has been defined, the TSA mouse adenocarcinoma cells engineered to express human CCL16 are rapidly rejected by syngenic mice. An adenovirus encoding CCL16 (AdCCL16) was generated using a Cre-Lox-based system and was used to determine whether this chemokine might also block pre-existing tumors. Both recombinant and viral CCL16 showed in vitro chemotactic activity for murine CD4+ and CD8+ lymphocytes and dendritic cells (DC). AdCCL16, but not the control empty vector, when injected in established nodules significantly delayed tumor growth. Immunohistochemistry revealed accumulation of CD4+ and CD8+ T cells and DC in the treated tumors as well as in draining lymph nodes. DC from such lymph nodes stimulated IFN-γ by a T cell clone specific for the known TSA tumor-associated Ag (TAA), suggesting the tumor origin of these cells. Lymphocytes from the same nodes showed specific CTL activity against TSA tumor cells and their immunodominant TAA peptide. Antitumor activity required CD4, CD8, and IFN-γ production, as shown using subset-depleted and knockout mice. Despite the robust and rapid immune response triggered by intratumoral injection of AdCCL16, the lesions were not completely rejected; however, the same treatment given before surgical excision of primary lesions prevented metastatic spread and cured 63% of mice bearing the 4T1 mammary adenocarcinoma, which is perhaps the most compelling model of spontaneous metastasis.
Proinflammatory Mediators and Genetic Background in Oncogene Mediated Tumor Progression
Authors: Russell John P. , Engiles Julie B. , Rothstein Jay L.
Published: April 2014

RET/PTC3 (RP3) is an oncogenic fusion protein which is frequently expressed in papillary thyroid carcinomas and has been detected in thyroid tissue from patients diagnosed with Hashimoto’s thyroiditis. The constitutive activation of the tyrosine kinase domain in the carboxyl-terminal end of RP3 induces signaling pathways within thyrocytes and causes cellular transformation. One of the signaling pathways activated in RP3-expressing cells involves the activity of the transcription factor NF-κB and the production of downstream targets including GM-CSF and macrophage chemotactic protein 1. These factors are known to be immunostimulatory, making RP3 a molecular adjuvant and potentially promoting tissue-specific immunity. However compelling, these in vitro data do not reliably predict gene function in vivo or the cumulative effects of time-dependent processes such as angiogenesis, inflammation, or the influence of genetic background. To address these issues, we analyzed the production of proinflammatory mediators in mouse thyroid organs and demonstrate consistency with in vitro studies performed previously that Il1α, Il1β, Il6, and Tnfα and the enzyme Cox2 are produced by RP3-transgenic thyroid tissue, but absent from nontransgenic thyroids. Furthermore, we find that that the genetic background of the host is important in the observed RP3-induced inflammation and tumor progression. These findings provide support for the notion that oncogene-induced cytokine secretion is important for the development and progression of thyroid carcinomas in genetically permissive hosts.
Src Homology 2 Domain-Containing Protein Tyrosine Phosphatase Substrate 1 Regulates the Migration of Langerhans Cells from the Epidermis to Draining Lymph Nodes
Authors: Fukunaga Atsushi , Nagai Hiroshi , Noguchi Tetsuya , Okazawa Hideki , Matozaki Takashi , Yu Xijun , Lagenaur Carl F. , Honma Nakayuki , Ichihashi Masamitsu , Kasuga Masato , Nishigori Chikako , Horikawa Tatsuya
Published: April 2014

Src homology 2 domain-containing protein tyrosine phosphatase substrate 1 (SHPS-1) is a member of the signal regulatory protein family in which the extracellular region interacts with its ligand, CD47. Recent studies have demonstrated that SHPS-1 plays an important role in cell migration and cell adhesion. We demonstrate in this study, using immunohistochemical and flow cytometric analyses, that murine Langerhans cells (LCs) express SHPS-1. Treatment of mice ears with 2,4-dinitro-1-fluorobenzene significantly reduced the number of epidermal LCs, and that reduction could be reversed by pretreatment with mAb to SHPS-1 or the CD47-Fc fusion protein. Treatment with the SHPS-1 mAb in vivo reduced the number of FITC-bearing cells in the lesional lymph nodes after the application of FITC to the skin. The SHPS-1 mAb inhibited the in vivo TNF-α-induced migration of LCs. The emigration of dendritic cells expressing I-Ab+ from skin explants to the medium was also reduced by the SHPS-1 mAb. We further demonstrate that the chemotaxis of a murine dendritic cell line, XS52, by macrophage inflammatory protein-3β was significantly inhibited by treatment with the SHPS-1 mAb or CD47-Fc recombinant protein. Finally, we show that migration of LCs was attenuated in mutant mice that lack the intracellular domain of SHPS-1. These observations show that the ligation of SHPS-1 with the SHPS-1 mAb or with CD47-Fc abrogates the migration of LCs in vivo and in vitro, which suggests that the SHPS-1-CD47 interaction may negatively regulate LC migration.
Genome-Wide Analysis of Molecular Changes in IL-12-Induced Control of Mammary Carcinoma via IFN-γ-Independent Mechanisms
Authors: Shi Xiaoyan , Cao Shanjin , Mitsuhashi Maki , Xiang Zhaoying , Ma Xiaojing
Published: April 2014

IL-12 is a major activator of tumor-killing NK cells and CTL. IFN-γ mediates most of the well-known immunological activities of IL-12. In this study, we report IFN-γ-independent activities induced by therapeutic application of rIL-12 in restricting tumor growth and metastasis in the 4T1 murine mammary carcinoma model. IFN-γ-deficient mice carrying 4T1 tumor exhibit no gross defect in the number of tumor-infiltrating lymphocytes but have exaggerated angiogenesis in the tumor. Administration of IL-12 is able to constrict blood vessels in the tumor in the absence of IFN-γ, and retains certain therapeutic efficacy even when applied late during tumor progression. IL-12 exposure in vivo does not irreversibly alter the immunogenicity of the tumor. Finally, global gene expression analysis of primary tumors reveals IL-12-induced molecular patterns and changes, implicating a number of novel genes potentially important for IFN-γ-independent immune responses against the tumor, for IL-12-mediated antiproliferation, antimetastasis, and antiangiogenesis activities.
Intestinal Intraepithelial Lymphocyte γδ-T Cell-Derived Keratinocyte Growth Factor Modulates Epithelial Growth in the Mouse
Authors: Yang Hua , Antony Paul A. , Wildhaber Barbara E. , Teitelbaum Daniel H.
Published: April 2014

Keratinocyte growth factor (KGF) promotes intestinal epithelial growth. To understand the relevance of intraepithelial lymphocyte (IEL)-derived KGF expression on epithelial growth, we used a mouse model of villus atrophy by the administration of total parenteral nutrition, and a model of villus hypertrophy by the creation of a short bowel syndrome. KGF expression was confined to γδ-ΤCR+ IELs. IEL-derived KGF expression was highest in the crypts, somewhat less in the lower portion of villi, and markedly lower in the upper portion of villi. Total parenteral nutrition administration was associated with a down-regulation of IEL-derived KGF expression, and short bowel syndrome was associated with an up-regulation of IEL-derived KGF expression. In the absence of γδ-ΤCR+ IEL, using γδ−/− mice, intestinal epithelial cell proliferation decreased in control, and in both mucosal atrophy (22% decline) and mucosal hypertrophy (14%) models. These results show that KGF from IELs is an important factor for maintenance of intestinal epithelial cell proliferation and villus growth.
Virus-Induced Activation of Self-Specific TCRαβ CD8αα Intraepithelial Lymphocytes Does Not Abolish Their Self-Tolerance in the Intestine
Authors: Saurer Leslie , Seibold Inge , Rihs Silvia , Vallan Claudio , Dumrese Tilman , Mueller Christoph
Published: April 2014

TCRαβ CD8αα intestinal intraepithelial lymphocytes (IEL) represent an enigmatic subset of T cells, particularly, in regard to their potential functions and the apparent persistence of cells expressing self-specific TCR. We have used mice that are transgenic for the TCRαβ specific for the lymphocytic choriomeningitis virus (LCMV)-derived peptide gp33, and TCRαβ-transgenic mice that coexpress the gp33 Ag ubiquitously, to analyze the functional properties of TCRαβ CD8αα IEL in the presence, or absence, of their specific MHC-restricted Ag, and to assess the impact of molecular mimicry during a potent LCMV infection on potentially self-reactive TCRαβ CD8αα IEL. In this study, we show that the presence of the specific self-Ag results in reduced expression of IL-2, IFN-γ, and IL-10 by resident TCRαβ CD8αα IEL while expression of mRNA for TGFβ is not affected. We further demonstrate that despite their secluded location in the epithelium, TCRαβ CD8αα IEL are activated after infection of the intestinal mucosa with LCMV. Importantly, LCMV-induced activation of self-specific TCRαβ CD8αα IEL does not reverse their tolerance as no cytotoxic activity or up-regulated expression of proinflammatory cytokines is detected and no overt signs of autoimmunity are seen. Taken together, these results are in support of an immunoregulatory role for self-specific TCRαβ CD8αα in the intestinal mucosa and clearly speak against an involvement of this cell subset in inflammatory reactions and tissue destruction.
CTLA-4+CD8+ T Cells That Encounter B7-2+ Iris Pigment Epithelial Cells Express Their Own B7-2 to Achieve Global Suppression of T Cell Activation
Authors: Sugita Sunao , Ng Tat Fong , Schwartzkopff Johannes , Streilein J. Wayne
Published: April 2014

Pigment epithelial (PE) cells cultured from the eye possess the novel property of suppressing TCR-dependent activation of T cells in vitro. Iris PE (IPE) cells accomplish this suppression by a direct cell contact mechanism in which B7-2 expressed by the PE cells interacts with CTLA-4 on responding T cells. Because CTLA-4 expression is constitutively expressed on a very small proportion of naive splenic T cells and since exposure of splenic T cells to IPE leads to global T cell suppression, we have inquired into the mechanism by which suppression is achieved. Using splenic T cells and IPE from donor mice with disrupted genes for CD80 (B7-1), CD86 (B7-2), CTLA-4, and/or CD28, we report that B7-2+ IPE in the presence of anti-CD3 supported selectively the activation of CTLA-4+ CD8+ T cells that express their own B7-2 and secrete enhanced amounts of active TGFβ. By contrast, activation of CTLA-4-negative T cells, especially CD4+ cells, in these cultures was profoundly suppressed. Because global suppression of T cell activation in these cultures was obtained only when both IPE and T cells possessed B7-2 genes and expressed the costimulators as surface molecules, we propose that T cells activated in the presence of parenchymal cells from the eye (an immune privileged site) express B7-2 in a manner that equips them to suppress bystander T cells. Thus, B7-2 expression on T cells participates in their eventual ability to function as regulators in vitro.
Monocyte Surface-Bound IL-15 Can Function as an Activating Receptor and Participate in Reverse Signaling
Authors: Neely Graham G. , Epelman Slava , Ma Ling Ling , Colarusso Pina , Howlett Christopher J. , Amankwah Ernest K. , McIntyre Amanda C. , Robbins Stephen M. , Mody Christopher H.
Published: April 2014

IL-15 is a short chain, four-α helix cytokine that shares some biological function with IL-2. One striking difference between IL-2 and IL-15 is the ability of monocytes to express IL-15 on their cell surface after activation. In the current study we have investigated the ability of human monocyte cell surface IL-15 to participate in reverse signaling. Cross-linking anti-IL-15 Abs were used as a surrogate ligand for surface IL-15 engagement. Ligation of cell surface-expressed IL-15 induced monocyte adhesion that required the activity of small m.w. GTPases. Reverse signals through surface IL-15 activated the Rho-GTPase Rac3. In addition, engagement of cell surface IL-15 was found to activate a number of signaling pathways, including both extracellular signal-regulated kinase 1/2 and p38, and resulted in the secretion of IL-8. IL-8 production required mitogen-activated protein kinase activity. Thus, the current study has established that cell surface IL-15 is more than just a ligand; it can function as a receptor and participate in reverse signaling that results in cellular adhesion and production of inflammatory cytokines.
Thymocytes between the β-Selection and Positive Selection Checkpoints Are Nonresponsive to IL-7 as Assessed by STAT-5 Phosphorylation
Authors: Van De Wiele C. Justin , Marino Julie H. , Murray Bryce W. , Vo Stephen S. , Whetsell Michael E. , Teague T. Kent
Published: April 2014

Interleukin-7 is widely accepted as a major homeostatic factor involved in T cell development. To assess the IL-7 responsiveness of thymocytes involved in selection processes, we used a new sensitive flow cytometry-based assay to detect intracellular phosphorylation of STAT-5 induced by IL-7 in defined mouse thymocyte subsets. Using this method, we found the earliest thymocyte subset (CD4−CD8−CD25−CD44+) to contain both IL-7-responsive and nonresponsive cells. Transition through the next stages of development (CD4−CD8−CD25+CD44+ and −) was associated with responsiveness of all thymocytes within these populations. Passage of thymocytes through β-selection resulted in a significant reduction in IL-7 sensitivity. In the next phases of development (TCR− and TCRlowCD69−), thymocytes were completely insensitive to the effects of IL-7. STAT-5 phosphorylation in response to IL-7 was again observed, however, in thymocytes involved in the positive selection process (TCRlowCD69+ and TCRintermediate). As expected, CD4 and CD8 single-positive thymocytes were responsive to IL-7. These findings delineate an IL-7-insensitive population between the β-selection and positive selection checkpoints encompassing thymocytes predicted to die by neglect due to failure of positive selection. This pattern of sensitivity suggests a two-signal mechanism by which survival of thymocytes at these checkpoints is governed.
IFN-γ Stimulates the Expression of a Novel Secretoglobin That Regulates Chemotactic Cell Migration and Invasion
Authors: Choi Moonsuk S. , Ray Rabindranath , Zhang Zhongjian , Mukherjee Anil B.
Published: April 2014

IFNs are a family of cytokines that alert the immune system against viral infections of host cells. The IFNs (IFN-α, IFN-β, and IFN-γ) interact with specific cellular receptors and stimulate the production of second messengers, leading to the expression of antiviral and immunomodulatory proteins. We report in this study that IFN-γ stimulates the expression of a novel gene that encodes a protein with 30% amino acid sequence identity with uteroglobin, the founding member of the newly formed Secretoglobin (SCGB) superfamily. We named this protein IFN-γ-inducible SCGB (IIS), because its expression in lymphoblast cells is augmented by IFN-γ treatment. IIS is expressed in virtually all tissues, and the highest level of expression is detectable in lymph nodes, tonsil, cultured lymphoblasts, and the ovary. Interestingly, although the expression of IIS mRNA is not significantly different in resting lymphoid cells, it is markedly elevated in activated CD8+ and CD19+ cells. Furthermore, treatment of lymphoblast cells with IIS antisense phosphorothioate (S)-oligonucleotides prevents chemotactic migration and invasion. Taken together, these results raise the possibility that this novel SCGB has immunological functions.
Plasmacytoid Dendritic Cells Regulate Th Cell Responses through OX40 Ligand and Type I IFNs
Authors: Ito Tomoki , Amakawa Ryuichi , Inaba Muneo , Hori Toshiyuki , Ota Maiko , Nakamura Kengo , Takebayashi Masashi , Miyaji Michihiko , Yoshimura Tomoo , Inaba Kayo , Fukuhara Shirou
Published: April 2014

Dendritic cells (DCs) show a functional plasticity in determining Th responses depending on their maturational stage or on maturational signals delivered to the DCs. Human plasmacytoid DCs (PDCs) can induce either Th1- or Th2-type immune responses upon exposure to viruses or IL-3, respectively. In this study we have investigated the Th-polarizing capacity of PDCs after short (24-h) or long (72-h) culture with stimuli and have assessed the expression and function of OX40 ligand (OX40L) in PDC-mediated Th polarization in addition to type I IFN-dependent responses. IL-3-treated PDCs expressed OX40L, but produced almost no IFN-α in response to T cell stimulation (CD40 ligand or T cell interaction), resulting in the preferential priming of Th2 cells through OX40L-dependent mechanisms. Meanwhile, PDCs were rapidly endowed by viral infection (Sendai virus) with a high potency to develop IFN-γ-producing Th cells depending on their capacity to residually produce IFN-α. Although Sendai virus-stimulated PDCs simultaneously expressed OX40L in their maturational process, the Th1-inducing effect of endogenous type I IFNs may overcome and thus conceal the OX40L-dependent Th2 responses. However, during maturation in response to Sendai virus over the longer 72-h period, the expression level of OX40L was up-regulated, whereas the residual IFN-α-producing ability was down-regulated, and consequently, the PDCs with prolonged Sendai virus stimulation induced Th2 responses to some extent. Thus, PDCs have the distinct means to dictate an appropriate response to environmental stimuli.
Smad3 Is Essential for TGF-β1 to Suppress IL-2 Production and TCR-Induced Proliferation, but Not IL-2-Induced Proliferation
Authors: McKarns Susan C. , Schwartz Ronald H. , Kaminski Norbert E.
Published: April 2014

Transforming growth factor-β1 is essential to maintain T cell homeostasis, as illustrated by multiorgan inflammation in mice deficient in TGF-β1 signaling. Despite the physiological importance, the mechanisms that TGF-β1 uses to regulate T cell expansion remain poorly understood. TGF-β1 signals through transmembrane receptor serine/threonine kinases to activate multiple intracellular effector molecules, including the cytosolic signaling transducers of the Smad protein family. We used Smad3−/− mice to investigate a role for Smad3 in IL-2 production and proliferation in T cells. Targeted disruption of Smad3 abrogated TGF-β1-mediated inhibition of anti-CD3 plus anti-CD28-induced steady state IL-2 mRNA and IL-2 protein production. CFSE labeling demonstrated that TGF-β1 inhibited entry of wild-type anti-CD3 plus anti-CD28-stimulated cells into cycle cell, and this inhibition was greatly attenuated in Smad3−/− T cells. In contrast, disruption of Smad3 did not affect TGF-β1-mediated inhibition of IL-2-induced proliferation. These results demonstrate that TGF-β1 signals through Smad3-dependent and -independent pathways to inhibit T cell proliferation. The inability of TGF-β1 to inhibit TCR-induced proliferation of Smad3−/− T cells suggests that IL-2 is not the primary stimulus driving expansion of anti-CD3 plus anti-CD28-stimulated T cells. Thus, we establish that TGF-β1 signals through multiple pathways to suppress T cell proliferation.
Lupus IgG VH4.34 Antibodies Bind to a 220-kDa Glycoform of CD45/B220 on the Surface of Human B Lymphocytes
Authors: Cappione Amedeo J. , Pugh-Bernard Aimee E. , Anolik Jennifer H. , Sanz Iñaki
Published: April 2014

Anti-lymphocyte autoantibodies are a well-recognized component of the autoimmune repertoire in human systemic lupus erythematosus (SLE) and have been postulated to have pathogenic consequences. Early studies indicated that IgM anti-lymphocyte autoantibodies mainly recognized T cells and identified CD45, a protein tyrosine phosphatase of central significance in the modulation of lymphocyte function, as the main antigenic target on T cells. However, more recent work indicates that lupus autoantibodies can also recognize B cells and that CD45 may also represent their antigenic target. In particular, IgM Abs encoded by VH4.34 appear to have special tropism for B cells, and strong, but indirect evidence suggests that they may recognize a B cell-specific CD45 isoform. Because VH4.34 Abs are greatly expanded in SLE, in the present study we investigated the antigenic reactivity of lupus sera VH4.34 IgG Abs and addressed their contribution to the anti-lymphocyte autoantibody repertoire in this disease. Our biochemical studies conclusively demonstrate that lupus IgG VH4.34 Abs target a developmentally regulated B220-specific glycoform of CD45, and more specifically, an N-linked N-acetyllactosamine determinant preferentially expressed on naive B cells that is sterically masked by sialic acid on B220-positive memory B cells. Strikingly, our data also indicate that this reactivity in SLE sera is restricted to VH4.34 Abs and can be eliminated by depleting these Abs. Overall, our data indicate that VH4.34 Abs represent a major component of the lupus IgG autoantibody repertoire and suggest that the carbohydrate moiety they recognize may act as a selecting Ag in SLE.
Identifiying Human MHC Supertypes Using Bioinformatic Methods
Authors: Doytchinova Irini A. , Guan Pingping , Flower Darren R.
Published: April 2014

Classification of MHC molecules into supertypes in terms of peptide-binding specificities is an important issue, with direct implications for the development of epitope-based vaccines with wide population coverage. In view of extremely high MHC polymorphism (948 class I and 633 class II HLA alleles) the experimental solution of this task is presently impossible. In this study, we describe a bioinformatics strategy for classifying MHC molecules into supertypes using information drawn solely from three-dimensional protein structure. Two chemometric techniques–hierarchical clustering and principal component analysis–were used independently on a set of 783 HLA class I molecules to identify supertypes based on structural similarities and molecular interaction fields calculated for the peptide binding site. Eight supertypes were defined: A2, A3, A24, B7, B27, B44, C1, and C4. The two techniques gave 77% consensus, i.e., 605 HLA class I alleles were classified in the same supertype by both methods. The proposed strategy allowed “supertype fingerprints” to be identified. Thus, the A2 supertype fingerprint is Tyr9/Phe9, Arg97, and His114 or Tyr116; the A3-Tyr9/Phe9/Ser9, Ile97/Met97 and Glu114 or Asp116; the A24-Ser9 and Met97; the B7-Asn63 and Leu81; the B27-Glu63 and Leu81; for B44-Ala81; the C1-Ser77; and the C4-Asn77.
Mutational Analyses of the Recombinant Globular Regions of Human C1q A, B, and C Chains Suggest an Essential Role for Arginine and Histidine Residues in the C1q-IgG Interaction
Authors: Kojouharova Mihaela S. , Gadjeva Mihaela G. , Tsacheva Ivanka G. , Zlatarova Aleksandra , Roumenina Liubka T. , Tchorbadjieva Magdalena I. , Atanasov Boris P. , Waters Patrick , Urban Britta C. , Sim Robert B. , Reid Kenneth B. M. , Kishore Uday
Published: April 2014

The first step in the activation of the classical complement pathway by immune complexes involves the binding of the globular domain (gC1q) of C1q to the Fc regions of aggregated IgG or IgM. Each gC1q domain is a heterotrimer of the C-terminal halves of one A (ghA), one B (ghB), and one C (ghC) chain. Our recent studies have suggested a modular organization of gC1q, consistent with the view that ghA, ghB, and ghC are functionally autonomous modules and have distinct and differential ligand-binding properties. Although C1q binding sites on IgG have been previously identified, the complementary interacting sites on the gC1q domain have not been precisely defined. The availability of the recombinant constructs expressing ghA, ghB, and ghC has allowed us, for the first time, to engineer single-residue substitution mutations and identify residues on the gC1q domain, which are involved in the interaction between C1q and IgG. Because C1q is a charge pattern recognition molecule, we have sequentially targeted arginine and histidine residues in each chain. Consistent with previous chemical modification studies and the recent crystal structure of gC1q, our results support a central role for arginine and histidine residues, especially Arg114 and Arg129 of the ghB module, in the C1q-IgG interaction.
Localization of the Domains in Runx Transcription Factors Required for the Repression of CD4 in Thymocytes
Authors: Telfer Janice C. , Hedblom Emmett E. , Anderson Michele K. , Laurent Micheline N. , Rothenberg Ellen V.
Published: April 2014

The runt family transcription factors Runx1 and Runx3 are expressed in developing murine thymocytes. We show that enforced expression of full-length Runx1 in CD4−CD8− thymocytes results in a profound suppression of immature CD4/CD8 double-positive thymocytes and mature CD4 single-positive thymocytes compared with controls. This effect arises from Runx1- or Runx3-mediated repression of CD4 expression, and is independent of positively selecting signals. Runx1 is able to repress CD4 in CD4/CD8 double-positive thymocytes, but not in mature splenic T cells. Runx-mediated CD4 repression is independent of association with the corepressors Groucho/TLE or Sin3. Two domains are required for complete Runx-mediated CD4 repression. These are contained within Runx1 aa 212–262 and 263–360. The latter region contains the nuclear matrix targeting sequence, which is highly conserved among runt family transcription factors across species. The presence of the nuclear matrix targeting sequence is required for Runx-mediated CD4 repression, suggesting that Runx transcription factors are stabilized on the CD4 silencer via association with the nuclear matrix.
Induction of a Rapid and Strong Antigen-Specific Intraepithelial Lymphocyte Response during Oral Encephalitozoon cuniculi Infection
Authors: Moretto Magali , Weiss Louis M. , Khan Imtiaz A.
Published: April 2014

Encephalitozoon cuniculi continues to pose a problem for immunocompromised patients. Previous studies from our laboratory have elucidated the importance of the CD8+ T cell subset in the protection against systemic parasite infection. There have been no studies related to the mucosal immunity induced against this orally acquired pathogen. In the present study, the immune response generated in the gut after oral E. cuniculi infection was evaluated. An early and rapid increase of the intraepithelial lymphocyte (IEL) population of orally infected animals was observed. This increase in the IEL population started as early as day 3 and peaked at day 7 postinfection with persistent elevation thereafter. At day 7 postinfection, IELs expressed strong cytokine messages (IFN-γ and IL-10) and were highly cytotoxic for parasite-infected syngeneic macrophages. At an E:T ratio of 80:1, these cells were able to cause >60% Ag-specific target cell lysis. A significant increase in the CD8αα subset of IEL in response to an oral E. cuniculi infection was observed. To the best of our knowledge, such an early expansion of an IEL population exhibiting strong ex vivo cytotoxicity has not been reported with infectious models. These data suggest that IELs act as important barriers for multiplication of this organism leading to the successful resolution of infection. The protective role of IELs may be due both to their inflammatory (IFN-γ production and cytotoxic response) as well as immunoregulatory (IL-10 production) properties.
Toll-Like Receptor 2 (TLR2)-Dependent-Positive and TLR2-Independent-Negative Regulation of Proinflammatory Cytokines by Mycobacterial Lipomannans
Authors: Quesniaux Valerie J. , Nicolle Delphine M. , Torres David , Kremer Laurent , Guérardel Yann , Nigou Jérôme , Puzo Germain , Erard François , Ryffel Bernhard
Published: April 2014

Lipoarabinomannans (LAM) and lipomannans (LM) are integral parts of the mycobacterial cell wall recognized by cells involved in the innate immune response and have been found to modulate the cytokine response. Typically, mannosylated LAM from pathogenic mycobacteria have been reported to be anti-inflammatory, whereas phosphoinositol-substituted LAM from nonpathogenic species are proinflammatory molecules. In this study, we show that LM from several mycobacterial species, including Mycobacterium chelonae, Mycobacterium kansasii, and Mycobacterium bovis bacillus Calmette-Guérin, display a dual function by stimulating or inhibiting proinflammatory cytokine synthesis through different pathways in murine primary macrophages. LM, but none of the corresponding LAM, induce macrophage activation characterized by cell surface expression of CD40 and CD86 and by TNF and NO secretion. This activation is dependent on the presence of Toll-like receptor (TLR) 2 and mediated through the adaptor protein myeloid differentiation factor 88 (MyD88), but independent of either TLR4 or TLR6 recognition. Surprisingly, LM exerted also a potent inhibitory effect on TNF, IL-12p40, and NO production by LPS-activated macrophages. This TLR2-, TLR6-, and MyD88-independent inhibitory effect is also mediated by LAM from M. bovis bacillus Calmette-Guérin but not by LAM derived from M. chelonae and M. kansasii. This study provides evidence that mycobacterial LM bear structural motifs susceptible to interact with different pattern recognition receptors with pro- or anti-inflammatory effects. Thus, the ultimate response of the host may therefore depend on the prevailing LM or LAM in the mycobacterial envelope and the local host cell receptor availability.
Toll-Like Receptors Are Temporally Involved in Host Defense
Authors: Weiss David S. , Raupach Bärbel , Takeda Kiyoshi , Akira Shizuo , Zychlinsky Arturo
Published: April 2014

Toll-like receptors (TLRs) are evolutionarily conserved proteins that recognize microbial molecules and initiate host defense. To investigate how TLRs work together to fight infections, we tested the role of TLRs in host defense against the Gram-negative bacterial pathogen, Salmonella. We show that TLR4 is critical for early cytokine production and killing of bacteria by murine macrophages. Interestingly, later on, TLR2, but not TLR4, is required for macrophage responses. Myeloid differentiation factor 88, an adaptor protein directly downstream of TLRs, is required for both early and late responses. TLR4, TLR2, and myeloid differentiation factor 88 are involved in murine host defense against Salmonella in vivo, which correlates with the defects in host defense observed in vitro. We propose a model where the sequential activation of TLRs tailors the immune response to different microbes.
Adenoviral Gene Delivery of Elafin and Secretory Leukocyte Protease Inhibitor Attenuates NF-κB-Dependent Inflammatory Responses of Human Endothelial Cells and Macrophages to Atherogenic Stimuli
Authors: Henriksen Peter A. , Hitt Mary , Xing Zhou , Wang Jun , Haslett Chris , Riemersma Rudolph A. , Webb David J. , Kotelevtsev Yuri V. , Sallenave Jean-Michel
Published: April 2014

Atherosclerosis is a chronic inflammatory disease affecting arterial vessels. Strategies to reduce the inflammatory responses of endothelial cells and macrophages may slow lesion development and prevent complications such as plaque rupture. The human protease human neutrophil elastase (HNE), oxidized low density lipoprotein, LPS, and TNF-α were chosen as model stimuli of arterial wall inflammation and led to production of the chemokine IL-8 in endothelial cells. To counteract the activity of HNE, we have examined the effects of adenoviral gene delivery of the anti-elastases elafin, previously demonstrated within human atheroma, and murine secretory leukocyte protease inhibitor (SLPI), a related molecule, on the inflammatory responses of human endothelial cells and macrophages to atherogenic stimuli. We developed a technique of precomplexing adenovirus with cationic lipid to augment adenoviral infection efficiency in endothelial cells and to facilitate infection in macrophages. Elafin overexpression protected endothelial cells from HNE-induced IL-8 production and cytotoxicity. Elafin and murine SLPI also reduced endothelial IL-8 release in response to oxidized low density lipoprotein, LPS, and TNF-α and macrophage TNF-α production in response to LPS. This effect was associated with reduced activation of the inflammatory transcription factor NF-κB, through up-regulation of IκBα, in both cell types. Our work suggests a novel and extended anti-inflammatory role for these HNE inhibitors working as effectors of innate immunity to protect tissues against maladaptive inflammatory responses. Our findings indicate that elafin and SLPI may be gene therapy targets for the treatment of atheroma.
Terminal Deoxynucleotidyltransferase Deficiency Decreases Autoimmune Disease in Diabetes-Prone Nonobese Diabetic Mice and Lupus-Prone MRL-Fas
lpr Mice
Authors: Robey Ian F. , Peterson Melissa , Horwitz Marc S. , Kono Dwight H. , Stratmann Thomas , Theofilopoulos Argyrios N. , Sarvetnick Nora , Teyton Luc , Feeney Ann J.
Published: April 2014

The wide diversity of the T and B Ag receptor repertoires becomes even more extensive postneonatally due to the activity of TdT, which adds nontemplated N nucleotides to Ig and TCR coding ends during V(D)J recombination. In addition, complementarity-determining region 3 sequences formed in the absence of TdT are more uniform due to the use of short sequence homologies between the V, D, and J genes. Thus, the action of TdT produces an adult repertoire that is both different from, and much larger than, the repertoire of the neonate. We have generated TdT-deficient nonobese diabetic (NOD) and MRL-Faslpr mice, and observed a decrease in the incidence of autoimmune disease, including absence of diabetes and decreased pancreatic infiltration in NOD TdT−/− mice, and reduced glomerulonephritis and increased life span in MRL-Faslpr TdT−/− mice. Using tetramer staining, TdT−/− and TdT+/+ NOD mice showed similar frequencies of the diabetogenic BDC 2.5 CD4+ T cells. We found no increase in CD4+CD25+ regulatory T cells in NOD TdT−/− mice. Thus, TdT deficiency ameliorates the severity of disease in both lupus and diabetes, two very disparate autoimmune diseases that affect different organs, with damage conducted by different effector cell types. The neonatal repertoire appears to be deficient in autoreactive T and/or B cells with high enough affinities to induce end-stage disease. We suggest that the paucity of autoreactive specificities created in the N region-lacking repertoire, and the resultant protection afforded to the newborn, may be the reason that TdT expression is delayed in ontogeny.
Recruitment of STAT3 for Production of IL-10 by Colon Carcinoma Cells Induced by Macrophage-Derived IL-6
Authors: Herbeuval Jean-Philippe , Lelievre Eric , Lambert Claude , Dy Michel , Genin Christian
Published: April 2014

The immunosuppressive cytokine IL-10 is associated with poor prognosis in colon cancer. Although macrophages are involved in antitumor defenses, production of IL-10 by tumor cells may permit malignant cells escape to cell-mediated immune defenses. To investigate interactions between macrophages and tumor cells in humans, we cultured macrophages isolated from patients and tested the effect of these macrophages on the production of IL-10 by several tumor cell lines. Macrophages were isolated from pleural effusions of patients with malignancy and from noncancer control patients. We demonstrated that culture supernatants of macrophages from both sources strongly stimulated IL-10 production by the three different human colon adenocarcinoma cell lines, Colo 205, Colo 320, and HT29. Recombinant IL-6, but not IL-10, TNF-α, and IFN-α, stimulated the secretion of IL-10 by colon tumor cells. mAbs against IL-6 and IL-6R prevented the effect of macrophage culture supernatants and of rIL-6, respectively, on the production of IL-10 by the three cell lines. Cocultures of macrophages and colon cancer cells showed that these tumor cells first stimulated macrophages to produce IL-6, which was then followed by IL-6-induced IL-10 production by colon cancer cells. Finally, we showed that IL-10 gene regulation was mediated by STAT3, which was phosphorylated after the binding of IL-6 to IL-6R. This is the first demonstration that IL-6, secreted by macrophages, can induce a STAT3-mediated IL-10 production by colon tumor cells.
Regulation of T Lymphocyte Metabolism
Authors: Frauwirth Kenneth A. , Thompson Craig B.
Published: April 2014

Upon stimulation, lymphocytes develop from small resting cells into highly proliferative and secretory cells. Although a great deal of study has focused on the genetic program induced by Ag receptor signals, lymphocytes must also regulate their metabolic function to meet the energetic demands of activation. In this review, we discuss the changes in cellular metabolism that accompany lymphocyte activation, with a particular emphasis on glucose metabolism, a major source of both energy and biosynthetic building blocks. We will also cover the signaling pathways that positively and negatively regulate these changes to maintain metabolic homeostasis in cells that are rapidly growing, dividing, and differentiating.
Cutting Edge: Early IL-4 Production Governs the Requirement for IL-27-WSX-1 Signaling in the Development of Protective Th1 Cytokine Responses following Leishmania major Infection
Authors: Artis David , Johnson Leanne M. , Joyce Karen , Saris Christiaan , Villarino Alejandro , Hunter Christopher A. , Scott Phillip
Published: April 2014

There are conflicting reports on the requirements for the IL-27-WSX-1 pathway in the development of Th type 1 responses and resistance to intracellular pathogens; although early IFN-γ production and resistance to Leishmania major are impaired in the absence of WSX-1 signaling, WSX-1−/− mice generate robust IFN-γ responses and control infection with other intracellular protozoan pathogens. In this report, we resolve these conflicting observations and demonstrate that, in the absence of IL-4, WSX-1 is not required for early IFN-γ production and control of L. major. Thus, the requirement for WSX-1 signaling in Th type 1 cell differentiation is restricted to conditions in which IL-4 is produced.
Preferential Activation of an IL-2 Regulatory Sequence Transgene in TCRγδ and NKT Cells: Subset-Specific Differences in IL-2 Regulation
Authors: Yui Mary A. , Sharp Leslie L. , Havran Wendy L. , Rothenberg Ellen V.
Published: April 2014

A transgene with 8.4-kb of regulatory sequence from the murine IL-2 gene drives consistent expression of a green fluorescent protein (GFP) reporter gene in all cell types that normally express IL-2. However, quantitative analysis of this expression shows that different T cell subsets within the same mouse show divergent abilities to express the transgene as compared with endogenous IL-2 genes. TCRγδ cells, as well as αβTCR-NKT cells, exhibit higher in vivo transgene expression levels than TCRαβ cells. This deviates from patterns of normal IL-2 expression and from expression of an IL-2-GFP knock-in. Peripheral TCRγδ cells accumulate GFP RNA faster than endogenous IL-2 RNA upon stimulation, whereas TCRαβ cells express more IL-2 than GFP RNA. In TCRγδ cells, IL-2-producing cells are a subset of the GFP-expressing cells, whereas in TCRαβ cells, endogenous IL-2 is more likely to be expressed without GFP. These results are seen in multiple independent transgenic lines and thus reflect functional properties of the transgene sequences, rather than copy number or integration site effects. The high ratio of GFP: endogenous IL-2 gene expression in transgenic TCRγδ cells may be explained by subset-specific IL-2 gene regulatory elements mapping outside of the 8.4-kb transgene regulatory sequence, as well as accelerated kinetics of endogenous IL-2 RNA degradation in TCRγδ cells. The high levels and percentages of transgene expression in thymic and splenic TCRγδ and NKT cells, as well as skin TCRγδ-dendritic epidermal T cells, indicate that the IL-2-GFP-transgenic mice may provide valuable tracers for detecting developmental and activation events in these lineages.
Requirements for Follicular Exclusion and Competitive Elimination of Autoantigen-Binding B Cells
Authors: Ekland Eric H. , Forster Reinhold , Lipp Martin , Cyster Jason G.
Published: April 2014

Results from several mouse tolerance models indicate that autoreactive B cells in peripheral lymphoid organs develop an anergic phenotype, migrate to the boundary between the T cell zone and the B cell follicle (T/B boundary), and undergo rapid cell death. We have used B cells from mice that are double-transgenic for soluble hen egg lysozyme (HEL) and an Ig that recognizes HEL with a high affinity to characterize the mechanisms underlying the migration and elimination of autoreactive B cells. In contrast to the situation for acutely activated B cells, we find that anergic B cells have reduced levels of CXCR5, the receptor for the follicular chemokine, CXCL13, and this contributes to their exclusion from follicles. CCR7 expression is required for follicular exclusion of anergic cells, although up-regulation of the receptor does not appear to be necessary. By TUNEL analysis, we observe that excluded anergic cells die in situ at the T/B boundary. We also show that this elimination occurs via a Fas-independent mechanism. Using CCR7−/−IgHEL-transgenic B cells we find that localization to the T/B boundary is not a necessary event to achieve the competitive elimination of autoantigen-binding B cells. These findings characterize the mechanism for follicular exclusion of autoantigen-binding B cells and they indicate that B cells compete for survival by mechanisms that are separate from competition for the follicular niche.
Carbon Monoxide Produced by Heme Oxygenase-1 Suppresses T Cell Proliferation via Inhibition of IL-2 Production
Authors: Pae Hyun-Ock , Oh Gi-Su , Choi Byung-Min , Chae Soo-Cheon , Kim Young-Myeong , Chung Khee-Rhin , Chung Hun-Taeg
Published: April 2014

Heme oxygenase-1 (HO-1) catabolizes heme into CO, biliverdin, and free iron and serves as a protective enzyme by virtue of its anti-inflammatory, antiapoptotic, and antiproliferative actions. Previously, we have demonstrated that human CD4+ T cells express HO-1 and that HO-1-overexpressing Jurkat T cells tend to display lower proliferative response. The aim of this study is to elucidate the mechanism(s) by which HO-1 can mediate its antiproliferative effect on CD4+ T cells. Among the three HO-1 byproducts, only CO showed suppressive effect on T cell proliferation in response to anti-CD3 plus anti-CD28 Abs, mimicking the antiproliferative action of HO-1. CO blocked the cell cycle entry of T cells, which was independent of the guanylate cyclase/cGMP pathway. CO also suppressed the secretion of IL-2, and this suppressive effect of CO on IL-2 secretion mediated the antiproliferative action of CO. CO selectively inhibited the extracellular signal-regulated kinase pathway, which could explain the suppressive effects of CO on T cell proliferation and IL-2 secretion. Based on these findings, we suggest that HO-1/CO suppresses T cell proliferation and IL-2 secretion, possibly via its inhibition of extracellular signal-regulated kinase activation.
Regulation of Dendritic Cell Function by NK Cells: Mechanisms Underlying the Synergism in the Combination Therapy of IL-12 and 4-1BB Activation
Authors: Pan Ping-Ying , Gu Peidi , Li Qingsheng , Xu Dongping , Weber Kaare , Chen Shu-Hsia
Published: April 2014

The interactions between NK cells and dendritic cells (DCs) have been previously demonstrated in vitro. In this report, the in vivo cross-regulation between NK cells and DCs was studied in tumor-bearing mice treated with adenoviral vector expressing IL-12 and agonistic anti-4-1BB Abs. NK cells are essential for both tumor rejection and CTL development in the combination therapy (IL-12 plus anti-4-1BB). The numbers and functional activities of both NK cells and DCs in tumor-infiltrating leukocytes were synergistically increased in the IL-12 plus anti-4-1BB-treated mice compared with treatment with either reagent alone. NK depletion in vivo resulted in a significant decrease in the number of DCs in tumor-infiltrating leukocytes, strongly suggesting that NK cells are involved in the activation and expansion of DCs. The mechanism by which IL-12-activated NK cells regulate DC functions is, in part, mediated through the secretion of IFN-γ that leads to the up-regulation of 4-1BB by DCs. Furthermore, 4-1BB activation in conjunction with IL-12 gene delivery increased tumor infiltration of green fluorescence protein-labeled DCs and enhanced their MHC class II expression. The activation of DCs by NK cells and the subsequent development of antitumoral CTL responses facilitated by 4-1BB-activated DCs may account for the synergistic effects observed in the combination therapy in comparison to adenoviral vector expressing IL-12 or anti-4-1BB treatment alone.