bluuebunny/crossref_metadata_2025_split huggingface dataset:
Macrophage migration inhibitory factor promotes resistance to glucocorticoids in experimental autoimmune encephalomyelitis (50.12)
Authors: Forsthuber Thomas G. , Salazar Elisabeth , Yang Yuye 
Published: January 2023

Abstract
Glucocorticoid (GC) treatment is the standard of care for acute attacks of Multiple sclerosis (MS). However, while initially highly efficacious in inducing remission of MS, GCs eventually loose efficacy and overall do not prevent progression of the disease. GCs have the unique property of inducing the release of Macrophage migration inhibitory factor (MIF), a pro-inflammatory cytokine with broad effects on the immune response. Thus, we hypothesized that MIF could play an important role in promoting disease by its unique ability to counter-regulate the immunosuppressive effects of GCs. Testing this question, we found that treatment of MIF knockout mice (KO) with GCs was substantially more efficacious as compared with GC-treatment of Wt mice and resulted in a substantial delay in disease onset and severity of EAE. Histological and immunofluorescence studies showed that inflammatory infiltrates were dramatically reduced in MIF KO mice. Furthermore, thymus and spleen cells from MIF KO mice showed higher extend of apoptosis upon incubation with GCs as compared with Wt mice. The results suggest that the blockade of MIF in combination with GC administration could be a promising strategy for the treatment of MS. Supported by grants NS052177 (NIH) and RG3499 (NMSS).
Inhibition of T cell activation by the phytochemical piperine (50.35)
Authors: Doucette Carolyn D , Rodgers Gemma , Liwski Robert , Hoskin David W 
Published: January 2023

Abstract
Piperine, a major alkaloid of the fruits of black and long pepper plants, exhibits anti-inflammatory activity both in vitro and in vivo. Although the effect of piperine on T cell function is not yet known, we hypothesized that piperine might inhibit T cell processes involved in inflammation. We therefore examined the effect of piperine on T cell proliferation, activation marker expression, and cytokine production. Cellular proliferation was determined by tritiated-thymidine incorporation and Oregon Green® 488 staining while activation marker expression was assessed by flow cytometry. Cytokine production and intracellular signalling pathways were examined by ELISA and Western blot analysis, respectively. Piperine inhibited T cell proliferation in a dose-dependent manner without affecting T cell viability. Piperine also inhibited expression of the T cell activation markers CD25, CD69, and CTLA-4, as well as production of the cytokines IFN-γ, IL-2, IL-4, and IL-17. Phosphorylation of extracellular signal-regulated kinase (ERK) and inhibitor of κBα (IκBα) was diminished in T cells stimulated in the presence of piperine, indicating that piperine affects signalling pathways involved in T cell activation. Collectively, these data suggest that piperine warrants further investigation as a possible immunosuppressive agent for the treatment of T cell-mediated inflammation. Supported by NSERC and CIHR.
T cell receptor-mediated protein geranylgeranylation controls transforming growth factor-beta-induced Foxp3 expression by regulating the induction of Smad6/7 (50.40)
Authors: Kim Yong Chan , Kim Kee Kwang , Shevach Ethan M 
Published: January 2023

Abstract
TGF- β plays a critical role as a differentiation factor for the generation of Foxp3+ induced T regulatory cells (iTregs) from naïve T cells. To evaluate the potential role of the mevalonate pathway in the control of iTreg development, we have used the mevalonate pathway inhibitor, Simvastatin. When CD4+Foxp3- T cells were activated with anti-CD3/CD28, the addition of Simvastatin increased the induction of Foxp3+ T cells. A marked synergistic induction of Foxp3 expression was observed when Simvastatin was added to the induction cultures with a suboptimal concentration of TGF-β. The action of Simvastatin was not mediated by enhancement of Smad3 phosphorylation, but was associated with marked inhibition of induction of the Smad 6/7 proteins. The synergistic effect was mediated at the level of mRNA transcription and was associated with increased DNA demethylation of the Foxp3 promoter. The effects of Simvastatin and TGF-βon the induction of Foxp3 expression were reproduced by the addition of an inhibitor of protein geranylgeranylation, but not an inhibitor of protein farnesylation. These studies demonstrate that protein geranylgeranylation represents of one of the key regulatory steps in the generation of iTregs by TGF-β. Pharmacologic manipulation of the mevalonate pathway may represents one mechanism for the induction of iTregs in vivo.
Blockade of the CD30/CD30L pathway inhibits renal disease in young, SLE-prone NZB/W F1 mice (50.41)
Authors: Rottman James  B , Hu Yi-Ling , Willis Cynthia 
Published: January 2023

Abstract
CD30 and CD30L are interacting members of the TNFR and TNF family, respectively. CD30 is expressed by subsets of activated T and B cells, whereas CD30L is expressed by subsets of activated T cells, macrophages and dendritic cells. The CD30 / CD30L interaction modulates T cell activation, germinal center formation and antibody isotype class switching. Given the importance of this pathway to B cell function, we tested the hypothesis that blockade of the CD30 / CD30L pathway would decrease or abrogate autoantibody formation and renal disease in the NZB/W F1 murine model of systemic lupus erythematosis (SLE). Young (5 mo) NZB/W F1 mice were treated with 300 μg CD30L blocking (M15-N297A) or blocking / depleting (M15-IgG2a) antibody weekly for 3 months during the onset of autoimmunity. Both treatments a) reduced the onset and severity of proteinuria, b) significantly decreased the severity of renal histologic scores, c) decreased glomerular immune complex and complement deposition and d) these effects were associated with reduced production of anti-DNA antibodies of the IgG, but not IgM isotype. CD30 / CD30L blockade may be a viable approach for the treatment of SLE.
Treatment with Cl-amidine, a peptidyl arginine deiminase (PAD) inhibitor, significantly reduces collagen-induced arthritis (CIA) (50.6)
Authors: Willis Van C , Gizinski A , Banda N K , Knuckley B , Cordova K , Luo Y , Causey C P , Levitt B , Glogowska M , Benbarak M , Chandra P , Kulik L , Arend W P , Robinson W H , Thompson P R , Holers V M 
Published: January 2023

Abstract
Antibodies to citrullinated protein antigens (ACPA) are specific for rheumatoid arthritis (RA). Post-translational citrullination of epitopes to which ACPA are directed is catalyzed by PADs. We have previously shown that ACPA develop in CIA and contribute to joint damage. In this study we used Cl-amidine, a small molecule that specifically inhibits all PAD enzymes, to determine whether limiting PAD activity can modify CIA. CIA and collagen antibody-induced arthritis (CAIA, a model of the antibody-mediated effector pathway of CIA) were induced in DBA/1j mice using standard methods. Mice received either no treatment, vehicle alone (PBS), or 1, 10 or 50 mg/kg/day Cl-amidine by daily IP injection. Cl-amidine reduced CIA disease activity scores by 42%, 53% and 55% in the respective treatment groups (1, 10, 50 mg/kg/day) as well as C3 deposition, IgG1 and IgG2a anti-mouse CII Abs and epitope spreading to citrullinated epitopes. Conversely, Cl-amidine treatment had no effect on the development of CAIA. These results suggest that PADs are essential components in the development of inflammatory arthritis. This work was funded by an ACR REF WOR Grant.
Analysis of the performance of peptide predicting methods using MHC class I peptide sequencing in the C57BL/6 mouse (78.11)
Authors: Delgado Julio , Escobar Hernando , Crockett David , Reyes-Vargas Eduardo , Jensen Peter 
Published: January 2023

Abstract
MHC class I peptide-binding motifs can defined by sequencing of peptides naturally bound to MHC class I molecules. More recently MHC class I-peptide binding motifs have be defined on the basis of quantitative MHC-peptide binding assays in vitro using peptide libraries. The information on peptide binding motifs obtained using binding assays have been useful to develop numerous bioinformatics-based tools to predict the binding of peptides to MHC class I molecules. To date few studies have analyzed the performance of these bioinformatics tools to predict peptides determined by sequencing of peptides eluted directly from MHC class I molecules. In this study we performed sequencing of endogenous peptides eluted from H2Kb and Db molecules expressed in the C57BL/6 mouse. Using data from 280 H2-class I-bound peptides we identified novel preferred anchor residues located in H2Kb and H2Db-associated peptides. When comparing the predicting affinity performance of 3 bioinformatics tools we found that between 60 to 95% of peptides eluted from H2Kb and H2Db molecules were correctly classified as binders by these 3 predicting algorithms, suggesting that these bioinformatics tools are reliable and efficient for prediction of naturally processed MHC class I ligands. These results expand our knowledge about H2 class I binding specificities and provide the identity of positions that can be used for better characterization of H2 class I peptide-binding motifs. Similar studies using sensitive methods for sequencing large numbers of peptides from other MHC molecules are needed to establish more precise motif information that can be used for the training of bioinformatics tool employed in the prediction of CD8 T-cell epitopes
A molecular understanding of how the immunomodulatory E3-19K protein from adenovirus interferes with the class I antigen presentation pathway (78.13)
Authors: Bouvier Marlene , Fu Jie 
Published: January 2023

Abstract
Adenoviruses (Ads) cause persistent infections. The Ad E3-19K protein binds and retains class I MHC molecules in the endoplasmic reticulum (ER), suppressing the cell-surface presentation of viral peptides. The molecular mechanism of E3-19K-mediated class I retention is mostly uncharacterized. This knowledge is important to better understand Ad pathogenicity, and to gain insights into the susceptibility of the class I antigen presentation pathway to viral interferences.
Using biophysical and cell-based approaches, we showed for the first time that E3-19K associates with immature (nascent) and mature (peptide-filled) class I molecules. We also showed that E3-19K does not compete with the class I assembly proteins for binding onto class I molecules. Importantly, immature class I sequestered by E3-19K can still bind peptides. Together, these results suggest that Ads have evolved to interfere with the early and late stages of the class I antigen presentation pathway. We also showed that E3-19K associates with HLA-A and -B molecules, but not HLA-C molecules. This locus specificity may provide a functional advantage to Ads by inactivating T-cell receptors, while avoiding activation of NK receptors. Finally, we showed that residue 56 in MHC and residue 93 in E3-19K are highly critical for class I association with E3-19K. Overall, our results provide a molecular understanding of Ad pathogenicity. Funded by NIH AI65943.
Adapter-mediated substrate selection by a viral immune evasion molecule (78.15)
Authors: Corcoran Kathleen M , Wang Xiaoli , Lybarger Lonnie 
Published: January 2023

Abstract
The MHC class I antigen presentation pathway is a frequent target of virus-encoded immune evasion molecules. Proteins of the viral K3 family are E3 ubiquitin ligases that downregulate immune modulatory molecules. Further, it has been established that the K3 family has cellular homologs (Membrane-Associated RING-CH proteins), some of which act to regulate immune molecules via ubiquitination. The mK3 molecule of γ-herpesvirus 68 has been shown to utilize ER-associated degradation pathways to degrade MHC class I, thereby inhibiting antigen presentation. Here, we have explored the basis for specific targeting of class I for ubiquitination by mK3. We provide direct evidence that adapter proteins (TAP/tapasin, in this case) in the ER membrane position the RING-CH domain of mK3 to permit ubiquitination of the cytosolic tail of the class I heavy-chain. This was accomplished by generating a novel substrate for mK3 which could be ubiquitinated only when placed within the proper orientation within the TAP complex. These findings demonstrate an essential role of adapter proteins in ubiquitin ligase substrate selection, with implications for substrate selection by other K3-related E3 ligases within the immune system.
Post-transcriptional regulation of MARCH1 expression (78.16)
Authors: Jabbour Maurice , Fares Hanna , Lybarger Lonnie 
Published: January 2023

Abstract
In antigen presenting cells (APC) ubiquitination regulates the trafficking of immune modulators (e.g. MHC II). MARCH1 (membrane-associated RING-CH), a newly identified ubiquitin E3 ligase expressed in APC, ubiquitinates MHC II and prevents efficient surface expression. Following LPS-induced maturation of dendritic cells (DC), MARCH1 mRNA is downregulated, permitting MHC II redistribution to the cell surface. Here, we show that MARCH1 expression is also regulated at the post-transcriptional level. In primary DC and APC cell lines, MARCH1 is degraded with a half-life of &lt;30 min. MARCH1 degradation appears to occur mostly, if not exclusively, in lysosomes, since inhibiting lysosomal activity stabilized MARCH1 protein levels. Similar stabilization was observed when MARCH1-expressing cells were treated with cysteine protease inhibitors. Mutational analyses of MARCH1 defined discrete domains required for destabilization, proper localization, and functional interaction with substrates. Together, these data suggest that MARCH1 expression is regulated at a post-transcriptional level by trafficking to endocytic compartments where MARCH1 is proteolysed. The short half-life of MARCH1 permits very rapid changes in the levels of the protein in response to changes in the mRNA, resulting in efficient induction of MHC class II and CD86 once APC receive maturational signals. Supported by Arizona Biomedical Research Commission
Paradoxical influence of the quantity of antigen expressed by the antigen donor cell on the efficiency of cross priming (78.30)
Authors: Kelly III John B , Srivastava Pramod K 
Published: January 2023

Abstract
Cross-priming is a critical component of T cell responses to cancers and viruses, and involves transfer of antigen from antigen donor cells to the antigen presenting cells. In spite of the centrality of antigen in this process, the influence of the quantity of antigen expressed by the antigen donor cell on the efficiency of cross-priming remains un-examined. Here, we have created a novel system where the model antigen ovalbumin is expressed in P815 (d haplotype) cells under the control of an inducible promoter. However, even in un-induced condition, a very low level of ovalbumin can be detected using highly sensitive methods. We have used titrated quantities of un-induced and induced cells, expressing vastly different quantities of ovalbumin, and have monitored cross-priming of the endogenous anti-SIINFEKL T cell response quantitatively, using in vivo cytolytic T lymphocytes assays. The experiments show, paradoxically, that minute quantities of antigen expressed by a large number of cells are far more effective at cross-priming than exponentially larger quantities of antigen expressed by fewer cells. The results point to the existence of cell-associated factors that enhance the availability of antigen in the antigen donor cells to the antigen presenting cells by orders of magnitude.
Intravenous immunoglobulin (IVIG) inhibit B cell-mediate antigen presentation (78.35)
Authors: Paquin Proulx Dominic , Aubin Éric , Lemieux Réal , Bazin Renée 
Published: January 2023

Abstract
IVIg are therapeutic preparations of IgG prepared from the plasma of thousands of donors and are currently used to treat more than one hundred autoimmune or inflammatory diseases, though their mechanisms of action are not precisely known in any of these diseases. Previous work from our laboratory done on human B cells revealed that IVIg interact with MHC class I and II molecules. These interactions led us to hypothesize that IVIg might interfere with B cell-mediated antigen presentation. In the present work, we used an in vitro antigen presentation system with an OVA-specific T cell line (DO11.10) and showed that IVIg inhibited OVA presentation by B cells. IVIg did not decrease OVA internalization or MHC II expression on B cells, suggesting that IVIg inhibited antigen presentation by interfering with either antigen processing or loading of peptides on MHC II molecules. We further showed, using the OVA peptide 323-339 specific for the TCR expressed by DO11.10 T cells which can be loaded directly on MHC II molecules, that IVIg significantly reduced OVA 323-339 presentation, suggesting that the mechanism by which IVIg inhibit OVA presentation by B cells is by competing for peptide occupancy of MHC II molecules. This study extends our previous observations on the spontaneous internalization of IVIg inside living cells by showing a measurable effect of internalized IVIg on the normal cellular process of antigen presentation.
Possible role of class I myosins in molecule segregation at B cell microvilli structures (78.37)
Authors: Maravillas-Montero José  Luis , Gillespie Peter G. , Patino-Lopez Genaro , Shaw Stephen , Santos-Argumedo Leopoldo 
Published: January 2023

Abstract
Cell cytoskeleton plasticity is now recognized as an important element of cell to cell and cell to antigen interactions. It has been shown that T cells and dendritic cells use shape changes in order to establish effective contacts between them. B lymphocytes also show cytoskeleton rearrangements during antigen recognition. The B cell surface change upon activation with LPS or anti-CD40 plus IL-4; these stimuli induce the generation of long thin microvilli, longer than those observed in resting conditions. These structures are formed by a central actin filaments bundle with bridging associated proteins that links them to plasma membrane. One of these proteins are class I myosins, which are molecular motors that interacts both with actin fibers and plasma membrane phosphoinositides; Myo1c and Myo1g are importantly expressed in B cells and appears to increase upon activation. By using live-cell microscopy we determined that they are present across microvilli structures and seems to be involved in their formation. Finally, our data suggest a role for microvilli by segregating molecules such as MHC-II, LFA-1, CD40, etc. possibly mediated by class I myosins.
Supported by CONACyT, project 56836
CLEC4F, A Kupffer Cells Specific Marker, Is Critical for Presentation of Alfa-Galactoceromide to NKT Cells (78.38)
Authors: Hsieh Shie-Liang Edmond , Yang Chi-Ya 
Published: January 2023

Abstract
CLEC4F, a member of C-type lectins, was firstly purified from rat liver extract with high binding affinity to fucose, galactose and N-acetylgalactosamine, and un-sialylated glucosphingolipids with GalNAc or Gal terminus. However, the biological functions of CLEC4F have not been elucidated. To address this question, we generated mAbs to detect the expression of murine CLEC4F (mCLEC4F) in vivo, and investigated its function using mCLEC4F-deficient mice. The anti-mCLEC4F mAbs bind to 293T cells transfected with mCLEC4F cDNA as determined by flow cytometry, and the binding specificity of anti-mCLEC4F mAbs is further confirmed in mCLEC4F-deficient mice. Histochemical staining showed that mCLEC4F is only expressed on F4/80+ cells localized in liver, and is undetectable in bone marrow, spleen, lymph nodes, or other tissues in adult mice. However, mCLEC4F is detected in the liver of embryonic day 11.5 (E11.5), which is 1.5 day earlier than the formation of liver (E10) and is 3.5 day earlier than the formation of bone marrow (E15-16). Moreover, recombinant mCLEC4F.Fc binds to alpha-galactoceramide in a Ca++-dependent manner, and both galactose and ceramide can partially inhibit CLEC4F.Fc binding to alpha-galactoceramide. Interestingly, mCLEC4F-deficient (mCEC4F k/o) mice produced far less cytokines than wild type littermates after intravenous injection ofalpha-galactoceramide. This suggests that mCLEC4F is not only a specific marker for Kupffer cells, but is also critical for the presentation of glycolipid antigen to NKT cells.
Eraap knockdown in CT26 alters antigenic response to the tumour invivo (78.39)
Authors: Reeves Emma , Bailey Ian , Elliott Tim , James Edd 
Published: January 2023

Abstract
Regulatory T cells (Tregs) play a pivotal role in the suppression of tumour antigen responses. It is well established that balb/c mice depleted of Tregs, using the anti-CD25 antibody pc61, are capable of rejecting the colon carcinoma line CT26. Mice challenged with CT26 in these circumstances have also been shown to reject a further challenge with CT26 or a second tumour line. The antigens responsible for this rejection are only partially characterised, with MHC class 1 antigens known to be restricted to all three H2-D molecules. Our laboratory has identified a Dd restricted antigen, GSW11, which is largely responsible for the cross protective response.
Investigation into the processing of GSW11 revealed a sensitivity to over-processing by Eraap. In an attempt to increase the immunogenicity we generated Eraap knockdown CT26 using a plasmid knockdown system. These CT26 derivatives with reduced Eraap mRNA and protein levels were found to stimulate a peptide specific hybridoma more than wild type CT26. In addition, balb/c mice challenged with Eraap knockdown CT26 gained an 80% protection verses 0% mice injected with wild type CT26. Further experimentation is being undertaken to elucidate the exact mechanisms behind this protection.
The threshold for negative selection and regulatory T-cell development is defined by peptide-MHC density (78.41)
Authors: Atibalentja Danielle F , Unanue Emil R 
Published: January 2023

Abstract
High avidity TCR/pMHC binding results in the deletion of thymocytes by negative selection. However, for natural regulatory T-cell (TR) precursors, high avidity TCR/pMHC interaction leads to differentiation and escape from negative selection. The process of diverting thymocytes into alternative pathways of development is incompletely understood. In this study, we consider the role that pMHC density may have in this process. Using two TCR transgenic mice against differentially presented Hen egg white lysozyme (HEL) epitopes, we evaluated negative selection and Foxp3+CD4SP T cell development in response to graded amounts of intravenously injected HEL. In both mice, thymocyte sensitivity to negative selection and TR induction depended on antigen dose and reflected the level of presentation of their cognate epitopes. The absolute increase in TR occurred at doses of HEL lower than the dose required for complete negative selection of conventional CD4SP. TR induction was inefficient in the absence of TCRα gene rearrangement and was not a result of TR subset expansion. Our data shows that pMHC density provides an important signal in the routing of TR precursors away from negative selection towards development as regulatory T-cells.