bluuebunny/crossref_metadata_2025_split huggingface dataset:
Presentation of αB-Crystallin to T Cells in Active Multiple Sclerosis Lesions: An Early Event Following Inflammatory Demyelination
Authors: Bajramović Jeffrey J. , Plomp Arianne C. , Goes Annette van der , Koevoets Cindy , Newcombe Jia , Cuzner M. Louise , van Noort Johannes M. 
Published: April 2014

Abstract
In the development of multiple sclerosis (MS), (re)activation of infiltrating T cells by myelin-derived Ags is considered to be a crucial step. Previously, αB-crystallin has been shown to be an important myelin Ag to human T cells. Since αB-crystallin is an intracellular heat shock protein, the question arises at what stage, if any, during lesional development in MS this Ag becomes available for CD4+ T cells. In 3 of 10 active MS lesions, αB-crystallin could be detected inside phagocytic vesicles of perivascular macrophages, colocalizing with myelin basic protein and myelin oligodendrocyte glycoprotein (MOG). Although the detectability of MOG in phagosomes is considered as a marker for very recent demyelination, MOG was detected in more macrophages and in more lesions than αB-crystallin. The disappearance of αB-crystallin from macrophages even before MOG was confirmed by in vitro studies; within 6 h after myelin-uptake αB-crystallin disappears from the phagosomes. αB-Crystallin-containing macrophages colocalized with infiltrating T cells and they were characterized by expression of MHC class II, CD40, and CD80. To examine functional presentation of myelin Ags to T cells, purified macrophages were pulsed in vitro with whole myelin membranes. These macrophages activated both myelin-primed and αB-crystallin-primed T cells in terms of proliferation and IFN-γ secretion. In addition, αB-crystallin-pulsed macrophages activated myelin-primed T cells to the same extent as myelin-pulsed macrophages, whereas myelin basic protein-pulsed macrophages triggered no response at all. These data indicate that, in active MS lesions, αB-crystallin is available for functional presentation to T cells early during inflammatory demyelination.
CD30+ T Cells in Rheumatoid Synovitis: Mechanisms of Recruitment and Functional Role
Authors: Gerli Roberto , Pitzalis Costantino , Bistoni Onelia , Falini Brunangelo , Costantini Vincenzo , Russano Anna , Lunardi Claudio 
Published: April 2014

AbstractHigh serum levels of soluble CD30 (sCD30) have been reported to better predict the response to second line therapy in rheumatoid arthritis (RA). It is believed that sCD30 is released by CD30+ T cells present in the RA synovium. However, both the mechanism of recruitment to the joint and the functional role of this T cell subset in the pathogenesis of the disease remain unknown. This study confirmed higher levels of sCD30 in the serum and synovial fluid (SF) of RA patients compared with normal controls. However, analysis of mRNA and cell surface CD30 expression showed that CD30+ T cells are detectable in the SF, but not in the synovial membrane. In contrast, T cells expressing the CD30 transcript, but not the surface molecule, were found in the peripheral blood of both RA and normal controls. CD30 surface expression was up-regulated by adhesion and migration through endothelium in vitro and in a delayed-type hypersensitivity model in vivo. Although the great majority of fresh or cloned CD30+ T cells from SF produced both IFN-γ and IL-4, CD30 expression strictly correlated with IL-4 synthesis in synovial T cell clones. In addition, CD30+ T cell clones also produced high amounts of the anti-inflammatory cytokine IL-10. On this basis, we would like to propose that synovial CD30+ cells may play a role in the control of the inflammatory response. Serum sCD30 may reflect such cell activity and, therefore, explain the previously demonstrated correlation between high sCD30 serum levels and positive response to therapy.
Blockade of T Cell Activation Using a Surface-Linked Single-Chain Antibody to CTLA-4 (CD152)
Authors: Griffin Matthew D. , Hong David K. , Holman Philmore O. , Lee Kyung-Mi , Whitters Matthew J. , O’Herrin Sean M. , Fallarino Francesca , Collins Mary , Segal David M. , Gajewski Thomas F. , Kranz David M. , Bluestone Jeffrey A. 
Published: April 2014

AbstractCTLA-4 (CD152) engagement can down-regulate T cell activation and promote the induction of immune tolerance. However, the strategy of attenuating T cell activation by engaging CTLA-4 has been limited by sharing of its natural ligands with the costimulatory protein CD28. In the present study, a CTLA-4-specific single-chain Ab (scFv) was developed and expressed on the cell surface to promote selective engagement of this regulatory molecule. Transfectants expressing anti-CTLA-4 scFv at their surface bound soluble CTLA-4 but not soluble CD28. Coexpression of anti-CTLA-4 scFv with anti-CD3ε and anti-CD28 scFvs on artificial APCs reduced the proliferation and IL-2 production by resting and preactivated bulk T cells as well as CD4+ and CD8+ T cell subsets. Importantly, expression of anti-CTLA-4 scFv on the same cell surface as the TCR ligand was essential for the inhibitory effects of CTLA-4-specific ligation. CTLA-4-mediated inhibition of tyrosine phosphorylation of components of the proximal TCR signaling apparatus was similarly dependent on coexpression of TCR and CTLA-4 ligands on the same surface. These findings support a predominant role for CTLA-4 function in the modification of the proximal TCR signal. Using T cells from DO11.10 and 2C TCR transgenic mice, negative regulatory effects of selective CTLA-4 ligation were also demonstrated during the stimulation of Ag-specific CD4+ and CD8+ T cells by MHC/peptide complexes. Together these studies demonstrate that selective ligation of CTLA-4 using a membrane-bound scFv results in attenuated T cell responses only when coengaged with the TCR during T cell/APC interaction and define an approach to harnessing the immunomodulatory potential of CTLA-4-specific ligation.
Vitamin D3 Affects Differentiation, Maturation, and Function of Human Monocyte-Derived Dendritic Cells
Authors: Piemonti Lorenzo , Monti Paolo , Sironi Marina , Fraticelli Paolo , Leone Biagio Eugenio , Dal Cin Elena , Allavena Paola , Di Carlo Valerio 
Published: April 2014

AbstractWe studied the effects of 1α,25-dihydroxyvitamin D3 (1α,25-(OH)2D3) on differentiation, maturation, and functions of dendritic cells (DC) differentiated from human monocytes in vitro in the presence of GM-CSF and IL-4 for 7 days. Recovery and morphology were not affected by 1α,25-(OH)2D3 up to 100 nM. DC differentiated in the presence of 10 nM 1α,25-(OH)2D3 (D3-DC) showed a marked decrease in the expression of CD1a, while CD14 remained elevated. Mannose receptor and CD32 were significantly increased, and this correlated with an enhancement of endocytic activity. Costimulatory molecules such as CD40 and CD86 were slightly decreased or nonsignificantly affected (CD80 and MHC II). However, after induction of DC maturation with LPS or incubation with CD40 ligand-transfected cells, D3-DC showed marginal increases in MHC I, MHC II, CD80, CD86, CD40, and CD83. The accessory cell function of D3-DC in classical MLR was also inhibited. Moreover, allogeneic T cells stimulated with D3-DC were poor responders in a second MLR to untreated DC from the same or an unrelated donor, thus indicating the onset of a nonspecific hyporesponsivity. In conclusion, our data suggest that 1α,25-(OH)2D3 may modulate the immune system, acting at the very first step of the immune response through the inhibition of DC differentiation and maturation into potent APC.
Analysis of Human Vα24+ CD4+ NKT Cells Activated by α-Glycosylceramide-Pulsed Monocyte-Derived Dendritic Cells
Authors: Takahashi Tsuyoshi , Nieda Mie , Koezuka Yasuhiko , Nicol Andrew , Porcelli Steven A. , Ishikawa Yoshihide , Tadokoro Kenji , Hirai Hisamaru , Juji Takeo 
Published: April 2014

AbstractHuman Vα24+ NKT cells with an invariant TCR (Vα24-JαQ) have been shown to be specifically activated by synthetic glycolipids such as α-galactosylceramide and α-glucosylceramide in a CD1d-restricted and Vα24 TCR-mediated manner. We recently characterized Vα24+ CD4− CD8− double negative (DN) NKT cells using α-galactosylceramide-pulsed monocyte-derived dendritic cells. Here, we compare Vα24+ CD4+ NKT cells with human Vα24+ DN NKT cells from the same donor using α-galactosylceramide-pulsed monocyte-derived dendritic cells. Human Vα24+ CD4+ NKT cells were phenotypically and functionally similar to the human Vα24+ DN NKT cells characterized previously. Both of them use Vα24-JαQ-Vβ11 TCR and express CD161 (NKR-P1A), but not the other NK receptors tested so far. They also produce cytokines such as IL-4 and IFN-γ, and, in regard to IL-4 production, Vα24+ CD4+ NKT cells produce more IL-4 than Vα24+ DN NKT cells. The cells exhibit marked cytotoxic activity against the U937 tumor cell line, but not against the NK target cell line, K562. Although at least some of the factors responsible for the stimulation of Vα24+ NKT cells have been clarified, little is known regarding the killing phase of these cells. Here we show that the cytotoxic activity of Vα24+ NKT cells against U937 cells is mediated mainly through the perforin pathway and that ICAM-1/LFA-1 as well as CD44/hyaluronic acid interactions are important for the effector phase of Vα24+ NKT cell-mediated cytotoxicity against U937 cells.
The Roles of CD28 and CD40 Ligand in T Cell Activation and Tolerance
Authors: Howland Kimberly C. , Ausubel Lara J. , London Cheryl A. , Abbas Abul K. 
Published: April 2014

AbstractCostimulation of T cell activation involves both the B7:CD28 as well as the CD40 ligand (CD40L):CD40 pathway. To determine the importance of these pathways to in vitro and in vivo T cell activation, a direct comparison was made of the responses of TCR transgenic T cells lacking either CD28 or CD40L. In vitro, CD28−/− T cells showed a greater reduction in proliferative responses to Ag than did CD40L−/− T cells. The absence of CD28 resulted in defective Th2 responses, whereas CD40L−/− T cells were defective in Th1 development. In vivo, CD28−/− T cells failed to expand upon immunization, whereas CD40L−/− T cells could not sustain a response. These results suggest that CD28 is critical for initiating T cell responses, whereas CD40L is required for sustained Th1 responses. The different functional roles of these costimulatory pathways may explain why blocking B7:CD28 and CD40L:CD40 interactions has an additive effect in inhibiting T cell responses.
The Regulation of CD95 (Fas) Ligand Expression in Primary T Cells: Induction of Promoter Activation in CD95LP-Luc Transgenic Mice
Authors: Norian Lyse A. , Latinis Kevin M. , Eliason Steve L. , Lyson Krzysztof , Yang Chunmei , Ratliff Timothy , Koretzky Gary A. 
Published: April 2014

AbstractThe interaction between CD95 (Fas) and CD95L (Fas ligand) initiates apoptosis in a variety of cell types. Although the regulation of CD95L expression on activated T cells is an area of intense study, knowledge related to the induction of CD95L promoter activity in primary T cells is lacking. In this report we describe the generation of a novel transgenic mouse strain, CD95LP-Luc, in which murine CD95L promoter sequence controls the expression of a luciferase reporter gene. We use these mice to illustrate several important findings related to transcriptional regulation of CD95L in primary T cells. We demonstrate that maximal CD95L promoter activity occurs only after prolonged T cell stimulation and requires costimulation through CD28. We provide evidence that thymocytes express CD95L/luciferase after strong TCR ligation and that inducible CD95L promoter activation is present, but unequal, in both Th1 and Th2 effector cells. We also illustrate that while agonist peptide presentation by APCs generates robust proliferation during a primary T cell response, the same stimulus induces only modest CD95L promoter activity. These results suggest alternate explanations for the well-characterized delay in CD95-mediated activation-induced cell death following initial ligation of the TCR.
Astrocyte-Targeted Expression of IL-12 Induces Active Cellular Immune Responses in the Central Nervous System and Modulates Experimental Allergic Encephalomyelitis
Authors: Pagenstecher Axel , Lassmann Silke , Carson Monica J. , Kincaid Carrie L. , Stalder Anna K. , Campbell Iain L. 
Published: April 2014

AbstractThe role of IL-12 in the evolution of immunoinflammatory responses at a localized tissue level was investigated. Transgenic mice were developed with expression of either both the IL-12 subunits (p35 and p40) or only the IL-12 p40 subunit genes targeted to astrocytes in the mouse CNS. Glial fibrillary acidic protein (GF)-IL-12 mice, bigenic for the p35 and p40 genes, developed neurologic disease which correlated with the levels and sites of transgene-encoded IL-12 expression. In these mice, the brain contained numerous perivascular and parenchymal inflammatory lesions consisting of predominantly CD4+ and CD8+ T cells as well as NK cells. The majority of the infiltrating T cells had an activated phenotype (CD44high, CD45Rblow, CD62Llow, CD69high, VLA-4 high, and CD25+). Functional activation of the cellular immune response was also evident with marked cerebral expression of the IFN-γ, TNF, and IL-1αβ genes. Concomitant with leukocyte infiltration, the CNS expression of immune accessory molecules was induced or up-regulated, including ICAM-1, VCAM-1, and MHC class II and B7-2. Glial fibrillary acidic protein-p40 mice with expression of IL-12 p40 alone remained asymptomatic, with no inflammation evident at any age studied. The effect of local CNS production of IL-12 in the development of experimental autoimmune encephalomyelitis was studied. After immunization with myelin oligodendrocyte glycoprotein-peptides, GF-IL-12 mice had an earlier onset and higher incidence but not more severe disease. We conclude that localized expression of IL-12 by astrocytes can 1) promote the spontaneous development of activated type 1 T cell and NK cellular immunity and cytokine responses in the CNS, and 2) promote more effective Ag-specific T cell dynamics but not activity in experimental autoimmune encephalomyelitis.
Delayed and Separate Costimulation In Vitro Supports the Evidence of a Transient “Excited” State of CD8+ T Cells During Activation
Authors: Pardigon Nathalie , Cambouris Christophe , Bercovici Nadège , Lemaı̂tre Fabrice , Liblau Roland , Kourilsky Philippe 
Published: April 2014

AbstractAlthough the two-signal model for T cell activation states that a signal-1 through the TCR and a costimulatory signal-2 are required for optimal stimulation, it is now clear that the requirement for costimulation can be bypassed under certain conditions. We previously reported that this is the case for naive CD8+ T cells in vitro. In the present study we tested the effect of signal-2 when delivered after signal-1 has been disrupted. Naive CD8+ T cells from TCR transgenic mice were stimulated in vitro by using immobilized recombinant single-chain MHC molecules alone as signal-1. This signal was then stopped after different lengths of time, and anti-CD28 mAb as signal-2 was given either immediately or after a time lag. We found that signal-2 can potentiate a short signal-1 when added sequentially. Moreover, a time lag between the two signals does not abolish this potentiation. If the strength of signal-1, but not its duration, is increased, then the time lag between the delivery of signals 1 and 2 can be lengthen without loss of potentiation. Together, our results indicate that the two signals do not need to be delivered concomitantly to get optimal T cell activation. We suggest that the CD8+ T cells can reach a transient “excited” state after being stimulated with signal-1 alone, characterized by the cell’s ability to respond to separate and delayed signal-2.
MHC Class I Antigen Processing of an Adenovirus CTL Epitope Is Linked to the Levels of Immunoproteasomes in Infected Cells
Authors: Sijts Alice J. A. M. , Standera Sybille , Toes René E. M. , Ruppert Thomas , Beekman Nico J. C. M. , van Veelen Peter A. , Ossendorp Ferry A. , Melief Cornelis J. M. , Kloetzel Peter M. 
Published: April 2014

AbstractProteasomes are the major source for the generation of peptides bound by MHC class I molecules. To study the functional relevance of the IFN-γ-inducible proteasome subunits low molecular mass protein 2 (LMP2), LMP7, and mouse embryonal cell (MEC) ligand 1 in Ag processing and concomitantly that of immunoproteasomes, we established the tetracycline-regulated mouse cell line MEC217, allowing the titrable formation of immunoproteasomes. Infection of MEC217 cells with Adenovirus type 5 (Ad5) and analysis of Ag presentation with Ad5-specific CTL showed that cells containing immunoproteasomes processed the viral early 1B protein (E1B)-derived epitope E1B192–200 with increased efficiency, thus allowing a faster detection of viral entry in induced cells. Importantly, optimal CTL activation was already achieved at submaximal immunosubunit expression. In contrast, digestion of E1B-polypeptide with purified proteasomes in vitro yielded E1B192–200 at quantities that were proportional to the relative contents of immunosubunits. Our data provide evidence that the IFN-γ-inducible proteasome subunits, when present at relatively low levels as at initial stages of infection, already increase the efficiency of antigenic peptide generation and thereby enhance MHC class I Ag processing in infected cells.
Development of Th1-Inducing Capacity in Myeloid Dendritic Cells Requires Environmental Instruction
Authors: Vieira Pedro L. , de Jong Esther C. , Wierenga Eddy A. , Kapsenberg Martien L. , Kaliński Paweł 
Published: April 2014

AbstractDendritic cells (DC) are key initiators of primary immune responses. Myeloid DC can secrete IL-12, a potent Th1-driving factor, and are often viewed as Th1-promoting APC. Here we show that neither a Th1- nor a Th2-inducing function is an intrinsic attribute of human myeloid DC, but both depend on environmental instruction. Uncommitted immature DC require exposure to IFN-γ, at the moment of induction of their maturation or shortly thereafter, to develop the capacity to produce high levels of IL-12p70 upon subsequent contact with naive Th cells. This effect is specific for IFN-γ and is not shared by other IL-12-inducing factors. Type 1-polarized effector DC, matured in the presence of IFN-γ, induce Th1 responses, in contrast to type 2-polarized DC matured in the presence of PGE2 that induce Th2 responses. Type 1-polarized effector DC are resistant to further modulation, which may facilitate their potential use in immunotherapy.
Evidence of Selective Processing of Immunodominant Epitopes in Virally Infected Cells
Authors: Zhang Qian-Jin , Chen Susan S. , Saari Carol-Ann , Massuci Maria G. , Tufaro Frank , Jefferies Wilfred A. 
Published: April 2014

AbstractRecent advances in clarifying the molecular mechanisms involved in Ag processing and presentation have relied heavily on the use of somatic cell mutants deficient in proteasome subunits, TAP transporter, and cell surface expression of MHC class I molecules. Of particular interest currently are those mutants that lack specific protease activity involved in the generation of antigenic peptides. It is theoretically possible that deficiencies of this nature could selectively prevent the cleavage of certain peptide bonds and thus generate only a subset of antigenic peptides. Gro29/Kb cell line is derived from the wild-type murine Ltk− cell line. This cell line is one example of a mutant that lacks specific protease activities. This deficiency manifests itself in an inability to generate a subset of immunodominant peptide epitopes derived from vesicular stomatitis virus and herpes simplex virus. This in turn leads to a general inability to present these viral epitopes to cytotoxic T lymphocytes (CTL). These studies describe a unique Ag processing deficiency and provide new insight into the role of proteasome-independent proteases in MHC class I-restricted peptide generation.
In Vivo Behavior of Peptide-Specific T Cells During Mucosal Tolerance Induction: Antigen Introduced Through the Mucosa of the Conjunctiva Elicits Prolonged Antigen-Specific T Cell Priming Followed by Anergy
Authors: Egan Rita M. , Yorkey Chris , Black Richard , Loh Wai Khan , Stevens Julia L. , Storozynsky Eugene , Lord Edith M. , Frelinger John G. , Woodward Jerold G. 
Published: April 2014

AbstractThe mucosa of the conjunctiva is an important site of entry for environmental Ags as well as Ags emanating from the eye itself. However, very little is known about T cell recognition of Ag introduced through this important mucosal site. We have characterized the in vivo process of CD4 T cell recognition of Ag delivered via the conjunctival mucosa. Application of soluble OVA to the conjunctiva of BALB/c mice induced potent T cell tolerance. APC-presenting OVA peptide in vivo was only found in the submandibular lymph node and not in other lymph nodes, spleen, or nasal-associated lymphoid tissue. Similarly, in TCR transgenic DO11.10 adoptive transfer mice, OVA-specific CD4+ T cell clonal expansion was only observed in the submandibular lymph node following conjunctival application of peptide. These experiments thus define a highly specific lymphatic drainage pathway from the conjunctiva. OVA-specific T cell clonal expansion peaked at day 3 following initiation of daily OVA administration and gradually declined during the 10-day treatment period, but remained elevated compared with nontreated adoptive transfer mice. During this period, the T cells expressed activation markers, and proliferated and secreted IL-2 in vitro in response to OVA stimulation. In contrast, these cells were unable to clonally expand in vivo, or proliferate in vitro following a subsequent OVA/CFA immunization. These results suggest that Ag applied to a mucosal site can be efficiently presented in a local draining lymph node, resulting in initial T cell priming and clonal expansion, followed by T cell anergy.
CD28-Specific Antibody Prevents Graft-Versus-Host Disease in Mice
Authors: Yu Xue-Zhong , Bidwell Sasha J. , Martin Paul J. , Anasetti Claudio 
Published: April 2014

AbstractThe costimulatory molecules B7-1 and B7-2 regulate T cell activation by delivering activation signals through CD28 and inhibitory signals through CTLA4. Graft-vs-host disease (GVHD) is caused by activated donor T cells. Previously, we showed that CD28-deficient donor T cells induced less-severe GVHD than wild-type donor T cells, suggesting that CD28 signals exacerbate GVHD. In this paper we demonstrate that CTLA4 signals attenuate the severity of GVHD. Targeting the CD28 receptor with a specific mAb modulates the receptor in vivo, inhibits donor T cell expansion, and prevents GVHD. CTLA4 signaling was necessary for this effect because treatment with a soluble ligand that blocks binding of B7 to both CD28 and CTLA4 did not prevent GVHD as effectively as anti-CD28 mAb. These results support the current model of T cell costimulation in which CD28 signals amplify GVHD while CTLA4 signals inhibit GVHD, providing evidence that selective targeting of CD28 might be a better therapeutic strategy for inducing immunological tolerance than blocking the ligands for both CD28 and CTLA4.