bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alterations in immunodominance of the Streptococcus mutans P1 adhesin: lessons learned from immunomodulatory monoclonal antibodies (38.4)
Authors: Robinette Rebekah , Oli Monika , Brady L. Jeannine , McArthur William 
Published: January 2023

Abstract
S. mutans is the bacterial agent of human dental caries. P1 (aka AgI/II, PAc) is a surface localized multifunctional protein adhesin that has been studied as an anti-caries vaccine antigen. Our laboratory has identified several anti-P1 MAbs that redirect the host immune response via an Fc-independent mechanism toward one of improved inhibition of bacterial adherence when administered as part of an immune complex (IC) with bacterial cells in BALB/c mice. A common feature of our immunomodulatory MAbs is a requirement for certain intramolecular interactions between discontinuous segments of P1 for their epitope formation. Binding of P1 by these MAbs appears to cause a structural alteration of the cell surface adhesin exposing normally cryptic and protective epitopes. We now utilize information gained by evaluating changes in serum Abs after immunization with IC to design and evaluate structural variants of the P1 protein itself as more effective immunogens. Also, an anti-AgI/II MAb previously reported as a passive immunotherapy in clinical trials was evaluated and shown to be immunomodulatory. Results varied with MAb concentration, thus providing an explanation of long-term protection observed in human subjects and the difficulty in reproducing these results in all studies. Our results indicate a delicate balance exists between P1 structure and the availability of putative T helper cell epitopes, but suggests development of a protein-based vaccine is achievable. (NIH DE13882)
Mice with the Xid defect have impaired control against Borrelia burgdorferi infection but are more resistant to carditis (38.5)
Authors: Malkiel Susan , Kuhlow Christopher , Mena Patricio , Monsalve Gloria , Benach Jorge 
Published: January 2023

Abstract
The antibody response is the main form of protection against Borrelia. Antibodies are functional in the elimination of the spirochetes and in resolution of disease. T cell-independent antibodies have been shown to have a protective role in defending the host against the Lyme disease spirochete B. burgdorferi. To determine the role of B1 cells in this antibody response, X-linked immunodeficient (Xid) CBA/N mice were used because they are severely deficient in B1 cells. Spirochete burdens were enhanced in the Xid mice compared to CBA/Ca controls at 3, 4 and 8 weeks postinfection, which may be explained by reduced levels of B. burgdorferi-specific IgM in the Xid mice. Meanwhile, the antibody repertoire of the IgM response to B.burgdorferi antigens appeared similar in both groups of mice by immunoblot. Despite impaired pathogen clearance, the Xids developed comparable arthritis but less carditis than controls. These results suggest that B1 cells play a dichotomous role in protecting the host against infection while promoting inflammation in the heart.
Computational analysis for prediction of HLA-DR-promiscuous regions and epitopes of Mycobacterium tuberculosis protein Rv1980c, and their recognition by human T cell lines (39.1)
Authors: Mustafa AbuSalim 
Published: January 2023

Abstract
Rv1980c, a major secreted antigen of Mycobacterium tuberculosis, is absent in many vaccine strains of BCG, and hence could be useful in the diagnosis or as a new vaccine against tuberculosis. However, to have world-wide application, Rv1980c should have HLA-promiscuous recognition by human Th1 cells. The aim of this study was to determine HLA-promiscuous regions/epitopes of Rv1980c using a computational method, and confirm the predictions experimentally. The sequence of Rv1980c protein was analyzed for binding to 51 HLA-DR alleles using PROPRED, a computational method. The prediction results were experimentally verified by testing 20-mer synthetic peptides corresponding to the predicted HLA-DR binding regions/epitopes with T-cell lines established from PPD-positive and HLA-heterogeneous healthy subjects in Th1-cell assays (antigen-induced proliferation and Interferon-gamma secretion). The PROPRED analysis showed that Rv1980c could bind to all 51 HLA-DR alleles with eight HLA-DR binding regions (9 to 35 aa in length), and five regions (aa 20-44, aa 68-102, aa 132-146, aa 164-186 and aa 194-202) being HLA-DR promiscuous. The results of testing synthetic peptides with T cell lines in Th1 cell assays showed that four peptides belonging to four HLA-promiscuous regions (aa 21-40, aa 81-100, aa 171-190 and aa 191-202) were immunodominant and HLA-DR promiscuous. These results show that PROPRED analysis was useful in identifying HLA- promiscuous regions/epitopes of Rv1980c.
Hepatitis C Virus-specific immune response among needle-stuck Egyptian healthcare workers at high risk of infection without viremia or seroconversion (39.15)
Authors: Abdelwahab Sayed , Sobhy Maha , Rewisha Eman , Galal Iman , Zakaria Zainab , Mahmoud Mohamed , Capone Stefania , Folgori Antonella , Hashem Mohamed , El-Kamary Samer , Strickland G. Thomas , Cortese Riccardo , Nicosia Alfredo 
Published: January 2023

Abstract
Hepatitis C Virus (HCV)-specific cell-mediated immunity (CMI) was reported in exposed individuals e.g. IV drug users without seroconversion or viremia. We investigated the HCV-specific CMI response in seronegative, aviremic healthcare workers (HCWs) at the National Liver Institute who are at high risk of becoming infected with HCV after occupational exposure as more than 70% of their patients are HCV-infected. We quantified the CMI responses in 15 Egyptian HCWs with a recent history of a needle stick injury and who remained seronegative and aviremic for at least four months. We used ex vivo enzyme-linked immunospot (ELISPOT) assay to quantify interferon gamma (IFNγ) production in response to 7 HCV genotype 4 overlapping 15mer peptide pools and phenotyped the responding cells by flow cytometry. A positive HCV-specific IFN-γ responses (&gt;55 spot forming cells (SFCs)/million PBMC) was elicited for 2-6 HCV pools in 8 (53%) of the HCW while 7 (47%) subjects responded to one or none of the pools tested with a total mean of 1069 (SEM ±239) and 118 (±17) IFNγ SFC, respectively. In summary, the majority of HCW demonstrated HCV-specific T cell responses for multiple HCV peptides and remained uninfected despite their high-risk of exposure. These responses suggest that the percentage of subjects clearing the infection is much higher than reported and their potential role in protection from HCV infection is important for understanding HCV pathogenesis and vaccine development.
Not just neutralizing Abs: prevention and cure of a viral disease by antibodies that block the biological function of a virulence factor (39.21)
Authors: Xu Renhuan , Sigal Luis 
Published: January 2023

Abstract
It is currently though that the neutralizing antibodies (Abs) are the most effective way to prevent viral infection. However, our recent work has shown that mousepox (the mouse equivalent of human smallpox) can be prevented by immunization with the Type I IFN binding protein (T1-IFNbp) of ectromelia virus (the agent of mousepox), which is a secreted non structural protein that can also attach to the surface of cells. Here we demonstrate that Abs to the T1-IFNbp are capable of preventing lethal mousepox when administered as late as 5 days post infection. The mechanism of protection was not dependent on viral particle neutralization or ADCC, but on blocking the biological function of the T1-IFNbp, which restored IFN signaling transduction in the liver as demonstrated by a dramatic increase in the transcription of IFN inducible genes such as Mx1 and IRF7. The increase IFN signaling led to reduced viral load and liver pathology and survival. Our results are the first to demonstrate that Abs directed to non-structural virulence factors can be highly effective at preventing and treating a viral disease even though they do not neutralize the viral particle.
Discordant immunodominant patterns of HIV-specific CD8 T cells defined by cytokine production or proliferative capacity in HIV elite controllers (39.4)
Authors: Ndhlovu Zaza , Proudfoot Jacqueline , Kaufmann Daniel , Walker Bruce 
Published: January 2023

Abstract
Several studies suggest that CTL proliferation is one of the functions specifically associated with elite control of HIV, but IFN-γ is generally used to define HIV epitope-specific CTL immunodominance. We performed multi-dimensional intra-donor analysis of HIV CTL-specific cytokine production and proliferation against panels of HLA-matched optimal epitopes. 9 elite controllers (EC) and 8 subjects with progressive infection (CP) were studied. Our analysis revealed two main immunodominance patterns defined by either predominant IFN-γ production or proliferative capacity with very different hierarchies of responses. In the EC, 40% of epitope-specific CTL that produced IFN-γ after 6 h stimulation did not proliferate whereas 47% of CTL with strong proliferative capacity did not produce IFN-γ after 6h stimulation. The contrasting patterns of immunodominance were associated with different phenotypes of memory and exhaustion markers. HIV CP usually had little HIV-specific proliferative capacity as compared to EC (21% vs 7% of tested epitopes, p=0.009). Our data indicate that immunodominance patterns of HIV-specific CD8 T cell responses differ markedly based on an IFN-γ read out assay compared to functional proliferation. The intra-individual heterogeneity of HIV-specific CTL responses shows that not all epitope specific responses are functionally similar. Assessing CTL functions at the single epitope level can facilitate identification of features critical for antiviral function.
Maine ScienceCorps fellows bring immunological research experiences into rural high school classrooms(41.1)
Authors: Tait Heidi , Cochrane Kelly 
Published: January 2023

Abstract
Teams of graduate students from the Departments of Applied Medical Sciences and Biology at the University of Southern Maine (USM), funded by the National Science Foundation’s Graduate STEM Fellows in K-12 Education (GK-12) program, together with faculty mentors design projects related to their graduate research to provide authentic laboratory-based research experiences in rural Maine high schools. Over the course of the school year the high school students gain hands-on experience with research methods that are applicable to current scientific inquiry in the context of immunology and molecular biology. The projects culminate in the opportunity for the students to present their research in poster format at Thinking Matters, a spring research symposium at USM. Throughout this experience the students learn about the scientific process how it is applied to questions posed by scientists around the world today, and in what ways these discoveries contribute to their understanding of the natural world. The scientific questions we have brought to the classroom involve Stephen Pelsue’s laboratory at USM, where they work on elucidating the role of Ttc7 (tetratricopeptide repeat domain7) in immune function. In this particular project the students are learning about the Ttc7fsn/fsn mouse model of lupus, how antibodies are made, the mechanics of autoimmune disease, and about applications of this research and the laboratory techniques used.
Case Study That Investigates the Role Environmental Toxins Play in Flu Infection (41.7)
Authors: Begy Elizabeth 
Published: January 2023

Abstract
There is growing evidence that environmental pollutants can cause cells in the body to work differently than normal, changing the immune system's ability to respond to respiratory infections. During infection with Influenza A virus, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; a dioxin and environmental toxin) enhances neutrophil recruitment and accumulation in the lungs, leading to detrimental inflammation. While neutrophils are necessary in the resolution of infection, excessive neutrophil recruitment generally has adverse effects. Within the first activity of this unit, students will gain a better understanding of the difference between the innate versus the adaptive immune response by completing cell differential counts for patients in various stages of flu infection. After graphing and analyzing cell differential data, students will explore how computers process the same data using flow cytometry. Next, students will investigate how TCDD plays a role during flu infection in laboratory mice. Students will apply what they learn with the mouse model to research dioxin issues in the environment and the subsequent effects on the human population. In culmination, students will write and perform a Public Service Announcement (PSA) regarding the immune response to the flu and the role that environmental toxins, such as TCDD, play in these infections.
DC-SIGN targeting carbohydrate moieties identified on 67 kDa mfa-1 fimbriae of mucosal pathogen Porphyromonas gingivalis (42.7)
Authors: Zeituni Amir , Scisci Elizabeth , McCaig William , Thanassi David , Cutler Christopher 
Published: January 2023

Abstract
We recently reported that the oral mucosal pathogen Porphyromonas gingivalis targets the C- type lectin receptor DC-SIGN for invasion and persistence within human monocyte-derived dendritic cells (DCs). The DCs respond by inducing an immunosuppressive and Th2-biased CD4+ T cell response (Zeituni et al 2009); moreover, DC invasion and immunosuppression are dependent upon expression of the 67 kDa mfa-1 fimbriae by P. gingivalis . We have now purified mfa-1 by ion exchange chromatography and sequenced it by tandem mass spectrometry (MS/MS), confirming its identify and revealing two putative N-glycosylation motifs as well as numerous O-glycosylation motifs. We further show mfa-1 is glycosylated by ProQ staining. Further monosaccharide analysis by gas chromatography-mass spectrometry (GC-MS) confirmed that mfa-1 contains fucose (1.35 nmol/mg) mannose (2.68 nmol/mg), N-acetylglucosamine (2.27 nmol/mg) and N-acetylgalactosamine (0.652 nmol/mg). Analysis by transmission electron microscopy reveals mfa-1 form oligomeric strains approximately 200 nm in length, which could be involved in targeting/ cross-linking DC-SIGN. These findings shed further light on mechanisms of invasion and immunosuppression by this unique mucosal pathogen.
Transducing the affinity of antigen recognition into graded structural modifications of the antibody product (43.21)
Authors: Kaattari Stephen , Ye Jianmin , Bromage Erin 
Published: January 2023

Abstract
We have found that the affinity of B cell interaction with its cognate antigen governs the degree of post-translational modification of the IgM product in trout. Affinity-based, antigen-driven lymphocytic selection and induction by the antigen, TNP-LPS, not only induced high affinity antibodies in vitro, but these antibodies also possessed a greater degree of disulfide polymerization. Affinity purification of high affinity vs. low affinity serum antibodies also simultaneously resulted in the partitioning of highly polymerized antibodies into a high affinity fraction, while the lightly polymerized antibodies partitioned into the low affinity fraction. The in vivo functional relevance of this distinctive post-translational modification was then revealed upon the transfer of labeled antibodies to naïve animals. These latter studies demonstrated that highly polymerized antibodies possessed longer half-lives. Finally, the degree of intermonomeric disulfide polymerization occurring at the C-terminal Cys 578, appears proportional to the concentration of available mannosyl residues, ostensibly at the proximal N-linked glycosylation site to Cys 578. This latter finding suggests mechanism(s) by which polymerization and half-life can be regulated via the affinity of BCR recognition. This research was supported by NIFA (National Institute of Food and Agriculture) Grant Nos. 2002-35204-11685, 2005-01594-16271 and VIMS intramural support.
Rapid evolution of a primate-restricted inflammasome regulator (43.25)
Authors: Harton Jonathan , Fuchs Travis , Atianand Maninjay 
Published: January 2023

Abstract
Pyrin-only protein 2 (POP2) is a small protein consisting solely of a pyrin domain capable of inhibiting IL-1β processing by preventing inflammasome assembly. Comparative genomic analysis reveals that POP2 is absent from the genomes of not only mice and rats, but those of other domestic mammals and new world monkeys as well. However, POP2 is present in the genomes of those primate species most closely related to humans. Interestingly, chimpanzee POP2 is identical to human POP2 at both the DNA and protein level but macaque POP2, although highly conserved, is not. Our analysis demonstrates that POP2 arose rapidly and recently in the mammalian genome and is likely derived from duplication and contraction of an extant NLR gene. Our findings support the hypothesis that mammalian NLR loci involved in innate and adaptive immunity as well as mammalian development, have been subject to recent and strong selective pressures driving their evolution. As POP2 is capable of regulating processes linked to innate immunity and inflammation, its highly restricted and conserved presence in the genomes of Old World primates suggests that further regulation of these events was critical in primate evolution.
Podoplanin interactions with CLEC-2 regulate dendritic cell migration (44.4)
Authors: Pinner Sophie , Mourao-Sa Diego , Turley Shannon 
Published: January 2023

Abstract
The migration of dendritic cells (DCs) from peripheral tissues to lymph nodes (LNs) is critical for the generation of protective immune responses and maintenance of self-tolerance. In our studies of DC trafficking we observed that migratory DCs, arriving in LNs from inflamed skin, exhibited elevated surface levels of the C-type lectin, CLEC-2. CLEC-2 activation in DCs was found to induce actin polymerization and increased protrusive activity, directly linking CLEC-2 to altered cytoskeletal dynamics and DC motility. CLEC-2 binds to podoplanin, a 38kDa surface glycoprotein required for correct formation of lymphatic vessels. Interestingly, podoplanin is normally expressed by both lymphatic endothelium (LECs) and fibroblastic reticular cells (FRCs); two stromal cell subtypes that directly interact with migratory DCs en route to the LN paracortex. Using a 3D in vitro culture system combined with time-lapse confocal microscopy we found that FRCs promote migration of DCs in a CCR7-independent manner. Podoplanin localizes to sites of contact between FRCs and DCs, and is required for DC migration along FRC scaffolds. Furthermore, hydrodynamic intradermal injection of podoplanin siRNA, used to silence podoplanin expression by LECs and FRCs, significantly impaired migration of DCs from skin to draining LNs. Our data illuminate important new features of DC-stromal cell interactions and reveal a critical role for podoplanin and its receptor CLEC-2 in regulating DC trafficking to LNs.
Depletion of dendritic cells enhances susceptibility to cell-free infection of HTLV-1 in CD11c-DTR transgenic mice (45.11)
Authors: Rahman Saifur , Manuel Sharron , Khan Zafar , Wigdahl Brian , Acheampong Edward , Jain Pooja 
Published: January 2023

Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is associated with HTLV-1-associated myelopathy/tropical spastic paraparesis and adult T-cell leukemia. The genesis of these diseases is believed to be associated with the route and mode (cell-free versus cell-associated) of primary infection. To explore the role of DCs during early HTLV-1 infection in vivo, we used a chimeric HTLV-1 with a replaced envelope gene from Mo-MLV to allow HTLV-1 to fuse with murine cells, which are generally not susceptible to infection with human retroviruses. We also used a CD11c-DTR transgenic mouse that permits conditional transient depletion of CD11c+ DCs. We infected these mice with HTLV-1 using both cell-free and cell-associated infection routes in the absence and presence of DCs. The ablation of DCs led to an enhanced susceptibility to infection with cell-free, but not cell-associated HTLV-1 in both the CD4 and non-CD4 fractions, as measured by the proviral load. Infection with cell-free virus in the absence of DCs was also found to have increased levels of Tax mRNA. Moreover, depletion of DCs significantly dampened the cellular immune response against both cell-free and cell-associated virus. These results uniquely differentiate the involvement of DCs in early cell-free versus late cell-associated infection of HTLV-1 and highlight a significant aspect of viral immunopathogenesis related to the progression of ATL and HAM/TSP after the initial infection.
Vaccine with cationic lipid DNA adjuvant (JVRS-100) provides durable protection against heterosubtypic influenza strain (45.15)
Authors: Vaughn Marla , Callejo Bernadette , Hill Tracy , Fairman Jeffery 
Published: January 2023

Abstract
Influenza A infection causes annual substantial morbidity and mortality worldwide. Current vaccines, are administered either unadjuvanted or adjuvanted with aluminum hydroxide (alum). Efficacy is highly dependent on close matching of the hemagglutinin and neuraminidase surface proteins of the vaccine with currently circulating virus. The optimal adjuvant for influenza would elicit a robust, durable antibody response and provide protection against strains of drifted or heterosubtypic strains of influenza. An adjuvant consisting of cationic lipid DNA complexes (JVRS-100) has been evaluated with whole inactivated influenza in mice. Heat-inactivated HKx31 (H3N2) or PR/8/34 (H1N1) influenza virus (5µg) with or without the JVRS-100 adjuvant (20µg) alone was administered intramuscularly at week 0 and 2. At three months post the final injection animals were either terminated for immunogenicity tests or challenged intranasally with live HKx31 (1xMLD50). Vaccination with JVRS-100 resulted in a significant increase in hemagglutination inhibiting (HAI) antibodies and an IgG2a isotype switch compared to virus alone. Furthermore, the animals vaccinated with the heterosuptypic strain plus adjuvant had decreased morbidity and mortality compared to the non-adjuvanted group. The results suggest that the JVRS-100 adjuvant increases the magnitude, durability and quality of the immune response, making it an attractive candidate for adjuvanting influenza vaccines.
IRF3 is an integral component in the host defense against Pseudomonas aeruginosa lung infection in mice. (45.6)
Authors: Lin Tong-Jun , Carrigan Svetlana 
Published: January 2023

Abstract
Pseudomonas aeruginosa is a major opportunistic pathogen. Host defense mechanisms involved in P. aeruginosa lung infection remains incompletely defined. Interferon regulatory factor 3 (IRF3) is a transcription factor and is primarily associated with host defense against viral infections. A role of IRF3 in P. aeruginosa infection has not been reported previously. Here we showed that IRF3 deficiency led to impaired clearance of P. aeruginosa from the lung in mice. P. aeruginosa infection induced IRF3 nucleus translocation, activation of ISRE and production of IFNβ, suggesting that P. aeruginosa induces the IRF3-ISRE-IFN pathway activation. In vitro, macrophages from IRF3 deficient mice showed complete inhibition on the production of CCL5 (RANTES) and CCL10 (IP-10), partial inhibition of CXCL1 (KC) and TNF and no effect on CXCL2 (MIP-2) in response to P. aeruginosa stimulation. In vivo, IRF3 deficient mice showed complete inhibition of CCL5 production and partial or no effects on other cytokine and chemokine production in the bronchoalveolar lavage fluids and lung tissues. Profiling of immune cells in the airways revealed that recruitment of neutrophils and macrophages into the airspace was reduced, while B cell, T cell, NK cells and NKT cells infiltrations were unaffected in IRF3 deficient mice in response to P. aeruginosa lung infection. These data suggest that IRF3 regulates a distinct profile of cytokines and chemokines and selectively modulate neutrophil and macrophage recruitment during P. aeruginosa infection. Thus, IRF3 is an integral component in the host defense against P. aeruginosa lung infection.