bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of the Isotype of the Light Chain on the Properties of IgG
Authors: Montaño Ramon F. , Morrison Sherie L. 
Published: April 2014

Abstract
It is widely appreciated that the isotype of the H chain of the Ab molecule influences its functional properties. We have now investigated the contribution of the isotype of the L chain to the structural and functional properties of the Ab molecule. In these studies, the L chain variable region of a murine anti-dansyl Ab was joined to either human κ or λ constant region domains and expressed with mouse-human chimeric H chains of the four human IgG isotypes. The resulting Abs were secreted as fully assembled molecules although, as has been previously observed, IgG4 with either κ or λ L chains was also secreted as HL half-molecules. However, the isotype of the L chain can influence the kinetics of intracellular assembly with IgG1λ, IgG2λ, and IgG4λ assembling more slowly than their κ counterparts. The isotype of the L chain also influenced the susceptibility of the interchain disulfide bonds to attack by reducing agents with variable effects, depending on the isotype of the H chains. For IgG2, but not for IgG1, -3, and -4, the isotype of the L chain influenced the rate of clearance in mice, with IgG2λ having a shorter in vivo half-life than IgG2κ. Only slight differences were also observed between λ and κ molecules in their kinetics of binding to and dissociation from the hapten dansyl. These studies demonstrate that the isotype of the L chain has only a slight impact on the structural and functional properties of variable region identical Abs.
HLA-DR1 (DRB1*0101) and DR4 (DRB1*0401) Use the Same Anchor Residues for Binding an Immunodominant Peptide Derived from Human Type II Collagen
Authors: Rosloniec Edward F. , Whittington Karen B. , Zaller Dennis M. , Kang Andrew H. 
Published: April 2014

Abstract
Rheumatoid arthritis is an autoimmune disease in which susceptibility is strongly associated with the expression of specific HLA-DR haplotypes, including DR1 (DRB1*0101) and DR4 (DRB1*0401). As transgenes, both of these class II molecules mediate susceptibility to an autoimmune arthritis induced by immunization with human type II collagen (hCII). The dominant T cell response of both the DR1 and DR4 transgenic mice to hCII is focused on the same determinant core, CII(263–270). Peptide binding studies revealed that the affinity of DR1 and DR4 for CII(263–270) was at least 10 times less than that of the model Ag HA(307–319), and that the affinity of DR4 for the CII peptide is 3-fold less than that of DR1. As predicted based on the crystal structures, the majority of the CII-peptide binding affinity for DR1 and DR4 is controlled by the Phe263; however, unexpectedly the adjacent Lys264 also contributed significantly to the binding affinity of the peptide. Only these two CII amino acids were found to provide binding anchors. Amino acid substitutions at the remaining positions had either no effect or significantly increased the affinity of the hCII peptide. Affinity-enhancing substitutions frequently involved replacement of a negative charge, or Gly or Pro, hallmark amino acids of CII structure. These data indicate that DR1 and DR4 bind this CII peptide in a nearly identical manner and that the primary structure of CII may dictate a different binding motif for DR1 and DR4 than has been described for other peptides that bind to these alleles.
How H13 Histocompatibility Peptides Differing by a Single Methyl Group and Lacking Conventional MHC Binding Anchor Motifs Determine Self-Nonself Discrimination
Authors: Ostrov David A. , Roden Matthew M. , Shi Wuxian , Palmieri Edith , Christianson Gregory J. , Mendoza Lisa , Villaflor Gilbert , Tilley Darcie , Shastri Nilabh , Grey Howard , Almo Steven C. , Roopenian Derry , Nathenson Stanley G. 
Published: April 2014

Abstract
The mouse H13 minor histocompatibility (H) Ag, originally detected as a barrier to allograft transplants, is remarkable in that rejection is a consequence of an extremely subtle interchange, P4Val/Ile, in a nonamer H2-Db-bound peptide. Moreover, H13 peptides lack the canonical P5Asn central anchor residue normally considered important for forming a peptide/MHC complex. To understand how these noncanonical peptide pMHC complexes form physiologically active TCR ligands, crystal structures of allelic H13 pDb complexes and a P5Asn anchored pDb analog were solved to high resolution. The structures show that the basis of TCRs to distinguish self from nonself H13 peptides is their ability to distinguish a single solvent-exposed methyl group. In addition, the structures demonstrate that there is no need for H13 peptides to derive any stabilization from interactions within the central C pocket to generate fully functional pMHC complexes. These results provide a structural explanation for a classical non-MHC-encoded H Ag, and they call into question the requirement for contact between anchor residues and the major MHC binding pockets in vaccine design.
Ceramide-Rich Membrane Rafts Mediate CD40 Clustering
Authors: Grassmé Heike , Jendrossek Verena , Bock Jürgen , Riehle Andrea , Gulbins Erich 
Published: April 2014

AbstractMany receptor systems use receptor clustering for transmembrane signaling. In this study, we show that acid sphingomyelinase (ASM) is essential for the clustering of CD40. Stimulation of lymphocytes via CD40 ligation results in ASM translocation from intracellular stores, most likely vesicles, into distinct membrane domains on the extracellular surface of the plasma membrane. Surface ASM initiates a release of extracellularly oriented ceramide, which in turn mediates CD40 clustering in sphingolipid-rich membrane domains. ASM, ceramide, and CD40 colocalize in the cap-like structure of stimulated cells. Deficiency of ASM, destruction of sphingolipid-rich rafts, or neutralization of surface ceramide prevents CD40 clustering and CD40-initiated cell signaling. These findings indicate that the ASM-mediated release of ceramide and/or metabolites of ceramide regulate clustering of CD40, which seems to be a prerequisite for cellular activation via CD40.
Regulation of Human β-Defensin-2 in Gingival Epithelial Cells: The Involvement of Mitogen-Activated Protein Kinase Pathways, But Not the NF-κB Transcription Factor Family
Authors: Krisanaprakornkit Suttichai , Kimball Janet R. , Dale Beverly A. 
Published: April 2014

Abstract
Stratified epithelia of the oral cavity are continually exposed to bacterial challenge that is initially resisted by neutrophils and epithelial factors, including antimicrobial peptides of the β-defensin family. Previous work has shown that multiple signaling pathways are involved in human β-defensin (hBD)-2 mRNA regulation in human gingival epithelial cells stimulated with a periodontal bacterium, Fusobacterium nucleatum, and other stimulants. The goal of this study was to further characterize these pathways. The role of NF-κB in hBD-2 regulation was investigated initially due to its importance in inflammation and infection. Nuclear translocation of p65 and NF-κB activation was seen in human gingival epithelial cells stimulated with F. nucleatum cell wall extract, indicating possible involvement of NF-κB in hBD-2 regulation. However, hBD-2 induction by F. nucleatum was not blocked by pretreatment with two NF-κB inhibitors, pyrrolidine dithiocarbamate and the proteasome inhibitor, MG132. To investigate alternative modes of hBD-2 regulation, we explored involvement of mitogen-activated protein kinase pathways. F. nucleatum activated p38 and c-Jun NH2-terminal kinase (JNK) pathways, whereas it had little effect on p44/42. Furthermore, inhibition of p38 and JNK partially blocked hBD-2 mRNA induction by F. nucleatum, and the combination of two inhibitors completely blocked expression. Our results suggest that NF-κB is neither essential nor sufficient for hBD-2 induction, and that hBD-2 regulation by F. nucleatum is via p38 and JNK, while phorbol ester induces hBD-2 via the p44/42 extracellular signal-regulated kinase pathway. Studies of hBD-2 regulation provide insight into how its expression may be enhanced to control infection locally within the mucosa and thereby reduce microbial invasion into the underlying tissue.
IFN-α Secretion by Type 2 Predendritic Cells Up-Regulates MHC Class I in the HIV-1-Infected Thymus
Authors: Keir Mary E. , Stoddart Cheryl A. , Linquist-Stepps Valerie , Moreno Mary E. , McCune Joseph M. 
Published: April 2014

Abstract
The ability of HIV-1 to evade the host immune response leads to the establishment of chronic infection. HIV-1 has been reported to up-regulate MHC I molecules on the surface of thymocytes from HIV-1-infected thymus. We demonstrate in this study that HIV-1 up-regulates MHC I on both HIV-1-infected and uninfected thymocytes in a manner that is independent of Nef, proportional to viral replication, and entirely mediated by IFN-α. IL-3Rα+ type 2 predendritic cells (preDC2) resident in the thymic medulla secrete IFN-α, which acts on IFN-αβR-expressing immature thymocytes to induce MHC I expression. Furthermore, thymic preDC2 are permissive for HIV-1 infection and positive for intracellular p24. These data demonstrate the ability of IFN-α secreted by preDC2 to induce MHC I up-regulation in the HIV-1-infected human thymus.
Intensity of the Vaccine-Elicited Immune Response Determines Tumor Clearance
Authors: Perez-Diez Ainhoa , Spiess Paul J. , Restifo Nicholas P. , Matzinger Polly , Marincola Francesco M. 
Published: April 2014

Abstract
Tumor Ag-specific vaccines used for cancer immunotherapy can generate specific CD8 responses detectable in PBMCs and in tumor-infiltrating lymphocytes. However, human studies have shown that detection of a systemic vaccine-induced response does not necessarily correlate with the occasional instances of tumor rejection. Because this discrepancy might partially be attributable to the genetic heterogeneity of human cancers, as well as to the immunosuppressive effects of previous treatments, we turned to a mouse model in which these variables could be controlled to determine whether a relationship exists between the strength of vaccine-induced immune responses and tumor rejection. We challenged mice with the β-galactosidase (β-gal)-expressing tumor cells, C25.F6, vaccinated them with β-gal-carrying viral vectors, and used quantitative RT-PCR to measure the vaccine-induced immune response of splenocytes directly ex vivo. We found that the strength of the response increased with increasing doses of β-gal-carrying vector and/or upon boosting with a heterologous β-gal-carrying virus. Most importantly, we found that the strength of the detected immune response against this foreign Ag strongly correlated with reduction in the number of lung metastases. The results from this mouse model have major implications for the implementation of tumor vaccines in humans.
The Protective Role of Nitric Oxide in a Neurotoxicant- Induced Demyelinating Model
Authors: Arnett Heather A. , Hellendall Ron P. , Matsushima Glenn K. , Suzuki Kinuko , Laubach Victor E. , Sherman Paula , Ting Jenny P.-Y. 
Published: April 2014

Abstract
Demyelination is often associated with acute inflammatory events involving the recruitment-activation of microglia/macrophage, astrocytes, and leukocytes. The ultimate role of inflammatory products in demyelinating disease and in the survival of oligodendrocytes, the myelin forming cells, is unresolved. The current study examines the role of inducible NO synthase (iNOS)-derived NO in a neurotoxicant-induced model of demyelination. NO levels were greatly elevated in the midline corpus callosum during demyelination in genetically intact C57BL/6 mice, and this NO was due solely to the induction of iNOS, as the correlates of NO were not found in mice lacking iNOS. C57BL/6 mice lacking iNOS exhibited more demyelination, but did not display an increased overall cellularity in the corpus callosum, attributable to an unimpeded microglia/macrophage presence. An enhanced course of pathology was noted in mice lacking iNOS. This was associated with a greater depletion of mature oligodendrocytes, most likely due to apoptosis of oligodendrocytes. Microglia and astrocytes did not undergo apoptosis during treatment. Our results suggest a moderately protective role for NO during acute inflammation-association demyelination.
Multilevel Dysregulation of STAT3 Activation in Anaplastic Lymphoma Kinase-Positive T/Null-Cell Lymphoma
Authors: Zhang Qian , Raghunath Puthryaveett N. , Xue Liquan , Majewski Miroslaw , Carpentieri David F. , Odum Niels , Morris Stephan , Skorski Tomasz , Wasik Mariusz A. 
Published: April 2014

Abstract
Accumulating evidence indicates that expression of anaplastic lymphoma kinase (ALK), typically due to t(2;5) translocation, defines a distinct type of T/null-cell lymphoma (TCL). The resulting nucleophosmin (NPM) /ALK chimeric kinase is constitutively active and oncogenic. Downstream effector molecules triggered by NPM/ALK remain, however, largely unidentified. Here we report that NPM/ALK induces continuous activation of STAT3. STAT3 displayed tyrosine phosphorylation and DNA binding in all (four of four) ALK+ TCL cell lines tested. The activation of STAT3 was selective because none of the other known STATs was consistently tyrosine phosphorylated in these cell lines. In addition, malignant cells in tissue sections from all (10 of 10) ALK+ TCL patients expressed tyrosine-phosphorylated STAT3. Transfection of BaF3 cells with NPM/ALK resulted in tyrosine phosphorylation of STAT3. Furthermore, STAT3 was constitutively associated with NPM/ALK in the ALK+ TCL cell lines. Additional studies into the mechanisms of STAT3 activation revealed that the ALK+ TCL cells expressed a positive regulator of STAT3 activation, protein phosphatase 2A (PP2A), which was constitutively associated with STAT3. Treatment with the PP2A inhibitor calyculin A abrogated tyrosine phosphorylation of STAT3. Finally, ALK+ T cells failed to express a negative regulator of activated STAT3, protein inhibitor of activated STAT3. These data indicate that NPM/ALK activates STAT3 and that PP2A and lack of protein inhibitor of activated STAT3 may be important in maintaining STAT3 in the activated state in the ALK+ TCL cells. These results also suggest that activated STAT3, which is known to display oncogenic properties, as well as its regulatory molecules may represent attractive targets for novel therapies in ALK+ TCL.
Cutting Edge: CpG DNA Inhibits Dendritic Cell Apoptosis by Up-Regulating Cellular Inhibitor of Apoptosis Proteins Through the Phosphatidylinositide-3′-OH Kinase Pathway
Authors: Park Yunji , Lee Seung Woo , Sung Young Chul 
Published: April 2014

Abstract
CpG DNA has been recognized as a powerful stimulant of dendritic cells (DCs). In this study, we demonstrate that CpG DNA inhibits spontaneous apoptosis of DCs. CpG DNA up-regulated cellular inhibitor of apoptosis proteins (cIAPs) as well as Bcl-2 and Bcl-xL, but down-regulated active caspase-3. Although CpG DNA activated p38 mitogen-activated protein kinase, extracellular signal-related kinase, and phosphatidylinositide-3′-OH kinase (PI3K), only the blocking of PI3K inhibited the CpG DNA-induced DC survival. Moreover, while the expression of Bcl-2 and Bcl-xL depends on both PI3K and p38 mitogen-activated protein kinase, the up-regulation of cIAPs and the down-regulation of active caspase-3 by CpG DNA require PI3K activation, suggesting PI3K-dependent up-regulation of cIAPs in the antiapoptotic activity of CpG DNA in DCs. This study indicates that CpG DNA provides a survival signal to DCs, which might be one of mechanisms by which bacterial DNA stimulates and maintains the innate immune responses.
Decreased IL-15 May Contribute to Elevated IgE and Acute Inflammation in Atopic Dermatitis
Authors: Ong Peck Y. , Hamid Qutayba A. , Travers Jeffrey B. , Strickland Ian , Kerithy Muhamed Al , Boguniewicz Mark , Leung Donald Y. M. 
Published: April 2014

AbstractPBMC and acute skin lesions of patients with atopic dermatitis (AD) are characterized by increased IL-4 and IL-13, but decreased IFN-γ production. This bias toward an increased Th2 cytokine profile may contribute to the elevated IgE levels and acute skin inflammation seen in AD. In this study, we examined the levels of IL-15, a Th1-like cytokine, in the PBMC and the skin lesions of AD patients. IL-15 secretion by Staphylococcal enterotoxin B-treated PBMC of AD patients was significantly lower than that of normals and psoriasis patients (p &lt; 0.001). Membrane-bound IL-15 expression as measured by mean fluorescence intensity and percentage of IL-15-positive cells in Staphylococcal enterotoxin B-treated monocytes of AD patients (644 ± 49% and 12.7 ± 0.6%, respectively) were significantly lower than that of normals (869 ± 56% and 15.8 ± 1.2%, respectively) and psoriasis patients (1488 ± 217% and 22.7 ± 0.8%, respectively; p &lt; 0.0007 and p &lt; 0.0001, respectively). The membrane-bound IL-15 expression was also significantly lower in the control monocytes of AD patients compared with that in normals and psoriasis patients. There was no significant difference in the absolute number or percentage of monocytes between the study subjects. However, psoriasis skin lesions were found to have significantly more IL-15 mRNA-expressing cells (22.4 ± 1.7) compared with that in acute AD (7.5 ± 1.7) and chronic AD (13.7 ± 1.7) skin lesions (p &lt; 0.05). IL-15 enhanced IFN-γ production by the PBMC of AD patients (p &lt; 0.01), but not by that of normal individuals or psoriasis patients. In addition, IL-15 was found to suppress IgE synthesis (p &lt; 0.01) by the PBMC of AD patients. These data support the concept that reduced IL-15 expression may contribute to the pathogenesis of AD.
Identification of Multiple Isolated Lymphoid Follicles on the Antimesenteric Wall of the Mouse Small Intestine
Authors: Hamada Hiromasa , Hiroi Takachika , Nishiyama Yasuhiro , Takahashi Hidemi , Masunaga Yohei , Hachimura Satoshi , Kaminogawa Shuichi , Takahashi-Iwanaga Hiromi , Iwanaga Toshihiko , Kiyono Hiroshi , Yamamoto Hiroshi , Ishikawa Hiromichi 
Published: April 2014

Abstract
We have revealed that 100–200 clusters, filled with closely packed lymphocytes, can be found throughout the length of the antimesenteric wall of the mouse small intestine. They are composed of a large B cell area, including a germinal center, and epithelia overlying the clusters contain M cells. A large fraction of B cells displays B220+CD19+CD23+IgMlowIgDhighCD5−Mac-1− phenotype, and the composition of IgA+ B cells is smaller but substantial. To our knowledge, these clusters are the first identification of isolated lymphoid follicles (ILF) in mouse small intestine. ILF can be first detected at 7 (BALB/c mice) and 25 (C57BL/6 mice) days after birth, and lymphoid clusters equivalent in terms of cellular mass to ILF are present in germfree, athymic nude, RAG-2−/−, TCR-β−/−, and Ig μ-chain mutant (μm−/−) mice, although c-kit+ cells outnumber B220+ cells in germfree and athymic nude mice, and most lymphoid residents are c-kit+B220− in RAG-2−/−, TCR-β−/−, and μm−/− mice. ILF develop normally in the progeny of transplacentally manipulated Peyer’s patch (PP)-deficient mice, and decreased numbers of conspicuously atrophied ILF are present in IL-7Rα−/− PPnull mice. Neither ILF nor PP are detectable in lymphotoxin α−/− and aly/aly mice that retain well-developed cryptopatches (CP) and thymus-independent subsets of intraepithelial T cells, whereas ILF, PP, CP, and thymus-independent subsets of intraepithelial T cells disappear from common cytokine receptor γ-chain mutant mice. These findings indicate that ILF, PP, and CP constitute three distinct organized gut-associated lymphoid tissues that reside in the lamina propria of the mouse small intestine.
Cutting Edge: Ectopic Expression of CD40 Ligand on B Cells Induces Lupus-Like Autoimmune Disease
Authors: Higuchi Tetsuya , Aiba Yuichi , Nomura Takashi , Matsuda Junichiro , Mochida Keiji , Suzuki Misao , Kikutani Hitoshi , Honjo Tasuku , Nishioka Kiyoshi , Tsubata Takeshi 
Published: April 2014

AbstractCD40 ligand (CD40L) is ectopically expressed on B cells in patients with systemic lupus erythematosus (SLE) and lupus-prone BXSB mice. To assess the role of the ectopic CD40L expression in development of SLE, we have established transgenic mice expressing CD40L on B cells. Some of the 12- to 14-mo-old CD40L-transgenic mice spontaneously produced autoantibodies such as antinuclear Abs, anti-DNA Abs, and antihistone Abs. Moreover, approximately half of the transgenic mice developed glomerulonephritis with immune-complex deposition, whereas the kidneys of the normal littermates showed either no pathological findings or only mild histological changes. These results indicate that CD40L on B cells causes lupus-like disease in the presence of yet unknown environmental factors that by themselves do not induce the disease. Thus, ectopic CD40L expression on B cells may play a crucial role in development of SLE.
Activation-Induced Expression of Carcinoembryonic Antigen-Cell Adhesion Molecule 1 Regulates Mouse T Lymphocyte Function
Authors: Nakajima Atsushi , Iijima Hideki , Neurath Markus F. , Nagaishi Takashi , Nieuwenhuis Edward E. S. , Raychowdhury Raktima , Glickman Jonathan , Blau Dianna M. , Russell Sara , Holmes Kathryn V. , Blumberg Richard S. 
Published: April 2014

AbstractCarcinoembryonic Ag cell adhesion molecule 1 (CEACAM1) consists of highly related homologs in humans and rodents that are characterized by significant alternate splicing generating isoforms capable of negative intracellular signaling by virtue of two immunoreceptor tyrosine-based inhibition motifs in its cytoplasmic (cyt) tail. Although human T cells have been recently observed to express CEACAM1, the expression and function of CEACAM1 in mouse T cells have not been defined. Although resting mouse spleen T cells exhibited no evidence of CEACAM1 on the cell surface, CEACAM1 was rapidly up-regulated on CD4+ and CD8+ T cells after activation with either Con A or anti-CD3 without a requirement for either de novo transcription or translation due to the fact that CEACAM1 was present intracellularly before activation. Using a GST-CEACAM1-cytoplasmic tail fusion protein, it was shown that the cytoplasmic tail of CEACAM1 bound the src homology domain-containing phosphatase 1 and adaptor protein 1 complex in its phosphorylated and nonphosphorylated states, respectively. CEACAM1 ligation with an anti-CEACAM1 mAb resulted in inhibition of an allogeneic MLR and anti-CD3 plus anti-CD28 Ab-induced proliferation of spleen T cells in vitro and inhibition of a delayed-type hypersensitivity response to oxazolone in vivo. Inhibition of the delayed-type hypersensitivity response required that the anti-CEACAM1-specific mAb be present at the time of T cell sensitization. These studies support a role for CEACAM1 as a novel class of immunoreceptor tyrosine-based inhibition motif-bearing regulatory molecules on T cells that are active during early phases of the immune response in mice.