bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of a regulatory region which controls inducible expression of the human CD200 gene (35.36)
Authors: Chen Zhiqi , Marsden Philip A , Gorczynski Reginald M 
Published: January 2023

Abstract
CD200 is a type I membrane glycoprotein and plays an important role in prevention of graft rejection, autoimmune diseases and spontaneous abortion by delivering an immunoregulatory signal through interaction with its receptor. The expression of CD200 is not only constitutive but also inducible. We previously documented evidence for C/EBPβ as being important in regulation of constitutive expression of CD200. However, the molecular mechanism(s) controlling inducible expression of CD200 are yet to be defined. Our current studies showed that the expression of CD200 was induced by ConA, IFN-γ and/or TNF-α. To investigate the potential regulatory regions responsible for inducible expression of CD200, a DNase I hypersensitivity assay was performed in Jurkat cells. A prominent hypersensitivity site was detected after stimulation and localized in the region ~ 5.6 kb upstream of the transcriptional start site. Four cis elements were identified in this region: one for NF-κB binding, one IFN-γ activation site (GAS) and two IRF binding sites. To test whether those cis elements play a critical role for inducible expression of CD200, the potential regulatory region was cloned upstream of the CD200 core promoter. Mutation of the binding site for NF-κB, GAS or the first IRF resulted in abolition of the activity of this region, whereas mutation of the second IRF had no effect. A ChIP assay was performed confirming this result.
GATA-6 mediates cell-type specific IFN-γresponse of the HLA-E gene (35.39)
Authors: Grant Quintesia , Barrett David , Zhu Sheng Zu , Ginder Gordon D 
Published: January 2023

Abstract
The human MHC Class Ib gene, HLA-E, has been shown to inhibit both Natural Killer cells and a subset of CD8+ cytotoxic T-cells by engaging the CD94/NKG2A inhibitory receptor. IFN-γ induces the expression of HLA-E as well as Class Ia molecules, which are required for killing of target cells. Since HLA-E has negative effects on immune cell killing of target cells, we have sought to identify locus-specific mechanisms of IFN-γ induction in order to identify molecular targets for selective activation of Class Ia genes, but not HLA-E. We have previously identified a unique upstream IFN-γ response region in the HLA-E promoter and showed that GATA-1 is required for its function in the K562 leukemic cell line. We have now examined the effect of GATA family members on IFN-γ induction of HLA-E in other cell types. HLA-E CAT reporter gene assays demonstrated that only epithelial cells which express GATA factors, as determined by western blot and real-time PCR, mediate a 2-to-4 fold enhanced response to IFN-γ stimulation. Functional analysis of HLA-E CAT reporter gene constructs containing mutations of the core nucleotides in the GATA binding site resulted in a four-fold decreased response to IFN-γ. Tetracycline regulated siRNA knockdown of GATA 6 expression in the SKOV3 ovarian carcinoma cell line revealed a two-to-three fold decrease in IFN-γ response of both HLA-E promoter driven constructs and the endogenous HLA-E gene. We conclude that GATA factors play a tissue specific role in regulation of IFN-γ mediated HLA-E expression.
This work was supported by National Institutes of Health Grant CA87496 and Immunology Training Grant 5T32AI007407-15.
EFFECTS OF B CELL COX-2/PGE2 ON ACTIVATION-INDUCED CYTOSINE DEAMINASE (AID) (35.4)
Authors: Mongini Patricia K. A. 
Published: January 2023

Abstract
The rate-limiting enzyme for prostaglandin E2 (PGE2) production, i.e. COX-2, was recently found to be expressed and functional within human B cells. In B2 cell cultures activated by limiting BCR:CD21 ligand and IL-4, delayed signals from BAFF and APRIL heightened COX-2 expression and ensuing PGE2 production from replicating blasts (Mongini et al., 2006, J. Immunol. 176:6736). The present study has begun to evaluate whether BAFF/APRIL-promoted COX-2/PGE2 contributes to quantitative/qualitative changes in human B cell expression of activation-induced cytosine deaminase (AID). This possibility was suggested from observations of others that
BAFF and APRIL upregulate AID and promote isotype switching andexogenous PGE2 promotes the heightened production of IgG and IgE in murine B cell cultures stimulated by LPS and IL-4.
Present studies with CFSE-labeled human B2 cells activated by BCR:CD21L, IL-4, and BAFF/APRIL indicate that by day 6 of culture, replicating blasts express significantly elevated levels of AID protein, while activated but non-replicating cells do not. AID levels were highest in daughter cells that had undergone the most divisions. While exogenously added PGE2 increased the level of AID detected within replicating blasts, COX-2 function was not essential for AID expression since COX-2 inhibitors did not block AID upregulation. Whether PGE2 may modulate the phosphorylation (activation) status of the expressed AID is being investigated. In sites of chronic inflammation, BAFF/APRIL-upregulated PGE2 in activated B cells might contribute to isotype switching and somatic hypermutation in the Ig locus, and potentially, lymphomagenic mutations in oncogenes.
The three different promoters regulate the expression of mouse 4-1BB (35.48)
Authors: Kim Jung D , Kim Chang H , Kim Young H , Kwon Byoung S 
Published: January 2023

Abstract
4-1BB(CD137) is a member of the tumor necrosis factor receptor superfamily and is expressed on avtivated T cells, monocytes and natural killer (NK) cells. The expression of 4-1BB has been known to be activation dependent except regulatory T cells. Interestingly, we found that 4-1BB has three promoter regions which could regulate 4-1BB mRNA level. Thus, we investigated expression level of three different transcripts of 4-1BB in naïve T cells and EL4 cell lines. It was reported that 4-1BB expresson was increased by several anti-cancer drugs in human peripheral blood mononuclear cells and CEM cells. We also test whether the treatment with anti-cancer drugs could induce 4-1BB expression in naïve T cells and EL4 cells. The data indicated that 4-1BB expression increased by agents such as mitomycin C, 5-FU, and doxorubicin. Especially, type II transcript of 4-1BB was preferentially induced in naïve T cells stimulated by anti-CD3 because of NFkB binding site in type II promoter region. It suggests that type II promoter region is major promoter which could be activated in naïve T cells by TCR signaling. We also found a splicing variant deleted exon 7 including transmembrane domain region could inhibit the 4-1BB signaling. Our studies demonstrated that 4-1BB has three promoter could induce the expression of 4-1BB mRNA but the type II promoter is a inducible promoter in naïve T cell and costimulatory effect through 4-1BB receptor could be modulated by soluble 4-1BB produced by splicing variant without transmembrane domain induced in activation of naïve T cells.
Alleles and isoforms of human membrane-bound IgA1 (35.50)
Authors: Hung Alfur Fu-Hsin , Chen Juin-Bo , Chang Tse Wen 
Published: January 2023

Abstract
In humans, IgA has two subclasses, IgA1 and IgA2, which contain α1 and α2 heavy chains, respectively. For both subclasses, there are also membrane-bound forms, mIgA1, and mIgA2, containing mα1 and mα2 heavy chains. Mα1 and mα2 differ from α1 and α2 by having a “membrane-anchor” peptide segment extending from the CH3 domain of α1 and α2. The membrane-anchor segment has three parts: an extracellular, a trans-membrane, and an intracellular segments. It was found previously that mα1 exists in a short and a long isoforms, referred to as mα1(I) and mα1(II), with the latter containing extra 6 amino acid residues, GSCSVA (residues 453–458), at the N-terminal of the extracellular segment. By studying the genomic and mRNA sequences of mα1 and mα2 from 30 individuals residing in Taiwan, we have found that, in addition to mα1(456S) allele, mα1 has a previously unknown allele, referred to as mα1(456C), which is present in the donor population at about the same proportion as mα1(456S). Moreover, mα1(456C) allele exists in the long isoform only and does not yield a short isoform corresponding to mα1(I). Furthermore, we have clarified that mα2 exist as short isoforms only. Future studies will examine the variations in mIgA1 in other races and the possible association of such variations with the regulation of IgA synthesis.
This research is supported by a grant, #94-2320-B007-004, from the National Science Council, Taiwan.
Regulation of Antigen Presentation by Amyloid Precursor-Like Protein 2 (36.1)
Authors: Tuli Amit , Sharma Mahak , Menezes Miriam Rose , Naslavsky Naava , Caplan Steve , McIlhaney Mary M , Solheim Joyce C. 
Published: January 2023

Abstract
The amyloid precursor-like protein 2 (APLP2) is a secreted protein that is ubiquitously expressed. We have found that APLP2 over-expression decreases the quantity of H2-Kd molecules on the plasma membrane. In addition, Kd thermostability was improved by APLP2 down-regulation, suggesting that APLP2 affects Kd peptide selection and/or retention. The effects of APLP2 on Kd are likely related to their physical association, as pulse-chase experiments demonstrated interaction for up to two hours after Kd synthesis. Furthermore, significant co-localization of Kd molecules with APLP2 was observed in vesicular structures both at steady state and during endocytosis of Kd molecules from the cell surface. Mutagenesis studies revealed that APLP2/MHC association is influenced by sequences in the peptide-binding region and the α3 domain of the MHC class I heavy chain. β2m has an impact on APLP2/MHC interaction, since introduction of human β2m into mouse fibroblasts increased the level of interaction between H2-Dd and APLP2. In summary, APLP2 affects MHC class I cell surface expression and thermostability by an interaction controlled by more than one domain of the MHC class I heavy chain and by β2m. These data support a model in which APLP2 regulates MHC class I trafficking, and thereby antigen presentation. (NIH Grants AI54645, GM57428, and GM74876)
Multiple round of stimulation renders B cells capable to drive type 2 helper T (TH2) cell response (36.13)
Authors: Nam Sang-Yun , Do Jeong-Su , Seo Hyo-Jung , Hwang Jin-Ki , Kim Jun-Hee 
Published: January 2023

Abstract
Using hybrid mice of HEL-specific BCR Tg mice and OVA-specific TCR Tg mice, we investigated whether activated B cells may modulate T cell differentiation in addition to antigen presentation. Analysis of cytokine secretion has revealed that primarily stimulated (1°) B cells are more potent APC than naive B cells. However, second (2°) and further round of stimulation renders B cells capable to strongly drive polarization of naive CD4 T cells toward TH2 response, and concomitantly inhibitory to TH1 response. In the presence of 2° B cells as APC, activation of STAT-4 and T-bet was selectively inhibited during Ag-specific priming of T cells, whereas STAT-6 and GATA-3 were promoted, compared to 1° B cells. Altered MHC expression on 2° B cells was uncoupled with TH2 polarization, because they similarly work in nonspecific CD3 stimulation of T cells. Second round of stimulation regulates expression of costimulatory molecules on B cells, but not positively any TH2-related ones. Rather, 2° B cells were more likely to drive toward TH2 response via soluble mediators. 2° B cells produced much lower level of IFNγ and TNFα, but markedly higher levels of TH2 cytokines including IL-4 and IL-10, which largely contributed to 2° B-mediated TH2 polarization. This study suggests a possible therapeutic application of activated B cells against diseases caused by inappropriate TH1/2 polarization.
IL-12-producing CD11c+NK1.1-DC predominate in the liver during protective immunity induced with radiation-attenuated Plasmodium berghei sporozoites (36.15)
Authors: Jobe ousman.jobe , Donofrio Gina , Schwenk Robert , Williams Jackie , Krzych Urszula 
Published: January 2023

Abstract
Immunizations with radiation-attenuated Plasmodium berghei (γPb) sporozoites (spz) culminate in protection against wild-type Pbspz challenge. Immune protection is considered to be largely mediated by Ag-specific, IFNγ-producing liver CD8+T cells; however the role of APC in the induction of CD8+T cells remain unexplored. In vivo deletion of DC results in loss of protection against spz challenge. Therefore, in this study we investigated the possible involvement of liver DC in the induction of liver CD8+TEM cells. γPbspz immunization induced CD11c+CD8α+DC which represented ~75% of the hepatic CD11c+NK1.1-DC. Coincidental with the appearance of CD11c+CD8α+DC, was a 7-fold increase in liver CD8+TEM cells. Adoptive transfer of γPbspz-immune liver CD11c+NK1.1-DC to naïve mice reduced parasite burden (4-fold) after challenge and the recipient mice survived 14 days beyond the infectivity controls. CD11c+CD8α+DC from γPbspz-immune mice produced IL-12 and activated naive CD8+T cells to exhibit a TEM phenotype in vitro. Thus, we hypothesize that IL-12-producing hepatic CD11c+CD8α+DC induced by γPbspz activate liver CD8+T cells that are the key cellular component of protective immunity to liver-stage parasites.
Supported by NIH NIAID, FNIH and the USAMC.
Antigen encapsulated in biodegradable nanospheres are cross-presented in a proteosome-independent, TAP-dependent pathway (36.2)
Authors: Young-Hee Lee , Trumunkh Gerelchuluun , Young-Ran Lee , Hyunjin Kim , Sun-A Im , Chong-Kil Lee 
Published: January 2023

Abstract
Various mechanisms have been proposed to explain cross-presentation such as the classical cytosolic, TAP-dependent MHC-I processing pathway, the noncytosolic alternate MHC-I pathway, and the fusion of the endoplasmic reticulum (ER) with the endosome/phagosome. Here we show that antigens encapsulated in biodegradable nanospheres are cross-presented in a cytosolic pathway that does not require proteosome. Nanospheres containing OVA were prepared with poly(DL-lactide-co-glycolide). OVA containing in the nanospheres were efficiently captured, processed and presented on MHC-I molecules by DCs. MHC-I presentation of OVA-nanospheres was resistant to lactacystin, a proteosome inhibitor, and was sensitive to brefeldin A, an inhibitor of anterograde endoplasmic reticulum-Golgi transport. Chloroquine, which inhibits phagolysomal enzymes by increasing phagolysomal pH, inhibited MHC-I-restricted presentation of OVA. MHC-I presentation of OVA-nanospheres was greatly reduced in DCs generated from TAP−/− mice. These results demonstrate that antigens encapsulated in the biodegradable nanospheres are cross-presented by a mechanism involving phagolysosomal degradation, subsequent release of the degraded peptides into the cytosol, and transport of the peptides from the cytosol into ER via TAP.
Human skin migratory dendritic cells that do not secrete IL-12p70 stimulate both Th17 and Th1 allogeneic responses (36.20)
Authors: Mathers Alicia R , Morelli Adrian E , Janelsins Brian , Rubin Joseph P , Tkacheva Olga A , Falo Louis D , Larregina Adriana T 
Published: January 2023

Abstract
We analyzed the ability of human skin migratory dendritic cells (smiDC) to stimulate allogeneic (allo)-CD4+ T helper cell responses and to induce differentiation of Th1 and Th17 cells. SmiDCs obtained from cultures of human skin explants consisted of Langerhans cells and dermal DCs, which synthesized IL-8, IL-15, IL-23, IL-10 and TGF-β1, but not IL-12p70, even after exposure to DC1-driving stimuli. Regardless of the lack of IL-12p70 smiLC and DDC induced differentiation of effector memory Th cells that expressed CD45RO, the skin homing molecule CLA, and decreased CD62L and CCR7. SmiDCs stimulated proliferation of allo-CD4+ T cells that differentiated into Th1 and Th17 cells during 5 day-MLCs. T cell proliferation depended on the expression of MHC-II, costimulatory and adhesion molecules by smiDCs. The Th1 biasing function of smiDCs depended on the production of IL-23. The Th17 response was supported by the proinflammatory cytokines IL-8 and IL-15 and was significantly increased by the blockade of IL-6, whereas the blockade of IL-23 did not affect the secretion of IL-17. Levels of IL-17 and IFN-γ secretion reached their maximum at day 4 and 5, respectively. IFN-γ (Th1) and IL-17 (Th17) was produced by two distinct Th cell subsets as demonstrated by flow cytometry. Therefore, human smiDCs support the induction and coexistence of Th1 and Th17 effector T cells by mechanisms distinct from those described in the mouse model.
A novel Lactococcus lactis antigen delivery system induces activation and maturation of neonatal dendritic cells and T cell stimulation. (36.22)
Authors: Ditamo Yanina , van Roosmalen Maarten L , Leenhouts Kees , Ramirez Karina , Pasetti Marcela F 
Published: January 2023

Abstract
Neonatal immune responses to vaccine antigens are usually short lived and Th-2 biased. This has been attributed, in part, to the immaturity of neonatal dendritic cells (DC) which lack full capacity for antigen presentation and T cell stimulation. Effective priming of the neonatal immune system can be achieved when antigens are delivered in the presence of adequate immunostimulatory signals. We investigated the capacity of a novel L. lactis-derived delivery system, designated Gram-positive Enhancer Matrix (GEM) particles, to stimulate neonatal immune cell populations. This system had been shown to enhance immunity to protein antigens when given mucosally in adult mice. To assess their capacity to activate the neonatal immune system, DC and macrophages derived from newborn mice were cultured in the presence of GEM particles. Adult-derived DC were included as controls. We showed that GEM particles induced upregulation of activation and maturation markers (CD80, CD86, CD40, MHCII) in neonatal DC and macrophages. Similar experiments were performed with human DC; GEM particle treatment also increased expression of activation and maturation markers of human cord blood- as well as adult-derived DC and increased allogeneic human T cell stimulation. These results indicate that GEM particles are proficient stimulators of neonatal immune cell populations, and likely to enhance in vivo immune responses in neonates.
Evaluation of function vs. purity of mouse bone marrow derived dendritic cells by analyzing FACS and ELISA profiles of CD11c-selected and non-selected populations (36.26)
Authors: Chou Ping-Jen , Newton Cathy , Perkins Izabella , Friedman Herman , Klein Thomas 
Published: January 2023

Abstract
Bone marrow derived dendritic cells are APCs and serve as “immunological sensors” that detect microbial invasion. The hallmark of BMDC purity is &gt;90% positive for the CD11c molecular marker and this level of purity can be achieved by the use of costly cell sorters. A confound to the methods of isolation and purification is that growing BMDC in GM-CSF enriched culture medium can increase the CD11c expression &lt;75%. In this study, BMDC were harvested and enriched by incubation for 9 days with GM-CSF medium followed by CD11c IMag™ Magnetic Particle selection. The selected and non-selected cells were analyzed for percentage expression of CD11c. The DCs were then treated with effective doses of anthrax toxins (200ng/ml PA with LF and EF at 25ng/ml each) for 5 hours prior to Legionella pneumophila infection for 18-hour incubation. The culture supernatants, examined by ELISA, showed that the proinflammatory cytokine response following various treatments, namely IL-12, IL-6, IL-1β, and TNF-α, was essentially the same between the selected and non-selected populations. In addition, flow data showed an increase in CD11c expression as DCs become mature upon stimulation, suggesting this marker is inducible. Overall, our data show that BMDC populations of &gt;65% and &gt;90% CD11c positive have a similar cytokine response following stimulation and can be generated by a much more cost effective technique.
Supported by NIAID grant AI45169.
Evaluation of Adjuvant Regimens for Antibody Development in Rabbits (36.29)
Authors: Hawksworth David , Tyner Joan 
Published: January 2023

Abstract
Several adjuvant regimens were assessed for their ability to safely develop a high titer, high affinity antibody response in rabbits. Female, New Zealand White (NZW) rabbits were given five monthly 20 ug immunizations with a 25 KDa recombinant protein using one of four adjuvant programs:
Adjulite® Complete and Adjulite® Incomplete Freund’s adjuvants,Alhydrogel® Aluminum hydroxide gel adjuvant in combination with oligodeoxynucleotides containing unmethylated CpG dinucleotides (Alum/CpG),Difco Freund’s adjuvant alternating with MPL+TDM+CWS orDifco Freund’s adjuvant alternating with Quil A supplemented with CpG-ODN.
Sera samples taken following all booster immunizations were evaluated for antibody titer and relative affinity in a microtiter enzyme immunoassay by testing for antibody reactivity to limiting amounts of the administered antigen. Animals were also monitored during the immunization period for any reaction at the sites of injection. Results show that the Adjulite® animals elicited a higher average titer compared to animals immunized using any of the alternate strategies. Additionally, Adjulite® rabbits developed an average relative antibody affinity similar to that for the Alum/CpG animals and higher than either of the groups employing Difco Freund’s adjuvant. One Adjulite® rabbit developed a temporary nodule at the site of injection compared to none of the Alum/CpG animals. Two of the five animals using Difco Freund’s adjuvant developed a nodule, both of which progressed to lesions. This study demonstrates that Adjulite® adjuvant can serve as a safe alternative to other adjuvant regimens for the development of a high titer, high affinity antibody response in rabbits.
Oxidant production by APCs in response to glycoantigens (36.9)
Authors: Lewis Colleen J. , Cobb Brian A. 
Published: January 2023

Abstract
Nitric oxide (NO) and reactive oxygen species (ROS) are generated during the oxidative burst and are thought to have redundant bactericidal functions. However, zwitterionic polysaccharide antigens (glycoantigens), such as polysaccharide A from the capsule of Bacteroides fragilis, are processed within APCs in a NO-dependent fashion leading to T cell activation and abscess formation. That observation suggests differential functions for ROS and NO in APCs. In order to understand these roles, the oxidative response to glycoantigens in APCs has been measured. We found that murine and human macrophage lines produce NO over a 48-hour period in an antigen dose-dependent manner, and this production can be blocked with the NO synthase inhibitor L-NAME. The macrophages also produce ROS, which can be ablated with apocynin, an inhibitor of superoxide production. Interestingly, maximal ROS production occurs earlier (T½ = 15.8 hrs) but requires a higher antigen concentration (24.8 μg) than NO production (T½ = 24.5 hrs; 14.6 μg). In addition, B cells produce small amounts of ROS and no detectable NO, despite their ability to process glycoantigens, revealing a NO-independent processing mechanism. These data suggest that NO and ROS are controlled independently and could serve different processing roles in macrophages and B cells during T cell responses to glycoantigens.
This work was supported by a grant to B.A. Cobb (AI062707).