bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mycobacterial Infection induces the secretion of High mobility group box 1 (HMGB1) protein (43.20)
Authors: Grover Ajay , Taylor Jennifer , Troudt Jolynn , Keyser Andrew , Sommersted Kirsa 
Published: January 2023

Abstract
High mobility group box protein 1 (HMGB1) is a nonhistone nuclear protein that acts as a pro-inflammatory cytokine and is released by monocytes and macrophages. Necrotic cells also secrete HMGB1 at the site of tissue damage that induces a variety of cellularresponses, including expression of proinflammatory mediatorssuch as TNF- , IL-1, and NO. This study investigated the secretion of HMGB1 during mycobacterial infection of macrophages in vitro and in the lungs of infected guinea pigs. We observed that infection with mycobacterium effectively induced HMGB1 release in both macrophage and monocytic cell cultures. Culture filtrate proteins from Mycobacterium tuberculosis (including Ag85A, Ag85B, ESAT-6 and CFP-10) induced maximum release of HMGB1 among different cellular components of mycobacterium. We demonstrated that HMGB1 is released by lung cells during infection of M. tuberculosis in guinea pig and increased HMGB1 secretion in lungs of guinea pigs was delayed by vaccination with BCG. The secretion of cytokines like TNF-α and IL-1β were significantly increased when J774A.1 cell cultures were incubated with HMGB1 during infection with M. bovis BCG. We conclude that HMGB1 is secreted by macrophages during tuberculosis and it may act as a signal of tissue or cellular injury and may act as a precursor to enhance the immune response.
Funding for this research was provided by NIH AI40091 (A.A.I.).
NKT cells suppress the replication of Listeria monocytogenes in cholestatic livers (43.22)
Authors: Hoffman Beth L. , Wintermeyer Philip , Holub Martin , Brossay Laurent , Gregory Stephen H. 
Published: January 2023

Abstract
Biliary obstruction and cholestasis can cause hepatocellular apoptosis and necrosis. Ligation of the common bile duct (BDL) in mice provides an excellent model in which to study the underlying mechanisms. NK1.1+ TCRαβint CD1d-restricted T (NKT) cells comprise approximately 30% of the hepatic lymphoid cells in mice, decidedly fewer reside in the spleen, thymus and peripheral blood. Purportedly, NKT cells play a key role in host defenses to infection. Indeed, it has been suggested that iNKT cells evolved primarily to respond to a diverse array of microbial pathogens. The increased replication of a limited number of parasites, bacteria and viruses in the organs of CD1d−/− or Jα18−/− [invariant (i)NKT cell-deficient] mice provides support for this suggestion. In many instances, however, NKT cells are not protective and their response to infection is largely detrimental. In agreement with the latter, we report here that iNKT cell-deficient mice express increased protective immunity to L. monocytogenes. Relative to wild-type animals, significantly fewer (≤1 log10) bacteria were recovered from the livers of Jα18−/− mice on day 3 post-infection i.v. with a sublethal dose of listeriae. In marked contrast to these findings, however, listerial replication, liver injury [plasma alanine aminotransferase activity (ALT)], and death from infection were increased sharply in iNKT cell-deficient mice subjected to BDL and cholestasis. Thus, iNKT cells play a critical role in host defenses to Listeria expressed in cholestatic, but not normal, livers.
The T Cell Response to Influenza in Neonates (43.29)
Authors: Lines J. Louise , Hollifield Melissa , Cauley Linda , Garvy Beth 
Published: January 2023

Abstract
Influenza is a significant cause of mortality and morbidity in children. However, very little data exists on the neonatal immune response to influenza. We have found that neonatal mice are highly vulnerable to influenza and only control much reduced doses of virus.
In this study, the T cell response to intranasal influenza infection was compared between mice infected as adults or at 2 days old. In neonates, despite significant expansion of T cells in draining lymph nodes, entry of T cells into the lungs was defective. In adults, high numbers of CD4 and CD8 T cells peaked in the lung interstitium and alveolar spaces by 10 days post infection. However, in neonates, CD8 T cells entered the lungs by day 10 post-infection, but not to high levels, while CD4 T cell entry was delayed until 3 weeks of age. Interestingly, while CD4 T cells reached adult levels in the interstitia, they were unable to cross the epithelial barrier into the alveoli. The delayed entry of CD4 T cells corresponded with a delay in TNFα production and a lack of IFNγ which may consequently lead to delayed upregulation of adhesion molecules and chemokines.
Despite the poor response to influenza as neonates, mice infected at 2 days old with the PR8 strain of influenza did develop T cell memory. Mice were protected when subsequently infected as adults with a lethal dose of HKx31, a strain that shares only the internal T cell antigens with PR8. These data suggest that the acute sensitivity of neonates to influenza may be a consequence of defective T cell migration.
Characterization of lymphoid DC during the resolution of Listeria monocytogenes infection (43.38)
Authors: Burt Bryan Michael , Plitas George , Nguyen Hoang , Stableford Jennifer , DeMatteo Ronald P. 
Published: January 2023

Abstract
Introduction: Dendritic cells are critical to innate immune responses based on their ability to secrete inflammatory cytokines and prime naïve T-cells. The role of DC during later stages of infection is not known.
Methods: Lymphoid DC (CD11c+CD8+NK1.1−B220−) were analyzed by flow cytometry and isolated by fluorescence activated cell sorting from the spleens of C57BL/6 mice infected with 5000 CFU of LM strain 10403s by tail vein injection. Mixed leukocyte reaction (MLR) was performed with 1x105 allogeneic T cells and 3x104 lymphoid DC.
Results: Following 24 hours of infection lymphoid DC accounted for 11% of conventional DC (CD11c+B220−NK1.1−) and had high expression of MHC II, CD40 and CD86. After 7 days of infection lymphoid DC increased to 47% of conventional DC and had less MHC II, CD40 and CD86 expression than uninfected controls. Lymphoid DC also lost their ability to stimulate allogeneic T cells in the MLR (6634±466 CPM for 12 hours of infection vs 320±80 for 7 days of infection).
Conclusion: Dynamic changes occur in the lymphoid DC compartment during the resolution phase of LM infection.
This work was supported by grant DK068346.
Reconstitution of immune responses occurs very rapidly after initiation of therapy for tuberculosis (43.54)
Authors: Dabitao Djeneba , Guindo O , Diallo H , Kassambara H , Washington J , Diallo S , Dao S , Tounkara A , Sereti I , Ciccone E , Catalfamo M , Lane HC , Siddiqui S 
Published: January 2023

Abstract
Introduction: Immune reconstitution syndrome is a potentially fatal sequelae of HAART therapy in 20% of patients with HIV and 3–5% with tuberculosis who begin treatment. The role of CD4+T cells in its pathogenesis is poorly understood.
Methods: This study was done under an IRB approved protocol to study MTb specific immunity. Groups based on HIV status and local or disseminated MTb were evaluated for CD4+ T cell counts, Purified Protein Derivative (PPD) induced proliferation and cytokine induction using intracellular cytokine staining for IFN γ, IL2, TNFα and CFSE dilution at predefined times before and after starting therapy.
Results: In preliminary results, the first 3 HIV negative patients with MTb exhibited striking increase in MTb specific immunity in the first week of therapy. Percentage of IFN γ producing CD4+T cells increased from 1.96 and 0.48 to 4.46 and 1.34, and of TNF α producing cells increased from 0.85 and 0.45 to 3.96 and 1.06 in 2 patients. Proliferative responses also showed marked increases. Percent dividing cells increased from 4.3, 4.4 and 16.3 at baseline to 36.9, 11.9 and 39.6 at 1 week and 54.8 and 72.3 at 4 weeks of therapy. Total number of CD4+ T cells also increased.
Conclusions: Tuberculosis like HIV causes quantitative and qualitative changes in CD4+T cells . These are rapidly reversed when therapy is begun .This data provides insight into the pathogenesis of the immune reconstitution syndrome.
Robust innate immune responses of murine neonates following orogastric Yersinia enterocolitica exposure (44.13)
Authors: Echeverry Andrea , Schesser Kurt , Adkins Becky 
Published: January 2023

Abstract
Neonates are generally thought to be highly susceptible to gastrointestinal disease, owing in part to immaturity in immune function. To study this phenomenon experimentally, we have developed a murine pediatric model of infection with the Gram-negative bacterium Yersinia enterocolitica (Ye). This model is highly relevant to the human pediatric population since Ye is a prevalent cause of gastrointestinal disorders in young children. LD50 experiments were performed on 7 day old and adult mice infected orogastrically with Ye. Remarkably, BALB/c or C57BL/6 neonatal mice were up to 50 times more resistant than adult mice. Bacterial colonization experiments indicated that Ye rapidly disseminated to the spleen and liver in adults. In striking contrast, colonization of the neonatal spleen and liver was very limited. Instead, bacterial colonization in neonates was largely restricted to the intestine and mesenteric lymph nodes (MLN). Flow cytometric and histological studies revealed markedly increased levels of neutrophils and macrophages in the neonatal MLN after infection. Importantly, in vivo neutrophil depletion led to efficient dissemination of the bacteria to the spleen and liver of neonates. Therefore, in response to some enteric bacteria, neonates appear to be able to mount vigorous mucosal immune responses, rapidly mobilizing innate phagocytes, and confining the bacterial infection to the gut.
This work was supported by NIAID grant R01 AI44923-02 (B.A.), NIAID Public Health Service grant AI53459 (K.S.), and the Department of Microbiology and Immunology, University of Miami.
Toll-like receptor 9 participation in experimental Th type 1 (Mycobacterial) pulmonary granuloma formation (44.15)
Authors: Ito Toshihiro , Schaller Matthew , Hogaboam Cory M. , Chensue Stephen W. , Kunkel Steven L. 
Published: January 2023

Abstract
We have established that experimental Th type 1 (Th1) responses can be studied in mice by sensitizing with Mycobacterium bovis purified protein derivative (PPD) followed by an intravenous challenge of agarose beads covalently coupled to the respective sensitizing Ags. Mycobacterial antigens (Ags) stimulate antigen presenting cells (APCs) through distinct Toll-like receptors (TLRs) resulting in rapid activation of the innate immune system. Toll-like receptor 9 (TLR9) is known to play an important role in the regulation of Th1 responses. The role of TLR9 during infection with Mycobacterium Ags has been under investigated. We demonstrate in this study that TLR9−/− mice showed greatly increased granuloma formation as assessed by morphometric analysis, and an increase in eosinophil and stromal cells, suggesting a Th-2 skewing, as compared with wild-type. Moreover, Th1 cytokine production of IL-12 and IFN-gamma was abrogated in TLR9−/− mice. These results suggest that TLR9 plays an important role in maintaining a Th1-type pulmonary granulomatous response.
This work was supported by NIH grants HL031963, HL074024, and HL031237.
Differential virus replication, cytokine production and antigen presenting function of microglia from susceptible and resistant mice after Theiler′s virus infection (44.26)
Authors: Jin Young-Hee , Mohindru Mani , Kang Min H , Fuller Alyson C , Kang Bongsu , Gallo Daniel , Kim Byung S 
Published: January 2023

Abstract
Infection of TMEV in CNS causes an immune-mediated demyelinating disease similar to human multiple sclerosis in susceptible (SJL) but not resistant (B6) strains of mice. To understand the mechanisms of differential susceptibility, we analyzed expression levels of co-stimulatory molecules, cytokine production and T cell stimulatory function of microglia and macrophages in the CNS of virus-infected mice. Our results indicate that a higher level of microglia and a lower level of infiltrating macrophages are found in the CNS of susceptible SJL mice compared to resistant B6 mice during early infection. In addition, the levels of TMEV replication, TNFα, IFNβ, IL-6 and MCP-1 production were consistently higher in microglia from virus-infected SJL mice. However, the levels of co-stimulatory molecule expression, as well as the ability to stimulate allogenic T cells, were significantly lower in TMEV-infected SJL mice compared to those in B6 mice. In addition, microglia from uninfected naïve mice displayed differential viral replication, T cell stimulation and cytokine production, similar to those of microglia from infected mice. These results suggest that intrinsic susceptibility to TMEV infection and glial cell cytokine production levels affect subsequent levels of cytokine production, cellular infiltration to the CNS and consequent inflammation in susceptible mice. (NS28752 / NS33008)
Inflammation by Gr+ bacteria involves LTA and its synergistic partner. (44.32)
Authors: Seo Ho-Seong , Nahm Moon H. 
Published: January 2023

Abstract
Innate immunity is important in early responses to bacterial infections. Although Gr+ infections constitute about 50% of bacterial invasive diseases, the innate immune response to Gr+ bacteria is much less understood than is the comparable response to Gr- bacteria. While TLR2 is known to play an important part in innate immunity and Gr+ bacterial LTA may be its ligand, the role of LTA is unclear because ¡°purified¡± LTA often has biologically active contaminants or is degraded. To investigate the role in innate immunity of LTA without these limitations, we have studied the inflammatory properties of Gr+ bacterial culture supernatant (GPCS) after using two different methods to inactivate the LTA: alkaline hydrolysis and PAF-acetylhydrolase digestion. Both inactivation methods reduce the potency of GPCS to induce TNF-a production by about 85–100%. Also, the LTA-depleted GPCS regains its activity when highly purified LTA is added to the depleted GPCS. These findings suggest that LTA is an important inflammatory molecule. However, purified LTA is more potent when it is mixed with LTA-depleted GPCS than when LTA is used alone. This discrepancy in potency suggests that while LTA is a key molecule in Gr+ bacteria-induced inflammation, a synergistic mechanism amplifies LTA-induced inflammation. We are currently investigating the synergistic molecule present in GPCS and the synergistic mechanism induced by this molecule.
Immunostimulatory activity of the heat shock protein DnaK from Francisella tularensis (45.18)
Authors: Ashtekar Amit R , Katz Jannet , Deivanayagam Champion , Larson Matt , Michalek Suzanne M 
Published: January 2023

Abstract
Francisella tularensis is the causative agent of tularemia, a severe debilitating disease of humans and other mammals. Since this microorganism is also considered as a ‘category A pathogen’ and a potential biowarfare agent, there is a need for an effective vaccine. Several antigens of F. tularensis including the heat shock protein DnaK have been proposed for use in a potential subunit vaccine. In this study we investigated the immunostimulatory properties of F. tularensis DnaK on murine bone marrow derived dendritic cells (DC). Recombinant DnaK was produced using a bacterial expression system and purified using a three-step purification procedure, i.e., affinity, ion exchange and size exclusion chromatography. DnaK induced DC to produce the proinflammatory cytokines IL-6, TNF-α and IL-12p40 in a dose dependant manner. DnaK did not induce IL-23p19 production. IL-10 production was low compared to IL-12p40. DnaK also induced DC maturation as demonstrated by an up-regulation of CD40 and CD86 expression. The responses were not mediated by endotoxin contamination, since the immunostimulatory activity of DnaK was resistant to polymixin B treatment, but sensitive to boiling or proteinase K digestion. An understanding of the interactions between virulence antigens of F. tularensis and immune cells is crucial for the development of a safe and efficacious vaccine against F. tularensis.
Identification of HIV gp41 membrane proximal epitope tetramer reactive populations of B220+ B cells and B220lo/neg basophils in gp41 peptide-immunized mice (45.3)
Authors: Verkoczy Laurent , Moody Anthony , Scearce Richard , Sutherland Laura , VanLeeuwen Stacie , Plonk Kelly , Cain Derek , Kelsoe Garnett , Haynes Barton 
Published: January 2023

Abstract
2F5 is a rare, neutralizing human mAb specific for the HIV gp41 membrane proximal region (MPER). Recently, we showed that 2F5 is a cardiolipin-binding, polyreactive autoantibody. To determine if MPER antibodies (Ab) are controlled by tolerance mechanisms, BALB/c mice were immunized with HIV-1 gp140 envelope or gp41 peptides. Immunized mice were screened for serum MPER Ab and for 2F5 antigen-specific B cells using 2F5 epitope B cell tetramers. Immunization in Ribi adjuvant did not induce anti-MPER Ab, whereas similar immunizations in TLR9, an adjuvant designed to break tolerance, did. Interestingly, in mice immunized with gp41 peptide, but not gp140, we found two distinct populations of 2F5 tetramer+ cells in bone marrow, spleen, and blood: a polyclonally-induced B220hi B-cell population that bound 2F5 tetramers via their surface Ig and a B220lo/neg cell population induced by immunization. Histological and cell surface phenotypic analysis of the B220lo/neg 2F5 tetramer+ cells indicated these were primarily basophils that bound 2F5 tetramers via MPER Ab bound to FcR. At present, the immunoregulatory significance of these distinct anti-MPER reactive populations is unknown, but their further characterization and the types of Ab they produce/bind should help in delineating why induction of neutralizing anti-MPER Ab is not achieved, despite the generation of a robust non-neutralizing MPER B cell and Ab response.
Silencing of HALP Decreases HIV-1 Infection of Primary CD4+ T-cells (45.4)
Authors: Selliah Nithianandan , Yin Jiyi , Finkel Terri H 
Published: January 2023

Abstract
HIV/AIDS is an ideal candidate for a novel gene therapy approach since it is an incurable and terminal disease. We have identified a set of candidate host cell genes, associated with survival of HIV-infected T-cells. We named one of these genes, “HALP”, for “HIV-Associated Life Preserver”. Recently, we used a lentiviral vector to stably express HALP shRNA in primary human CD4 T-cells. In the absence of HIV infection, silencing of HALP appeared to have no effect on viability of these cells. As predicted, silencing of HALP markedly reduced HIV infection of primary CD4+ T-cells, as measured by the percent of p24+ cells and by supernatant p24. Published data suggest that hypoxia induces HALP expression by increasing the activity of the transcription factor, Hif-1α. HIF-1 binding sites have been identified within the HALP promoter and HALP is responsive to HIF-1 in non-immune cells. We show here that HIV-1 infection of primary CD4+ T-cells increases Hif-1α mRNA expression, as measured by real time RT-PCR. Transfection of T-cells with wild-type Hif-1α or with a mutated form of Hif that is resistant to proteolysis (Hif-DPA) also increased expression of HALP mRNA. These data are consistent with a pathway of Hif-induced HALP expression in HIV-1 infected cells, leading to a hypoxia-like stress response and, ultimately, to cell survival. Our work represents one of the first attempts to search for novel cellular genes that contribute to viral inhibition of host cell apoptosis and, thus, to viral latency. HALP represents a candidate for a host cell anti-apoptotic protein, which is triggered by HIV infection, and may provide a novel molecular target for drug use and design.
NKT cells play a role in inducing toxic shock-like syndrome in severe ehrlichiosis (46.21)
Authors: Stevenson Heather Lynne , Walker David H. , Ismail Nahed 
Published: January 2023

Abstract
Infection with a virulent Ehrlichia strain (IOE) results in toxic shock-like syndrome characterized by severe liver injury, a weak CD4+ Th1 response, and systemic overproduction of TNF-α by CD8+ T cells. Mice lacking functional CD8+ T cells (β2m−/−) survived infection with a lethal low-dose of IOE to 30 days post-infection. Since β2m−/− mice lack conventional CD8+ T cells and CD1d-restricted NKT cells, we examined the role of NKT cells in the pathogenesis of ehrlichiosis using CD1d−/− mice. CD1d−/−mice also succumbed to lethal infection with high dose IOE, yet did not develop signs of toxic shock-like syndrome, i.e. serum TNF-α was low, liver enzymes were normal, lymphopenia was not present, and there were few apoptotic hepatic cells. CD1d−/− mice also had less activation of CD8+ T cells in the spleen and liver as indicated by lower expression of intracellular granzyme B in lymphocytes harvested from these sites. Our data provide evidence that NKT cells play a role in initiating the pathogenic CD8+ T cell response in IOE-induced toxic shock-like syndrome.
PD-1 and PDL-1 expression in patients with chronic HIV-1 infection: relationship to CD4%, immune activation and antiretroviral therapy (ART) (46.22)
Authors: Sachdeva Meenakshi , Fischl Margaret A , Pahwa Savita 
Published: January 2023

Abstract
In chronic HIV-1 infection, CD8 T-cell exhaustion is linked to an increased expression of programmed death molecule (PD-1), a negative regulator of activated T cells. We investigated the relative expression of PD-1 and its ligand PD-L1 in T cells and monocytes of HIV-1 infected patients at different time points of ART. In healthy controls (n=3), &lt;10%of CD4 or CD8 T cells expressed PD-1; in comparison, expression of PD-1 was increased (P&lt;0.05) in treatment naïve patients (n=9) in both CD4 and CD8 T cells. In patients, PD-1 expression on CD4 T cells was correlated with activation marker, HLA-DR (P=0.0004) and inversely related to percentage of CD4 T cells (P=0.0004). Percentage of cells expressing PD-L1 was significantly higher in monocytes (CD14+) versus CD4 T cells and CD8 T cells (P&lt;0.05). Culture of PBMC with cytokines IL-2, IL-7 and IL-15 for 6 days in vitro resulted in increased expression of PD-1 and PD-L1 in CD4 and CD8 T cells, coupled with increased expression of Ki67 and HLA-DR in 3 ART naïve patients. ART was associated with a trend towards decreasing PD-1 expression. We conclude that PD-1 and PDL-1 interaction contributes to CD4 T cell loss in a state of chronic immune activation associated with HIV-1 infection.
Supported in part by the “The International Maternal Pediatric Adolescent AIDS Clinical Trials Network of the National Institute of Allergy and Infectious Diseases” (UOI-A141089 and N01-HD-3-3345) and Institutional support.