bluuebunny/crossref_metadata_2025_split huggingface dataset:
Innate immunity is initially effective in killing Mycobacterium tuberculosis (129.20)
Authors: Walker Tracey A , Heard Gladys T , Liao Reiling , Gill Wendy P , Urdahl Kevin B , Sherman David R 
Published: January 2023

Abstract
Mycobacterium tuberculosis (MTB) is a slow growing pathogen often resulting in lifelong infection. To investigate whether slow replication is an immune evasion strategy for MTB, we developed a replication tracking tool consisting of an unstable plasmid that is lost from replicating MTB at a constant rate. Mice were infected with MTB harboring this plasmid and at various times total and plasmid bearing bacteria in lungs were enumerated. MTB replication and death rates were derived using a mathematical model. Lung bacterial numbers increase for 21 days until antigen specific T cells arrive, after which time they remain constant. Using the unstable plasmid, we observed that replication and death rates were highest early and then slowed during chronic infection. Closer analysis of the acute phase revealed the dynamics of MTB replication and death. High replication and death rates were observed in the first 5 days and then both abruptly slowed. Killing was also observed in Rag1-/- mice indicating that innate immunity is effective in killing MTB. Our studies demonstrate that standard plating methods provide an incomplete picture. Using a replication tracking tool, we found that innate immunity is initially effective in killing MTB but that this is short lived. Which innate immune response mechanisms are at work and why both MTB replication and death so rapidly decrease are topics of ongoing studies.
This work was funded by the Paul G Allen Family Foundation.
Burn injury induces a myeloid suppressor phenotype and susceptibility to Pseudomonas infection (129.24)
Authors: Neely Crystal J , Wang Ming-Jin , Fuchs Erin , Vadlamudi Sivaram , Wolfgang Matthew , Cairns Bruce A , Maile Rob 
Published: January 2023

Abstract
Following severe burn injury, the immune system is dramatically altered resulting in a susceptibility to bacterial infections. Using a mouse model of burn injury and subsequent Pseudomonas aeruginosa infection, we hypothesized that 1) clearance will be decreased after burn and 2) expression of TLR2, important for P. aeruginosa clearance, and/or Gr1.1, a marker of myeloid suppressive ability, is altered by burn. Female C57BL/6 mice were subjected to a 20% full thickness contact burn or sham procedure. After one day, mice were inoculated s/c at the wound with 2 x104 CFU of P. aeruginosa. CFU were calculated for various organs after two days. Splenocytes were analyzed by FACS for CD11b, Gr1.1 and TLR2. Burn mice had significant morbidity (weight loss) and mortality versus sham. Burn mice developed a systemic infection (e.g. mean±SEM 4.4±0.6 x104 CFU/lung, n=6) while no CFU were recovered from sham (n=6). Infected burn mice had a significantly higher number and percent of CD11b+ TLR2hi splenocytes (22.6±3.5%) than the infected sham (3.4±0.4%). A higher number and percent of burn CD11b+ cells were Gr1.1+ (75.5±5.7%) compared to sham mice (43.3±1.2%). Therefore, although we observed an increase in TLR2+ myeloid cells following burn injury, the increased percentage of GR1.1+ CD11b+ myeloid suppressor cells could contribute to the development of a systemic P. aeruginosa infection after burn.
Supported by NIH K08 067147.
Differences in antibody and immune responses between Balb/c and C57Bl/6 mice infected with Trypanosoma cruzi (129.5)
Authors: Guyach Siobhan Elysse , Bryan Marianne A , Norris Karen A 
Published: January 2023

Abstract
Methods: Susceptible Balb/c and resistant C57Bl/6 mice were infected with Y strain T. cruzi. Parasitemia was monitored; plasma was collected and analyzed for specific and total antibody. T. cruzi specific responses were measured by reactivity to recombinant T. cruzi complement regulatory protein (CRP). In separate experiments, Balb/c and C57Bl/6 mice were immunized intradermally via particle bombardment (gene-gun) with plasmid DNA containing the CRP gene.
Results: Experimentally infected mice increase total plasma immunoglobulin (IgM, IgG) prior to specific response. Development of T. cruzi specific IgG response was delayed in Balb/c mice compared to C57Bl/6 mice, with comparable parasitemia. After immunization, Balb/c mice generated a higher titer IgG response than C57Bl/6 mice.
Conclusion: Experimental infection of mice with T. cruzi leads to an early increase in total plasma immunoglobulin levels, but a delayed antigen-specific response in Balb/c compared to C57Bl/6 mice. The lack of specific response early in infection in the Balb/c model was not due to an inherent inability to produce IgG in response to T. cruzi CRP antigen as these mice were more responsive to the CRP antigen in an immunization model. This suggests that the delayed T. cruzi specific response in Balb/c mice is a result of a host/pathogen interaction involving a polyclonal humoral response to the parasite.
T cell immune response to liposomal influenza A tri-peptide vaccine (130.2)
Authors: Tai Wendy , Shan Ming , Roberts Luz , Seryshev Alexander , Gilbert Brian , Corry David B. 
Published: January 2023

Abstract
A bivalent influenza virus (INFV) A vaccine composed of purified HA and NA surface proteins have long been available. Disadvantages of this vaccine include annual reformulation. We have developed a novel T cell-based vaccine comprised of short and highly conserved peptides derived from M2, HA, and NP peptides formulated with TLR ligands in a lipid matrix. We hypothesized that IN immunization with short and well conserved peptides will confer protection to lethally infected mice.
The tri-peptide (TP) vaccine was given IN to mice on d-21, -14, and -7 prior to INFV A and B aerosol infection (d0). Control animals received only sham liposomes (DLPC). For memory studies, mice were infected on 60d or 90d post treatment. 100% survival was observed in TP treated vs. DLPC treated mice (&lt;10%). PAS staining of lung sections showed reduced inflammation associated with TP treatment. Although TP treatments were not long lasting, it conferred partial protection to boosted mice (40% survival), and 17% NP+ CD8 T lungs cells were observed after booster. Lung viral burden was reduced by 2 log TP treated vs. naïve mice (d2). Divergent trends of IFN-γ and IL-6 production between TP treated and naïve animals on d6 and d8 post infection were observed.
Our findings indicate that T cells play an important role in viral clearance and mediation of flu. Future studies will aim at the understanding of the recruitment and egress of these T cell populations.
Searching H5N1 Strain-Specific Hemagglutinin Epitope Restricted by HLA DR4 (130.3)
Authors: Yang Junbao , Gebe John A. , James Eddie , Yu Betty B. , Tan Venus , Kwok William W. 
Published: January 2023

Abstract
CD4+ T cells play a pivotal role in the viral immunity, and as such identification of unique strain specific HLA class II restricted epitopes is essential for monitoring cellular strain specific viral immunity. Using Tetramer-Guided Epitope Mapping technique, we identified HLA-DR0401 restricted HA epitopes that are strain-specific to H5N1 virion. Two immunodominant epitopes H5HA441-460 and H5HA57-76 were identified from in vitro stimulated human PBMC. Both epitopes elicit strong cellular immune responses when HLA-DR0401 transgenic mice are immunized with H5N1 subvirion indicating in vivo naturally processed immunodominant epitopes. The H5HA57-76 epitope is unique for the H5N1 strain but conserved among all H5N1 clades recommended for vaccine development by World Health Organization. The unique H5HA57-76 response was uncommon in unexposed individuals and only observed in the naïve T cell subset. Thus, H5N1 strain-specific H5HA57-76 immunogenic epitope represents a unique marker for monitoring the efficacy of vaccination or as a candidate vaccine peptide.
Evidence that prolonged antigen-driven inflammation after influenza infection helps shape the specificity of the CD8 T cell recall response (130.5)
Authors: Suarez-Ramirez Jenny E , Khanna Kamal M , Aguila Carolina , Mohni Kareem , Cauley Linda S 
Published: January 2023

Abstract
Influenza viruses encode four major epitopes (NP, PA, PB1 and PB2) that are recognized by naïve CD8 T cells in C57BL/6 mice. MHC class I tetramer analysis has shown that CD8 T cells specific for the NP and PA epitopes are equally represented during the response to a primary infection with the reassortant HKx31 influenza virus. Secondary challenge with the serologically distinct A/PR/8 strain, however leads to a change in the dominance hierarchy so that NP-specific cells outnumber PA-specific cells in most tissues by approximately 5:1. We recently found that processed NP antigen persists in vivo long after infectious influenza virus has been eliminated. Large numbers of endogenous NP-specific CD8 T cells in the antigen bearing lymph nodes showed signs of a response to recent antigen stimulation. In contrast, there were much smaller numbers of PA-specific CD8 T cells in the mediastinal lymph node (MLN), with a much lower frequency of activated T cells. Since DC carry viral antigens to the MLN immediately after influenza infection, we have investigated whether the local specificities of antigen-specific memory CD8 T cells in the MLN at the time of reinfection help shape the specificity of the recall response. Since there is evidence in the literature that NP epitope is more protective than PA epitope, these studies will help us to elucidate the role of antigen and the biology of local specific memory CD8 T cell response in the shaping of the CD8 T cell response during secondary infections with influenza virus. This work was supported by NIH grants AI065895 & AI071213 (LSC),
Regulation of influenza virus-induced germinal center reactions (130.9)
Authors: Boyden Alexander , Legge Kevin , Waldschmidt Thomas 
Published: January 2023

Abstract
Previous work from our laboratory has demonstrated a steady state environment within primary splenic germinal center (GC) reactions as measured by the ratio of non-switched (IgM+) to switched (IgM-) GC B cells, following i.p. challenge with SRBC or protein Ags precipitated in alum. Since both of these experimental antigens induce a Th2-biased response, we sought to analyze the GC reaction after challenge with influenza virus, a natural pathogen that induces B cell activation under Th1 conditions. BALB/c mice were challenged i.p. or i.n. with the H1N1 PR8 virus and splenocytes subjected to multi-parameter flow cytometric analysis. After i.p. challenge, we again observed a steady ratio of IgM+ to switched GC B cells in the spleen. Surprisingly, an intense GC response was found in the spleen following respiratory (i.n.) challenge, with loss of a steady state environment at later time points. To evaluate the degree to which Tregs contribute to control of GC responses during influenza infection, mice were treated with anti-GITR or anti-CD25 mAb prior to and during viral challenge. Treg disruption resulted in a marked abrogation of GC homeostasis in the spleen, leading to exaggerated numbers of switched GC B cells.
Viral infection alters mRNA expression of nuclear hormone receptors (NRs) and their coregulators in mouse dendritic cells (DCs) (131.1)
Authors: Ng Sinnie Sin Man , Tailor Prafullakumar , Chang Tsung-Hsien , Ozato Keiko , Kino Tomoshige 
Published: January 2023

Abstract
DCs, versatile regulators of host immune response against viral infection, capture antigens and present them to T-cells and subsequently activate both innate and acquired immunity. NRs, on the other hand, are intracellular receptors which function as hormone-dependent transcription factors. Some of the NRs, such as the glucocorticoid receptor and the peroxisome proliferators-activated receptors (PPARs), suppress inflammatory reactions. Thus, we examined with real-time PCR using our custom NR PCR arrays for the mRNA expression of all mice NRs and their coregulators in bone marrow derived DCs (BMDCs) infected with viruses. At the baseline, BMDCs expressed 21 NRs. PPARγ, thyroid hormone receptor-α, retinoid X receptor-α, NGF-induced factor B and Nur related factor 1 were significantly down-regulated by virus infection (15-, 6-, 6-, 50- and 15-fold reduction, respectively), while liver X receptor-α and neuron-derived orphan receptor-1 were strongly upregulated (6- and 20-fold induction, respectively). All coregulators were expressed in BMDCs at the baseline, whereas histone deacetylase 4, 6 and 10, nuclear receptor corepressor-1 and Set-TAF-Iβ were significantly down-regulated by viruses (10-, 4-, 12-, 4- and 2-fold reduction, respectively). These results indicate that viral infection alters mRNA, and possibly, protein expression of some NRs and their coregulators. Our results suggest that NR signaling pathways are integral components of the global response of DCs to viral infection.
Th17 Cells Are Not Required for Host Defense Against Murine Disseminated Candidiasis, But Are Required for Vaccine-Mediated Protection (132.10)
Authors: Lin Lin , Ibrahim Ashraf S. , Avanesian Valentina , Xu Xin , Farber Joshua , Fu Yue , Baquir Beverly , Spellberg Brad 
Published: January 2023

Abstract
Background: We are developing a vaccine based on the recombinant N-terminus of the candidal adhesin, Als3p (rAls3p-N), which results in significant protection against disseminated candidiasis. Vaccine protection requires upstream T lymphocytes and downstream functional phagocytes. We therefore sought to determine the role of Th17 cells in vaccine-mediated protection. Methods: We compared Th1 (CD4+IFN- ƒ×+), Th17 (CD4+IL-17+), and Th1/17 (CD4+IFN- ƒ×+IL-17+) cell frequencies in mice vaccinated with rAls3p-N + Al(OH)3 or Al(OH)3 adjuvant alone. We also compared vaccine efficacy in IL-17 deficient, CCR6 (cell surface marker of Th17 cells) deficient, or congenic wild type control mice infected via the tail-vein with C. albicans. Results: Vaccination increased Th1, Th17, and Th1/Th17 frequencies in mice. Splenocytes from vaccinated mice stimulated with rAls3p-N ex vivo produced significantly higher levels of IFN- ƒ×, IL-17, and KC than splenocytes from control mice. IL-17 and CCR6 deficient mice were not more susceptible to disseminated candidiasis than control mice. However, vaccine efficacy was abrogated in both IL-17 and CCR6 deficient mice. Conclusion: Th17 cells are not required for host defense against disseminated candidiasis in unvaccinated mice. However, the rAls3p-N vaccine stimulates Th17 and Th1/17 cells, and Th17 cells are required for vaccine efficacy in mice.
Vaccinia-specific CD4 T-cell responses in humans are predominantly restricted by HLA DR (132.22)
Authors: Jing Lichen , Mayo McCaughey Stella , Davies D Huw , Chong Tiana M , Felgner Phillip L , Kwok William W , Wilson Christopher B , Koelle David M 
Published: January 2023

Abstract
In humans, three to five loci encode cell-surface HLA class II heterodimers capable of binding peptides. Anecdotally, HLA DR dominates the restriction of pathogen-reactive CD4 T-cells. It is rare that primary cells have been examined on a per-cell basis, or that a large number of clones or unique fine specificities have been studied. Direct PBMC assays with multiple cytokine readouts show that HLA DR had the strongest contribution for vaccinia-specific memory CD4 T-cells. These data were reinforced by detailed investigation of the CD4 response in vaccinated persons. Amongst large panels of vaccinia-specific clones, most were DR-restricted. Genetic and proteomic tools were used to define a large number of CD4 specificities. A minimum of 42 novel CD4 antigenic regions were defined with peptides. The majority of evaluable specificities were HLA DR-restricted. This is the highest resolution data set available concerning the relative contributions of HLA class II loci to the CD4 response to a pathogen, and implies that antigen processing and presentation to HLA DR has a selective advantage in vivo in the context of live vaccinia infection. Supported by NIH AI40069 and AI067496
Anti-inflammatory effects of PDMP in Pneumocystis pneumonia (133.1)
Authors: Vuk-Pavlovic Zvezdana , Henriques Forsythe Marshaleen , Krajicek Bryan J , Behrens Marshall D , Knutson Keith L , Limper Andrew H 
Published: January 2023

Abstract
Glycosphingolipid (GSL) Lactosyl Ceramide (LacCer) is thought to be involved in Pneumocystis interaction with the host. Our previous results show that treatment with glycosphingolipid synthesis inhibitor PDMP reduces the fungus lung burden as well as symptoms of inflammation in mice with Pneumocystis pneumonia (PCP). Experiments were set up to resolve whether anti-inflammatory effects were due to the specific mechanisms involved in innate immune responses to Pneumocystis, or to some general anti-inflammatory property of PDMP. Animals were infected with live organisms, or challenged with either beta-glucan (the pro-inflammatory component of Pneumocystis cell wall) or LPS (inducer of lung inflammation unrelated to Pneumocystis). At the experimental endpoint the following inflammatory parameters were assessed: leukocyte recruitment to the lungs, production of pro-inflammatory cytokines and chemokines, histopathology and lung damage. Results show that glucan-induced acute inflammation partially mimics the inflammation caused by the whole organism, and PDMP suppresses some of the inflammatory parameters affected in PCP. In contrast, although LPS induces comparable intensity of inflammation as live Pneumocystis or glucan, PDMP does not suppress any inflammatory parameters measured in this group. These results suggest that the mechanism of PDMP action is related to the features specific to Pneumocystis and host recognition of the microorganism. Further studies will attempt to determine the role of LacCer in these processes.
Supported by NIH-RO1-HL62150 and Mayo Clinic
The Mycobacterium marinum RD1 locus promotes virulence and macrophage aggregation into tuberculous granulomas by enhancing induction of host matrix metalloproteinase 9 in proximal epithelial cells (133.19)
Authors: Volkman Hannah E , Pozos Tamara , Zheng John , Rawls John F , Ramakrishnan Lalita 
Published: January 2023

Abstract
Granulomas are organized aggregates of differentiated macrophages and other immune cells that form in response to mycobacterial infection and other persistent stimuli. While the tuberculous granuloma has long been considered a host-protective structure, our recent work in the genetically tractable and optically transparent zebrafish embryo-Mycobacterium marinum model of tuberculosis, has suggested that the early granuloma actually benefits mycobacteria. The mycobacterial RD1 virulence locus, a specialized bacterial secretion system, enhances granuloma formation, which in turn, promotes bacterial expansion and dissemination. Here we present the molecular and cellular details of RD1-induced granuloma formation. RD1-secreted effectors induce host matrix metalloproteinase 9 (mmp9) in epithelial cells neighboring the infected macrophages. By specifically knocking down host mmp9, we have shown that its expression facilitates macrophage recruitment to form granulomas and bacterial expansion. Selective mmp9 induction in immotile epithelial cells neighboring infected macrophages may serve as a mechanism to fix and expand infection foci at optimal sites. Our results provide direct evidence that early granulomas benefit mycobacteria and suggest new tuberculosis therapeutic strategies that target granuloma-promoting host susceptibility determinants like mmp9.
Lipoteichoic acid synergizes with ATP to activate dendritic cells for a pro-inflammatory TH17-polarizing phenotype (133.22)
Authors: Paustian Christopher C , Johnson Terrence D , Czerniecki Brian J , Shu Suyu , Cohen Peter A , Koski Gary K 
Published: January 2023

Abstract
Stimulation of dendritic cells (DCs) by exogenous danger signals such as single Toll-like receptor (TLR) ligands results in generalized DC activation. Recently, Napolitani and co-workers showed select TLR ligand pairings induced a more specialized DC activation program including enhanced IL-12 p70 secretion and the capacity to polarize CD4 T cells into IFN-γ-secreting Th1 cells. We therefore examined the effect of pairing an exogenous TLR2 ligand (lipoteichoic acid) with an endogenous danger signal, ATP, which is found in high extracellular concentrations in damaged tissues, malignant tumors, and possibly other pathophysiological settings. ATP added to LTA modified somewhat the expression of common DC activation markers, but primarily induced a distinct pattern of cytokines with greatly enhanced levels of both IL-23 and IL-1β, while TNF, IL-10 and IL-6 remained mostly unchanged. IL-12 was not produced. These DC induced a Th17 response when stimulating allogeneic T cells in a manner partially dependent on IL-1β. These studies show that pairing of endogenous and exogenous danger signals can induce a specialized DC activation program that may have important physiological implications.
Interleukin-23 is required for protection against Listeria monocytogenes (133.24)
Authors: Meeks Karen D. , Sieve Amy N. , Kolls Jay K. , Berg Rance E. 
Published: January 2023

Abstract
Listeria monocytogenes (LM) is a gram-positive, intracellular bacterium that can induce spontaneous abortion, septicemia, and meningitis. Recently, it has been demonstrated that interleukin (IL)-17A is necessary for an optimal immune response against LM in the liver. As IL-23-dependent cytokines, IL-17A and IL-17F induce the mobilization of neutrophils to sites of infection. The importance of IL-23 during infection with LM has not been studied. We demonstrate here that IL-23 and the IL-17 receptor A (IL-17RA), which mediates both IL-17A and IL-17F signaling, are necessary for resistance against LM infection. During infection with LM, mice deficient in either IL-23 (IL-23p19 KO) or the IL-17RA (IL-17RA KO) have increased susceptibility to infection and increased bacterial burden in the spleen and liver. Interestingly, IL-17A, IL-17F, and IL-22 are decreased in supernatants from cells of LM infected IL-23p19 KO mice. Furthermore, neutrophils are decreased in IL-23p19 KO and IL-17RA KO mice at early time points. When IL-23p19 KO mice are rescued with the administration of exogenous IL-17A, a protective phenotype similar to that seen during infection of wild-type mice is achieved. Therefore, it is likely that IL-23 regulates the optimal production of IL-17A/F during LM infection which results in early neutrophil recruitment and bacterial clearance.
Association of Toll-like Receptor polymorphisms with variation in BCG-induced immunity (133.33)
Authors: Randhawa April Kaur , Peixoto Blas , Shey Muki , de Kock Marwou , Kaplan Gilla , Hanekom Willem , Hawn Thomas 
Published: January 2023

Abstract
While the development of an efficacious vaccine against TB remains a global priority, the mechanisms of protection and reasons for variability of the BCG vaccine remain poorly understood. Several studies suggest that variation in host genes can affect susceptibility to TB infection. We hypothesized that variation in innate immunity genes is associated with altered immune responses to BCG and its clinical efficacy. Infants (N=12000) were vaccinated at birth with BCG and followed prospectively in a nested case-control study to identify those with active TB and exposed individuals who did not develop disease. Blood samples were collected and re-stimulated with BCG to assess innate and T cell responses. We are examining single nucleotide polymorphisms in TLR pathway genes to determine which variants are associated with BCG-induced cytokine responses. In preliminary analyses, individuals with TLR1 deficiency (TLR1_T1805G) had decreased IL-10 production, but no alteration in IFN-γ or IL-2. Studies are underway to determine whether polymorphisms in 10 additional TLR pathway genes are associated with these responses. To our knowledge, this is the first study to examine whether variation in innate immune genes is associated with different types of BCG-induced immunity.
Supported by: Puget Sound Partners for Global Health, the Dana Foundation, and NIH Contract NO1-AI-70022.