bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soluble MHC-Peptide Complexes Induce Rapid Death of CD8+ CTL
Authors: Cebecauer Marek , Guillaume Philippe , Hozák Pavel , Mark Silke , Everett Helen , Schneider Pascal , Luescher Immanuel F. 
Published: April 2014

Abstract
Soluble MHC-peptide (pMHC) complexes, commonly referred to as tetramers, are widely used to enumerate and to isolate Ag-specific CD8+ CTL. It has been noted that such complexes, as well as microsphere- or cell-associated pMHC molecules compromise the functional integrity of CTL, e.g., by inducing apoptosis of CTL, which limits their usefulness for T cell sorting or cloning. By testing well-defined soluble pMHC complexes containing linkers of different length and valence, we find that complexes comprising short linkers (i.e., short pMHC-pMHC distances), but not those containing long linkers, induce rapid death of CTL. This cell death relies on CTL activation, the coreceptor CD8 and cytoskeleton integrity, but is not dependent on death receptors (i.e., Fas, TNFR1, and TRAILR2) or caspases. Within minutes of CTL exposure to pMHC complexes, reactive oxygen species emerged and mitochondrial membrane depolarized, which is reminiscent of caspase-independent T cell death. The morphological changes induced during this rapid CTL death are characteristic of programmed necrosis and not apoptosis. Thus, soluble pMHC complexes containing long linkers are recommended to prevent T cell death, whereas those containing short linkers can be used to eliminate Ag-specific CTL.
The Role of Protein Kinase A Anchoring via the RIIα Regulatory Subunit in the Murine Immune System
Authors: Schillace Robynn V. , Andrews Sarah F. , Galligan Sarah G. , Burton Kimberly A. , Starks Holly J. , Bouwer H. G. Archie , McKnight G. Stanley , Davey Michael P. , Carr Daniel W. 
Published: April 2014

Abstract
Intracellular cAMP may inhibit T cell activation and proliferation via activation of the cAMP-dependent protein kinase, PKA. PKA signaling is maintained through interactions of the regulatory subunit with A-kinase anchoring proteins (AKAPs). We demonstrated that T cells contain AKAPs and now ask whether PKA anchoring to AKAPs via the RIIα regulatory subunit is necessary for cAMP-mediated inhibition of T cell activation. We studied the immune systems of mice lacking the RIIα regulatory subunit of PKA (−/−) and the ability of cells isolated from these mice to respond to cAMP. Dissection of spleen and thymus from wild-type (WT) and −/− mice, single cell suspensions generated from these organs, and flow cytometry analysis illustrate that the gross morphology, cell numbers, and cell populations in the spleen and thymus of the −/− mice are similar to WT controls. In vitro, splenocytes from −/− mice respond to anti-CD3/anti-CD28 and PMA/ionomycin stimulation and produce IL-2 similar to WT. Cytokine analysis revealed no significant difference in Th1 or Th2 differentiation. Finally, equivalent frequencies of CD8+ IFN-γ producing effector cells were stimulated upon infection of WT or −/− mice with Listeria monocytogenes. These data represent the first study of the role of RIIα in the immune system in vivo and provide evidence that T cell development, homeostasis, and the generation of a cell-mediated immune response are not altered in the RIIα −/− mice, suggesting either that RIIα is not required for normal immune function or that other proteins are able to compensate for RIIα function.
Sequential Immune Escape and Shifting of T Cell Responses in a Long-Term Survivor of Melanoma
Authors: Yamshchikov Galina V. , Mullins David W. , Chang Chien-Chung , Ogino Takeshi , Thompson Lee , Presley Jennifer , Galavotti Holly , Aquila William , Deacon Donna , Ross William , Patterson James W. , Engelhard Victor H. , Ferrone Soldano , Slingluff Craig L. 
Published: April 2014

Abstract
Immune-mediated control of tumors may occur, in part, through lysis of malignant cells by CD8+ T cells that recognize specific Ag-HLA class I complexes. However, tumor cell populations may escape T cell responses by immune editing, by preventing formation of those Ag-HLA complexes. It remains unclear whether the human immune system can respond to immune editing and recognize newly arising escape variants. We report an example of shifting immune responses to escape variants in a patient with sequential metastases of melanoma and long-term survival after surgery alone. Tumor cells in the first metastasis escaped immune recognition via selective loss of an HLA haplotype (HLA-A11, -B44, and -Cw17), but maintained expression of HLA-A2. In the second metastasis, immune escape from an immunodominant MART-1-specific T cell response was mediated by HLA class I down-regulation, resulting in a failure to present this epitope, but persistent presentation of a tyrosinase-derived epitope. Consequent to this modification in tumor Ag presentation, the dominant CTL response shifted principally toward a tyrosinase-targeted response, even though tyrosinase-specific CTL had been undetectable during the initial metastatic event. Thus, in response to immune editing of tumor cells, a patient’s spontaneous T cell response adapted, gaining the ability to recognize and to lyse “edited” tumor targets. The observation of both immune editing and immune adaptation in a patient with long-term survival after surgery alone demonstrates an example of immune system reactivity to counteract the escape mechanism(s) developed by tumor cells, which may contribute to the clinical outcome of malignant disease.
CD8+ T Cell Dynamics during Primary Simian Immunodeficiency Virus Infection in Macaques: Relationship of Effector Cell Differentiation with the Extent of Viral Replication
Authors: Monceaux Valérie , Viollet Laurence , Petit Frédéric , Fang Raphaël Ho Tsong , Cumont Marie-Christine , Zaunders John , Hurtrel Bruno , Estaquier Jérôme 
Published: April 2014

Abstract
Immunological and virological events that occur during the earliest stages of HIV-1 infection are now considered to have a major impact on subsequent disease progression. We observed changes in the frequencies of CD8bright T cells expressing different chemokine receptors in the peripheral blood and lymph nodes of rhesus macaques during the acute phase of the pathogenic SIVmac251 infection; the frequency of CD8bright T cells expressing CXCR4 decreased, while the frequency of those expressing CCR5 increased. These reciprocal changes in chemokine receptor expression were associated with changes in the proportion of cycling (Ki67+) CD8bright T cells, and with the pattern of CD8bright T cell differentiation as defined by expression of CCR7 and CD45RA. In contrast, during the primary phase of the attenuated SIVmac251Δnef infection, no major change was observed. Whereas during the acute phase of the infection with pathogenic SIV (2 wk postinfection) no correlate of disease protection was identified, once the viral load set points were established (2 mo postinfection), we found that the levels of cycling and of CCR5- and CXCR4-positive CD8bright T cells were correlated with the extent of viral replication and therefore with SIV-infection outcome. Our data reveal that, during primary SIV infection, despite intense CD8 T cell activation and an increase in CCR5 expression, which are considered as essential for optimal effector function of CD8+ T cells, these changes are associated with a poor prognosis for disease progression to AIDS.
Association of B-1 B Cells with Follicular Dendritic Cells in Spleen
Authors: Wen Lijun , Shinton Susan A. , Hardy Richard R. , Hayakawa Kyoko 
Published: April 2014

Abstract
Although CD5+ B-1 B cells have been recognized as an infrequent B cell subset in mice for many years, attempts to identify their histologic location in normal mouse spleen have proven difficult due to both their paucity and low level expression of CD5. In this study we have studied VH11/DH/JH gene-targeted mice, VH11t, that develop elevated numbers of CD5+ VH11/Vk9 B cells with an anti-phosphatidylcholine (anti-PtC) autoreactive specificity, allowing B-1 B cell detection by anti-PtC Id-specific Abs in spleen section staining. Using this approach we found that anti-PtC B-1 cells first appear within the white pulp in neonates, expand in association with follicular dendritic cells (FDC), and localize more centrally than other (non-B-1) IgDhigh follicular B cells in adults. Among neonatal B cells, CD5+ B-1 cells in both normal and VH11t mouse spleen and peritoneal cavity express the highest levels of CXCR5, which is important for FDC development. Injection of purified spleen or peritoneal B-1 cells into RAG knockout mice resulted in B-1 cell follicle formation in spleen, inducing FDC development and plasma cell generation. These results indicate that B-1 B cells are the first B cells to express fully mature levels of CXCR5, thereby promoting the development of FDC.
Cross-Desensitization among CXCR1, CXCR2, and CCR5: Role of Protein Kinase C-ε
Authors: Nasser Mohd W. , Marjoram Robin J. , Brown Stephan L. , Richardson Ricardo M. 
Published: April 2014

Abstract
The IL-8 (or CXCL8) chemokine receptors, CXCR1 and CXCR2, activate protein kinase C (PKC) to mediate leukocyte functions. To investigate the roles of different PKC isoforms in CXCL8 receptor activation and regulation, human mononuclear phagocytes were treated with CXCL8 or CXCL1 (melanoma growth-stimulating activity), which is specific for CXCR2. Plasma membrane association was used as a measure of PKC activation. Both receptors induced time-dependent association of PKCα, -β1, and -β2 to the membrane, but only CXCR1 activated PKCε. CXCL8 also failed to activate PKCε in RBL-2H3 cells stably expressing CXCR2. ΔCXCR2, a cytoplasmic tail deletion mutant of CXCR2 that is resistant to internalization, activated PKCε as well as CXCR1. Expression of the PKCε inhibitor peptide εV1 in RBL-2H3 cells blocked PKCε translocation and inhibited receptor-mediated exocytosis, but not phosphoinositide hydrolysis or peak intracellular Ca2+ mobilization. εV1 also inhibited CXCR1-, CCR5-, and ΔCXCR2-mediated cross-regulatory signals for GTPase activity, Ca2+ mobilization, and internalization. Peritoneal macrophages from PKCε-deficient mice (PKCε−/−) also showed decreased CCR5-mediated cross-desensitization of G protein activation and Ca2+ mobilization. Taken together, the results indicate that CXCR1 and CCR5 activate PKCε to mediate cross-inhibitory signals. Inhibition or deletion of PKCε decreases receptor-induced exocytosis and cross-regulatory signals, but not phosphoinositide hydrolysis or peak intracellular Ca2+ mobilization, suggesting that cross-regulation is a Ca2+-independent process. Because ΔCXCR2, but not CXCR2, activates PKCε and cross-desensitizes CCR5, the data further suggest that signal duration leading to activation of novel PKC may modulate receptor-mediated cross-inhibitory signals.
The Antiapoptotic Protein Bcl-xL Is Dispensable for the Development of Effector and Memory T Lymphocytes
Authors: Zhang Nu , He You-Wen 
Published: April 2014

Abstract
The antiapoptotic protein Bcl-xL is induced in activated T lymphocytes upon costimulation through CD28, 4-1BB, and OX40. Bcl-xL is also highly enriched in memory T lymphocytes. Based on this body of evidence, it was thought that Bcl-xL plays an essential role in the generation of effector and memory T lymphocytes. We report that mice with a conditional deletion of Bcl-x in T lymphocytes develop a normal CD8+ T cell response to Listeria monocytogenes infection. Furthermore, Bcl-x conditional knockout mice exhibit normal T-dependent humoral immune responses. These results indicate that Bcl-x is dispensable for the generation of effector and memory T lymphocytes and suggest that costimulation of T lymphocytes promotes their survival through a Bcl-xL independent mechanism.
C5a-Mediated Leukotriene B4-Amplified Neutrophil Chemotaxis Is Essential in Tumor Immunotherapy Facilitated by Anti-Tumor Monoclonal Antibody and β-Glucan
Authors: Allendorf Daniel J. , Yan Jun , Ross Gordon D. , Hansen Richard D. , Baran Jarek T. , Subbarao Krishnaprasad , Wang Li , Haribabu Bodduluri 
Published: April 2014

AbstractIntravenous and orally administered β-glucans promote tumor regression and survival by priming granulocyte and macrophage C receptor 3 (CR3, iC3bR and CD11b/CD18) to trigger the cytotoxicity of tumor cells opsonized with iC3b via anti-tumor Abs. Despite evidence for priming of macrophage CR3 by oral β-glucan in vivo, the current study in C57BL/6 and BALB/c mice showed that granulocytes were the essential killer cells in mAb- and oral β-glucan-mediated tumor regression, because responses were absent in granulocyte-depleted mice. Among granulocytes, neutrophils were the major effector cells, because tumor regression did not occur when C5a-dependent chemotaxis was blocked with a C5aR antagonist, whereas tumor regression was normal in C3aR−/− mice. Neutrophil recruitment by C5a in vivo required amplification via leukotriene B4, because both C5a-mediated leukocyte recruitment into the peritoneal cavity and tumor regression were suppressed in leukotriene B4R-deficient (BLT-1−/−) mice.
Reduction of Spontaneous Metastases through Induction of Carbohydrate Cross-Reactive Apoptotic Antibodies
Authors: Monzavi-Karbassi Behjatolah , Artaud Cecile , Jousheghany Fariba , Hennings Leah , Carcel-Trullols Jaime , Shaaf Saeid , Korourian Soheila , Kieber-Emmons Thomas 
Published: April 2014

Abstract
The selective targeting of tumor-associated carbohydrate Ags by the induction of serum Abs that trigger apoptosis of tumor cells as a means to reduce circulating tumor cells and micrometastases would be an advantage in cancer vaccine development. Some plant lectins like Griffonia simplicifolia lectin I and wheat germ agglutinin mediate the apoptosis of tumor cells. We investigated the possibility of using these lectins as templates to select peptide mimotopes of tumor-associated carbohydrate Ags as immunogens to generate cross-reactive Abs capable of mediating apoptosis of tumor cells. In this study, we show that immunization with a mimotope selected based on its reactivity with Griffonia simplicifolia lectin I and wheat germ agglutinin induced serum IgM Abs in mice that mediated the apoptosis of murine 4T1 and human MCF7 cell lines in vitro, paralleling the apoptotic activity of the lectins. Vaccine-induced anti-carbohydrate Abs reduced the outgrowth of micrometastases in the 4T1 spontaneous tumor model, significantly increasing survival time of tumor-bearing animals. This finding parallels suggestions that carbohydrate-reactive IgM with apoptotic activity may have merit in the adjuvant setting if the right carbohydrate-associated targets are identified.
In Silico Identification of Supertypes for Class II MHCs
Authors: Doytchinova Irini A. , Flower Darren R. 
Published: April 2014

Abstract
The development of epitope-based vaccines, which have wide population coverage, is greatly complicated by MHC polymorphism. The grouping of alleles into supertypes, on the basis of common structural and functional features, addresses this problem directly. In the present study we applied a combined bioinformatics approach, based on analysis of both protein sequence and structure, to identify similarities in the peptide binding sites of 2225 human class II MHC molecules, and thus define supertypes and supertype fingerprints. Two chemometric techniques were used: hierarchical clustering using three-dimensional Comparative Similarity Indices Analysis fields and nonhierarchical k-means clustering using sequence-based z-descriptors. An average consensus of 84% was achieved, i.e., 1872 of 2225 class II molecules were classified in the same supertype by both techniques. Twelve class II supertypes were defined: five DRs, three DQs, and four DPs. The HLA class II supertypes and their fingerprints given in parenthesis are DR1 (Trp9β), DR3 (Glu9β, Gln70β, and Gln/Arg74β), DR4 (Glu9β, Gln/Arg70β, and Glu/Ala74β), DR5 (Glu9β, Asp70β), and DR9 (Lys/Gln9β); DQ1 (Ala/Gly86β), DQ2 (Glu86β, Lys71β), and DQ3 (Glu86β, Thr/Asp71β); DPw1 (Asp84β and Lys69β), DPw2 (Gly/Val84β and Glu69β), DPw4 (Gly/Val84β and Lys69β), and DPw6 (Asp84β and Glu69β). Apart from the good agreement between known binding motifs and our classification, several new supertypes, and corresponding thematic binding motifs, were also defined.
Influence of Maternal-Fetal Histocompatibility and MHC Zygosity on Maternal Microchimerism
Authors: Kaplan Joseph , Land Susan 
Published: April 2014

Abstract
To investigate the relationship between maternal-fetal histocompatibility and maternal microchimerism, we developed a sensitive quantitative PCR assay for the neomycin resistance gene (neoR), and, in a mouse model system, used neoR as a noninherited maternal allele marker of maternal cells to detect and quantitate maternal microchimerism in tissues of neoR−/− N2 backcross progeny of (neoR+/−)F1 females mated with neoR−/− males. Using this approach, we obtained evidence for the presence of chimeric maternal cells in the brain, spleen, and thymus of all weanling and adult mice so tested. The numbers of chimeric maternal cells present in the spleen did not differ significantly from those in the thymus regardless of age or maternal-fetal histocompatibility. At all ages, brain tissue had higher level of maternal microchimerism than lymphoid tissue in mice MHC identical with their mothers, but the levels were similar in mice MHC disparate with their mothers. The levels of chimeric maternal cells in both brain and lymphoid tissue of mice with homozygous syngenicity and maternal allogenicity were similar, and tended to be higher than tissue-specific levels in mice with either combined maternal-fetal allogenicity or heterozygous syngenicity. Thus, MHC homozygous progeny had higher levels of maternal microchimerism than MHC heterozygous progeny. We conclude that normal mice possess small numbers of maternal cells in spleen, thymus, brain, and probably most other tissues, and that maternal-fetal histocompatibility influences the levels of these cells by mechanisms related to MHC zygosity of the progeny.
Adoptive Transfer of In Vitro-Stimulated CD4+CD25+ Regulatory T Cells Increases Bacterial Clearance and Improves Survival in Polymicrobial Sepsis
Authors: Heuer Josef G. , Zhang Tonghai , Zhao Jingyong , Ding Chunjin , Cramer Martin , Justen Kathy L. , Vonderfecht Steven L. , Na Songqing 
Published: April 2014

Abstract
Regulatory CD4+CD25+ T cells (Tregs) suppress autoimmune and inflammatory diseases through mechanisms that are only partly understood. Previous studies suggest that Tregs can suppress bacterially triggered intestinal inflammation and respond to LPS through TLRs with enhanced suppressive activity. In this study, we have used murine cecal ligation and puncture as a model of polymicrobial sepsis to explore the effects of adoptive transfer of Tregs on septic outcome. Adoptive transfer of in vitro-stimulated Tregs in both prevention and therapeutic modes significantly improved survival of cecal ligation and puncture mice. Furthermore, the effect was dependent on both the number of Tregs adoptively transferred and the presence of host T cells. Animals that received stimulated Tregs had significantly increased peritoneal mast cells and peritoneal TNF-α production. More importantly, adoptive transfer of in vitro-stimulated Tregs significantly improved bacterial clearance, which resulted in improved survival. Our results suggest a novel role for Tregs in sepsis.
IL-4-Transfected Tumor Cell Vaccines Activate Tumor-Infiltrating Dendritic Cells and Promote Type-1 Immunity
Authors: Eguchi Junichi , Kuwashima Naruo , Hatano Manabu , Nishimura Fumihiko , Dusak Jill E. , Storkus Walter J. , Okada Hideho 
Published: April 2014

AbstractWe previously demonstrated that IL-4 gene-transfected glioma cell vaccines induce effective therapeutic immunity in preclinical glioma models, and have initiated phase I trials of these vaccines in patients with malignant gliomas. To gain additional mechanistic insight into the efficacy of this approach, we have treated mice bearing the MCA205 (H-2b) or CMS-4 (H-2d) sarcomas. IL-12/23 p40−/− and IFN-γ−/− mice, which were able to reject the initial inoculation of IL-4 expressing tumors, failed to mount a sustained systemic response against parental (nontransfected) tumor cells. Paracrine production of IL-4 in vaccine sites promoted the accumulation and maturation of IL-12p70-secreting tumor-infiltrating dendritic cells (TIDCs). Adoptive transfer of TIDCs isolated from vaccinated wild-type, but not IL-12/23 p40−/−, mice were capable of promoting tumor-specific CTL responses in syngeneic recipient animals. Interestingly, both STAT4−/− and STAT6−/− mice failed to reject IL-4-transfected tumors in concert with the reduced capacity of TIDCs to produce IL-12p70 and to promote specific antitumor CTL reactivity. These results suggest that vaccines consisting of tumor cells engineered to produce the type 2 cytokine, IL-4, critically depend on type 1 immunity for their observed therapeutic efficacy.
Overexpression of Stat3C in Pulmonary Epithelium Protects against Hyperoxic Lung Injury
Authors: Lian Xuemei , Qin Yulin , Hossain Shaikh Abu , Yang Li , White Amanda , Xu Huan , Shipley J. Michael , Li Tingyu , Senior Robert M. , Du Hong , Yan Cong 
Published: April 2014

Abstract
Acute lung injury is a side effect of therapy with a high concentration of inspired oxygen in patients. The molecular mechanism underlining this effect is poorly understood. In this study, we report that overexpression of Stat3C, a constitutive active form of STAT3, in respiratory epithelial cells of a doxycycline-controlled double-transgenic mouse system protects lung from inflammation and injury caused by hyperoxia. In this mouse line, &gt;50% of transgenic mice survived exposure to 95% oxygen at day 7, compared with 0% survival of wild-type mice. Overexpression of STAT3C delays acute capillary leakage and neutrophil infiltration into the alveolar region. This protection is mediated at least partially through inhibition of hyperoxia-induced synthesis and release of matrix metalloproteinase (MMP)-9 and MMP-12 by neutrophils and alveolar resident cells. In some MMP-9−/− mice, prolonged survival was observed under hyperoxic condition. The finding supports a concept that activation of the Stat3 pathway plays a role to prevent hyperoxia-induced inflammation and injury in the lung.
Intrinsic Resistance of Hepatocytes to Complement-Mediated Injury
Authors: Koch Cody A. , Kanazawa Akiyoshi , Nishitai Ryuta , Knudsen Bruce E. , Ogata Kiyoshi , Plummer Timothy B. , Butters Kim , Platt Jeffrey L. 
Published: April 2014

Abstract
When activated on or in the vicinity of cells, complement usually causes loss of function and sometimes cell death. Yet the liver, which produces large amounts of complement proteins, clears activators of complement and activated complexes from portal blood without obvious injury or impaired function. We asked whether and to what extent hepatocytes resist injury and loss of function mediated by exposure to complement. Using cells isolated from porcine livers as a model system, we found that, in contrast to endothelial cells, hepatocytes profoundly resist complement-mediated lysis and exhibit normal synthetic and conjugative functions when complement is activated on their surface. The resistance of hepatocytes to complement-mediated injury was not a function of cell surface control of the complement cascade but rather an intrinsic resistance of the cells dependent on the PI3K/Akt pathway. The resistance of hepatocytes to complement might be exploited in developing approaches to the treatment of hepatic failure or more broadly to the treatment of complement-mediated disease.