bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of IgH isotypes in ancestral mucosal immune model of class switch (170.3)
Authors: Du Christina , Mashoof Sara , Criscitiello Michael 
Published: January 2023

Abstract
The major barrier breached by most pathogens is the gut mucosal surface. Secretory IgA is the predominate immunoglobulin of mucosal surfaces in mammals. Induction of the mucosal immune response by ingestion of antigen usually elicits some localized response, but a poor systemic response. The importance of gut associated lymphoid tissues (or GALT) has been extensively reported in higher vertebrates, but less is known in lower vertebrates. In mammals IgA is the primary immunoglobulin of mucosal immunity. But no IgA has been identified in cold-blooded animals. In higher vertebrates, antigen must stimulate the lymphoid tissues in the intestines to elicit an IgA response, and cytokines from CD4 positive helper T cells are required for B cell switch. It is not known if this is the case in lower vertebrates, or if T cell help evolved before or after class switch recombination. My study will fill in these gaps in our knowledge by inoculating frogs orally and compare this route to intraperitoneal immunized frogs in our unique larval thymectomy model. Oral immunization is a novel approach to eliciting immune response in Xenopus. I propose that IgX will increase with oral inoculation compared to intraperitoneal injection. This would be the first demonstration of class switch upon oral immunization to a mucosal isotype in the first vertebrates that employs our Ig heavy chain switch mechanism, which would shed light on the most fundamental aspects of our humoral adaptive immune system.
Evolution of the T cell receptor: expression of non-conventional TCRδ chains in Xenopus (170.7)
Authors: Jackson Shawn , Undieh Ada , Steiner Harold , Parra Zuly , Miller Robert , Ohta Yuko , Flajnik Martin 
Published: January 2023

Abstract
γδ T cell receptors (TCR) that have structural differences from conventional γδ T cells in mammals have been observed in non-eutherian vertebrates. Three different types of V regions are present in the frog Xenopus tropicalis genomic TCRδ locus (Eur. J. Immunol. 40: 2319, 2010), most similar to Vδ, Vα, and VHδ (evolutionarily derived from the V regions of Ig H chains). We have begun a survey of the tissue distribution of TCRδ expression in X. laevis tadpoles and adults by 5’ RACE PCR. The deduced amino acid sequences predicted from X. tropicalis genome sequences were aligned with those from X. laevis TCRδ V RACE clones, revealing similar Vδ, Vα, and VHδ families in X. laevis. Analyses of the TCRδ RACE nucleotide sequences have identified the putative D and J gene segments in X. laevis as well. Although we find representatives of all TCRδ V sub-families in all tested adult tissues, the distribution of the data suggests that the expressed repertoire is skewed in some tissues, especially in the skin, where a majority of recovered sequences were of the Vα type. Interestingly, analyses of the Vδ type indicate a lack of N-nucleotide addition in the CDR3 in adults, suggestive of a population of T cells that is generated during larval life that persists through metamorphosis. Continued study of these unique TCR in Xenopus will illuminate apparent plasticity in TCR evolution, and shed light on how γδ TCR recognize antigen in all vertebrates.
Fli-1 transcription factor affects inflammatory cell infiltration in the lupus nephritis development by regulating expression of inflammatory chemokines (44.12)
Authors: Zhang Xian , Williams Sarah , Suzuki Eiji , Karam Eva , Gilkeson Gary 
Published: January 2023

Abstract
Expression of Fli-1, a member of the Ets family of transcription factors, is implicated in the development of nephritis in murine models of systemic lupus erythematosus (SLE). Expression of monocyte chemotactic protein-1 (MCP-1) and Chemokine (C-C motif) ligand 5 (CCL5, also known as RANTES) plays an important role in the inflammatory cell infiltration. In this study, we examined the role of Fli-1 on chemokine production and inflammatory cell infiltration in conjunction with nephritis development in NZM2410 mice, an animal model of SLE. We generated Fli-1 heterozygous knockout NZM2410 mice (Fli1+/-; Fli-1 homozygous knockout is embryonic lethal) and wild-type (WT) littermate (Fli1+/+) mice as controls. Expression of MCP-1 and CCL5 in the kidneys from 18-week old Fli-1+/- NZM2410 mice was significantly decreased compared to that from WT littermates. The number of macrophages, neutrophil granulocytes, T cells and B cells in the kidneys from 34-week Fli-1+/- NZM2410 mice decreased by 44 - 75% compared to WT littermate controls. The productions of MCP-1 in endothelial cells transfected with specific Fli-1 siRNA were significantly reduced compared to cells transfected with negative control siRNA. Our data indicate that Fli-1 plays an important role in production of inflammatory chemokine MCP-1 and inflammatory cell infiltration in the lupus nephritis development.
Role of interferon-producing killer dendritic cells in the development of autoimmune disease (44.14)
Authors: Voynova Elisaveta , Bolland Silvia 
Published: January 2023

Abstract
Interferon-producing killer dendritic cells (IKDCs) share functional characteristics with NK cells and DCs. We investigated their role in the autoimmune disease developed by transgenic mice that overexpress TLR7 (TLR7tg). We determined that a cell population resembling IKDCs expands in TLR7tg mice through their intrinsic sensitivity to TLR7 stimulation. We confirmed that they are bona fide NK cells by their ability to kill cells lacking MHC I molecules in vitro. These cells were also able to present antigen to naïve T cells in in vitro assays. Adoptive transfer of IKDCs isolated from TLR7tg mice into wild type mice induced priming and activation of naïve T cells. In vitro stimulation with TLR7 agonists of IKDCs derived from TLR7tg resulted in the production of TNFa, MCP-1, IFNa and high levels of IL-10. We also tested the requirement of cytokines that are essential for NK cell development. We found that the expansion of IKDCs in TLR7tg mice was IL15 dependent but IL18 independent. We observed that lack of IL15 reduced many pro-inflammatory subsets (Ly6C+monocytes, granulocytes, DCs and memory T cells) and delayed the development of glomerulonephritis in TLR7tg mice. These results reveal expansion of IKDCs in autoimmune inflammatory conditions and suggest a dual role for these cells in both the priming of autoreactive T cells and the release of inflammatory cytokines.
The inflammasome and caspase-1 involvement in systemic sclerosis fibroblasts mediates fibrosis and myofibroblast differentiation (44.33)
Authors: Artlett Carol , Sassi-Gaha Sihem , Rieger Judy , Boesteanu Alina , Feghali-Bostwick Carol , Katsikis Peter 
Published: January 2023

Abstract
Systemic sclerosis (SSc) is a chronic idiopathic disease of unknown etiology that is characterized by fibrosis of the skin and visceral organs mediated by activated myofibroblasts. The recently identified inflammasomes are cytosolic receptors that tightly regulate the activity of caspase-1 and downstream signaling molecules such as IL-1β and IL-18. The NLRP3 inflammasome has been implicated in the development of idiopathic pulmonary fibrosis; however the role of the inflammasome has not been studied in SSc dermal or lung fibrosis. We identified increased expression of 40 genes associated with the inflammasome or downstream signaling molecules in SSc fibroblasts. Inhibition of caspase-1 in SSc dermal and lung fibroblasts abrogated secretion of collagens, and IL-1β and IL-18. In fibrotic SSc lesions, persistently activated fibroblasts called myofibroblasts mediate the excessive secretion of collagen and other extracellular matrix proteins in both the dermis and visceral organs. We observed decreased expression of the myofibroblast protein α-smooth muscle actin in SSc dermal fibroblasts treated with the caspase-1 inhibitor. NLRP3-/- and ASC-/- mice were resistant to bleomycin-induced skin fibrosis suggesting a key role for the inflammasome in in vivo dermal fibrosis. We report that innate immune signaling contributes to SSc fibrosis via the activation of the inflammasome and caspase-1 and suggest that inflammasome activation may play an important role in the pathogenesis of SSc.
Regulated release of nitric oxide by fibroblastic reticular cells controls the frequency and pathogenicity of autoreactive T cells in a model of intestinal tolerance (44.37)
Authors: Lukacs-Kornek Veronika , Malhotra Deepali , Fletcher Anne , Pinner Sophie , Tayalia Prakriti , Turley Shannon 
Published: January 2023

Abstract
Fibroblastic reticular cells (FRCs) are non-hematopoietic stromal cells of lymphoid organs wielding significant immunological impact. They exert important effects on the migration and homeostasis of naïve T cells however, their influence on activated T cells is undescribed. Here we report that nitric oxide (NO) release by FRCs profoundly inhibits T cell proliferation without altering early activation signals. Mechanistically, the expression of nitric oxide synthase 2 and production of NO paralleled the activation of T cells and required a tripartite synergism between IFNgamma, TNFalpha, and direct contact with activated CD8 T cells. We have also assesed the role of NOS2 in the iFABP-tOVA transgenic mouse model in which a truncated, cytosolic form of ovalbumin (tOVA136-336) is expressed as a self-antigen by mature intestinal epithelial cells under the control of the intestinal fatty acid binding protein (iFABP) promoter. In this model, where FRCs play a major role in the induction of CD8 T cell tolerance, FRC-derived NO controlled the magnitude of the response at the level of T cell proliferation. The percentage and absolute number of self-reactive CD8 T cells was increased in NOS2-/- iFABP mice, resulting in increased weight loss and more severe ileocolitis. Our study illuminates a hitherto unrecognized role of FRCs in regulating T cell responses that may have important implications for inflammatory bowel diseases.
Characterization of B cell repertoires in Sjögren’s syndrome by microengraving (44.48)
Authors: Nguyen Cuong , Ogunniyi Adebola , Love Christopher 
Published: January 2023

Abstract
Microengraving is a novel technology that uses an array of microfabricated wells to isolate and characterize large numbers of single cells. Using printing technique, secreted antibodies can be captured and characterized on glass slides. Using microengraving, we profiled the antigenic repertoires of B cells reacting against salivary gland (SG) tissues in Sjögren’s syndrome (SjS), an autoimmune disease targeting the exocrine glands. Cells from spleens and cervical lymph nodes (CLN) of normal C57BL/6 (B6) and SjS-susceptible (SjSs) C57BL/6.NOD-AecAec2 mice were isolated and loaded onto microwells. Capture slides preincubated with mouse Igs were used for printing. Detection antibodies included IgG1, IgG3, and SG lysates of B6 and SjSs mice that were labeled with different fluorescent dyes. Data indicated an increase in the frequency of IgG1 antibodies against SG lysates of B6 and SjSs mice when printed using CLN cells of SjSs mice but not B6 mice. In contrast, an increase in the frequency of IgG3 antibodies against SG tissues of B6 and SjSs mice was only observed when printed with SjSs mice splenocytes. These data demonstrate the diversity in the isotypic repertoire of antibodies during autoimmune process, and further revealed a dichotomy in peripheral tolerance. The result supports the generation of self-reactive B cell repertories during the autoimmune process. Furthermore, the use of micrograving of single cells might allow for identification of novel biomarkers.
Role of PD-L1/PD-L2 expression by human brain endothelial cells in regulating T cell responses in the context of Multiple Sclerosis. (44.6)
Authors: Pittet Camille , Ifergan Igal , Prat Alexandre , Arbour Nathalie 
Published: January 2023

Abstract
T lymphocytes have been implicated in the CNS injury observed in Multiple Sclerosis (MS), an inflammatory disease of the central nervous system (CNS). Engagement of Programmed Death-1 (PD-1), expressed on activated T cells, by its ligands (PD-L1 or PD-L2) suppresses T cell responses. We have previously shown that PD-L1 is upregulated on human CNS glial cells upon inflammation both in vitro and in MS lesions. We observed that several infiltrating CD8 T cells are devoid of PD-1 in MS lesions. Whether human brain endothelial cells (HBECs) which sit at the CNS entrance also express PD-L1 or PD-L2 and thereby block PD-1+ cells migration into CNS has not been established. We assess the expression of PD-L1 and PD-L2 by HBECs and establish its impact on immune responses. Under basal condition, PD-L2 is already highly expressed by HBECs, while PD-L1 is not detected. After stimulation with pro-inflammatory cytokines mimicking MS CNS environment, both proteins are significantly upregulated to similar levels. Blocking PD-L1/2 on HBECs leads to enhanced alloreactive CD4 and CD8 T cell responses in coculture assays and increased migration of CD4 and CD8 T cells using an in vitro model of the blood brain barrier. Our results show that PD-L1 and PD-L2 are both expressed by HBECs upon pro-inflammatory stimuli, and that HBECs-provided PD-L1/2 molecules have a role in dampening T cell responses, as well as in blocking T cell migration into the CNS.
Leptin serum levels in different subtypes of Multiple sclerosis: does leptin play a role in progress of Multiple sclerosis? (44.9)
Authors: Zarkesh-Esfahani Sayyed Hamid , Bahrami Ehsan , Maghzi Amir Hadi , Etemadifar Masoud , Kardi Mohammad 
Published: January 2023

Abstract
Background: Multiple Sclerosis (MS) is a chronic inflammatory demyelinating disease of the CNS resulting in accumulating neurological disability. Recent evidences have strongly indicated that leptin has influence on the immune system and maybe involved in the pathogenesis of autoimmune diseases such as MS. Objectives: To compare serum leptin levels among healthy volunteers and patients with different subtypes of MS and to investigate its association with disease progression. Material and Methods: Leptin concentrations in sera of 114 healthy volunteers and 136 patients with different types of MS, including 93 relapsing remitting (RR), 18 primary progressive (PP), 13 secondary progressive (SP), and 12 progressive relapsing (PR) after matching for sex, age and BMI were measured using ELISA technique. Results: Statistically significant difference was observed between healthy volunteers and MS patients (18.55±23.55 vs 38.86±39.59 ng/ml, p&lt;0.001), SP and PP (25.80±22.05 vs 70.64±53.01, p&lt;0.01), and also between RR and PP (42.10±42.35 vs 70.64±53.01, p&lt;0.05). There was a tight correlation between Progression Index and leptin serum concentrations (F=21.7, P&lt;0.001). Conclusion: Leptin serum level is significantly higher in the sera of MS patients compared to healthy sex, age and BMI matched group. Patients with progressive forms have elevated leptin levels that seem to be associated with their disease progression. Our data suggests a pro-inflammatory role for leptin in MS.
CD4 T cells must be present during B cell development for B cells to respond to a T-dependent foreign antigen (45.19)
Authors: Eisenberg Robert , Choudhury Arpita 
Published: January 2023

Abstract
We have previously shown that normal B cells from C57BL/6 (B6) mice must develop in the presence of syngeneic CD4 T cells if they are to be capable of producing antinuclear autoantibodies in response to allohelp from bm12 CD4 T cells (Clin Immunol 136, 105, 2010). We have now determined that B cells require a similar ‘nurturing’ from CD4 T cells during ontogeny, if they are to become capable of responding to a T-dependent foreign antigen. B6.CD4-/- mice given B6 CD4 T cells do not respond to OVA immunization. In addition, B cells isolated from B6.CD4-/- mice and transferred to B6.rag1-/- mice along with B6 CD4 T cells completely failed to respond to immunization with OVA in alum, whereas B cells isolated from CD4-sufficient mice responded strongly. Autoreconstituting B cells in B6.CD4-/- mice irradiated to 500 rads on day 0 require the presence of CD4 T cells administered on day 1 in order to be able to respond to OVA + B6 T cells on day 21. B cells from B6.CD4-/- mice are also deficient in stimulating the antigen-specific proliferation of OVA-specific OTII T cells in vitro. This deficiency could not be accounted for by phenotypic differences. Overall, our data reveal a role for CD4 T cells in the development of B cells before they encounter antigen. This ‘nurturing’ role allows the B cells to stimulate antigen specific T cells to proliferate to antigen and then respond themselves by the production of specific antibody.
Induction of antigen-specific B cell tolerance through the development of a versatile platform to target siglecs (45.4)
Authors: Macauley Matthew , Pfrengle Fabian , Paulson James 
Published: January 2023

Abstract
CD22 and SiglecG are proposed to be negative regulators of B cell receptor signaling through their ability to recognize sialic acid-containing glycans. Recent studies have shown that multivalent presentation of high affinity CD22 and SiglecG ligands in cis with a T-independent antigen can tolerize B cells (Duong et al., J. Exp. Med., 2010). Here we describe studies aimed at showing the generality of this phenomenon. To realize this aim, a novel liposomal nanoparticle platform was developed for presentation of both high affinity Siglec ligands and antigen. Chemical conjugation of the Siglec ligand and antigen to this platform is facile and, importantly, this platform is highly compatible with in vivo studies. Using this new platform, robust B cell tolerance is achieved toward both T-independent and T-dependent antigens in mice. Mechanistic studies provide clear evidence that: i) CD22 and SiglecG are the targets; ii) apoptosis of B cells is the mode of tolerance; iii) tolerization is highly selective to B cells containing a BCR that is specific for the targeted antigen. These studies reinforce the hypothesis that CD22 and SiglecG are critical components of a B cell that allows it to distinguish self from non-self. This method has clear potential for treatment of autoimmune diseases and allergies by antigen specific tolerization of B cells.
Cannabinoid receptor 2 plays a critical role in marginal zone B cell retention and T-independent humoral responses (45.6)
Authors: Basu Sreemanti , Ray Avijit , Dittel Bonnie 
Published: January 2023

Abstract
Marginal zone (MZ) B cells play a very important role in the early defense against blood borne pathogens by producing natural IgM and inducing T-independent (TI) humoral responses. Lack of MZ B cells has been associated with higher susceptibility to bacterial infections. However, the development/maintenance of these cells is not fully understood. Mice deficient in cannabinoid receptor (CB) 2, a Gi protein-coupled receptor highly expressed on B cells, showed a significant reduction in MZ B cells. We found that CB2 deficiency correlated with significantly decreased natural and TI IgM levels (post-immunization) in CB2-/- mice. We investigated the mechanism by which CB2 regulates MZ B cell numbers. Analysis of mixed BM chimeras showed a B cell intrinsic CB2 requirement, although additional data suggested no involvement of CB2 in MZ B cell development or survival. We next studied whether CB2 regulates MZ B cell adhesion/retention. Interestingly, WT B cells showed significantly higher adhesion to ICAM-1+VCAM-1, critical for MZ B cell retention in the splenic MZ, compared to CB2-/-. 2-AG, an endogenous CB2 ligand further enhanced WT B cell adhesion and blocking of CB2 signaling in WT mice with a CB2-antagonist dislodged MZ B cells from the spleen, increasing their numbers in the blood. Unmanipulated CB2-/- mice also exhibited increased MZ B cells in the blood compared to WT. Collectively, our study identifies a crtical role of CB2 in MZ B cell retention and TI humoral responses.
The interplay between TGFβ and cγc cytokine signaling in CD8+ T cell biology (46.19)
Authors: Sanjabi Shomyseh , Pham Joey , Mosaheb Munir , Ishigame Harumichi , Flavell Richard 
Published: January 2023

Abstract
Role of TGFβ signaling in peripheral tolerance is well appreciated. However, little is known about the role of TGFβ signaling in cytotoxic T lymphocytes during an inflammatory immune response. As naive CD8+ T cells become activated, they undergo clonal expansion followed by contraction where 90-95% of these cells die through apoptosis and the remaining 5-10% form long-lasting memory T cells. The effector cells that die during this process are called short-lived effector cells (SLECs) and the ones that survive to become memory cells are called memory precursor effector cells (MPECs). The apoptotic process during contraction is crucial as it resets T cell homeostasis, promotes protective immunity by allowing the formation of long-lived memory cells, and aids to limit autoimmunity. The survival of the effector T cells is directly proportional to the level of Bcl-2 they have. In effector CD8+ T cells, Bcl-2 can be induced in response to both IL-7 and IL-15, with IL-7 being in general a stronger inducer of Bcl-2 than IL-15. We have shown that while IL-15 promotes the survival of SLECs during expansion and contraction of effector CD8+ T cells, TGFβ promotes their apoptosis. The opposing effect of these two cytokines converges at the Bcl-2 promoter, where IL-15 induces Bcl-2 expression, while TGFβ reduces the amount of this anti-apoptotic molecule. The molecular mechanism by which these two cytokines control the expression of Bcl-2 is currently being investigated.
CXCR3 expression affects the balance of effector and memory CD8 T cell generation (46.6)
Authors: Hu Joyce , Kagari Takashi , Clingan Jonathan , Matloubian Mehrdad 
Published: January 2023

Abstract
In response to infection, activated CD8 T cells differentiate in vivo into a heterogeneous population of cells consisting of short-lived, terminally differentiated effector cells and memory precursor cells that give rise to long-lived memory cells. The strength and duration of antigenic stimulation and inflammatory signals influence CD8 T cell differentiation and the balance between these two fates. However, cell extrinsic cues, such as chemokines, that affect the localization and hence the exposure of CD8 T cells to antigenic and inflammatory signals are not completely understood. Here, we find that the inflammatory chemokine receptor CXCR3 is upregulated on activated CD8 T cells and influences their differentiation. CXCR3 guides activated CD8 T cells towards marginal zone areas where they are exposed to antigenic and potentially inflammatory stimuli. In the absence of CXCR3 expression, activated CD8 T cells are localized to the T zones of the splenic white pulp where they are less likely to receive antigenic stimulation. The increased exposure to antigen is associated with an increase in the generation of short-lived effector cells while the decreased exposure to antigen is associated with a quantitative and qualitative enhancement of memory cells. Our findings demonstrate that chemokine receptors and T cell positioning in secondary lymphoid organs can influence the balance of effector and memory T cell generation.