bluuebunny/crossref_metadata_2025 huggingface dataset:
Substance P Stimulates Cyclooxygenase-2 and Prostaglandin E2 Expression through JAK-STAT Activation in Human Colonic Epithelial Cells
Authors: Koon Hon-Wai , Zhao Dezheng , Zhan Yanai , Rhee Sang Hoon , Moyer Mary P. , Pothoulakis Charalabos
Published: April 2014

Substance P (SP) via its neurokinin-1 receptor (NK-1R) regulates several gastrointestinal functions. We previously reported that NK-1R-mediated chloride secretion in the colon involves formation of PG. PGE2 biosynthesis is controlled by cyclooxygenase-1 (COX-1) and COX-2, whose induction involves the STATs. In this study, we examined whether SP stimulates PGE2 production and COX-2 expression in human nontransformed NCM460 colonocytes stably transfected with the human NK-1R (NCM460-NK-1R cells) and identified the pathways involved in this response. SP exposure time and dose dependently induced an early (1-min) phosphorylation of JAK2, STAT3, and STAT5, followed by COX-2 expression and PGE2 production by 2 h. Pharmacologic experiments showed that PGE2 production is dependent on newly synthesized COX-2, but COX-1 protein. Inhibition of protein kinase Cθ (PKCθ), but not PKCε and PKCδ, significantly reduced SP-induced COX-2 up-regulation, and JAK2, STAT3, and STAT5 phosphorylation. Pharmacological blockade of JAK inhibited SP-induced JAK2, STAT3, and STAT5 phosphorylation; COX-2 expression; and PGE2 production. Transient transfection with JAK2 short-interferring RNA reduced COX-2 promoter activity and JAK2 phosphorylation, while RNA interference of STAT isoforms showed that STAT5 predominantly mediates SP-induced COX-2 promoter activity. Site-directed mutation of STAT binding sites on the COX-2 promoter completely abolished COX-2 promoter activity. Lastly, COX-2 expression was elevated in colon of mice during experimental colitis, and this effect was normalized by administration of the NK-1R antagonist CJ-12,255. Our results demonstrate that SP stimulates COX-2 expression and PGE2 production in human colonocytes via activation of the JAK2-STAT3/5 pathway.
CDR3 Spectratyping Analysis of the TCR Repertoire in Myasthenia Gravis
Authors: Matsumoto Yoh , Matsuo Hidenori , Sakuma Hiroshi , Park Il-Kwon , Tsukada Yukiko , Kohyama Kuniko , Kondo Takayuki , Kotorii Satoshi , Shibuya Noritoshi
Published: April 2014

Because myasthenia gravis (MG) is an autoimmune disease mediated by Abs specific for the acetylcholine receptor, helper T cells play a role in Ab production. In this study, we have performed large-scale cross-sectional and longitudinal TCR studies by CDR3 spectratyping using PBL and thymus tissues from MG patients. We found that there was no preferential usage of any particular TCR β-chains that was identical among MG patients. However, the longitudinal study clearly demonstrated that one or more TCR Vβ expansions persisted frequently in MG patients. Importantly, persistent TCR expansions correlated with clinical severity and high anti-acetylcholine receptor Ab titer. Finally, examinations of T cells expressing CXCR5, i.e., follicular B-helper T cells, revealed that spectratype expansions in MG patients were detected mainly in the CD4+ CXCR5+ T cell populations, whereas CD8+ T cells were the major source of clonal expansion in healthy subjects. These findings suggest that persistent clonal expansions of T cells in MG patients are associated with the development and maintenance of MG. Close examination of pathogenic T cells in MG provides useful information to elucidate the pathogenesis and to estimate the disease status.
Cutting Edge: Lupus Susceptibility Interval Sle3/5 Confers Responsiveness to Prolactin in C57BL/6 Mice
Authors: Peeva Elena , Gonzalez Juana , Hicks Ruthmarie , Diamond Betty
Published: April 2014

Prolactin is of interest in the pathogenesis of systemic lupus erythematosus (SLE) because almost 25% of SLE patients display hyperprolactinemia, and serum prolactin correlates with disease activity in some patients. Furthermore, hyperprolactinemia causes early mortality in lupus-prone mice and induces a lupus-like phenotype in nonspontaneously autoimmune mice. We show here that the immunomodulatory effects of prolactin are genetically determined; hyperprolactinemia breaks B cell tolerance and causes a lupus-like serology in BALB/c mice expressing a transgene encoding the H chain of an anti-DNA Ab but not in C57BL/6 transgenic mice. In C57BL/6 mice that express both the H chain transgene and the lupus susceptibility interval Sle3/5, prolactin induces increased serum titers of anti-DNA Ab and glomerular Ig depositions. The increase in costimulation due to prolactin-mediated up-regulation of both CD40 on B cells and CD40L on T cells would appear to play a central role in lupus induction in this model.
Cutting Edge: Unique T Cells That Recognize Citrullinated Peptides Are a Feature of Protein Immunization
Authors: Ireland Jamie , Herzog Jeremy , Unanue Emil R.
Published: April 2014

Abs against citrullinated proteins are present in patients with rheumatoid arthritis. In this study, we describe a unique cohort of T cells that selectively responded to citrullinated variants of two epitopes of hen egg-white lysozyme, a major and a minor one, bound to the MHC molecule, I-Ak. In addition, we show that when given an intact, unmodified lysozyme protein, dendritic cells and peritoneal macrophages presented citrullinated peptides and stimulated modification-specific T cells. Thus, presentation of citrullinated-peptide-MHC complex is a feature of immune responses to protein Ags.
Suppression of Disease in New Zealand Black/New Zealand White Lupus-Prone Mice by Adoptive Transfer of Ex Vivo Expanded Regulatory T Cells
Authors: Scalapino Kenneth J. , Tang Qizhi , Bluestone Jeffrey A. , Bonyhadi Mark L. , Daikh David I.
Published: April 2014

An increasing number of studies indicate that a subset of CD4+ T cells with regulatory capacity (regulatory T cells; Tregs) can function to control organ-specific autoimmune disease. To determine whether abnormalities of thymic-derived Tregs play a role in systemic lupus erythematosus, we evaluated Treg prevalence and function in (New Zealand Black × New Zealand White)F1 (B/W) lupus-prone mice. To explore the potential of Tregs to suppress disease, we evaluated the effect of adoptive transfer of purified, ex vivo expanded thymic-derived Tregs on the progression of renal disease. We found that although the prevalence of Tregs is reduced in regional lymph nodes and spleen of prediseased B/W mice compared with age-matched non-autoimmune mice, these cells increase in number in older diseased mice. In addition, the ability of these cells to proliferate in vitro was comparable to those purified from non-autoimmune control animals. Purified CD4+CD25+CD62Lhigh B/W Tregs were expanded ex vivo 80-fold, resulting in cells with a stable suppressor phenotype. Adoptive transfer of these exogenously expanded cells reduced the rate at which mice developed renal disease; a second transfer after treated animals had developed proteinuria further slowed the progression of renal disease and significantly improved survival. These studies indicate that thymic-derived Tregs may have a significant role in the control of autoimmunity in lupus-prone B/W mice, and augmentation of these cells may constitute a novel therapeutic approach for systemic lupus erythematosus.
RasGRP1 Transmits Prodifferentiation TCR Signaling That Is Crucial for CD4 T Cell Development
Authors: Priatel John J. , Chen Xiaoxi , Dhanji Salim , Abraham Ninan , Teh Hung-Sia
Published: April 2014

TCR signaling plays a governing role in both the survival and differentiation of bipotent double-positive thymocytes into the CD4+ and CD8+ single-positive T cell lineages. A central mediator of this developmental program is the small GTPase Ras, emitting cytoplasmic signals through downstream MAPK pathways and eventually affecting gene expression. TCR signal transduction orchestrates the activation of Ras by integrating at least two Ras-guanyl nucleotide exchange factors, RasGRP1 and Sos. In this study, we have characterized the relationship between RasGRP1 function and its potential roles in promoting ERK activity, cell survival, maturation, and lineage commitment. Investigations on RasGRP1−/− mice expressing a transgenic (Tg) MHC class II-restricted TCR revealed that the development of CD4 T cells expressing this Tg TCR is completely dependent on RasGRP1. Unexpectedly, a small number of functional CD8 single-positive thymocytes expressing the Tg MHC class II-restricted TCR exists in mutant mice. In addition, RasGRP1−/− double-positive thymocytes exhibit marked deficits in TCR-stimulated up-regulation of the positive selection marker CD69 and the antiapoptotic protein Bcl-2, whereas CD5 induction is unaffected. To evaluate the role of RasGRP1 in providing cellular survival signaling, we enforced Bcl-2 expression in RasGRP1−/− thymocytes. These studies demonstrate that RasGRP1 function cannot be fully complemented by Tg Bcl-2 expression. Therefore, we propose that RasGRP1 transmits differentiation signaling critically required for CD4 T cell development.
Phosphorylation of Nonmuscle Myosin Heavy Chain IIA on Ser1917 Is Mediated by Protein Kinase CβII and Coincides with the Onset of Stimulated Degranulation of RBL-2H3 Mast Cells
Authors: Ludowyke Russell I. , Elgundi Zehra , Kranenburg Tanya , Stehn Justine R. , Schmitz-Peiffer Carsten , Hughes William E. , Biden Trevor J.
Published: April 2014

Dynamic remodeling of the actinomyosin cytoskeleton is integral to many biological processes. It is regulated, in part, by myosin phosphorylation. Nonmuscle myosin H chain IIA is phosphorylated by protein kinase C (PKC) on Ser1917. Our aim was to determine the PKC isoform specificity of this phosphorylation event and to evaluate its potential role in regulated secretion. Using an Ab against the phosphorylated form of Ser1917, we show that this site is not phosphorylated in unstimulated RBL-2H3 mast cells. The physiological stimulus, Ag, or the pharmacological activators, PMA plus A23187, induced Ser1917 phosphorylation with a time course coincident with the onset of granule mediator secretion. Dephosphorylation at this site occurred as Ag-stimulated secretion declined from its peak, but dephosphorylation was delayed in cells activated with PMA plus A23187. Phosphate incorporation was also enhanced by PMA alone and by inhibition of protein phosphatase 2A. Gö6976, an inhibitor of conventional PKC isoforms, abolished secretion and Ser1917 phosphorylation with similar dose dependencies consistent with involvement of either PKCα or PKCβ. Phorbol ester-stimulated Ser1917 phosphorylation was reconstituted in HEK-293 cells (which lack endogenous PKCβ) by overexpression of both wild-type and constitutively active PKCβII but not the corresponding PKCβI or PKCα constructs. A similar selectivity for PKCβII overexpression was also observed in MIN6 insulinoma cells infected with recombinant PKC wild-type adenoviruses. Our results implicate PKC-dependent phosphorylation of myosin H chain IIA in the regulation of secretion in mast cells and suggest that Ser1917 phosphorylation might be a marker of PKCβII activation in diverse cell types.
The Thymus Plays a Role in Oral Tolerance in Experimental Autoimmune Encephalomyelitis
Authors: Song Fei , Guan Zhen , Gienapp Ingrid E. , Shawler Todd , Benson Jacqueline , Whitacre Caroline C.
Published: April 2014

The oral administration of myelin proteins has been used for the successful prevention and treatment of experimental autoimmune encephalomyelitis (EAE). We questioned whether the thymus was involved in oral tolerance. In this study, euthymic myelin basic protein (MBP) TCR transgenic mice are protected from EAE when fed MBP but are not protected when thymectomized. Similarly, in a cell transfer system, T cell responses to OVA measured in vivo were suppressed significantly only in the OVA-fed euthymic mice but not in the thymectomized mice. We observed that the absence of the thymus dramatically enhanced the Th1 response. We explored three alternatives to determine the role of the thymus in oral tolerance: 1) as a site for the induction of regulatory T cells; 2) a site for deletion of autoreactive T cells; or 3) a site for the dissemination of naive T cells. We found that Foxp3+CD4+CD25+ T cells are increased in the periphery but not in the thymus after Ag feeding. These CD4+CD25+ T cells also express glucocorticoid-induced TNFR and intracellular CTLA4 and suppress Ag-specific proliferation of CD4+CD25− cells in vitro. The thymus also plays a role in deletion of autoreactive T cells in the periphery following orally administered MBP. However, thymectomy does not result in homeostatic proliferation and the generation of memory cells in this system. Overall, the oral administration of MBP has a profound effect on systemic immune responses, mediated largely by the generation of regulatory T cells that act to prevent or suppress EAE.
Priming Protective CD8 T Cell Immunity by DNA Vaccines Encoding Chimeric, Stress Protein-Capturing Tumor-Associated Antigen
Authors: Schirmbeck Reinhold , Riedl Petra , Kupferschmitt Mark , Wegenka Ursula , Hauser Hansjörg , Rice Jason , Kröger Andrea , Reimann Jörg
Published: April 2014

DNA vaccines encoding heat shock protein (hsp)-capturing, chimeric peptides containing antigenic determinants of the tumor-associated Ag (TAA) gp70 (an envelope protein of endogenous retrovirus) primed stable, specific, and tumor-protective CD8 T cell immunity. Expression of gp70 transcripts was detectable in most normal tissues but was particularly striking in some (but not all) tumor cell lines tested (including the adenocarcinoma cell line CT26). An ∼200 residue gp70 fragment or its Ld-binding antigenic AH1 peptide cloned in-frame behind an hsp-capturing (cT272) or noncapturing (T60) N-terminal large SV40 tumor Ag sequence was expressed as either hsp-binding or -nonbinding chimeric Ags. Only hsp-capturing, chimeric fusion proteins were expressed efficiently in transfected cell lines and primed TAA-specific CD8 T cell immunity. This immunity mediated protection in the CT26 and mKSA models. A vaccination strategy based on delivering antigenic, hsp-associated TAA fragments can thus prime protective CD8 T cell immunity even if these TAA are of low intrinsic immunogenicity.
Extracellular Targeting of Endoplasmic Reticulum Chaperone Glucose-Regulated Protein 170 Enhances Tumor Immunity to a Poorly Immunogenic Melanoma
Authors: Wang Xiang-Yang , Arnouk Hilal , Chen Xing , Kazim Latif , Repasky Elizabeth A. , Subjeck John R.
Published: April 2014

We have demonstrated previously that immunization with tumor-derived endoplasmic reticulum (ER) chaperone glucose-regulated protein 170 (grp170) elicits potent antitumor immunity. In the present study, we determine the impact of extracellular targeting grp170 by molecular engineering on tumor immunogenicity and potential use of grp170-secreting tumor cells as a cancer vaccine. grp170 depleted of ER retention sequence “KNDEL,” when secreted by B16 tumor cells, maintained its highly efficient chaperoning activities and was significantly superior to both hsp70 and gp96. The continued secretion of grp170 dramatically reduced the tumorigenicity of B16 tumor cells in vivo, although the modification did not alter its transformation phenotype and cell growth rate. C57BL/6 mice that rejected grp170-secreting B16 tumor cells (B16-sgrp170) developed a strong CTL response recognizing melanocyte differentiation Ag TRP2 and were resistant to subsequent tumor challenge. B16-sgrp170 cells also stimulated the production of proinflammatory cytokines by cocultured dendritic cells. Depletion studies in vivo indicate that NK cells play a primary role in elimination of viable B16-sgrp170 tumor cells inoculated into the animals, whereas both NK cells and CD8+ T cells are required for a long-term protection against wild-type B16 tumor challenge. Both the secreted and endogenous grp170, when purified from the B16 tumor, exhibited potent tumor-protective activities. However, the B16-sgrp170 cell appears to be more effective than tumor-derived grp170. Thus, molecular engineering of tumor cell to release the largest ER chaperone grp170 is capable of eliciting innate as well as adaptive immune responses, which may provide an effective cell-based vaccination approach for cancer immunotherapy.
Pertussis Toxin Reduces the Number of Splenic Foxp3+ Regulatory T Cells
Authors: Cassan Cécile , Piaggio Eliane , Zappulla Jacques P. , Mars Lennart T. , Couturier Nicolas , Bucciarelli Florence , Desbois Sabine , Bauer Jan , Gonzalez-Dunia Daniel , Liblau Roland S.
Published: April 2014

Pertussis toxin (PTx) is a bacterial toxin used to enhance the severity of experimental autoimmune diseases such as experimental autoimmune encephalomyelitis. It is known to promote permeabilization of the blood-brain barrier, maturation of APC, activation of autoreactive lymphocytes and alteration of lymphocyte migration. In this study, we show that i.v. injection of PTx in mice induces a decrease in the number of splenic CD4+CD25+ regulatory T cells (Treg cells). Furthermore, PTx not only induces a depletion of the dominant CD4+CD25+Foxp3+ subpopulation of splenic Treg cells, but also reduces to a similar extent the CD4+CD25−Foxp3+ subpopulation. On a per cell basis, the suppressive properties of the remaining Treg cells are not modified by PTx treatment. The reduction in splenic Treg cells is associated with preferential migration of these cells to the liver. Additionally, Treg cells exhibit a high sensitivity to PTx-mediated apoptosis in vitro. Finally, in vivo depletion of Treg cells by injection of an anti-CD25 Ab, and PTx treatment, present synergistic experimental autoimmune encephalomyelitis exacerbating effects. Therefore, we identify a new effect of PTx and provide an additional illustration of the influence of microbial components on the immune system affecting the balance between tolerance, inflammation and autoimmunity.
A Critical Role for Prostaglandin E2 in Podosome Dissolution and Induction of High-Speed Migration during Dendritic Cell Maturation
Authors: van Helden Suzanne F. G. , Krooshoop Daniëlle J. E. B. , Broers Karin C. M. , Raymakers Reinier A. P. , Figdor Carl G. , van Leeuwen Frank N.
Published: April 2014

Dendritic cells (DCs) are professional APCs of the immune system that play a key role in regulating T cell-based immunity. The capacity of DCs to activate T cells depends on their maturation state as well as their ability to migrate to the T cell areas of draining lymph nodes. In this study, we investigated the effects of DC maturation stimuli on the actin cytoskeleton and β1 integrin-dependent adhesion and migration. Podosomes, specialized adhesion structures found in immature monocyte-derived DCs as well as myeloid DCs, rapidly dissolve in response to maturation stimuli such as TNF-α and PGE2, whereas the TLR agonist LPS induces podosome dissolution only after a long lag time. We demonstrate that LPS-mediated podosome disassembly as well as the onset of high-speed DC migration are dependent on the production of PGs by the DCs. Moreover, both of these processes are inhibited by Ab-induced activation of β1 integrins. Together, these results show that maturation-induced podosome dissolution and loss of α5β1 integrin activity allow human DCs to undergo the transition from an adhesive to a highly migratory phenotype.
CXCL16 Influences the Nature and Specificity of CpG-Induced Immune Activation
Authors: Gursel Mayda , Gursel Ihsan , Mostowski Howard S. , Klinman Dennis M.
Published: April 2014

Unmethylated CpG motifs are present at high frequency in bacterial DNA. They provide a danger signal to the mammalian immune system that triggers a protective immune response characterized by the production of Th1 and proinflammatory cytokines and chemokines. Although the recognition of CpG DNA by B cells and plasmacytoid dendritic cells is mediated by TLR 9, these cell types differ in their ability to bind and respond to structurally distinct classes of CpG oligonucleotides. This work establishes that CXCL16, a membrane-bound scavenger receptor, influences the uptake, subcellular localization, and cytokine profile induced by D oligonucleotides. This is the first example of a surface receptor modifying the cellular specificity and nature of the immune response mediated by an intracellular TLR.
Accumulation of Immunosuppressive CD11b+ Myeloid Cells Correlates with the Failure to Prevent Tumor Growth in the Anterior Chamber of the Eye
Authors: McKenna Kyle C. , Kapp Judith A.
Published: April 2014

The purpose of these studies is to determine why an immunogenic tumor grows unchecked in the anterior chamber (a.c.) of the eye. The OVA-expressing EL4 tumor, E.G7-OVA, was injected into the a.c. or skin of immunocompetent and immunodeficient mice. Tumor growth and tumor-specific immune responses were monitored. Ocular tumor-infiltrating leukocytes were characterized phenotypically and functionally. Growth of E.G7-OVA was inhibited when limiting numbers of cells were injected in the skin but not in the a.c. of C57BL/6 mice, although both routes primed OVA-specific immune responses, which prevented the growth of a subsequent injection with E.G7-OVA in the skin or opposite eye. Tumor regression was OVA-specific because growth of the parental EL-4 tumor was not inhibited in primed mice. E.G7-OVA growth in the skin was not inhibited in immunodeficient Rag−/− or CD8 T cell-deficient mice, suggesting that CD8+ CTLs mediate tumor elimination. CD8+ T cell numbers were significantly increased in eyes of mice primed with E.G7-OVA, but few were detected in primary ocular tumors. Nevertheless, growth of E.G7-OVA was retarded in the a.c. of TCR-transgenic OT-I mice, and CD8+ T cell numbers were increased within eyes, suggesting that tumor-specific CD8+ CTLs migrated into and controlled primary ocular tumor growth. E.G7-OVA did not lose antigenicity or become immunosuppressive after 13 days of growth in the eye. However, CD11b+ cells accumulated in primary ocular tumors and contained potent immunosuppressive activity when assayed in vitro. Thus, CD11b+ cells that accumulate within the eye as tumors develop in the a.c. may contribute to immune evasion by primary ocular tumors by inhibiting CTLs within the eye.
Crucial Commitment of Proteolytic Activity of a Purified Recombinant Major House Dust Mite Allergen Der p1 to Sensitization toward IgE and IgG Responses
Authors: Kikuchi Yuko , Takai Toshiro , Kuhara Takatoshi , Ota Mikiko , Kato Takeshi , Hatanaka Hideki , Ichikawa Saori , Tokura Tomoko , Akiba Hisaya , Mitsuishi Kouichi , Ikeda Shigaku , Okumura Ko , Ogawa Hideoki
Published: April 2014

The major proteolytic allergen derived from the house dust mite Dermatophagoides pteronyssinus, Der p1, is one of the most clinically relevant allergens worldwide. In the present study, we evaluate the contribution of the proteolytic activity and structure of a highly purified rDer p 1 to immune responses. Mice were i.p. immunized with three forms of rDer p 1 adsorbed to Alum: one enzymatically active, one treated with an irreversible cysteine protease-specific inhibitor, E-64, and one heat denatured. Immunization with E-64-treated or heat-denatured rDer p 1 elicited much less production of serum total IgE and not only rDer p 1-specific IgE but also IgGs compared with immunization with active rDer p 1. Assays for Ab-binding and its inhibition and structural analyses indicated that E-64-treated rDer p 1 retained its global structure and conformational B cell epitopes. A proliferative response and production of IL-5 by spleen cells restimulated with rDer p 1 were observed on immunization with the active rDer p 1 but not E-64-treated rDer p 1. The cells from mice immunized with heat-denatured rDer p 1 exhibited the highest levels of proliferation and production of IL-5 and IFN-γ. The results indicate that the proteolytic activity of the highly purified rDer p 1 crucially commits to the sensitization process, including both IgE and IgG responses. Additionally, we demonstrated immunogenic differences by functional or structural manipulations of the rDer p 1. The findings have implications for sensitization to this relevant allergen in humans and for the design of modified allergen-vaccines for future allergen-specific immunotherapy.
Visualization of IL-12/23p40 In Vivo Reveals Immunostimulatory Dendritic Cell Migrants that Promote Th1 Differentiation
Authors: Reinhardt R. Lee , Hong Seokmann , Kang Suk-Jo , Wang Zhi-en , Locksley Richard M.
Published: April 2014

IL-12p40 is induced in macrophages and dendritic cells (DC) after activation by microbial TLR ligands and cytokines and constitutes a component of IL-12 and IL-23. In an effort to understand the location and kinetics of these cytokines during the course of an immune response, we generated knockin (gene-targeted) mice that express the p40 gene linked via a viral internal ribosome entry site element with fluorescent reporters, eYFP or eGFP. Macrophages and DC from these mice faithfully reported biallelic p40 induction using the fluorescent marker. s.c. inoculation with Listeria monocytogenes or LPS led to a rapid, but transient, accumulation of p40-expressing DC in draining lymph nodes, which could be blocked by the addition of pertussis toxin. In situ analysis also revealed the accumulation of IL-12p40 protein around high endothelial venules located in close proximity to p40-expressing DC. Consistent with the in vivo findings, in vitro-activated DC that expressed p40 migrated to draining lymph nodes and promoted Th1 differentiation more efficiently than DC that did not express p40. Accordingly, these mice provide a valuable tool for tracking critical functions of DC in vivo and should bestow a useful reagent for exploring the effector biology of these cells in models of infectious disease, cancer immunity, and vaccine development.
Intestinal Helminths Protect in a Murine Model of Asthma
Authors: Kitagaki Kunihiko , Businga Thomas R. , Racila Doina , Elliott David E. , Weinstock Joel V. , Kline Joel N.
Published: April 2014

Underdeveloped nations are relatively protected from the worldwide asthma epidemic; the hygiene hypothesis suggests this is due to suppression of Th2-mediated inflammation by increased exposure to pathogens and their products. Although microbial exposures can promote Th2-suppressing Th1 responses, even Th2-skewing infections, such as helminths, appear to suppress atopy, suggesting an alternate explanation for these observations. To investigate whether induction of regulatory responses by helminths may counter allergic inflammation, we examined the effects of helminth infection in a murine model of atopic asthma. We chose Heligosomoides polygyrus, a gastrointestinal nematode, as the experimental helminth; this worm does not enter the lung in its life cycle. We found that H. polygyrus infection suppressed allergen-induced airway eosinophilia, bronchial hyperreactivity, and in vitro allergen-recall Th2 responses in an IL-10-dependent manner; total and OVA-specific IgE, however, were increased by worm infection. Finally, helminth-infected mice were protected against eosinophilic inflammation induced by adoptive transfer of OVA-stimulated CD4+ cells, and transfer of cells from helminth-infected/OVA-exposed mice suppressed OVA-induced eosinophilic inflammation, suggesting a role for regulatory cells. Increased CD4+CD25+Foxp3+ cells were found in thoracic lymph nodes of helminth-infected/OVA-exposed mice. Helminthic colonization appears to protect against asthma and atopic disorders; the regulatory cytokine, IL-10, may be a critical player.
Genetic Dissection of the Effects of Stimulatory and Inhibitory IgG Fc Receptors on Murine Lupus
Authors: Lin Qingshun , Xiu Yan , Jiang Yi , Tsurui Hiromichi , Nakamura Kazuhiro , Kodera Sanki , Ohtsuji Mareki , Ohtsuji Naomi , Shiroiwa Wakana , Tsukamoto Kazuyuki , Amano Hirofumi , Amano Eri , Kinoshita Katsuyuki , Sudo Katsuko , Nishimura Hiroyuki , Izui Shozo , Shirai Toshikazu , Hirose Sachiko
Published: April 2014

Immune complex (IC)-mediated tissue inflammation is controlled by stimulatory and inhibitory IgG Fc receptors (FcγRs). Systemic lupus erythematosus is a prototype of IC-mediated autoimmune disease; thus, imbalance of these two types of FcγRs is probably involved in pathogenesis. However, how and to what extent each FcγR contributes to the disease remains unclear. In lupus-prone BXSB mice, while stimulatory FcγRs are intact, inhibitory FcγRIIB expression is impaired because of promoter region polymorphism. To dissect roles of stimulatory and inhibitory FcγRs, we established two gene-manipulated BXSB strains: one deficient in stimulatory FcγRs (BXSB.γ−/−) and the other carrying wild-type Fcgr2b (BXSB.IIBB6/B6). The disease features were markedly suppressed in both mutant strains. Despite intact renal function, however, BXSB.γ−/− had IC deposition in glomeruli associated with high-serum IgG anti-DNA Ab levels, in contrast to BXSB.IIBB6/B6, which showed intact renal pathology and anti-DNA levels. Lymphocytes in BXSB.γ−/− were activated, as in wild-type BXSB, but not in BXSB.IIBB6/B6. Our results strongly suggest that both types of FcγRs in BXSB mice are differently involved in the process of disease progression, in which, while stimulatory FcγRs play roles in effecter phase of IC-mediated tissue inflammation, the BXSB-type impaired FcγRIIB promotes spontaneous activation of self-reactive lymphocytes and associated production of large amounts of autoantibodies and ICs.
Anti-Mitochondrial Antibodies and Primary Biliary Cirrhosis in TGF-β Receptor II Dominant-Negative Mice
Authors: Oertelt Sabine , Lian Zhe-Xiong , Cheng Chun-Mei , Chuang Ya-Hui , Padgett Kerstien A. , He Xiao-Song , Ridgway William M. , Ansari Aftab A. , Coppel Ross L. , Li Ming O. , Flavell Richard A. , Kronenberg Mitchell , Mackay Ian R. , Gershwin M. Eric
Published: April 2014

Primary biliary cirrhosis (PBC) is an autoimmune disease of the liver, characterized by lymphocytic infiltrates in portal tracts, selective destruction of biliary epithelial cells, and anti-mitochondrial Abs (AMAs). The elucidation of early events in the induction of tissue inflammation and autoimmunity in PBC has been hampered by the cryptic onset of the disease, the practical limitations in accessing the target tissue, and the lack of a suitable animal model. We demonstrate in this study that a mouse transgenic for directed expression of a dominant-negative form of TGF-β receptor type II (dnTGFβRII), under the direction of the CD4 promoter, mimics several key phenotypic features of human PBC, including spontaneous production of AMAs directed to the same mitochondrial autoantigens, namely PDC-E2, BCOADC-E2, and OGDC-E2. The murine AMAs also inhibit PDC-E2 activity. Moreover, there is lymphocytic liver infiltration with periportal inflammation analogous to the histological profile in human PBC. Additionally, the serum cytokine profile of affected mice mimics data in human PBC. The concomitant presence of these immunopathological features in the transgenic mice suggests that the TGF-βRII pathway is implicated in the pathogenesis of PBC. Finally, these data point away from initiation of autoimmunity by mechanisms such as molecular mimicry and more toward activation of an intrinsically self-reactive T cell repertoire in which necessary regulatory T cell influences are lacking.
Yeast β-Glucan Amplifies Phagocyte Killing of iC3b-Opsonized Tumor Cells via Complement Receptor 3-Syk-Phosphatidylinositol 3-Kinase Pathway
Authors: Li Bing , Allendorf Daniel J. , Hansen Richard , Marroquin Jose , Ding Chuanlin , Cramer Daniel E. , Yan Jun
Published: April 2014

Anti-tumor mAbs hold promise for cancer therapy, but are relatively inefficient. Therefore, there is a need for agents that might amplify the effectiveness of these mAbs. One such agent is β-glucan, a polysaccharide produced by fungi, yeast, and grains, but not mammalian cells. β-Glucans are bound by C receptor 3 (CR3) and, in concert with target-associated complement fragment iC3b, elicit phagocytosis and killing of yeast. β-Glucans may also promote killing of iC3b-opsonized tumor cells engendered by administration of anti-tumor mAbs. In this study, we report that tumor-bearing mice treated with a combination of β-glucan and an anti-tumor mAb show almost complete cessation of tumor growth. This activity evidently derives from a 25-kDa fragment of β-glucan released by macrophage processing of the parent polysaccharide. This fragment, but not parent β-glucan, binds to neutrophil CR3, induces CBRM 1/5 neoepitope expression, and elicits CR3-dependent cytotoxicity. These events require phosphorylation of the tyrosine kinase, Syk, and consequent PI3K activation because β-glucan-mediated CR3-dependent cytotoxicity is greatly decreased by inhibition of these signaling molecules. Thus, β-glucan enhances tumor killing through a cascade of events, including in vivo macrophage cleavage of the polysaccharide, dual CR3 ligation, and CR3-Syk-PI3K signaling. These results are important inasmuch as β-glucan, an agent without evident toxicity, may be used to amplify tumor cell killing and may open new opportunities in the immunotherapy of cancer.
Dendritic Cells Transduced with SOCS-3 Exhibit a Tolerogenic/DC2 Phenotype That Directs Type 2 Th Cell Differentiation In Vitro and In Vivo
Authors: Li Yonghai , Chu Niansheng , Rostami Abdolmohamad , Zhang Guang-Xian
Published: April 2014

Dendritic cells (DCs) have been suggested to direct a type of Th differentiation through their cytokine profile, e.g., high IL-12/IL-23 for Th1 (named DC1/immunogenic DCs) and IL-10 for Th2 (DC2/tolerogenic DCs). Suppressor of cytokine signaling (SOCS)-3 is a potent inhibitor of Stat3 and Stat4 transduction pathways for IL-23 and IL-12, respectively. We thus hypothesize that an enhanced SOCS-3 expression in DCs may block the autocrine response of IL-12/IL-23 in these cells, causing them to become a DC2-type phenotype that will subsequently promote Th2 polarization of naive T cells. Indeed, in the present study we found that bone marrow-derived DCs transduced with SOCS-3 significantly inhibited IL-12-induced activation of Stat4 and IL-23-induced activation of Stat3. These SOCS-3-transduced DCs expressed a low level of MHC class II and CD86 on their surface, produced a high level of IL-10 but low levels of IL-12 and IFN-γ, and expressed a low level of IL-23 p19 mRNA. Functionally, SOCS-3-transduced DCs drove naive myelin oligodendrocyte glycoprotein-specific T cells to a strong Th2 differentiation in vitro and in vivo. Injection of SOCS-3-transduced DCs significantly suppressed experimental autoimmune encephalomyelitis, a Th1 cell-mediated autoimmune disorder of the CNS and an animal model of multiple sclerosis. These results indicate that transduction of SOCS-3 in DCs is an effective approach to generating tolerogenic/DC2 cells that then skew immune response toward Th2, thus possessing therapeutic potential in Th1-dominant autoimmune disorders such as multiple sclerosis.
Local Intrahepatic CD8+ T Cell Activation by a Non-Self- Antigen Results in Full Functional Differentiation
Authors: Wuensch Sherry A. , Pierce Robert H. , Crispe I. Nicholas
Published: April 2014

The response of T cells to liver Ags sometimes results in immune tolerance. This has been proposed to result from local, intrahepatic priming, while the expression of the same Ag in liver-draining lymph nodes is believed to result in effective immunity. We tested this model, using an exogenous model Ag expressed only in hepatocytes, due to infection with an adeno-associated virus vector. T cell activation was exclusively intrahepatic, yet in contrast to the predictions of the current model, this resulted in clonal expansion, IFN-γ synthesis, and cytotoxic effector function. Local activation of naive CD8+ T cells can therefore cause full CD8+ T cell activation, and hepatocellular presentation cannot be used to explain the failure of CTL effector function against some liver pathogens such as hepatitis C.
Autoimmunity as a Result of Escape from RNA Surveillance
Authors: Bachmann Michael P. , Bartsch Holger , Gross Joanne K. , Maier Shannon M. , Gross Timothy F. , Workman Jennifer L. , James Judith A. , Farris A. Darise , Jung Bettina , Franke Claudia , Conrad Karsten , Schmitz Marc , Büttner Cordula , Buyon Jill P. , Semsei Imre , Harley John B. , Rieber E. Peter
Published: April 2014

In previous studies, we detected a frame shift mutation in the gene encoding the autoantigen La of a patient with systemic lupus erythematosus. The mutant La mRNA contains a premature termination codon. mRNAs that prematurely terminate translation should be eliminated by RNA quality control mechanisms. As we find Abs specific for the mutant La form in ∼30% of sera from anti-La-positive patients, we expected that mutant La mRNAs circumvent RNA control and the expression of mutant La protein could become harmful. Indeed, real-time PCR, immunostaining, and immunoblotting data of mice transgenic for the mutant La form show that mutant La mRNAs are not repressed in these animals and are translated to mutant La protein. In addition to the mutant La protein, we detected a minor portion of native human La in the mutant La-transgenic mice. Therefore, ribosomal frame shifting may allow the mutant La mRNA to escape from RNA control. Interestingly, expression of the mutant La mRNA results in a lupus-like disease in the experimental mice. Consequently, escape of mutant La mRNA from RNA control can have two effects: it 1) results in the expression of an immunogenic (neo)epitope, and 2) predisposes to autoimmunity.
Specific Patterns of Cdc42 Activity Are Related to Distinct Elements of T Cell Polarization
Authors: Tskvitaria-Fuller Irina , Seth Abhinav , Mistry Neeta , Gu Hua , Rosen Michael K. , Wülfing Christoph
Published: April 2014

T cell polarization toward and within the cellular interface with an APC is critical for effective T cell activation. The Rho family GTPase Cdc42 is a central regulator of cellular polarization. Using live-cell imaging, we characterized the spatiotemporal patterns of Cdc42 activity and their physiological regulation. Using three independent means of experimental manipulation of Cdc42 activity, we established that Cdc42 is a critical regulator of T cell actin dynamics, TCR clustering, and cell cycle entry. Using quantification of three-dimensional data, we could relate distinct spatiotemporal patterns of Cdc42 activity to specific elements of T cell activation. This result suggests that Cdc42 activity in specific locations at specific times is most critical for its function in T cell activation.
B Cells and CD4−CD8− T Cells Are Key Regulators of the Severity of Reactivation Histoplasmosis
Authors: Allen Holly L. , Deepe George S.
Published: April 2014

The fungus, Histoplasma capsulatum, produces a persistent infection. Reactivation histoplasmosis is largely a result of impaired immunity, but the perturbations associated with escape of the fungus from host defenses remain ill-defined. We analyzed a murine model of reactivation to elucidate the host defects that permit reactivation. C57BL/6 mice were infected intranasally and, 42 days later, they were depleted of CD4+ and CD8+ cells. Elimination of these cells, but not either alone, produced a persistent infection over several weeks. Neutralization of IFN-γ, TNF-α, or both did not induce reactivation. Endogenous IL-10 exacerbated reactivation. Depletion of T cells in B cell−/− mice induced a markedly higher burden in organs when compared with wild type. However, the infection remained persistent. Elimination of CD4+ cells alone or neutralization of cytokines increased the fungal load. The persistent infection was not dependent on γδ T cells or NK cells. Elimination of Thy-1.2+ cells in mice given mAb to CD4 and CD8 transformed reactivation into a progressive, lethal infection in B cell−/− and wild-type mice, but the tempo of progression was accelerated in the former. The data reveal the complex control by the host to prevent reactivation of this fungus.
A Protein Associated with Toll-Like Receptor 4 (PRAT4A) Regulates Cell Surface Expression of TLR4
Authors: Wakabayashi Yasutaka , Kobayashi Makiko , Akashi-Takamura Sachiko , Tanimura Natsuko , Konno Kazunori , Takahashi Koichiro , Ishii Takashi , Mizutani Taketoshi , Iba Hideo , Kouro Taku , Takaki Satoshi , Takatsu Kiyoshi , Oda Yoshiya , Ishihama Yasushi , Saitoh Shin-ichiroh , Miyake Kensuke
Published: April 2014

TLRs recognize microbial products. Their subcellular distribution is optimized for microbial recognition. Little is known, however, about mechanisms regulating the subcellular distribution of TLRs. LPS is recognized by the receptor complex consisting of TLR4 and MD-2. Although MD-2, a coreceptor for TLR4, enhances cell surface expression of TLR4, an additional mechanism regulating TLR4 distribution has been suggested. We show here that PRAT4A, a novel protein associated with TLR4, regulates cell surface expression of TLR4. PRAT4A is associated with the immature form of TLR4 but not with MD-2 or TLR2. PRAT4A knockdown abolished LPS responsiveness in a cell line expressing TLR4/MD-2, probably due to the lack of cell surface TLR4. PRAT4A knockdown down-regulated cell surface TLR4/MD-2 on dendritic cells. These results demonstrate a novel mechanism regulating TLR4/MD-2 expression on the cell surface.
Phenotypical and Functional Analysis of Memory and Effector Human CD8 T Cells Specific for Mycobacterial Antigens
Authors: Caccamo Nadia , Meraviglia Serena , La Mendola Carmela , Guggino Giuliana , Dieli Francesco , Salerno Alfredo
Published: April 2014

Mycobacterium tuberculosis infects one-third of the global population and claims two million lives every year. Because memory CD8 T cells exhibit a high heterogeneity in terms of phenotype and functional characteristic, we investigated the frequency, phenotype, and functional properties of Ag85A epitope-specific HLA-A*0201 CD8 T cells in children affected by tuberculosis (TB) before and 4 mo after chemotherapy and healthy contact children. Using Ag85A peptide/HLA-A*0201 pentamer, we found a low frequency of blood peptide-specific CD8 T cells in tuberculous children before therapy, which consistently increased after therapy to levels detected in healthy contacts. Ex vivo analysis of the expression of CD45RA and CCR7 surface markers indicated a skewed representation of Ag85A epitope-specific CD8 T cells during active TB, with a predominance of T central memory cells and a decrease of terminally differentiated T cells, which was reversed after therapy. Accordingly, pentamer-specific CD8 T cells from tuberculous patients produced low levels of IFN-γ and had low expression of perforin, which recovered after therapy. The finding of an elevated frequency of pentamer-specific CD8 T cells with T effector memory and terminally differentiated phenotypes in the cerebrospinal fluid of a child with tuberculous meningitis strongly indicates compartmentalization of such CD8 effectors at the site of disease. Our study represents the first characterization of Ag-specific memory and effector CD8 T cells during TB and may help to understand the type of immune response that vaccine candidates should stimulate to achieve protection.
T-bet Deficiency Facilitates Airway Colonization byMycoplasma pulmonisin a Murine Model of Asthma
Authors: Bakshi Chandra Shekhar , Malik Meenakshi , Carrico Pauline M. , Sellati Timothy J.
Published: April 2014

Epidemiological and clinical evidence suggest a correlation between asthma and infection with atypical bacterial respiratory pathogens. However, the cellular and molecular underpinnings of this correlation remain unclear. Using the T-bet-deficient (T-bet−/−) murine model of asthma and the natural murine pathogen Mycoplasma pulmonis, we provide a mechanistic explanation for this correlation. In this study, we demonstrate the capacity of asthmatic airways to facilitate colonization by M. pulmonis and the capacity of M. pulmonis to exacerbate symptoms associated with acute and chronic asthma. This mutual synergism results from an inability of T-bet−/− mice to mount an effective immune defense against respiratory infection through release of IFN-γ and the ability of M. pulmonis to trigger the production of Th2-type cytokines (e.g., IL-4 and IL-5), and Abs (e.g., IgG1, IgE, and IgA), eosinophilia, airway remodeling, and hyperresponsiveness; all pathophysiological hallmarks of asthma. The capacity of respiratory pathogens such as Mycoplasma spp. to dramatically augment the pathological changes associated with asthma likely explains their association with acute asthmatic episodes in juvenile patients and with adult chronic asthmatics, >50% of whom are found to be PCR positive for M. pneumoniae. In conclusion, our study demonstrates that in mice genetically predisposed to asthma, M. pulmonis infection elicits an inflammatory milieu in the lungs that skews the immune response toward the Th2-type, thus exacerbating the pathophysiological changes associated with asthma. For its part, airways exhibiting an asthmatic phenotype provide a fertile environment that promotes colonization by Mycoplasma spp. and one which is ill-equipped to kill and clear respiratory pathogens.
Alveolar Epithelial Cells Direct Monocyte Transepithelial Migration upon Influenza Virus Infection: Impact of Chemokines and Adhesion Molecules
Authors: Herold Susanne , von Wulffen Werner , Steinmueller Mirko , Pleschka Stephan , Kuziel William A. , Mack Matthias , Srivastava Mrigank , Seeger Werner , Maus Ulrich A. , Lohmeyer Juergen
Published: April 2014

Influenza A virus pneumonia is characterized by severe lung injury and high mortality. Early infection elicits a strong recruitment of monocytes from the peripheral blood across the endo-/epithelial barrier into the alveolar air space. However, it is currently unclear which of the infected resident lung cell populations, alveolar epithelial cells or alveolar macrophages, elicit monocyte recruitment during influenza A virus infection. In the current study, we investigated whether influenza A virus infection of primary alveolar epithelial cells and resident alveolar macrophages would elicit a basal-to-apical monocyte transepithelial migration in vitro. We found that infection of alveolar epithelial cells with the mouse-adapted influenza A virus strain PR/8 strongly induced the release of monocyte chemoattractants CCL2 and CCL5 followed by a strong monocyte transepithelial migration, and this monocytic response was strictly dependent on monocyte CCR2 but not CCR5 chemokine receptor expression. Analysis of the adhesion molecule pathways demonstrated a role of ICAM-1, VCAM-1, integrin-associated protein (CD47), and junctional adhesion molecule-c on the epithelial cell surface interacting with monocyte β1 and β2 integrins and integrin-associated protein in the monocyte transmigration process. Importantly, addition of influenza A virus-infected alveolar macrophages further enhanced monocyte transmigration across virus-infected epithelium in a TNF-α-dependent manner. Collectively, the data show an active role for virus-infected alveolar epithelium in the regulation of CCL2/CCR2-dependent monocyte transepithelial migration during influenza infection that is essentially dependent on both classical β1 and β2 integrins but also junctional adhesion molecule pathways.