bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of two immunoglobulin binding proteins is necessary for S. aureus to avoid host mediated innate and adaptive immune systems (P3138)
Authors: Kim Hwan Keun , Falugi Fabiana , Missiakas Dominique , Schneewind Olaf 
Published: January 2023

Abstract
Human or animal infections with S. aureus do not elicit protective immunity against staphylococcal diseases. Staphylococci are notorious to deploy a wide spectrum of strategies to avoid host immune system. Previous work revealed that both innate and adaptive immune systems are hampered by the expression of two immunoglobulin binding proteins; staphylococcal protein A (SpA) and staphylococcal binder of immunoglobulins (Sbi). Staphylococcal protein A, a molecule that associates with both Fc and Fab portions of immunoglobulins, is necessary 1) to neutralize the antibody mediated opsonophagocytosis and 2) to trigger the expansion and apoptotic demise of B cell populations. The second immunoglobulin binding protein, Sbi, can associate with Fc portion of immunoglobulin and complement factor C3 to disable a critical juncture between the innate and adaptive immunity. Although much of biochemical analysis revealed how the two staphylococcal proteins engage with immunoglobulins for many years, their role as immuno modulatory virulence factors in vivo has not been fully understood. We have investigated the significance of immunoglobulin association with staphylococci during acute and chronic infection in animal model and characterized the molecular mechanisms to avert host immune defense system. Strategies are also discussed on how the two secreted products of staphylococci may be exploited for the development of vaccines and therapeutics.
Yersinia pseudotuberculosis persistence in the lungs is enabled by Ail and YadA targeting of Yops into neutrophils. (P3150)
Authors: Paczosa Michelle 
Published: January 2023

Abstract
A murine model of Yersinia pseudotuberculosis (Yptb) pneumonia was previously developed using the IP2666 strain, which was found to robustly colonize the lungs but only sporadically colonize the liver and spleen (Fisher et al, 2007). Here we show that when the Yptb IP32953 strain was intranasally inoculated into mice, it colonized and persisted in the lungs at high levels, and had dramatically increased bacterial dissemination as compared to IP2666. As adhesins are important for infection and dissemination by Yersinia in other infection models, their role was investigated during IP32953 lung infection using isogenic ΔyadA, Δail, ΔpsaE and Δinv mutants in IP32953. Ail and YadA were critical and redundant for persistence in, but not colonization of, the lung. When a neutropenic mouse was infected with the ΔailΔyadA mutant, the mutant survived as well as wild-type, indicating that a major function of Ail and YadA is to circumvent killing by neutrophils. Further investigation indicated that these adhesins are necessary for selective translocation of Yops by the Type III Secretion System into neutrophils over other immune cell types. This enrichment of translocation into neutrophils correlates with altered binding by the ΔailΔyadA compared to the wild-type. In conclusion, Ail and YadA combined are critical for persistence in the lungs during Yptb infection, because they thwart the bactericidal effects of neutrophils by directing translocation of Yops into these cells.
Mycobacterium tuberculosis culture filtrate protein of 10 kDa inhibits B cell function (P3120)
Authors: Samten Buka , Wang Xisheng , Huang Fang-fang , Barnes Peter 
Published: January 2023

Abstract
Culture filtrate protein 10 kD (CFP10) and early secreted antigenic target of 6 kD (ESAT-6), are required in pathogenesis of tuberculosis in part by manipulation of host immunity. We reported the immune modulatory effects of ESAT-6, and the effect of CFP10 in this regard remains unexplored. We now demonstrate that recombinant CFP10 binds to peripheral blood B cells and monocytes, but not to T-cells. Stimulation of B cells through the B cell receptor BCR plus TLR9 induced IL-6, IL-8 and IL-10 production, and CFP10 but not rAg85 markedly reduced IL-10 secretion and mRNA expression, without affecting IL-6 and IL-8. CFP10 did not affect LPS-stimulated cytokine production by monocytes. CFP10 reduced BCR plusTLR9 stimulated B cell proliferation and IgG secretion. Using B cells as antigen-presenting cells, we found that CFP10 inhibited expression of CD80 and CD86, but not that of CD69 and MHC-II expression, resulting in reduced M. tuberculosis-specific T cell IFN-γ production. The effects of CFP10 on B cells were not due to changes in B-cell TLR9 expression, viability or apoptosis. However, CFP10 inhibited BCR plus TLR9 stimulated nuclear translocation of NF-κB, activation of AP-1 transcription factors and expression of BLIMP1, the master regulator of B cell maturation and activation. We conclude that CFP10 inhibits B functions by blocking TLR9 and BCR signaling, suggesting potential cell specific immune regulatory functions for CFP10 during tuberculosis infection.
Antigen specificity of tuberculosis-specific CD4+ T cells in IKEPLUS immunized mice (P3122)
Authors: Johnson Alison , Goldberg Michael , Lindestam Arlehamn Cecilia , Hegde Subray , Blanchard John , Sette Alessandro , Chan John , Jacobs William , Porcelli Steven 
Published: January 2023

Abstract
Mycobacterium tuberculosis (Mtb) infects one-third of the global population. A more efficacious vaccine is urgently needed for control and prevention of disease. We recently reported a genetically modified strain of M. smegmatis, IKEPLUS, which is a promising vaccine candidate due to its ability to generate an unprecedented level of bactericidal immunity against Mtb in mice. Since protective immunity induced by IKEPLUS is dependent on antigen-specific CD4+ T cell memory, we hypothesized that specificity of the CD4+ T cell response was critical for protection. To determine CD4+ T cell specificity directly, we generated MHC class II (I-Ab) restricted T cell hybridomas from IKEPLUS-immunized mice. Screening of T cell hybridomas against anion exchange-fractionated IKEPLUS and Mtb proteins provided evidence for multiple specific targets, one of which was identified as the AtpA protein, a product of the Mtb Rv1308 gene. In a complementary approach, using in vitro assays of IFNγ production by splenocytes from IKEPLUS-immunized mice, we identified an immunogenic peptide within the Mtb RplJ protein encoded by the Rv0651 gene. Our results demonstrate the CD4+ T cell response in IKEPLUS-immunized mice has multiple targets, among which AtpA and RplJ represent novel specificities for protective responses against Mtb. Further studies to more fully define the range of specificities of CD4+ T cells in IKEPLUS-immunized mice should help to inform the design of effective vaccines against Mtb.
Inhibition of B and T cell responses by Salmonella Pathogenicity Island II (P3124)
Authors: Nanton Minelva , Atif Shaikh , Lee Seung-Joo , Taylor Justin , Nuccio Sean-Paul , Way Sing Sing , McSorley Stephen 
Published: January 2023

Abstract
New vaccines against NTS and typhoid are urgently required and human and mouse infection models indicate a critical role for CD4+ T cells and B cells in protective immunity. Previous studies also suggest that live Salmonella can actively inhibit host protective immunity, but the mechanism remains poorly defined. Here, we utilized a novel OVA-B cell tetramer approach to examine the antigen-specific B cell response to live Salmonella-OVA vaccination. OVA-B cell expansion and germinal center formation were delayed until 45 days in vaccinated mice, suggesting active inhibition by bacteria. The Salmonella Pathogenicity Island II locus has been implicated in culling CD4+T cell responses during live vaccination. Thus, we examined the effect of the SPI2 locus on B cell responses by concurrently infecting mice with a ΔSPI2 mutant, immunizing with OVA protein and measuring the expansion and germinal center formation of OVA-B cells. Wildtype, and not ΔSPI2, Salmonella inhibited expansion of OVA-specific B cells 7 days after immunization. The results of this work suggest two dilemmas for Salmonella vaccination. 1. SPI2 effectors cause a sub-optimal Salmonella-specific B and T cell response during live vaccination. 2. Subunit vaccination in conjunction with active Salmonella infection, may elicit a weaker immune response to the administered vaccine. Studies are underway to identify the SPI2 effector protein responsible for dampening Salmonella-specific adaptive immune responses.
Ibrutinib (PCI-32765) administration modulates a Th1 dominated immune response during cutaneous leishmaniasis infection (P3070)
Authors: Natarajan Gayathri , Dubovsky Jason , Satoskar Abhay , Muthusamy Natarajan , Johnson Amy , Byrd John 
Published: January 2023

Abstract
Treatment for leishmaniasis, a neglected tropical disease with worldwide disease burden of 12 million, is ineffective due to rising drug resistance and toxicity. Hence, chemotherapies that modulate host immune response towards a leishmanicidal Th1 response are required. In this study we show that Ibrutinib (PCI-32765), a drug shown to be effective in Phase I/II lymphoma trials, is capable of modulating a Th1 dominated immune response during cutaneous leishmaniasis caused by Leishmania major. L.major infected BALB/c mice treated with Ibrutinib had similar lesion progression compared to vehicle treated L.major infected mice until six weeks of infection and subsequently developed smaller lesions from week-6 to week-9 post-infection. Draining lymph node cells from week-9 Ibrutinib treated mice stimulated with L.major antigen produced significantly lower concentrations of IL-4, IL-10 and IL-13 compared to vehicle treated mice while ratios of IFN-γ:IL-4, IFN-γ:IL-10 and IFN-γ:IL-13 were significantly higher in Ibrutinib treated mice compared to vehicle treated mice. Serum IgG1 antibody titers at week-8 post-infection were significantly lower in Ibrutinib treated mice compared to vehicle treated mice while IgG2a titers were similar between the two groups. Thus, our studies indicate that Ibrutinib (PCI-32765) administration leads to development of a Th1 dominated immune response in L.major infection. This drug requires exploration as a therapeutic agent against leishmaniasis.
IL-15 deficiency promotes accelerated colitis upon expansion of CD4+ T cells (P1231)
Authors: Tosiek Milena , Fiette Laurence , Freitas Antonio 
Published: January 2023

Abstract
Inflammatory bowel diseases (IBD) are idiopathic chronic inflammatory disorders affecting small intestine and/or colon. One of established animal models of IBD can be induced by adoptive transfer of naïve CD4+T lymphocytes from healthy wild type mice into syngeneic recipients lacking T and B cells (RAGko mice). IBD is becoming an attractive field of research for development of new therapeutic agents, including cytokines involved in intestinal inflammation. The clinical relevance of a pleiotropic cytokine IL-15, which shares some similarities with IL-2 and IL-21, was already demonstrated for rheumatoid arthritis, multiple sclerosis and suggested for IBD. In our study, we observed that adoptive transfers of wild type CD4+ T cells result in accelerated manifestation of IBD symptoms, i.e. remarkable body weight loss, rectal bleeding and diarrhoea when recipient mice are IL-15-deficient (IL-15koRAGko). Histologically, colitic IL-15koRAGko mice demonstrate marked infiltration of CD4+ T cells in the colon together with mucosal surface distortion and gland atrophy. Activation of CD4+ T cells transferred into IL-15-deficient mice positively correlates with enhanced IL-17 production and accumulation of neutrophils and lineage-negative cells at the site of inflammation. At the same time the frequency of regulatory T cells (CD4+CD25+Foxp3+) significantly decreases in colitic IL-15koRAGko, which addresses a question of unbalanced Treg function in colitis developed upon IL-15 deficiency.
Diacylglycerol kinase-ζ limits natural regulatory T cell generation. (P1213)
Authors: Schmidt Amanda , Zou Tao , Kambayashi Taku 
Published: January 2023

Abstract
Development of natural regulatory T cells (nTregs) is requisite to maintain central tolerance. nTregs are believed to develop after receiving strong T cell receptor (TCR) signals during T cell maturation in the thymus. This notion comes from experimental systems wherein TCR transgenic T cells adopt the Treg fate only if their cognate antigen is present in the thymus during development. However, whether strong TCR signals drive nTreg development in a polyclonal setting and the specific signaling pathways downstream of the TCR necessary for nTreg development remain elusive. In this study, we selectively perturbed the lipid second messenger diacylglycerol (DAG), which is a critical component of TCR signaling. Using mice that lack DAG kinase-ζ (DGKζ), a negative regulator of DAG, we demonstrate that enhanced DAG signals result in a significant increase in nTreg development in a cell-autonomous manner. DGKζ-deficient T cells exhibited increased c-Rel and ERK signaling, suggesting that these downstream pathways may contribute to enhanced Treg development in DGKζ-deficient mice. Indeed, the absence of c-Rel almost completely abrogated the increase in Treg development observed in DGKζ-deficient mice. Moreover, inhibition of ERK also prevented Treg development in the absence of DGKζ. Our study shows that (1) nTreg development is enhanced by increased TCR signaling in a polyclonal setting and (2) DGKζ limits nTreg development by attenuating signals leading to ERK and c-Rel activation.
The role of Discs Large Homolog 1 phosphorylation in translating TCR signal strength into discrete CTL functions (P1168)
Authors: Crocetti Jillian , Silva Oscar , Humphries Lisa , Miceli M. 
Published: January 2023

Abstract
In cytotoxic T lymphocytes (CTLs), engagement of the T cell receptor (TCR) triggers signaling pathways that culminate in cytokine production and cytotoxic killing. TCR signal strength is linked to CTL function with low signal triggering cytotoxicity while high signal leads to both cytotoxicity and cytokine production. Scaffold protein Dlg1 (Discs Large Homolog 1) is a key point of control downstream of the TCR that coordinates both cytokine production and cytotoxic functional output. However, the molecular mechanism by which Dlg1 regulates cytokine production and cytotoxicity in response to TCR signal strength remains elusive. We report that Dlgh1 is tyrosine phosphorylated in response to TCR stimulation, and that phosphorylation is a key step in Dlg1-mediated activation of the alternative p38 pathway and downstream cytokine gene expression. We demonstrate that Dlg1 phosphorylation is mediated by Dlg1-associated Lck, not Zap70; and that Dlg1 Tyr222 is a major site of TCR-induced phosphorylation. Importantly, T cells expressing Dlg1 with a tyrosine to phenylalanine mutation (Y222F) show a defect in TCR-induced activation of the alternative p38 pathway, activation of NFAT and transcriptional upregulation of TNFα and IFNγ genes, but not the transcriptional upregulation of the granzyme B gene or CTL degranulation. These data position Dlg1 phosphorylation as a molecular switch allowing selective activation of p38-dependent events in response to the strength of the TCR signal.
A novel mouse model for immune mediated skin dermatitis and fibrosis through targeted deletion of phosphoinositide dependent kinase-1 (P4132)
Authors: Yu Minjun , Ghosh Sankar , Farber Donna 
Published: January 2023

Abstract
We developed a novel conditional knockout mouse model in which the PDK1 is specifically ablated by OX40 Cre in a subset of CD4+ effector/memory T cells and Tregs , which are also concomitantly labeled with a fluorescent reporter YFP molecule, enabling tracking of the mutant PDK1-deficient cell populations in vivo. The resultant mice (designated PDK1-CKO) are born healthy similar to conditional heterozygous control mice (PDK1-CHET), but gradually and spontaneously develop symptoms and immune manifestations of human scleroderma- including skin dermatitis, fibrosis and thickening with increased collagen deposition, immune infiltration into the skin, an increase in Th2 effector cells, and elevations in Type 2 and pro-inflammatory cytokines in serum, including IL-4, IL-10, IL-13 and IL-6 also found in sera of human scleroderma. Moreover, the proportion of regulatory T cells is reduced compared to effector T cells, which are mostly activated Th2 cells in lymphoid organs. Transfer of wild type Tregs into PDK1-CKO mice ameliorates skin dermatitis, fibrosis and dampens the Th2 response, and transfer of effector CD4 T cells from PDK-CKO mice into immunodeficient hosts triggers skin pathology. Our results suggest a model for disease development in PDK1-CKO mice: Tregs are functionally impaired, enabling the development of pathogenic YFP+ Th2 effector CD4 T cells which migrate to skin and also promote systemic Th2-driven pathology.
IL-21 promotes autoreactive germinal center development in BXD2 mice partially by regulating TFR. (P4116)
Authors: Ding Yanna , Hsu Hui-Chen , Li Jun , Yang PingAr , Zajac Allan , Mountz John 
Published: January 2023

Abstract
Follicular regulatory T cells (TFR) are a regulatory CD4 (Treg) subset that suppress germinal center (GC) B cell differentiation. Interleukin 21 (IL-21) promotes T follicular helper (TFH) differentiation. In the present study we investigated the modulatory effects of IL-21 on TFR in autoimmune BXD2 mice that develop spontaneous GCs with accumulation of IL-21+TFH cells in the spleen. In BXD2-Il21-/- mice, GL-7+Fas+GC B cells and CXCR5+ICOS+TFHs were significantly reduced, but the frequency of TFR cells was 2-fold higher than that in wild-type BXD2 mice. Most CXCR5+ICOS+CD4 T cells in BXD2-Il21-/- mice highly expressed Treg markers including FoxP3, CTLA4, TGF-β1 and GITR. FoxP3+TFR cells were localized in spleen follicular areas of BXD2-Il21-/- mice. Surprisingly, transfer of TFRs from BXD2-Il21-/- mice into BXD2 mice reduced IgM but not IgG autoantibody producing B cells in the spleen. This may be due to the suppressive effects of IL-21 on TFRs as administration of AdIL-21 increased GC B cells and decreased the ratio of TFR/TFH in the spleen of BXD2-Il21-/- mice in vivo. In vitro, IL-21 increased TFH but decreased TFR cells and significantly reduced Tgfb expression by TFRs. IL-21 also counteracted TFR-induced B cells death and inhibition of TFHs. The present study suggests that IL-21 positively promotes autoreactive GC reactions in BXD2 mice at least partially by decreasing TFRs and compromising the suppressive function of TFRs on B cells and TFHs.
Highly suppressive CD39+ Tregs decrease during disease activity in patients with Systemic Lupus Erythematosus (P4124)
Authors: Syed Ahamed kabeer Basirudeen , Teo Yi Wei , Som Wen Chi , Foong Shu Fen Charlene , Thio Szu-Tien , Wang Linda , Salcido-Ochoa Francisco , Thumboo Julian , Ling Khoon Lin , Kok Yong Fong 
Published: January 2023

Abstract
Objective: Reports on changes in the number and function of Tregs in Systemic Lupus Erythematosus (SLE) have been contradictory, possibly because most of those studies focused on identifying the whole Treg population, without dissecting the Treg subsets. This study aimed to enumerate the number and to study the role of various Treg subsets such as CD39+ Tregs , Naïve Tregs and activated Tregs in SLE patients. Results: Thirty SLE patients, 8 with active disease and 22 in remission, were recruited. The proportion of Tregs (CD4+CD25+Foxp3+) did not differ between patients with active lupus and those in remission (8.2±2.4% vs 7.5±3.8%, respectively; p=0.83). Similarly, there were no differences in these two groups of SLE patients in respect to the numbers of the naïve (CD4+CD45RA+Foxp3+) and activated Tregs (CD4+CD45RA-Foxp3high). However, the proportion of CD39+ Tregs was found to be significantly lower SLE patients with a flare, compared to those on remission (21.6±8.1% vs 41.9±4.7%, respectively; p=0.01). FACS-sorted CD39+ Tregs were found to be significantly more suppressive than CD39- Tregs. At the cut-off point 15.3%, CD39+ Tregs differentiated patients with active lupus from those in remission with the sensitivity of 95% and specificity of 75%. Conclusions: Fewer CD39+ Tregs in patients with active lupus indicates that CD39+ Tregs may play a crucial role in the pathogenesis of SLE. Furthermore, peripheral blood CD39+ Treg may be a biomarker for flares in SLE patients.
An innovative method for assessing autophagy using the FlowSight imaging flow cytometer (P3253)
Authors: Kong Raymond , Friend Sherree , Hall Brian , Basiji David , Pugsley Haley 
Published: January 2023

Abstract
Autophagy is a process in which normal cellular components that accumulate during growth and differentiation are degraded via the lysosome; it is a survival mechanism that reallocates nutrients from unnecessary processes to more vital processes in the cell. Basal levels of autophagy are usually low but can be up-regulated by numerous stimuli including starvation, physiological stress, pharmacological agents and infections. In addition, suppression of autophagy has been associated with cancer, neurodegenerative disorders, infectious diseases and inflammation. During autophagy, cytoplasmic LC3 is processed and recruited to the autophagosomal membranes; therefore, cells undergoing autophagy can be identified by visualizing LC3 puncta using immunofluorescence microscopy. While manual microscopy allows visual identification of autophagy on a per-cell basis, an objective and statistically rigorous assessment is difficult to obtain. To overcome these problems, we used the FlowSight imaging cytometry platform collect imagery of large numbers of cells to assess autophagy in an objective, quantitative, and statistically robust manner. In this study, we demonstrate a method for determining the best image-based parameter for assess the LC3 puncta in starved and non-starved U2OS RFP-LC3 human osteosarcoma reporter cells.
Innovative nanotherapy for the treatment of the chronic skin condition, rosacea. (P3259)
Authors: Mahajan Supriya , Aalinkeel Ravikumar , Reynolds Jessica , Nair Bindukumar , Sykes Donald , Law Wing-Cheung , Prasad Paras , Schwartz Stanley 
Published: January 2023

Abstract
A chronic skin disorder called Rosacea is primarily characterized by inflammation associated with abnormal innate immune response and the current treatments include oral and topical antibiotics and antimicrobials. CD163 plays a key role in etiology of Rosacea and a combination targeted nanotherapy which includes an topical antibiotic such as doxycycline, an anti-microbial such as Azelaic acid and the anti CD163 antibody would be an effective therapy for Rosacea. We developed a nanoemulsion for the treatment of Rosacea using fluorophores called nanophosphors which are upconversion nanoparticles (UCNPs), that have the ability to convert near infrared radiations with lower energy into visible radiations with higher energy via a nonlinear optical process and exhibit unique luminescent properties, including high penetration depth into tissues. Our goal was to evaluate the transdermal delivery of this nanoemulsion using an in-vitro skin barrier model (EpiDerm™). Dermal permeability coefficient is calculated and drug concentrations are determined by HPLC. Our results show a significantly higher 72% increase (p&lt;0.01) in uptake of this nanoemulsion by dermal keratinocytes and fibroblasts and deeper penetration into the skin layers as compared to topical application of the antibiotic and/or antimicrobial alone. Although, this nanoformulation is specific to the treatment of Rosacea, this nano-therapeutic approach can be applied to other skin disorders.