bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dasatinib promotes an expanded and therapeutically-superior T cell repertoire in response to vaccination against melanoma (VAC12P.1014)
Authors: Storkus Walter , Taylor Jennifer , Lowe Devin , Bose Anamika , Lin Yan , Kirkwood John , Tawbi Hussein 
Published: January 2023

Abstract
Dasatinib (DAS) is a potent inhibitor of the BCR-ABL, SRC, c-KIT, PDGFR and ephrin tyrosine kinases that has demonstrated only modest clinical efficacy in patients with melanoma. Given reports suggesting that DAS enhances T cell infiltration into the tumor microenvironment (TME), we analyzed whether therapy employing the combination of DAS plus specific active vaccination (VAC) would promote superior anti-melanoma efficacy in mice bearing s.c. M05 (B16.OVA) melanomas. We observed that a 7-day course of orally-administered DAS (0.1 mg/day) combined with VAC against the OVA (257-264) peptide epitope resulted in extended overall survival versus either single modality. Immunotherapeutic benefits associated with the DAS + VAC protocol included reduced levels of suppressor cell (MDSC and Treg) populations in the TME, enhanced production of CXCR3 ligand chemokines in the tumor stroma, recruitment of Type-1, vaccine-induced CXCR3+CD8+ tumor-infiltrating lymphocytes (TIL) and IL12p70+CD11c+ dendritic cells (DC) into the TME, and profound “spreading” in the repertoire of tumor-associated antigens recognized by CD8+ TIL. These results have fueled the development of UPCI 12-048 (NCT01876212), a randomized phase II pilot clinical trial of type I-polarized autologous DC vaccines incorporating tumor blood vessel antigen-derived peptides in combination with DAS that is currently enrolling HLA-A2+ patients with metastatic melanoma.
Engineering AFP and GPC3 to create highly immunogenic gene vaccines to prevent carcinogen-induced murine autochthonous hepatocellular carcinoma (VAC12P.1015)
Authors: He Yukai , Hong Yuan , Peng Yibing , Butterfield Lisa , Guo Sheng , Bartlett David , Munn David , Guevara-Patino Jose , Pang Junfeng , Mivechi Nahid 
Published: January 2023

Abstract
In this study, we investigated whether alpha-fetoprotein (AFP) and glypican 3 (GPC3) could be engineered to create effective vaccines to potently activate CD8 T cells to prevent clinically relevant carcinogen-induced autochthonous hepatocellular carcinoma (HCC) in mice. We found that the approach of epitope-optimization created a highly immunogenic AFP and GPC3 and that immunization with lentivector expressing the epitope-optimized AFP and GPC3, but not wild-type AFP and GPC3, potently activated CD8 T cells. Critically, the activated CD8 T cells not only cross-recognized native AFP peptides, but also recognized and killed tumor cells expressing native AFP and GPC3 protein. Immunization with lentivector expressing optimized AFP, but not native AFP, completely protected mice from tumor challenge and reduced the incidence of carcinogen-induced autochthonous HCC. In addition, prime-boost immunization with the optimized AFP significantly increased the frequency of AFP-specific memory CD8 T cells in the liver that were highly effective against emerging HCC tumor cells, further enhancing the tumor prevention of carcinogen-induced autochthonous HCC. Our data demonstrate that epitope-optimization is required to potently activate AFP- and GPC3- specific CD8 T cells, generating effective antitumor effect to prevent carcinogen-induced HCC in mice. Our study provides a roadmap to develop effective human HCC vaccines that may result in an improved antitumor effect.
Titration of T cell help into epitope-based self-assembling vaccines (VAC12P.1017)
Authors: Pompano Rebecca , Chen Jianjun , Verbus Emily , Han Huifang , Collier Joel , Chong Anita 
Published: January 2023

Abstract
Distinct ratios of T effector cells are necessary for effective protective immunity. T cell epitope content plays a critical role in determining T effector cell outcome, but its effects are nonlinear and difficult to predict when designing vaccines. Here, we developed a precise experimental approach to generate vaccines with optimized antibody and CD4+ T cell responses, using non-covalent self-assembly of peptides to titrate a high-affinity universal T cell epitope (PADRE) into a nanoparticulate vaccine. Co-assembly of a B cell epitope (B peptide) from methicillin-resistant Staphylococcus aureus with PADRE produced a modular vaccine that resembled a traditional protein conjugate, requiring cognate T-B interactions to raise an antibody response. Varying the PADRE concentration over nearly three orders of magnitude, from 5 μM to 1 mM, elicited bell-shaped dose-response curves for the anti-B peptide titers and PADRE-specific CD4+ cells, but these peaked at 10-fold different concentrations (0.05 and 0.005 mM, respectively). The antibody titer correlated with a peak in the T follicular helper response, while the total PADRE-specific T cell count reflected a peak in the Th1 and Th2 cells. Peak titers and affinities were similar to those obtained from an alum-adjuvanted B peptide-conjugate vaccine, indicating that titrating the T cell epitope provides a means to optimize the T effectors cells and generate strong responses in chemically precise vaccines.
HPV based photodynamic therapy: a new approach for anti-cancer therapy (VAC12P.1019)
Authors: Kines Rhonda , Çuburu Nicolas , Kobayashi Hisataka , MacDougall John , de los Pinos Elisabet , Schiller John 
Published: January 2023

Abstract
A new method of targeted photodynamic therapy (PDT) is proposed for potentiating anti-tumor immunity. Human papillomavirus (HPV) virus-like particles (VLPs) bind a broad range of tumor types both, in vitro and in vivo, but do not bind healthy, intact tissues. We have linked a photosensitizer dye, IR700, to the HPV VLPs and applied the dye-coupled particles (IR700-VLP) to tumor cells. When exposed to 690nm light, the bound conjugates induced immediate necrotic-like cell death in ovarian, lung, melanoma and cervical cancer cell lines in vitro, and in melanoma and lung tumors in vivo. We are currently expanding these studies to examine long-term tumor growth/survival and the generation of anti-tumor immunity in C57Bl/6 mice using the TC-1 tumor model, which expresses the HPV oncogenes, E6 and E7. This model allows us to track the T-cell responses generated against the HPV oncogenes, in both primary and metastatic tumor settings. Treatment with IR700-VLP and light exposure induced an influx of CD8+ and CD4+ T-cells into the treated tumors. Ex vivo cultures of whole tumor cell suspensions showed IFN-γ production in PMA/ionomycin-stimulated CD8+ and CD4+ T cells and to a lower extent without stimulation, suggesting that these T-cells may have been primed against the tumor antigens. Our data suggest that local anti-tumor immunity can be induced through the rapid tumor cell death caused by IR700, in conjunction with the ability of HPV VLP to induce an innate immune response.
Absence of organized lymphoid tissues in the intestine of the freshwater fish, C. commersonii (VET2P.1042)
Authors: Taylor Rebekah , Kleponis Jennifer , Tatum Russia , Terrero Fernando 
Published: January 2023

Abstract
Microscopic organized lymphoid tissues in the small intestine, such as cryptopatches (CP) and isolated lymphoid follicles (ILF), have been well characterized in the laboratory mouse. Descriptions of these structures have also been reported in rat and human, but the presence or absence of CP and ILF in other animals has not been explored. Given the evolutionary development of the adaptive immune system beginning in jawed fish, we hypothesized that CP and ILF would be present in the intestines of fish. We examined the intestines of 10 wild-caught Catostomus commersonii, a bottom-feeding freshwater fish found in local streams in Western Maryland and throughout the United States. The intestines of these fish were opened longitudinally and arranged in flattened layers for horizontal sectioning. Samples of mouse small intestine were prepared simultaneously as a positive control. After quick-freezing and sectioning, the tissue was stained with hematoxylin and eosin. Interestingly, a complete absence of organized lymphoid tissue was noted, suggesting that CP and ILF, in addition to the well-known Peyer’s patches, are limited to higher-order animals and potentially only mammals. Plans to study other fish species, especially carnivorous varieties (since the composition of the intestinal immune system can change in response to diet) are currently underway to further support this finding.
Effects of regulatory T cells on peripheral blood mononuclear cell responses to live Mycobacterium avium subspecies paratuberculosis in cows with Johne’s disease. (VET2P.1035)
Authors: Roussey Jonathan , Coussens Paul 
Published: January 2023

Abstract
Johne’s disease (paratuberculosis) is a chronic wasting disease of wild and domestic ruminants caused by infection with Mycobacterium avium subspecies paratuberculosis (MAP). Previously, we proposed that the chronic nature of Johne’s disease may result in development of a regulatory T cell (Treg) population in the host. These cells function to shift the immune balance away from a pro-inflammatory Th1 response to an unproductive Th2 response. Due to the inherently low abundance of Tregs in the periphery and the relatively low proportion of Tregs reactive toward any one particular infectious agent, we have developed an in vitro method to stimulate expansion of MAP-reactive Treg populations from CD4+CD25+ peripheral blood mononuclear cells (PBMCs). Enriched Tregs may subsequently be used in Treg-mediated suppression assays. A simplified version of this procedure is also used to determine differences in naïve T cell responses to MAP antigen stimulation, including induction of FoxP3 expression. Following PBMC stimulation with live MAP bacteria and with MAP-reactive Tregs, real-time PCR is used to analyze expression of Th1, Th2, and Treg transcription factors as well as pro- and anti-inflammatory cytokines including. Results are compared between cattle that are test-negative and test-positive for Johne’s disease, with results from test-positive cattle further subdivided between animals exhibiting symptoms of clinical vs subclinical disease.
B cell subpopulations alteration in pathogenic and nonpathogenic SIV infections (VIR7P.1061)
Authors: Brocca Cofano Egidio , Siewe Basile , Kurt Dave , Xu Cui Ling , Kristoff Jan , Ma Dongzhu , Haret-Richter George Sebastian , Montefiore David , Landay Alan , Pandrea Ivona , Apetrei Cristian 
Published: January 2023

Abstract
SIV/HIV infection is associated with B cell dysfunction, the significance of which is not known. We compared the B cell dynamics in blood, lymph nodes (LNs) and gut during SIVsab pathogenic infection of pigtailed macaques (PTMs) and nonprogressive SIVsab infection of African green monkeys (AGMs) by monitoring the B cell subsets, B regulatory cells (Bregs), CD4+ T follicular helper (Tfh) cells, B cell immune activation, apoptosis, exhaustion and homing to the intestine. Binding anti-gp41 and neutralizing antibodies (Nabs) were also measured. Acute SIV infection induced a transient but significant loss of total circulating B cells in PTMs only. In AGMs, total B cell from LNs increased during chronic infection. B cells transiently increased in the gut and naïve subset decreased in all three compartments in both species. Memory B cell subsets showed a different dynamic for both species. Bregs increased in PTM, correlated with IL-10 expression. B cell proliferation occurred in both species. PTMs expressed high baseline levels of α4β7, high degree of B cell activation and apoptosis and high frequency of Tfh. The dynamics of Ab response was similar in both species, but rapid progressor PTMs lacked the ability to mount anti-gp41. Our data show that B cell dysfunction only occurs in pathogenic SIV infection. While B cell changes were not correlated with production of Nabs, rapid disease progression associated a severe incapacity to mount an anti-SIV Ab response.
Identification of PRRSV cross-neutralizing memory B cells (VIR7P.1062)
Authors: Murtaugh Michael , Rahe Michael , Robinson Sally , Taylor Justin , Jenkins Marc 
Published: January 2023

Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) is widely considered to be the most important pathogen of swine. Yet, there are no vaccines that produce effective broadly neutralizing antibodies to genetically diverse viral genotypes. We recently showed that adult sows develop cross-neutralizing antibodies following infection outbreaks. However, the relevant B-cells producing the cross-neutralizing antibodies have not been identified. Thus, we have characterized surface markers that differentiate porcine B-cell subpopulations and determined their antibody secretion characteristics. Culture of CD21+ B-cells sorted by surface Ig expression showed that surface IgM- and IgG-positive cells proliferated in response to mitogenic stimulation. Sequencing of light and heavy chain variable region mRNA revealed more extensive somatic mutation in the order of plasma cell &lt; IgM-positive &lt; IgG- positive complexity. The CD21+, IgG+ B-cells are putative class-switched peripheral memory B-cells. The isolation of class-switched memory B cells that display cross-neutralizing activity to PRRSV and the subsequent characterization of class-switched memory B cell genetic sequences will allow us to ascertain the necessary somatic mutations that result in the production of PRRSV cross-neutralizing antibodies.
Vaccine induced immunopathology mediated by memory CD4 T cells following chronic viral infection (VIR7P.1054)
Authors: Penaloza-MacMaster Pablo , Barber Daniel , Wherry John , Provine Nicholas , Teigler Jeffrey , Blackmore Steven , Borducchi Erica , Bronson Roderick , Barouch Dan 
Published: January 2023

Abstract
CD4 T cells are important for promoting functional adaptive immune responses following viral infections, but the specific contribution of vaccine-elicited CD4 T cell responses to immune protection remains unclear. We interrogated whether selective induction of virus-specific CD4 T cell responses by vaccination, in the absence of other adaptive immune responses, would improve immune protection against a chronic lymphocytic choriomeningitis virus (LCMV) challenge in mice. Surprisingly, we observed that immunization of mice with a vaccine that induced predominantly CD4 T cell responses resulted in severe immunopathology and mortality following chronic LCMV clone 13 challenge. Vaccinated mice exhibited impaired adaptive responses, severe inflammation, accelerated destruction of lymphoid tissues, and fulminant mortality as compared with naïve mice following challenge. This immunopathology was caused by uncontrolled antigen-driven stimulation of memory CD4 T cells that resulted in cytokine storm and widespread inflammation. The adverse effects of vaccination were abrogated by co-immunization with vaccines that generated CD8 T cell responses, adoptive transfer of virus-specific CD8 T cells, or passive immunization with virus-specific immunoglobulins. Altogether, these data raise important concerns for vaccines that predominantly elicit CD4 T cell responses.
Reversible nerve damage regulates pathology in murine herpes simplex stromal keratitis. (VIR7P.1056)
Authors: Yun Hongmin , Rowe Alexander , Lathrop Kira , Harvey Stephen , Hendricks Robert 
Published: January 2023

Abstract
Herpes simplex type 1 (HSV-1) keratitis (HSK) is characterized by recurrent bouts of immunopathology consisting of corneal opacity, vascularization, and progressive scarring that is triggered by viral reactivation from a latent state and release from sensory nerves in the cornea. Nerve damage and loss of corneal blink reflex (BR) accompanies HSK recurrences, but testing BR is usually not part of the clinical HSK workup in humans or mouse models. Although loss of BR can lead to desiccation of the corneal surface, especially in mice that lack consensual blink reflex, a possible contribution of nerve damage to HSK immunopathology has not been explored. Here we show that chronic HSK in mice is associated with loss of corneal BR, and that preventing corneal desiccation through tarsorrhaphy (eyelid stitching) dramatically reduces HSK severity and resolves existing severe HSK. Tarsorrhaphy dramatically reduced the neutrophilic infiltrate and expression of the neutrophil chemotactic factor CXCL1 in infected corneas. Mice that were depleted of CD4+ T cells exhibited transient severe HSK, with concurrent resolution of HSK, recovery of corneal BR, and regeneration of corneal nerves. Thus, CD4-mediated chronic, but reversible nerve damage and the accompanying corneal desiccation accounts for much of the inflammation associated with HSK in mice.
Hydrophobicity is a hallmark of immunogenic MHC class I T cell epitopes (APP2P.111)
Authors: Chowell Diego , Krishna Sri , Blattman Joseph , Anderson Karen 
Published: January 2023

Abstract
The molecular mechanisms underlying MHC class I-peptide immunogenicity are not well defined. Here, we investigated the biochemical properties that are associated with immunogenicity from immunogenic (n=5035) and non-immunogenic (n=4853) MHC-I peptides curated from the Immune Epitope Database (IEDB). Using a bioinformatic comparative analysis, we evaluated three amino acid properties (hydrophobicity, side chain mass, and polarity) for an association with immunogenicity within the pMHC dataset. We found a strong bias towards hydrophobic amino acid usage within immunogenic peptides (Spearman ρ = 0.71, P = 4.24 x 10^-4); this difference in hydrophobicity is due to preferential usage of non-polar hydrophobic amino acids in TCR-contact residues for peptides restricted by HLA-A2, H-2Db, H-2Kb (P-values &lt; 0.01). We used amino acid hydrophobicity to design an artificial neural network (ANN) model of immunogenicity for MHC-I peptides. We trained this model to predict mouse H2Db-restricted immunogenic epitopes for 4 different antigens from LCMV, Adenovirus, and Influenza A virus. Our findings suggest that hydrophobicity of TCR contact residues may be a fundamental biochemical hallmark that favors immunogenicity of MHC/peptide complexes. Incorporating hydrophobicity into epitope prediction algorithms may improve prediction of immunogenic CTL epitopes.
Contribution of the lymph antigens to the MHC II self-peptidome (APP2P.102)
Authors: Santambrogio Laura , Stern Lawrence 
Published: January 2023

Abstract
Thymic MHC class II peptide presentation shapes the CD4+ T cell repertoire. Conventional migratory dendritic cells (cDC) participate in this process by presenting peripheral self antigens to the developing thymocytes after migration to the thymus. To evaluate the contribution of cDC in central tolerance we analyzed their HLA-DR1 eluted peptidome. Over 3000 peptides with a prediction score above identity, were sequenced. Peptides derived from both intracellular and extracellular sources displayed a snap shot of the HLA-DR1-restricted self peptidome presented under physiological conditions. Processing enzymes responsible for generating these peptides were identified and included cathepsins, metalloproteases, calpains and caspases among others. Comparative analysis between the HLA-DR1 eluted peptidome and naturally processed peptides found in the human lymph identified peptides that shared common sequences, common N or C terminal cleavage site, and few peptides that completely overlapped, indicating that peptides found in biological fluids can contribute to the overall MHC-II peptidome presented by cDC. HLA-DR1 binding affinity and HLA-DM sensitivity was evaluated for several of the mapped peptides. Peripheral injection of the eluted peptides in HLA-DR1 mice identified their role in CD4+ thymocytes selection. Altogether our data indicate that peptides found in biological fluids can shape the thymic T cell repertoire and contribute to the generation of central tolerance.
Effect of pH on cooperativity in peptide binding to MHC class II (APP2P.105)
Authors: Crane Kyle , Castellini J. Margaret , Hoffman Megan , Gotti Marie , Ferrante Andrea 
Published: January 2023

Abstract
Initiation of an adaptive immune response occurs when peptides bound to class II MHC (MHCII) molecules expressed on the surface of Antigen Presenting Cells are recognized by CD4+ T Cells. Formation of peptide-MHCII complexes (pMHCII) occurs within acidic endosomal compartments. The effect of acid pH on peptide binding is well known, and is usually associated with an enhancement of binding and acceleration in kinetics relative to pH 7.4. We have shown that peptide binding to and release from MHCII at extracellular pH are function of structural permissiveness and affected by cooperative effects. To resolve whether cooperativity, thus system flexibility, is a function of pH, we measured the affinity of peptides derived from influenza H3 HA306-319 via cycle-mutation for the human MHCII allele HLA-DR1 (DR1) at pH 5.4, 6.4, and 7.4. In keeping with prior results, cooperativity affects peptide affinity in an exponential fashion, and increasing values of pH are associated to increasing values of cooperativity. This pH-dependence of cooperativity can be observed for destabilizing combinations of mutations, as well as for multiple substituted peptides whose binding is improved as compared to the single substituted sequences. These results indicate that the endosomal pH enhances system permissiveness with respect to extracellular conditions, increasing the probability of peptides with suboptimal chemistry to complex with MHCII.
Identifying the upstream events of innate autoimmunity in intestinal reperfusion injury (BA3P.204)
Authors: Zhang Ming , Lee Haekyung 
Published: January 2023

Abstract
Acute intestinal ischemia is a medical emergency with a high mortality rate, attesting to the need to understand its pathogenesis and develop effective therapies. Recent studies show that innate autoimmune response initiated by natural IgM and complement plays an important role in the reperfusion injury after intestinal ischemia. The goal of this study was to identify the upstream events of innate autoimmunity in intestinal reperfusion injury. To study this, we used a murine model of natural IgM-mediated intestinal I/R. Our results showed that mice overexpressing anti-oxidant enzyme SOD1 had significantly reduced intestinal tissue damage and blocked IgM-mediated complement activation compared with WT controls. To determine if cell membrane instability is an intermediate event between ROS formation and natural IgM-mediated innate autoimmune response, a cell membrane stabilizer was administered to WT mice prior to the induction of intestinal ischemia. Treatment with cell membrane stabilizer significantly protected animals from I/R injury along with inhibition of IgM-mediated complement activation. Stabilizing the cell membrane did not affect ROS formation in the intestinal model. Thus, these data indicate that intracellular ROS formation is an upstream event of cell membrane instability which leads to subsequent innate autoimmune response by natural IgM and complement.