bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of Experimental Autoimmune Encephalomyelitis in the C57BL/6J Mouse by NK1.1+, DX5+, αβ+ T Cells
Authors: Fritz Robert B. , Zhao Ming-Lang 
Published: April 2014

AbstractC57BL/6 (B6) mice with targeted mutations of immune function genes were used to investigate the mechanism of recovery from experimental autoimmune encephalomyelitis (EAE). The acute phase of passive EAE in the B6 mouse is normally resolved by partial recovery followed by mild sporadic relapses. B6 TCR β-chain knockout (KO) recipients of a myelin oligodendrocyte glycoprotein p35–55 encephalitogenic T cell line failed to recover from the acute phase of passive EAE. In comparison with wild-type mice, active disease was more severe in β2-microglobulin KO mice. Reconstitution of TCR β-chain KO mice with wild-type spleen cells halted progression of disease and favored recovery. Spleen cells from T cell-deficient mice, IL-7R KO mice, or IFN-γ KO mice were ineffective in this regard. Irradiation or treatment of wild-type spleen cell population with anti-NK1.1 mAb before transfer abrogated the protective effect. Removal of DX5+ cells from wild-type spleen cells by anti-DX5 Ab-coated magnetic beads before reconstitution abrogated the suppressive properties of the spleen cells. TCR-deficient recipients of the enriched DX5+ cell population recovered normally from passively induced acute disease. DX5+ cells were sorted by FACS into DX5+ αβTCR+ and DX5+ αβTCR− populations. Only recipients of the former recovered normally from clinical disease. These results indicate that recovery from acute EAE is an active process that requires NK1.1+, DX5+ αβ+ TCR spleen cells and IFN-γ.
Molecular Basis of Deficient IL-2 Production in T Cells from Patients with Systemic Lupus Erythematosus
Authors: Solomou Elena E. , Juang Yuang-Taung , Gourley Mark F. , Kammer Gary M. , Tsokos George C. 
Published: April 2014

Abstract
Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease characterized by diverse cellular and biochemical aberrations, including decreased production of IL-2. Here we show that nuclear extracts from unstimulated SLE T cells, unlike extracts from normal T cells, express increased amounts of phosphorylated cAMP-responsive element modulator (p-CREM) that binds the −180 site of the IL-2 promoter. Nuclear extracts from stimulated normal T cells display increased binding of phosphorylated cAMP-responsive element binding protein (p-CREB) to the −180 site of the IL-2 promoter, whereas nuclear extracts from stimulated SLE T cells display primarily p-CREM and decreased p-CREB binding. In SLE T cells, p-CREM bound to the transcriptional coactivators, CREB binding protein and p300. Increased expression of p-CREM correlated with decreased production of IL-2. The transcription of a reporter gene driven by the −180 site was enhanced in normal T cells, but was suppressed in SLE T cells. These experiments demonstrate that transcriptional repression is responsible for the decreased production of IL-2 by SLE T cells.
Identification of a Matrix-Degrading Phenotype in Human Tuberculosis In Vitro and In Vivo
Authors: Price Nicholas M. , Farrar Jeremy , Chau Tran Thi Hong , Mai Nguyen Thi Hoang , Hien Tran Tinh , Friedland Jon S. 
Published: April 2014

Abstract
Tuberculous meningitis is characterized by cerebral tissue destruction. Monocytes, pivotal in immune responses to Mycobacterium tuberculosis, secrete matrix metalloproteinase-9 (MMP-9), which facilitates leukocyte migration across the blood-brain barrier, but may cause cerebral injury. In vitro, human monocytic (THP-1) cells infected by live, virulent M. tuberculosis secreted MMP-9 in a dose-dependent manner. At 24 h, MMP-9 concentrations increased 10-fold to 239 ± 75 ng/ml (p = 0.001 vs controls). MMP-9 mRNA became detectable at 24–48 h. In contrast, tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) gene expression and secretion were similar to constitutive levels from controls at 24 h and increased just 5-fold by 48 h. In vivo investigation revealed MMP-9 concentration per leukocyte in cerebrospinal fluid (CSF) from tuberculous meningitis patients (n = 23; median (range), 3.19 (0.19–31.00) ng/ml/cell) to be higher than that in bacterial (n = 12; 0.23 (0.01–18.37) ng/ml/cell) or viral meningitis (n = 20; 0.20 (0.04–31.00) ng/ml/cell; p &lt; 0.01). TIMP-1, which was constitutively secreted into CSF, was not elevated in tuberculous compared with bacterial meningitis or controls. Thus, a phenotype in which MMP-9 activity is relatively unrestricted by TIMP-1 developed both in vitro and in vivo. This is functionally significant, since MMP-9 concentrations per CSF leukocyte (but not TIMP-1 concentrations) were elevated in fatal tuberculous meningitis and in patients with signs of cerebral tissue damage (unconsciousness, confusion, or neurological deficit; p &lt; 0.05). However, MMP-9 activity was unrelated to the severity of systemic illness. In summary, M. tuberculosis-infected monocytic cells develop a matrix-degrading phenotype, which was observed in vivo and relates to clinical signs reflecting cerebral injury in tuberculous meningitis.
A Milk Protein Lactoferrin Enhances Human T Cell Leukemia Virus Type I and Suppresses HIV-1 Infection
Authors: Moriuchi Masako , Moriuchi Hiroyuki 
Published: April 2014

Abstract
Human T cell leukemia virus type I (HTLV-I) and HIV-1, causative agents of adult T cell leukemia/lymphoma and AIDS, respectively, are transmitted vertically via breast milk. Here we demonstrate that lactoferrin, a milk protein that has a variety of antimicrobial and immunomodulatory activities, facilitates replication of HTLV-I in lymphocytes derived from asymptomatic HTLV-I carriers and transmission to cord blood lymphocytes in vitro. Transient expression assays revealed that lactoferrin can transactivate HTLV-I long terminal repeat promoter. In contrast, lactoferrin inhibits HIV-1 replication, at least in part, at the level of viral fusion/entry. These results suggest that lactoferrin may have different effects on vertical transmission of the two milk-borne retroviruses.
Environmental Modulation of Autoimmune Arthritis Involves the Spontaneous Microbial Induction of T Cell Responses to Regulatory Determinants Within Heat Shock Protein 65
Authors: Moudgil Kamal D. , Kim Eugene , Yun Oliver J. , Chi Howard H. , Brahn Ernest , Sercarz Eli E. 
Published: April 2014

Abstract
Both genetic and environmental factors are believed to be involved in the induction of autoimmune diseases. Adjuvant arthritis (AA) is inducible in susceptible rat strains by injection of Mycobacterium tuberculosis, and arthritic rats raise T cell responses to the 65-kDa mycobacterial heat-shock protein (Bhsp65). We observed that Fischer 344 (F344) rats raised in a barrier facility (BF-F344) are susceptible to AA, whereas F344 rats maintained in a conventional facility (CV-F344) show significantly reduced incidence and severity of AA, despite responding well to the arthritogenic determinant within Bhsp65. The acquisition of protection from AA can be circumvented if rats are maintained on neomycin/acidified water. Strikingly, naive unimmunized CV-F344 rats but not BF-F344 rats raised T cell responses to Bhsp65 C-terminal determinants (BCTD) (we have previously shown that BCTD are involved in regulation of acute AA in the Lewis rat); however, T cells of naive CV-F344 and BF-F344 gave a comparable level of proliferative response to a mitogen, but no response at all to an irrelevant Ag. Furthermore, adoptive transfer into naive BF-F344 rats of splenic cells of naive CV-F344 rats (restimulated with BCTD in vitro) before induction of AA resulted in a considerably reduced severity of AA. These results suggest that spontaneous (inadvertent) priming of BCTD-reactive T cells, owing to determinant mimicry between Bhsp65 and its homologues in microbial agents in the conventional environment, is involved in modulating the severity of AA in CV-F344 rats. These results have important implications in broadening understanding of the host-microbe interaction in human autoimmune diseases.
Opposite Effects of IL-10 on the Ability of Dendritic Cells and Macrophages to Replicate Primary CXCR4-Dependent HIV-1 Strains
Authors: Ancuta Petronela , Bakri Youssef , Chomont Nicolas , Hocini Hakim , Gabuzda Dana , Haeffner-Cavaillon Nicole 
Published: April 2014

AbstractWe investigated the effect of IL-10 on replication of primary CXCR4-dependent (X4) HIV-1 strains by monocyte-derived dendritic cells (DCs) and macrophages (MΦs). MΦs efficiently replicated CXCR4-dependent HIV-1 (X4 HIV-1) strains NDK and VN44, whereas low levels of p24 were detected in supernatants of infected DCs. IL-10 significantly increased X4 HIV-1 replication by DCs but blocked viral production by MΦs as determined by p24 levels and semiquantitative nested PCR. IL-10 up-regulated CXCR4 mRNA and protein expression on DCs and MΦs, suggesting that IL-10 enhances virus entry in DCs but blocks an entry and/or postentry step in MΦs. The effect of IL-10 on the ability of DCs and MΦs to transmit virus to autologous CD4+ T lymphocytes was investigated in coculture experiments. DCs exhibited a greater ability than did MΦs to transmit a vigorous infection to CD4+ T cells despite their very low replication capacity. IL-10 had no effect on HIV-1 replication in DC:T cell cocultures but markedly decreased viral production in MΦ:T cell cocultures. These results demonstrate that IL-10 has opposite effects on the replication of primary X4 HIV-1 strains by DCs and MΦs. IL-10 increases X4-HIV-1 replication in DCs but does not alter their capacity to transmit virus to CD4+ T lymphocytes. These findings suggest that increased levels of IL-10 observed in HIV-1-infected patients with disease progression may favor the replication of X4 HIV-1 strains in vivo.
Dendritic Cells Injected Via Different Routes Induce Immunity in Cancer Patients
Authors: Fong Lawrence , Brockstedt Dirk , Benike Claudia , Wu Lijun , Engleman Edgar G. 
Published: April 2014

Abstract
Dendritic cells (DC) represent potent APCs that are capable of generating tumor-specific immunity. We performed a pilot clinical trial using Ag-pulsed DC as a tumor vaccine. Twenty-one patients with metastatic prostate cancer received two monthly injections of DC enriched and activated from their PBMC. DC were cocultured ex vivo with recombinant mouse prostatic acid phosphatase as the target neoantigen. Following enrichment, DC developed an activated phenotype with up-regulation of CD80, CD86, and CD83 expression. During culture, the DC maintained their levels of various adhesion molecules, including CD44, LFA-1, cutaneous lymphocyte-associated Ag, and CD49d, up-regulated CCR7, but lost CD62 ligand and CCR5. In the absence of CD62 ligand, such cells would not be expected to prime T cells efficiently if administered i.v. due to their inability to access lymphoid tissue via high endothelial venules. To assess this possibility, three patient cohorts were immunized with Ag-pulsed DC by i.v., intradermal (i.d.), or intralymphatic (i.l.) injection. All patients developed Ag-specific T cell immune responses following immunization, regardless of route. Induction of IFN-γ production, however, was seen only with i.d. and i.l. routes of administration, and no IL-4 responses were seen regardless of route, consistent with the induction of Th1-type immunity. Five of nine patients who were immunized by the i.v. route developed Ag-specific Abs compared with one of six for i.d. and two of six for i.l. routes. These results suggest that while activated DC can prime T cell immunity regardless of route, the quality of this response and induction of Ag-specific Abs may be affected by the route of administration.
Cutting Edge: Intravenous Soluble Antigen Is Presented to CD4 T Cells by CD8− Dendritic Cells, but Cross-Presented to CD8 T Cells by CD8+ Dendritic Cells
Authors: Pooley Joanne L. , Heath William R. , Shortman Ken 
Published: April 2014

AbstractMouse spleen contains three distinct mature dendritic cell (DC) populations (CD4+8−, CD4−8−, and CD4−8+) which retain a capacity to take up particulate and soluble Ags. Although the three splenic DC subtypes showed similar uptake of injected soluble OVA, they differed markedly in their capacity to present this Ag and activate proliferation in OVA-specific CD4 or CD8 T cells. For class II MHC-restricted presentation to CD4 T cells, the CD8− DC subtypes were more efficient, but for class I MHC-restricted presentation to CD8 T cells, the CD8+ DC subtype was far more effective. This differential persisted when the DC were activated with LPS. The CD8+ DC are therefore specialized for in vivo cross-presentation of exogenous soluble Ags into the class I MHC presentation pathway.
Cutting Edge: Distinct Motifs Within CD28 Regulate T Cell Proliferation and Induction of Bcl-XL
Authors: Burr John S. , Savage Nigel D. L. , Messah Grace E. , Kimzey Stephanie L. , Shaw Andrey S. , Arch Robert H. , Green Jonathan M. 
Published: April 2014

Abstract
CD28 provides an important costimulatory signal in T cell activation that regulates multiple cellular processes including proliferation and survival. Several signal transduction pathways are activated by CD28; however, the precise biochemical mechanism by which CD28 regulates T cell function remains controversial. Retroviral gene transfer into primary T cells from TCR-transgenic, CD28-deficient mice was used to determine the specific sequences within CD28 that determine function. Discrete regions of the cytoplasmic domain of CD28 were identified that differentially regulate T cell proliferation and induction of the anti-apoptotic protein Bcl-XL. Mutation of C-terminal proline residues abrogated the proliferative and cytokine regulatory features of CD28 costimulation while preserving Bcl-XL induction. Conversely, mutation of residues important in phosphatidylinositol 3-kinase activation partially inhibited proliferation but prevented induction of Bcl-XL. Thus the ability of CD28 to regulate proliferation and induction of Bcl-XL map to distinct motifs, suggesting independent signaling cascades modulate these biologic effects.
The Role of NF-κB in TNF-Related Apoptosis-Inducing Ligand (TRAIL)-Induced Apoptosis of Melanoma Cells
Authors: Franco Agustin V. , Zhang Xu Dong , Van Berkel Elisabeth , Sanders Jayne E. , Zhang Xi Yi , Thomas Wayne D. , Nguyen Tam , Hersey Peter 
Published: April 2014

Abstract
Previous studies have shown that activation of NF-κB can inhibit apoptosis induced by a number of stimuli. It is also known that TNF-related apoptosis-inducing ligand (TRAIL) can activate NF-κB through the death receptors TRAIL-R1 and TRAIL-R2, and decoy receptor TRAIL-R4. In view of these findings, we have investigated the extent to which activation of NF-κB may account for the variable responses of melanoma lines to apoptosis induced by TRAIL and other TNF family members. Pretreatment of the melanoma lines with the proteasome inhibitor N-acetyl-l-leucinyl-l-leucinyl-l-norleucinal (LLnL), which is known to inhibit activation of NF-κB, was shown to markedly increase apoptosis in 10 of 12 melanoma lines with death receptors for TRAIL. The specificity of results for inhibition of NF-κB activation was supported by an increase of TRAIL-induced apoptosis in melanoma cells transfected with a degradation-resistant IκBα. Furthermore, studies with NF-κB reporter constructs revealed that the resistance of melanoma lines to TRAIL-induced apoptosis was correlated to activation of NF-κB in response to TRAIL. TRAIL-resistant sublines that were generated by intermittent exposure to TRAIL were shown to have high levels of activated NF-κB, and resistance to TRAIL could be reversed by LLnL and by the superrepressor form of IκBα. Therefore, these results suggest that activation of NF-κB by TRAIL plays an important role in resistance of melanoma cells to TRAIL-induced apoptosis and further suggest that inhibitors of NF-κB may be useful adjuncts in clinical use of TRAIL against melanoma.
Papillomavirus-Like Particles Induce Acute Activation of Dendritic Cells
Authors: Lenz Petra , Day Patricia M. , Pang Yuk-Ying S. , Frye Stephan A. , Jensen Peter N. , Lowy Douglas R. , Schiller John T. 
Published: April 2014

AbstractThe role of viral structural proteins in the initiation of adaptive immune responses is poorly understood. To address this issue, we focused on the effect of noninfectious papillomavirus-like particles (VLPs) on dendritic cell (DC) activation. We found that murine bone marrow-derived dendritic cells (BMDCs) effectively bound and rapidly internalized bovine papillomavirus VLPs. Exposure to fully assembled VLPs of bovine papillomavirus, human papillomavirus (HPV)16 or HPV18, but not to predominately disordered HPV16 capsomers, induced acute phenotypic maturation of BMDCs. Structurally similar polyomavirus VLPs bound to the DC surface and were internalized, but failed to induce maturation. DCs that had incorporated HPV16 VLPs produced proinflammatory cytokines IL-6 and TNF-α; however, the release of these cytokines was delayed relative to LPS activation. Production of IL-12p70 by VLP-exposed DCs required the addition of syngeneic T cells or rIFN-γ. Finally, BMDCs pulsed with HPV16 VLPs induced Th1-dominated primary T cell responses in vitro. Our data provide evidence that DCs respond to intact papillomavirus capsids and that they play a central role in VLP-induced immunity. These results offer a mechanistic explanation for the striking ability of papillomavirus VLP-based vaccines to induce potent T and B cell responses even in the absence of adjuvant.
Three-Cell Interactions in T Cell-Mediated Suppression? A Mathematical Analysis of Its Quantitative Implications
Authors: León Kalet , Peréz Rolando , Lage Agustin , Carneiro Jorge 
Published: April 2014

Abstract
Aiming to further our understanding of T cell-mediated suppression, we investigate the plausibility of the hypothesis that regulatory T cells suppress other T cells (target cells), while both cells are conjugated with one APC. We use a mathematical model to analyze the proliferation inhibition scored during in vitro suppression assays. This model is a radical simplification of cell culture reality, assuming that thymidine incorporation is proportional to the number of target cells that would instantaneously form conjugates with APCs that are free of regulatory cells. According to this model the inhibition index should be mainly determined by the number of regulatory cells per APC and should be insensitive to the number of target cells. We reanalyzed several published data sets, confirming this expectation. Furthermore, we demonstrate that the instantaneous inhibition index has an absolute limit as a function of the number of regulatory cells per APC. By calculating this limit we find that the model can explain the data under two non-mutually exclusive conditions. First, only ∼15% of APCs used in the suppression assays form conjugates with T cells. Second, the growth of the regulatory cell population depends on the target cells, such that the number of regulatory cells per APC increases when they are cocultured with target cells and overcomes its limit. However, if neither of these testable conditions is fulfilled, then one could conclude that suppression in vitro does not require the formation of multicellular conjugates.
Defined Flanking Spacers and Enhanced Proteolysis Is Essential for Eradication of Established Tumors by an Epitope String DNA Vaccine
Authors: Velders Markwin P. , Weijzen Sanne , Eiben Gretchen L. , Elmishad Amira G. , Kloetzel Peter-M. , Higgins Terry , Ciccarelli Richard B. , Evans Mererid , Man Stephen , Smith Larry , Kast W. Martin 
Published: April 2014

Abstract
Loss of immunogenic epitopes by tumors has urged the development of vaccines against multiple epitopes. Recombinant DNA technologies have opened the possibility to develop multiepitope vaccines in a relatively rapid and efficient way. We have constructed four naked DNA-based multiepitope vaccines, containing CTL, Th cell, and B cell epitopes of the human papillomavirus type 16. Here we show that gene gun-mediated vaccination with an epitope-based DNA vaccine protects 100% of the vaccinated mice against a lethal tumor challenge. The addition of spacers between the epitopes was crucial for the epitope-induced tumor protection, as the same DNA construct without spacers was significantly less effective and only protected 50% of the mice. When tested for therapeutic potential, only the epitope construct with defined spacers significantly reduced the size of established tumors, but failed to induce tumor regression. Only after targeting the vaccine-encoded protein to the protein degradation pathway by linking it to ubiquitin, the vaccine-induced T cell-mediated eradication of 100% of 7-day established tumors in mice. The finding that defined flanking sequences around epitopes and protein targeting dramatically increased the efficacy of epitope string DNA vaccines against established tumors will be of importance for the further development of multiepitope DNA vaccines toward clinical application.
Engineering of Macrophages to Produce IFN-γ in Response to Hypoxia
Authors: Carta Luca , Pastorino Sandra , Melillo Giovanni , Bosco Maria C. , Massazza Stefano , Varesio Luigi 
Published: April 2014

Abstract
Activation of murine macrophages (Mφ) requires the collaboration of signals derived from the immune system and the environment. In this study, we engineered a murine Mφ cell line to become activated in response to an environmental signal, hypoxia, as the sole stimulus. Hypoxia is a condition of low oxygen tension, occurring in several pathological tissues, which acts in synergy with IFN-γ to induce full Mφ activation. We transfected the ANA-1 murine Mφ cell line with a construct containing the IFN-γ gene controlled by a synthetic promoter inducible by hypoxia (HRE3x-Tk), and we characterized the cellular and molecular biology of the engineered Mφ under normoxia or hypoxia. Engineered Mφ in normoxia expressed basal levels of IFN-γ mRNA and protein that were strongly augmented by shifting the cells to hypoxia. Furthermore, they responded to the synthesized IFN-γ with induction of IFN-responsive factor-1 and 2′-5′-oligoadenylate synthase expression. Under normoxic conditions, the engineered Mφ had a significant constitutive level of Ia Ags and Fc receptors. Hypoxia induced further augmentation of Ia and Fc expression. Finally, hypoxia induced inducible NO synthase expression, and subsequent reoxygenation led to the production of NO. In conclusion, the engineered Mφ, which produce IFN-γ in an inducible manner, express new biochemical and functional properties in response to low oxygen environment as the sole stimulus, thereby circumventing the need for costimulation by other immune system-derived signals.