bluuebunny/crossref_metadata_2025_split huggingface dataset:
N-glycan branching regulates B cell peripheral functions
Authors: Mortales Christie-Lynn , Demetriou Michael 
Published: January 2023

Abstract
N-glycosylation is important for regulating many immune cell functions. To date, the role of N-glycan branching on influencing B cell antigen presenting cell (APC) function is not known. Proper CD4+ TH cell activation requires APC peptide presentation together with CD80/CD86 co-stimulation. CD80 and CD86 respectively promote TH1 cell-mediated and TH2 humoral immune responses. APCs then release cytokines that further dictate TH cell polarization into TH1, TH2, TH17 or TREG cells. In vitro stimulated N-glycan branching deficient B cells have higher CD80 and lower CD86 surface levels, and produce more pro-inflammatory TNFα and less anti-inflammatory IL-10. Furthermore, N-glycan branching deficient B cells have increased toll-like receptor 4 (TLR4) surface levels resulting from lack of endocytosis. Sustained surface TLR4 enhanced intracellular signaling towards NFκB activation as measured by increased phosphorylation of TAK1 and p38. Endosomal TLR4 signaling, which can lead to IRF3 activation, was diminished as seen by decreased expression of TRAF3 and phosphorylation of TBK1. Our results show N-glycan branching on peripheral B cells restricts NFκB activation to limit pro-inflammatory cytokine expression and CD80 surface levels, ultimately dampening TH1 cell-mediated responses. This study demonstrates N-glycosylation is important for regulating B cell APC function.
Inflammatory monocytes enhance disease progression during post-influenza MRSA pneumonia
Authors: Fischer Karl Jacob , Sun Keer , Bauer Christopher , Yajjala Vijaya Kumar 
Published: January 2023

Abstract
Morbidity associated with influenza pandemics of the last century has been significantly associated with secondary bacterial infections. It is generally believed that the enhanced susceptibility to secondary bacterial infection is due to influenza-suppressed innate immunity. Interestingly, preceding influenza infection does not inhibit inflammatory cell recruitment during secondary bacterial infection. In fact, due to the recruitment of inflammatory monocytes, there are increased numbers of phagocytes in influenza and bacterial coinfected airways. The protective role of monocytes during influenza infection alone is well recognized; however, it is not clear how this phagocyte population contributes to post-influenza bacterial pneumonia. Using CC-Chemokine Receptor 2 deficient (CCR2−/−) mice defective in airway monocyte recruitment, we are currently investigating the role of inflammatory monocytes during influenza and methicillin-resistant Staphylococcus aureus (MRSA) coinfection. Specifically, C57BL/6 mice were infected intranasally with a sublethal dose of PR8 and subsequently MRSA on day seven post-influenza infection. Despite their delay in viral clearance, coinfected CCR2−/− mice exhibited significantly reduced bacterial burdens and importantly, improved survival rates compared with WT mice. Moreover, pro-inflammatory cytokine response in coinfected CCR2−/− mice was significantly decreased, suggesting an attenuation in lung inflammation. In summary, we found that by inhibiting bacterial clearance and perpetuating lung inflammation, inflammatory monocytes exacerbate adverse disease outcome during post-influenza MRSA pneumonia.
Platelets mediate host-defense against S. aureus through direct bactericidal activity and by enhancing macrophage activities
Authors: Ali Ramadan , Weuscher Leah , Dona Keith , Worth Randall 
Published: January 2023

Abstract
Platelets are chief effector cells in hemostasis. However, recent evidence suggests that platelets have multiple roles in host defense against infection. Recent reports by us and others showed that platelets functionally contribute to protection against Staphylococcus aureus infection. In the current study, the capacity of mouse and human platelets to participate in host defense against S.aureus infection was determined by assessing two possibilities: First, the ability of platelets to directly kill S. aureus; and second, the possibility that platelets enhance macrophage phagocytosis and intracellular killing of S. aureus. Both human and mouse platelets effectively killed S. aureus (&gt;35% and &gt;40% killing in 60 min., respectively) in an activation-dependent (0.1U.ml thrombin) manner. Interestingly, thrombin-stimulated mouse platelets also significantly enhanced peritoneal macrophage phagocytosis of S. aureus by 70% and intracellular killing by 43%. To determine if platelet-enhanced uptake and killing was due to direct interaction or through releasable products, peritoneal macrophages were exposed to releasates collected from resting or thrombin-activated platelets. The data show that releasates collected from thrombin-activated platelets induce similar increases in both uptake and killing of S. aureus by macrophages. These data confirm our hypothesis that platelets participate both directly and indirectly in protection against S. aureus infection.
The Characterization of Nonclassical T cells and their Responses during Mtb Infection
Authors: Simpson Allison , Foreman Taylor W , Rout Namita , Kaushal Deepak 
Published: January 2023

Abstract
Tuberculosis (TB) is a catastrophic infectious disease, affecting roughly one third of the world’s population. Typically 5–10% of infections will develop into active TB, however co-morbidities such as HIV present an increased risk of TB reactivation, leading to life-threatening active infection. While it is well-known that T cells, and in particular, Class II restricted, IFN-γ expressing classical CD4+ T cells are essential for immunity to TB, these are by themselves not sufficient correlates of protection, especially during reactivation of LTBI by HIV co-infection. Recently lymphocytic subsets that recognize nonpeptidic antigens have been classified as nonclassically activated T cells. These cells are, however, poorly characterized as regulators of the immune system, particularly in patients infected with M. tuberculosis (Mtb). We hypothesize that non-classically activated T cells recognize bacterial antigens during Mtb infection, as well as Mtb/HIV co-infection, and may play a role in protective immunity. As part of this project, we will enumerate and phenotype the populations of nonclassical T cells based on expression of their surface antigens at different time points of Mtb and Mtb/SIV infection in rhesus macaques. Furthermore, we will characterize the function of the non-classical T cells by analyzing their secreted factors. Better understanding the role of nonclassical T cells in TB pathogenesis may enable us to develop better vaccines and treatments against TB.
Impact of Silver and Carbon Nanoparticle Exposures on Macrophage Responses to Mycobacterium tuberculosis (M.tb)
Authors: Sarkar Srijata , Carranza Claudia , Theodorou Ioannis , Fen Leo Bey , Ellis Timothy , Porter Alexandra , Ryan Mary , Zhang Junfeng , Tetley Teresa , Schwander Stephan 
Published: January 2023

Abstract
To assess biological risks of nanoparticle (NP) exposures, we examined the effects of silver (Ag) core Ag20-citrate (Ag20) and carbon black (CB) on human host innate immune responses to M.tb, a respiratory pathogen that causes tuberculosis. Human peripheral blood monocyte-derived macrophages (MDMs) were exposed to 1, 10, 25 and 50 μg/mL of Ag20 and CB for 4 and 24 h. At 4 h no significant cytotoxicity was observed with neither of the NPs at none of the concentrations examined relative to unexposed MDMs. At 24 h, viability of the MDMs was reduced by 60–70% and 20% following Ag20 and CB exposure, respectively, at doses ≥25 μg/mL. M.tb-induced host immune responses are mediated by the activation of TLR signalling pathways that culminate in NF-κB activation. Effects of Ag20 and CB (10μg/mL for 4 h, a nontoxic dose) on TLR signalling in M.tb-infected and uninfected MDMs were compared using a human TLR signaling pathway-specific profiler array. Ag20 exposure suppressed the M.tb-induced expression of a subset of NF-κB-mediated target genes (CSF2, CSF3, IFNG, IL1A, IL1B, IL6, IL10, TNFA, NFKB1A). Ag20-mediated suppression of M.tb-induced activation of the TLR-signalling pathway was not due to decreased uptake of M.tb by MDMs or mycobacteriocidal effects of Ag20. Ag20 exposure increased the expression of HSPA1A mRNA that encodes for the stress-induced Hsp72. In contrast, exposure to CB resulted in little effects on M.tb-induced host gene expression indicating that immunosuppressive effects of Ag20 are NP-specific. Since Hsp72 has been shown to suppress NF-κB activation, we propose that Ag20-mediated Hsp72 upregulation contributes to the suppression of M.tb-induced NF-κB activation and host immune responses.
Funding NIEHS 5U19 ES019536
Ankyrin Repeat Domain 22 Mediates Host Defense Against Viral Infection Through STING Signaling Pathway
Authors: Bin Lianghua , Li Xiaozhao , Feng Juntao , Richers Brittany , Leung Donald Y.M. 
Published: January 2023

Abstract
The innate immune system is critical for early detection of invading viruses and for initiating cellular host defense countermeasures, which include the production of interferons. Ankyrin repeat domain 22 (ANKRD22) encodes a protein of 191 amino acids containing 2 ankyrin repeating domain, and its biological function was unknown. In this study, we find that ANKRD22 expression can be significantly induced in human peripheral blood mononuclear cells (PBMCs) by DNA virus herpes simplex virus -1(HSV-1) and RNA virus respiratory syncytial virus (RSV) as well as IFN-α and IFN-γ. Its induction in PBMCs by viruses is largely a secondary effect of virus-induced interferons. We further demonstrate that ANKRD22 was majorly induced in monocytes and dendritic cells from PBMCs. Over-expression of ANKRD22 confers protection against HSV-1 and RSV infection in multiple tested cell lines. Vice versa, inhibition of ANKRD22 leads to enhanced HSV-1 and RSV replication in host cells. Furthermore, we identifies that ANKRD22 specifically interacts with STING, a critical protein function in multiple antiviral innate immune pathways. ANKRD22 by itself can only slightly induce type I IFNs IFN-α and IFN-β, and can’t induce type III IFN IL-29. However, it significantly synergizes STING-induced both type I and type III interferon production. Collectively, our studies indicate that ANKRD22 plays an important role for host defense against both DNA and RNA viruses by optimizing STING’s function on inducing type I and type III IFNs.
Neutrophil recruitment to the lymph node in response to S. aureus infection
Authors: Zuba Ania M , Kubes Paul 
Published: January 2023

Abstract
Bacterial skin infections can be cleared and pose no immediate threat to the host. However, if a bacterial infection is not contained and disseminates into the bloodstream, this can lead to system-wide bacteremia and death. Lymph nodes along lymphatic vessels may act as barriers by filtering the lymphatic fluid. This barrier is not merely passive, but is actively modulated in response to inflammation. In tissues, neutrophils are extremely important in controlling bacterial infections and are robustly recruited to the lymph node upon infection with pathogens at a distant site. Intriguingly, how the neutrophils reach the lymph node and their role upon arrival is only beginning to be understood. Neutrophil recruitment to the popliteal lymph node occurs within 2 hours of Staphylococcus aureus infection in the footpad, plateauing at 6 hours. Using intravital multiphoton imaging and the Lysm eGFP reporter mouse we have visualized the behaviour of neutrophils in lymph node blood vessels and in the lymph node tissue. Neutrophils accumulate within wide blood vessels in the lymph node, exhibiting rolling, adhesion, crawling and transmigration from vessel lumen into lymph node tissue. No neutrophils can be seen in afferent lymphatics. Imaging of the subcapsular sinus shows neutrophil accumulation and swarming as well as neutrophils actively phagocytosing S. aureus. This suggests neutrophils are being quickly recruited to the lymph node to prevent dissemination from an initial site of infection via lymphatics. This project aims to define the role of neutrophils as cellular barriers in preventing dissemination of bacteria via lymphatics.
Distinct T cell signatures define subsets of multiple sclerosis patients
Authors: Johnson Mark C , Pierson Emily R , Spieker Andrew J , Nielsen A. Scott , Posso Sylvia , Kita Mariko , Buckner Jane H , Goverman Joan M 
Published: January 2023

Abstract
Studies of the frequencies of myelin-specific T cells in peripheral blood mononuclear cells (PBMCs) from MS patients compared to healthy controls (HCs) have varied in their results, but no previous work has considered the potential influence of lesion localization on these frequencies. While the majority of relapse-remitting MS (RRMS) patients have lesions localized predominantly in the brain, a subset of RRMS patients (~5%) has neuroinflammation localized predominantly in the spinal cord. Importantly, spinal cord localized lesions are associated with a worse prognosis for patients due to their effect on motor function. Animal models of MS suggest that distinct T cell effector functions correlate with brain versus spinal cord lesions. Therefore, we analyzed PBMCs from MS patients with lesions predominantly in the brain or predominantly in the spinal cord and HCs using ELISPOT to assess the frequency of IFN-γ+ and IL-17+ cells responding to two myelin antigens, myelin basic protein (MBP) and myelin oligodendrocyte glycoprotein (MOG). Significant differences in T cell frequencies were determined in some, but not all, comparisons, with MBP-specific IFN-γ+ frequencies showing the greatest separation between our three groups. Strikingly, combining the IFN-γ+ and IL-17+ responses to both MBP and MOG using logistic regression defined distinct T cell signatures that distinguished MS patients with predominantly brain versus predominantly spinal cord lesions. Collectively, this suggests that different myelin-specific T cell responses may influence neuroinflammatory patterns in RRMS patients. Such patterns of peripheral T cell responses may be useful in generating more tailored therapies for patients with MS.
Enhanced IFN-γ signals and STAT5-phosphatase dependent attenuated IL-2 signals in the pathogenesis of rheumatoid arthritis.
Authors: Boland Molly , Vinod Surabhi , Bridges Louis , Raman Chander 
Published: January 2023

Abstract
The importance of type I interferons as a driver of pathogenesis in autoimmunity, including rheumatoid arthritis (RA) is well recognized. However, in this context the contribution of type II interferons (IFN-γ) has been equivocal. This study developed from our recent discovery that the expression of IFN-γ receptor gene Ifngr1 strongly associates with RA disease and expression of Ifngr2 associates with radiographic severity. In this study we show that IFN-γ induced activation is significantly greater in naïve, central memory, Tfh and Treg subsets of CD4+ T cell populations from RA patients compared to healthy controls (HC). Remarkably, such enhanced IFN-γ induced STAT1 activation was not observed in CD8 T cell populations from RA patients. The activation of STAT1 and consequently, IFN-γ signals are regulated by tyrosine phosphatases. Treatment with phenyl-arsine oxide (PAO), a broadly active phosphatase inhibitor, had no effect on IFN-γ induced STAT1 activation in any T cell population from RA or HC. In contrast, such treatment with PAO greatly enhanced IL-2 induced activation of STAT5 in RA CD4 T cell populations (naïve, central memory effector memory, Treg, Tfh) but not from HC or in CD8 T cell populations. This result suggests that the regulatory activity of IL-2 in RA is dampened by a STAT5-specific phosphatase. We further determined that such a STAT5-phosphatase was also expressed and active in regulatory and effector CD4 T cell populations from the spontaneously autoimmune BXD2 mice. Overall our results indicate that CD4 T cell subpopulation dependent enhanced IFN-γ signals and dampened IL2-STAT5 signals contributes to pathogenesis in RA.
Unveiling the specificity of islet-antigen specific regulatory T cells in T1D patient using single cell deep-sequencing
Authors: Xu Daqi , Dong Shen , Martínez-Llordella Marc , Chopra Gaurav , Bluestone Jeffrey 
Published: January 2023

Abstract
CD4+CD25hiCD127loFoxp3+ T Regulatory cells (Tregs) are critical in controlling autoreactive T cells. The deficiency of functional Tregs is associated with Type 1 diabetes (T1D) and many other autoimmune diseases. In addition, antigen-specific Tregs suppresses more efficiently compared to polyclonal Tregs in mouse models. Thus, identifying the antigen specificity of Tregs, especially at the site of inflammation, is critical to improve our understanding of Treg deficiencies in T1D and may lead to clinically applicable advances. However, the Treg TCRs recognizing self-antigens in autoimmune diseases are less clarified due to the rare frequency and the anergic status of Treg in vitro. In this study, by the combination of sub-culturing, polyclonal stimulation and antigen stimulation, we can identify islet-antigen specific Tregs from both PBMC and pancreatic draining lymph node of T1D patients using antigen-driven Treg proliferation assay we developed in our lab. The majority of islet antigen-specific Tregs is CD45RO+Tregs compared to the CD45RA+ counterpart. Importantly, we confirmed the enrichment and identified the specificity of the islet antigen-specific Tregs using single cell deep-sequencing. In the future, we will further characterize the uncovered Treg TCR and the phenotype of the identified islet antigen-specific Tregs via comparison between healthy and T1D subjects.
Dysfunction and depletion of human antigen-specific CD4 T cells by HIV: a mechanism for pathogen-specific immune failure in AIDS
Authors: Hu Haitao , Liu Fengliang , Fan Xiuzhen , Ferguson Monique , Sun Jiaren , Soong Lynn 
Published: January 2023

Abstract
HIV infection causes dysfunction and progressive depletion of human CD4 T cells, leading to enhanced host susceptibility to opportunistic infections (OIs). However, loss of immune control over different OIs occurs at different stages of HIV disease in patients; while CMV infection usually causes active disease at late stage with low CD4 counts, mucosal candidiasis caused by fungal pathogen C. albicans can become evident earlier at fairly high CD4 counts. The underlying mechanism is not well defined. We have established an in vitro system to model the interactions between HIV and pathogen-specific CD4 T-cell populations, and have shown that C. albicans-specific CD4 T cells are more permissive to HIV than CMV-specific cells in vitro. We further examined the in vivo impact of HIV on these two groups of pathogen-specific CD4 T cells in HIV-infected patients and the functional parameters involved. We found that compared to CMV-specific CD4 T cells, which manifest a polarized Th1 phenotype, C. albicans-specific CD4 T cells demonstrate mixed Th17-Th1 phenotype, producing high levels of IL-22, IL-17 and IL-2, in addition to IFN-γ and MIP-1β. The Th17 functional subsets (IL-22, IL-17 and IL-2) of C. albicans-specific CD4 T cells are more permissive to HIV in vitro and manifest an earlier impairment in vivo in HIV-infected individuals. Longitudinal analysis of infected subjects with ongoing CD4 depletion showed that C. albicans-specific CD4 response was preferentially and progressively depleted. These data altogether provide compelling evidence for differential susceptibility of pathogen-specific CD4 T cells to HIV infection and dysfunction, suggesting a mechanisms for pathogen-specific immune failure in AIDS.
IL-4 signaling via STAT6 induces human resistin expression
Authors: Batugedara Hashini Maneesha , Jang Jessica C , Patel Jay J , Nair Meera G 
Published: January 2023

Abstract
Human resistin (hRetn) has been implicated as a detrimental protein during helminth infection, where it impairs helminth expulsion. Current literature shows that LPS signaling via NFkB can promote hRetn expression. Promoter analysis of the hRetn gene revealed both NFκB and STAT6 transcription factor binding sites. This suggested that hRetn is not only regulated by TLR ligands but also by Th2 cytokines. Accordingly, we tested the ability of various TLR ligands and IL-4 to stimulate hRetn in bone marrow-derived macrophages (BMDM) from hRetn transgenic (Tg+) mice. We found that LPS and IL-4 stimulation significantly increased hRetn. Further, IL-4-induced hRetn expression was abrogated when BMDM were treated with a STAT6 inhibitor, confirming STAT6 dependent hRetn expression. We tested the effects of IL-4 in vivo by administering IL-4 complexes (IL-4c) intratracheally and intraperitoneally to hRetn Tg+ mice. We observed local and systemic IL-4-induced hRetn mRNA in blood cells, peritoneal exudate cells and the whole lung. To elucidate the relevance of these findings in humans, we stimulated human neutrophils, monocytes and peripheral blood mononuclear cells (PBMC) with IL-4 and discovered that neutrophils produced the most hRetn. Similar to mouse BMDM, the IL-4-induced hRetn in human PBMCs was blocked by STAT6 inhibitors. Collectively, these data suggest that IL-4 signaling via STAT6 induces hRetn and these results are supportive of a novel signaling pathway for hRetn. Future studies will investigate the functional relevance of STAT6 regulation of hRetn, which could provide new insights into controlling the outcome of several Th2 inflammatory diseases such as helminth infection and asthma.
Intracerebral Mycobacterium tuberculosis infection-induced immune response in the central nervous system
Authors: Hernandez Gianna L , Ritter Anna , Mergaert Aisha , Rayasam Aditya , Gerhart Christian , Sandor Matyas , Fabry Zsuzsanna 
Published: January 2023

Abstract
The World Health Organization declared a tuberculosis (TB) global emergency. Central nervous system (CNS) TB is a rare, highly devastating manifestation of extra-pulmonary TB. To date, research has focused on pulmonary TB, with no significant advancements being made in understanding the mechanisms associated with CNS TB. This study uses a small animal model of CNS TB that permits us to investigate the immune responses following CNS Mycobacterium tuberculosis (Mtb) infection. We use intracranial infection of mice with the H37Rv strain of Mtb which has been fluorescently tagged with a TdTomato plasmid, allowing us to track it in vivo, and analyzed the cellular composition of the subsequent immunological response in the brain. At 7 days post infection (PI), we show a robust infiltration of immune cells into the CNS including the infiltration of CD11c+ dendritic cells. We can also see Mtb-containing granuloma-like lesions. We adoptively transferred Mtb-specific P25 CD4+ T and found that these cells also accumulate in the brain and were found activated in the peripheral lymphoid tissue, including the spleen and cervical draining lymph nodes. The P25 T cells present in the brain display extensive proliferation. Moreover, P25 T cells present in the peripheral lymphoid organs of Mtb infected mice show increased proliferation when compared to non-infected controls suggesting a systemic sampling of CNS Mtb antigen. We also show that at 7 days PI there is a significantly higher percentage of activated, INFγ producing, CD4+ T in the brain. Both INFγ and IL-17 producing T cell populations increase in size by day 21. This study will provide knowledge into the pathogenesis of CNS TB, and provide possible treatment strategies to lessen its destructive outcome.