bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of the CD8 T cell response to Influenza virus by Lymph Node Dendritic Cells (46.2)
Authors: Langlois Ryan Andrew , Legge Kevin L 
Published: January 2023

Abstract
Mice infected with high dose lethal inoculums of Influenza virus display increased morbidity and mortality when compared with sublethal inoculums. Previously, we have demonstrated that the increased disease observed in lethally infected mice is a result of a severe lymphopenia of influenza-specific CD8 T cells. This decrease in CD8 T cells following lethal inoculums is mediated through FasL+ lymph node dendritic cell (LNDC) driven apoptosis of activated Fas+ CD8 T cells. In contrast, during sublethal inoculums, FasL expression on LNDC is down regulated allowing for strong CD8 T cells responses and recovery from infection. Interestingly, our data suggests that only a fraction of LNDC down-regulate FasL expression during sublethal inoculums. Therefore, we herein determined which of the 6 subsets of LNDC mediate the apoptosis of influenza-specific CD8 T cells during lethal influenza virus inoculums. Our results demonstrate that while both plasmacytoid DC (pDC) and CD8α+DC down regulation FasL expression during sublethal inoculums, our initial studies show that CD8?+DC but not pDC are able to mediate apoptosis of influenza-specific CD8 T cells. Overall our results suggest that regulation of FasL expression on CD8α+DC may control the magnitude of the influenza-specific CD8 T cell response and ultimately the outcome of influenza virus infections.
Evasion of the innate response of circulating DC populations by foot-and-mouth disease virus (46.6)
Authors: Nfon Charles K. , Ferman Geoffery S. , Golde William T. 
Published: January 2023

Abstract
The evolution among viruses of multiple mechanisms to evade the innate immune response, particularly the actions of interferons, has been described for FMDV infected cells. However, mechanisms involving the response of cells of the innate immune system, especially uninfected cells, are not well understood. Here we report the analysis of IFN producing dendritic cell subsets of PBMC. When pigs were infected with two serotypes of FMDV, viremia developed and serum IFNa peaked at 2–3 days after inoculation. IFNa in serum is no longer detectable 4 to 5 days post infection. The IFNa response to CpG of plasmacytoid dendtritic cells (pDC) was significantly diminished. In addition, monocyte derived dendritic cells (MoDC) of pigs produce IFNa in response to poly I:C but not CpG. During FMDV infection, the MoDC response to poly I:C stimulation is blocked with similar kinetics to viral inhibition of pDC. Analysis shows no infection of PBMC taken from these animals. We propose that this virus has evolved a mechanism to shut down the IFNa response of DC in the periphery. The virus induces a rapid IFN response from dendritic cells which is then blocked by anti-inflammatory signals from viral infected cells. This skews the balance of the host/pathogen interaction in favor of lateral viral spread during acute infection. We are currently evaluating potential mechanisms by which the virus blocks cytokine responses in non-infected cells.
Binding of the green tea catechin, epigallocatechin gallate, to the CD4 receptor on human immune cells resulting in inhibition of HIV-1-gp120 binding and HIV-1 infectivity (47.18)
Authors: Nance Christina L , Siwak Edward , Westerfield Susan , Willis Van , Shearer William T 
Published: January 2023

Abstract
Binding of HIV-1 envelope glycoprotein, gp120, to the CD4 T cell receptor results in HV-1 infection. We previously presented evidence of high affinity binding of the green tea catechin, epigallocatechin gallate (EGCG) to the CD4 molecule. We now present evidence in parallel studies that EGCG inhibits the binding of gp120 on human CD4+ T cells and PBMC and prevents the HIV-1 infectivity of macrophages and PBMC. Binding studies utilized spectroscopy and flow cytometry. HIV-1 infectivity was assessed by HIV-1 p24 EIA. Studies indicated that EGCG binds to CD4 at the same binding pocket as gp120. EGCG markedly inhibited the binding of HIV-1-gp120 to CD4+T cells in a dose-dependent manner at physiologically relevant levels (32% at 0.2uM p&lt;0.05, 42% at 2uM, 47% at 20uM p&lt;0.01). EGCG significantly inhibited the HIV-1infectivity of human primary macrophages in a dose-dependent manner. There was 100% inhibition of p24 production by EGCG at 25–100uM (p&lt;0.0001), 95% at 12uM, and 79% at 6uM (p&lt;0.001). The response by human PBMC was similar. The control catechin did not alter gp120 binding nor inhibit HIV-1 infectivity. We conclude that EGCG is able to significantly reduce the attachment of HIV-1-gp120 to CD4, along with a decrease in the infectivity of HIV-1 to target cells. The competitive binding properties of EGCG for the CD4 binding sites by gp120 may translate to an HIV-1 preventative strategy.
Supported by NIH grant R21AT003084.
Lethally-irradiated Yersinia pestis immunization protects against the plague: a novel vaccine candidate (47.23)
Authors: Lambert Nathaniel Dane , Nilles Matthew L. , Bradley David Sherman 
Published: January 2023

Abstract
We provide evidence here that immunization with lethally γ-irradiated Yersinia pestis provides an effective and novel vaccine against the plague. Traditionally, neither chemical nor heat killing of bacteria has been successful in inducing an appropriate immune response to provide protection against further infection. It has been postulated, however, that inactivation via γ-irradiation would allow for retention of both adjuvant and antigenic components necessary for an effective vaccine. We hypothesize that, unlike many vaccines that induce predominately an antibody response, γ-irradiated whole bacteria will result in both a protective humoral and cellular immune response. Recent evidence that γ-irradiated Listeria monocytogenes protected mice from future exposure to L. monocytogenes supports this hypothesis.
Y. pestis, the cause of the plague, is endemic in much of the world. It creates a considerable health risk and is now also considered a putative agent for bioterrorism, although current vaccine candidates have potential pitfalls. Immunization with lethally γ-irradiated Y. pestis (600 kRads from a 137Ce source) provides significant protection against the plague in the absence of any additional stimulatory adjuvant in both inbred B10.T(6R) mice and out-bred Swiss Webster mice, LD50’s of greater than 106 CFUs in both strains, compared to 103 CFUs and 20 CFUs in sham immunized B10.T(6R) and Swiss Webster mice respectively. These data suggest both a new and effective vaccine for Y. pestis, as well as potential vaccines that have remained elusive for other bacteria.
CD8+ T cells primed by a non-replicating adeno-associated virus vector undergo apoptosis at the site of antigen expression (47.4)
Authors: Best Victoria , Bowen David , Walker Christopher 
Published: January 2023

Abstract
Adeno-associated virus (AAV) vectors facilitate prolonged expression of proteins in tissues of rodents and primates despite induction of cellular immune responses. To address the paradox of how these antigens persist in the face of a CD8+ T cell response, we delivered an AAV vector expressing the enhanced green fluorescent protein (eGFP) to the quadriceps muscle of Balb/c mice. Expression of eGFP in the muscle was stable for months even though high frequencies of CD8+ T cells targeting an immunodominant epitope were detected as early as two weeks after vector administration. MHC class I tetramer staining revealed effector CD8+ T cells in multiple tissues for at least 9 months. Long-lived eGFP-specific CD8+ T cells in spleen and liver maintained an effector phenotype, suggesting a block in the development of memory populations. Importantly, antigen-specific CD8+ T cells were enriched in the muscle, the site of antigen expression, when compared to spleen and liver. Moreover antigen-specific CD8+ T cells in the muscle, but not spleen or liver, bound annexin V, suggesting that localized apoptosis might also prolong expression of AAV-encoded eGFP. The possibility that programmed death of CD8+ T cells at the site of antigen expression may contribute to antigen persistence has important implications for both gene therapy and vaccine applications.
The TLR3 agonist poly (I:C) acted directly on mouse CD8 T cells and augmented their antigen-specific responses upon adoptive transfer into naïve recipient mice (48.31)
Authors: Salem Mohamed Labib , Diaz-Montero C. Marcela , Chen Yian , EL-Naggar Sabry A. , Kadima Andre N. , Gillanders William E. , Cole David J. 
Published: January 2023

Abstract
We have reported that in vivo administration of the toll-like receptor 3 ligand (TLRL) poly (I:C) induced rapid stimulation of the innate mediators, including NK cells, Mϕ, dendritic cells, and inflammatory cytokines. These effects strikingly augmented post vaccination CD8 T cells responses. It is not clear, however, whether poly (I:C) acts directly on CD8 T cells. Therefore, we analyzed the expression of TLRs on both CD4 and CD8 T cells and tested whether CD8 T cells respond directly to poly (I:C). Real-time PCR analysis revealed that TLRs (TLR1-TLR13) are expressed in the purified CD4 and CD8 T cells, and their in vitro treatment with 50 μg/ml poly 10 nM PMA, or with OVA peptide-pulsed splenocytes modulated the expression of the tested TLRs. Utilizing OT-1 TCR adoptive transfer transgenic mouse model, in vitro treatment of purified naïve OT-1 cells with 50 μg/ml poly (I:C) for 18 hours in the absence of antigen stimulation triggered their activation as evidenced by upregulation of the early activation markers CD69 and CD25, and downregulation of CD62L expression. Importantly, when these cells were adoptively transferred into naïve recipient followed by peptide vaccination, they showed superior expansion and activation to their naïve counterparts. These results clearly reveal a direct effect of poly (I:C) on CD8 T cells and supports the notion of direct involvement of TLRs in adaptive immune responses.
Origin and Dynamics of Tumor-Associated Foxp3+ Regulatory T Cells (49.4)
Authors: Duramad Omar , Perng Olivia , Zal M. Anna , Liu Yong-Jun , Zal Tomasz , Qin F. Xiao-Feng 
Published: January 2023

Abstract
Regulatory T cells (Tregs) expressing the forkhead transcription factor Foxp3 play a central role in the dominant control of immunological tolerance. Compelling evidence obtained from both animal and clinical studies have now linked the expansion and accumulation of Foxp3+ Tregs at the tumor site to the failure of immune-mediated tumor rejection. However, little is known regarding tumor-associated Foxp3+ Tregs within tumor tissues. Using both subcutaneous (s.c.) tumor and lung metastasis models of MCA-205 fibrosarcoma, we have found that tumor-associated Foxp3+ Tregs are highly activated and undergo vigorous cellular proliferation. Tumor-associated Foxp3+ Tregs were also found to be more potent functionally by in-vitro suppression assays and express higher levels of membrane-bound TGF-b1. To visualize endogenous Foxp3+ Tregs, we have generated Foxp3-GFP transgenic reporter mice by inserting GFP into a bacterial artificial chromosome (BAC) encompassing the Foxp3 locus. Using multi-photon microscopy, we observed a rapid recruitment and accumulation of Foxp3+ Tregs to the nascent lung tumor metastasis as early as 3 days after tumor inoculation. Intravital imaging of established s.c. tumors revealed a distinctive behavior of Foxp3+Tregs: the suppressor cells form a well-defined periperipheral layer encasing the tumor mass, moving rapidly within the superficial plain but not perpendicularly in and out of the tumor. Together, these data highlight that tumor-associated Foxp3+ Tregs are highly dynamic in function, behavior, and origin, perhaps contributing to overall poor immunogenicty of tumors.
Tumor induced senescence of T-lymphocytes (TIST): a novel mechanism of immune evasion (49.7)
Authors: Montes Carolina Lucia , Orhue Vbenosa , Chapoval Andrei , Strome Scott , Gastman Brian 
Published: January 2023

Abstract
Tumor immune evasion exhibits passive and active components. Passive components include tumors becoming inconspicuous and resistant to immune-mediated killing. The active components consist of tumors induced cellular dysfunction, like apoptosis of immune effectors cells. We hypothesized that tumor infiltrating lymphocytes that encounter cancer at a low tumor:T cell ratio, for a short time, undergo senescence instead of apoptosis. Senescence is a form of cellular dysfunction that leads to the demise of the cell. We demonstrated that a high percentage of human T cells from healthy donors incubated with different tumor cell lines for 6 hours at a 1:1 Tumor/T cell ratio and then cultured for 7 days in media only, undergo senescence as judged by the incremental loss of CD27 and CD28 expression and telomere shortening. Cell to cell contact does not seem necessary in the induction of this process. We also showed increases in the senescence associated molecules (p53, p21 and p16) in TIST. In addition, TIST occurs equally in CD4+ and CD8+ cells and both cells types suppress the proliferation of CD3− stimulated or allogenic effector cells but do not express CD25 nor Foxp3. Increased levels of INF gamma, IL10 and IL6 suggest a role for these cytokines in TIST mediated immunosuppression. This novel mechanism of immune evasion has impact in both diagnostic and treatment aspects of cancer.
Supported by Otorhinolaryngology Department.
A murine model for studying the immunobiology of basal cell carcinoma (50.12)
Authors: Mavers Melissa , Shah Maulik 
Published: January 2023

Abstract
The incidence of basal cell carcinoma (BCC), the most frequent human tumor, is rising. BCC incidence and aggressiveness are greatly increased in immunocompromised patients, indicating a role for the immune response in their prevention, formation, and growth. Human biopsies have exhibited a peritumoral infiltrate of lymphocytes with low numbers within the tumor itself. The Ptc1 mouse, a phenocopy of nevoid BCC syndrome, in which patients may acquire thousands of BCCs, develops tumors ~12 months after radiation exposure. To further study the immunobiology of BCC, a more practical tumor model was needed. We evaluated the use of ASZ001, a murine BCC cell line isolated and cultured from a Ptc mouse. Injection of 2.5x106 cells s.c. into Ptc1 mice elicited rapid tumor development with an average tumor volume of 58mm3 on day 2. Microscopic analysis showed an aggressive phenotype and a paucity of intratumoral T cells, similar to BCCs in the Ptc1 mouse and human biopsies. Thus, injection of ASZ001 cells into Ptc1 mice is a rapid tumor model that will be used to study the immune response to BCC.
This work was supported by the Saint Louis University Cancer Center and Department of Pediatrics.
T and B Cell Immune Responses to Tumor Antigen MUC1 are Induced by Targeting Antigen to B Lymphocytes (50.20)
Authors: Ding Chuanlin , Wang Li , Al-Gwahi Hayma , Marroquin Jose , Hansen Richard , yan jun 
Published: January 2023

Abstract
To test the hypothesis that MUC1 specific T cell responses may be induced by targeting MUC1 to B cells in the presence of CpG ODN adjuvant, we first conjugated a model Ag ovalbumin (OVA) with anti-CD19 mAb as a means to target Ag to B cells. OVA TCR transgenic CD8 T cells (OT-I) and CD4 T cells (OT-II) were used to exam if targeting OVA to B cells through CD19 leads to Ag presentation in the context of MHC class I and II for T cell activation. The results indicated that OVA conjugates could significantly induce CD4 and CD8 T cells proliferation and activation. These expanded T cells were not deleted or anergized, and were characterized by proliferation (OT-II T cells) and IFN-γ release (OT-I T cells) in response to OVA peptide. CpG ODN could significant enhance the survival of CD8+ T cells and IFN-γ production. To further extend these observations to tumor Ag, MUC1 transgenic (Tg) mice that are tolerized to MUC1 Ag, resembling cancer patients, were immunized with anti-CD19 conjugated MUC1 with or without CpG ODN. The data demonstrated that MUC1 conjugates in combination with CpG ODN elicit high-titer anti-MUC1 Abs. In addition, MUC1-specific cytotoxicity and vigorous IFN-γ secretion was generated. In contrast, Tg mice immunized with MUC1 peptide, even in the presence of CpG ODN, did not elicit Ab production and T cell responses. These results indicated that Ag targeted to B cells via CD19 in combination with TLR agonist could reverse immunological tolerance to MUC1 Ag and generate MUC1-specific B cell and T cell responses.
In vivo synergy of TLR ligands through activation of distinct signaling pathways in dendritic cells (52.1)
Authors: Zhu Qing , Belyakov Igor M , Klinman Dennis M , Berzofsky Jay A 
Published: January 2023

Abstract
Toll-like receptors (TLRs) play a critical role for the host to generate cellular immunity against invading microorganisms. Each TLR is specific for a certain range of microbial components and more than one is likely to be involved in any natural infection. We found that certain TLRs can act synergistically in response to microbial stimuli in specific, non-random, combinations. Vaccination of mice with antigenic peptide together with pairs of ligands for TLR2 and 3 or 3 and 9 effectively primed T cells in vivo, while each individual ligand or paired TLR2 and 9 ligands at the same doses were ineffective. Dendritic cells (DCs) appeared to play a central role in response to the synergistic combinations of TLR ligands by amplifying production of inflammatory cytokines and chemokines, such as IL-12, TNFα and RANTES, through MyD88-dependent signaling pathway. Costimulatory molecules like CD86 were upregulated by TLR3 ligand alone but not further increased when either TLR2 or 9 ligand was added. Also, no synergy was observed between TLR2 and 9 ligands in DC activation. We conclude that triggering of TLR3, which signals only through TRIF, enhanced the potency of the MyD88-dependent pathway used by TLR2 and 9, leading to a synergistic effect of DCs on T-cell priming. Our results suggest a strategic use of TLRs in host defense mechanisms, and may also have important implications in the design of vaccine adjuvants.
Expression of Perforin-2 is regulated via transcriptional and translational mechanisms (52.18)
Authors: SHIRATSUCHI MOTOAKI , Ramos Jahir , Deyev Vadim V , Podack Eckhard R 
Published: January 2023

Abstract
At the last AAI meeting we identified a macrophage-expressed protein as a pore-forming protein and called it Perforin-2 (P2). We also reported that P2 translation from the cap-structure is impaired. We further assessed the regulatory mechanisms of P2 translation.
The P2 gene has a long 5′-UTR which contains a short intron near the translation start site. Various lengths of 5′-UTR sequences were cloned into the discistronic luciferase vector, transfected into 293 or RAW cells, and luciferase activity was measured. We also performed promoter assay by using luciferase constructs containing various lengths of P2 promoter. Finally, bone marrow cells from mice were differentiated into mature dendritic cells with GM-CSF and LPS, and mRNA levels were quantified by real-time RT-PCR.
Bicistronic reporter assays showed that P2 protein expression is under translational control by an internal ribosome entry site (IRES) in the 5′-UTR. Part of the IRES is included in an intron, indicating that control of splicing affects translation.
Promoter assays demonstrated much stronger promoter activity in RAW cells than in 293 cells. The P2 gene has an ectopic promoter in the 5′-UTR. P2 transcription is upregulated dramatically during differentiation of bone marrow precursors into mature dendritic cells.
Since P2 is a pore-forming protein, the expression of P2 protein thus is tightly regulated by transcriptional and post-transcriptional mechanisms to avoid self-killing.
LPS-mediated microRNA expression in mouse macrophage (52.19)
Authors: Mi Qing-Sheng , Seo Kook-Heon , Zhou Li 
Published: January 2023

Abstract
MicroRNAs (miRNAs) are a recently discovered class of evolutionarily conserved small noncoding RNAs that lead to post-transcriptional repression, which is involved in the regulation of diverse biological processes including cell development and proliferation. Macrophage activation is an important event in the innate immune responses. To examine the potential involvement of miRNAs in regulation of the innate immune response, we analyzed the expression of over 270 mouse miRNAs, using miRNA array, after exposure of mouse macrophage cell line RAW264.7 to LPS. We found that more than 25 miRNAs were differentially regulated in LPS-treated RAW264.7 cells compared to untreated cells, including the up-regulation of miR-155, miR-132, miR-22, miR-342 and miR-146 genes in LPS-treated cells and the down-regulation of miR-696, miR-805, miR-706, miR-710 and miR-214 genes. These founding suggests that the miRNAds are probably involved in the regulation of mouse innate immune responses. (JDRF, 5-2006-918)
Retinoids accelerate B lineage lymphoid differentiation (83.12)
Authors: Chen Xinrong , Kincade Paul W. 
Published: January 2023

Abstract
Retinoids are known to have potent effects on hematopoietic cells, and all trans retinoic acid (ATRA) is widely used to treat patients with acute promyelocytic leukemia. Retinoids may normally maintain stem cell integrity, and our main objective was to learn if B lineage lymphoid progenitors express functional receptors. Total CD19+ cells increased substantially in the bone marrow, while early lymphoid progenitors (ELP) and pro-lymphocytes (Pro-L) were reduced in mice treated with time-release ATRA pellets. Culture experiments with highly enriched progenitors demonstrated they were direct drug targets. Overall cell yields at short culture intervals were reduced, but CFSE labeling indicated this did not result from reduced proliferation. ELP are very primitive progenitors and 10 days is normally required for them to generate CD19+ cells in culture. Remarkably, lymphoid cells and IL-7 responding progenitors emerged in just 7 days when ATRA was present. Treatment with a panel of agonists suggested that RAR rather than RXR mediates these responses. ATRA had similar effects on human B cell differentiation. That is, it inhibited the expansion of human CD34+CD38− progenitor cells and accelerated the differentiation of human CD19+ cells. There may be previously unsuspected side effects of ATRA therapy, and retinoids might normally contribute to the lymphopoietic environment in bone marrow.
Structural Transitions that Regulate the Apoptotic Activity of BAX are Dependent on its C-terminal Alpha-9 Helix (84.10)
Authors: Khaled Annette R. , Tschammer Nuska , Zhang Ge , Selby Thomas A. 
Published: January 2023

Abstract
Apoptosis is essential for lymphocyte development and the maintenance of cellular homeostasis. Previously, we showed that the apoptotic protein, BAX, is a critical mediator of IL-7-withdrawal induced death; yet, how this deadly protein is activated is poorly understood. Under apoptotic stress, BAX translocates to mitochondria, causing cell death. To explain this transitional behavior, we tested the hypothesis that the C-terminal α9 helix of BAX is essential for mitochondrial membrane binding. Using a multi-disciplinary approach, we demonstrated that the lysine at position 189, near the end of the α9 helix, is required for membrane association. Hence, the α9 helix could function as a membrane anchor. However, computational docking analysis revealed a new function for the α9 helix. By binding in reverse orientation to the internal hydrophobic grooves of adjacent BAX molecules, this helix enables dimerization and the release of additional membrane-spanning domains. This reverse orientation of binding places the lysine at position 189 in binding proximity to conserved acidic residues in the BH3 domain of BAX, enabling the interaction between the α9 helix and the pocket. We have, therefore, identified a novel and indispensable role for the C-terminal α9 helix of BAX, demonstrating that, by binding in trans to a hydrophobic groove, this domain unleashes the protein’s lethal activity.