bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potentiating dendritic cells to target hypoxic environment of brain tumor (TUM4P.911)
Authors: Ginwala Rashida , Sagar Divya , Karakashev Sergey , Khan Zafar , Reginato Mauricio , Jain Pooja 
Published: January 2023

Abstract
Glioblastoma multiforme (GBM) is the most malignant type of brain tumor with a mean survival time of one year. The most difficult problem to treat tumors is their hypoxic microenvironment that changes the phenotypic characteristic of immune cells. In hypoxic conditions, HIF-1α, a transcription factor, accumulates and stimulates various genes that promote angiogenesis and tumor growth. We studied tumor-mediated adaptations to hypoxia in glioblastoma cells and showed an upregulation of HIF-1α and VEGF expression in a 2- and 3- dimensional culture model. We then confirmed that hypoxic environment increases HIF-1α expression in dendritic cells (DCs), but downregulates the expression of HLA-DR, CD86 and HLA-ABC and affects their antigen processing and presentation capability. First, we reversed the effect of cancer-driven hypoxia on DC functionality in vitro. Then by injecting DCs containing antisense HIF-1α plasmid into mice with GBM, in vivo imaging revealed fluorescently labeled DCs migrating away from the site of injection into the spleen and mediastinal lymph nodes by 54h p.i., indicating chemoattraction of DCs to areas of ongoing inflammation. Finally, these DCs were loaded with glioblastoma tumor antigens via a glycotargeting approach which lead to potentiation of DC functionality and antigen presentation under hypoxic conditions. This translational approach has applicability in eradicating tumors by DC-based vaccination or being adjunct to existing radio- and chemotherapy.
Evaluation of myeloid cell suppression related to cancer cell released products (TUM4P.913)
Authors: Motta Juliana , Sperandio Aline , Castelo-Branco Morgana , Locati Massimo , Rumjanek Vivian 
Published: January 2023

Abstract
Dendritic cells (DCs) and macrophages may recognize tumor antigens and initiate an antitumoral response before and after the formation of tumor mass. However, the secretion of cytokines and factors that inhibit myeloid cells is a mechanism used by tumor cells to escape from immune attack. Our aim was to understand how tumor cells modulate the generation of murine macrophages and human DCs. For this, we collected bone marrow cells from C57Bl/6 mice and differentiated with M-CSF in the presence of 3LL (Lewis lung carcinoma) or MN/MCA (fibrosarcoma) supernatants. Some cells were activated with IFN-γ and LPS to obtain M1 macrophages or IL-4 to M2. Data showed increased expression of arginase-1 mRNA in macrophages differentiated with MN/MCA supernatant and it happened both in M1 and M2. About 20% of cells proliferate in the presence of supernatants, even in the absence of M-CSF and they express higher level of CD16. Moreover, we differentiated human DCs from monocytes with IL-4 and GM-CSF in the presence of K562 (chronic myeloid leukemia) supernatants. TNF-α was added to activate the cells. It was observed higher percentage of cells expressing CD80 when the differentiation was done with K562 supernatant. Higher secretion of IL-10 and lower production of IL-12 were found in cells differentiated with K562 supernatant and later activated. Therefore, the development and function of macrophages and DCs are affected by tumor products and both cells present some suppressive features.
Macrophage migration inhibitory factor has a role in controlling colorectal cancer (TUM4P.918)
Authors: Rodriguez-Sosa Miriam , Pacheco-Fernández Thalia , Juárez-Avelar Imelda , Chirino Yolanda , León-Cabrera Sonia , Perez-Plasencia Carlos , Avila-Moreno Federico , Terrazas Luis I. 
Published: January 2023

Abstract
Chronic Inflammation has been related with cancer development by counteracting and unbalancing the immune response. The inflammatory cytokine macrophage migration inhibitory factor (MIF) is overexpressed in many carcinogenic tumors, stimulates angiogenesis and metastasis promoting proliferation and survival in malignant cells. In the inflammatory disease ulcerative colitis, MIF is early expressed and favors the inflammatory cytokine production like TNF-α and IL-1β. As intestinal chronic inflammation may proceed to colorectal cancer, we are interested in determining the role of MIF on development and pathology on colorectal cancer. To elucidate this point we used MIF-KO and WT mice, both with BALB/c genetic background, to develop a colorectal cancer model of Dextran Sodium Sulfate and Azoxymethan. As expected, MIF-KO mice showed low levels of serum inflammatory cytokines TNF-α, IL-1β and IFN-γ compare to WT mice. Strikingly, we found significantly more tumors and in a higher development stage on MIF-KO mice (24.4+/-2) compared to WT mice (12.6+/-2). Higer numbers of CD4+ cells were detected in intestinal epithelial cells on WT mice compared to MIF-KO mice. Therefore, although MIF has been recognized as a promoter of inflammation, which could favor the development of cancer, our results suggest that MIF is involved in controlling the development of colorectal cancer, possibly by its chemokine properties.
Tumor-derived alpha-fetoprotein impairs the differentiation and T cell stimulatory activity of human dendritic cells (TUM4P.929)
Authors: Pardee Angela , Shi Jian , Butterfield Lisa 
Published: January 2023

Abstract
Alpha-fetoprotein (AFP) is a well-established serum biomarker used in the diagnosis of several epithelial cancers and abnormalities of prenatal development. It has been proposed that AFP, an oncofetal antigen that is re-expressed particularly in hepatocellular carcinomas (HCC), plays an immunoregulatory role. In this study, human peripheral blood monocytes were cultured in the presence of cord blood-derived normal AFP (nAFP) or HCC tumor-derived AFP (tAFP). We unexpectedly observed that low doses of tAFP, but not nAFP, interferes with DC differentiation. These tAFP-conditioned DC expressed diminished levels of DC maturation markers, retained a monocyte-like morphology, and exhibited limited production of inflammatory mediators. Moreover, the ability of tAFP-conditioned DC to induce a robust T cell proliferative response to both alloantigen and cognate antigen was markedly compromised. Further analysis revealed that low molecular weight species that co-purify with AFP must be present in order for tAFP-mediated DC dysfunction to occur. Notably, in HCC patients exhibiting high levels of serum AFP, we have observed a lower ratio of myeloid-to-plasmacytoid circulating DC in comparison to AFPlow patients, suggesting that elevated levels of tAFP in cancer patients impair DC differentiation and function on multiple levels. Therefore, novel therapeutic approaches that antagonize tAFP regulatory circuits will be critical to improve clinical outcomes.
IL-17 regulates Toll-like receptor-mediated activation of dendritic cells (TUM4P.905)
Authors: Terada Satoshi , Wakita Daiko , Sumida Kentaro , Kaneumi Shun , Masuko Kazutaka , Ohtake Junya , Kishikawa Takuto , Ohno Yousuke , Kita Toshiyuki , Kitamura Hidemitsu 
Published: January 2023

Abstract
We have proposed that IL-17 produced by γδ T cells promoted angiogenesis and subsequent tumor progression in tumor microenvironment. However, the precise effect of IL-17 on immune system was remained unclear. Since dendritic cells (DCs) play a crucial role in immune regulation, we investigated the impact of IL-17 on DC function. Bone marrow-derived DCs were treated with IL-17 for 16 h and then stimulated with various toll-like receptor (TLR) ligands. IL-17 treatment significantly reduced IL-12, TNF-α, or IL-6 production by the DCs in a dose dependent manner. Interestingly, we found that IL-12 production was most clearly decreased compared to the other cytokines. In addition, IL-17 markedly suppressed the upregulation of MHC class II, CD40, and CD86 expressions on DCs after the stimulation. To evaluate effects of IL-17 on T cell-stimulating activity, IL-17-treated DCs were co-cultured with OVA antigen-specific T cells in the presence of OVA peptides or OVA proteins. We confirmed that IFN-γ production and T cell proliferation were suppressed by the IL-17-treatment. To determine effects of IL-17 on in vivo DC function, we established a novel tumor-bearing model using IL-17-producing cancer cells. As a result, expression levels of MHC class II and costimulatoly molecules on DCs were reduced in this model. These findings clearly indicated that IL-17 would inhibit activation of DCs including cytokine production and T cell activation in tumor microenvironment.
Attenuated listeria monocytogenes reprograms M2-polarized tumor-associated macrophages in ovarian cancer leading to iNOS-mediated tumor cell lysis (TUM4P.908)
Authors: Lizotte Patrick , Baird Jason , Stevens Cynthia , Lauer Peter , Green William , Brockstedt Dirk , Fiering Steven 
Published: January 2023

Abstract
A principal mechanism by which tumors evade immune-mediated elimination is through immunosuppression. Previous approaches to tumor immunotherapy have focused on modifying the immunosuppressive environment with immune checkpoint inhibitors, cytokine therapy, and other modalities with the intent to generate T-cell based anti-tumor immunity. We hypothesized that transformation of the suppressive ovarian cancer microenvironment could be achieved by introduction of the attenuated ΔactA/ΔinlB strain of Listeria monocytogenes. ΔactA/ΔinlB introduced into the microenvironment of the aggressive ID8-Defb29/Vegf-A murine ovarian carcinoma is preferentially phagocytosed by tumor-associated macrophages (TAMs) and reprograms that population from one of suppression to immunostimulation. TAMs in the peritoneum upregulated their co-stimulatory molecules CD80 and CD86, increased transcription of inflammatory cytokines, and downregulated transcription of suppressive effector molecules. Surprisingly, therapeutic benefit was not mediated by T- or NK-cell activity. ΔactA/ΔinlB-induced repolarization of TAMs activated direct tumor cell lysis via Nos2 production of nitric oxide. Modulation of the immunosuppressive nature of the ID8-Defb29/Vegf-A microenvironment, specifically by reprogramming of the TAM suppressive population from M2 to M1 polarization, is critical for our observed immune-mediated survival benefit.
Broadly neutralizing hemagglutinin stalk-specific antibodies require FcγR interactions for protection against influenza virus in vivo (VAC6P.951)
Authors: DiLillo David , Tan Gene , Palese Peter , Ravetch Jeffrey 
Published: January 2023

Abstract
Neutralizing antibodies (Abs) against influenza viruses have traditionally been thought to provide protection exclusively through their variable region; the contributions of mechanisms conferred by the Fc domain remain controversial. We investigated the in vivo contributions of Fc interactions with their cognate receptors for a collection of neutralizing anti-influenza Abs. Whereas five broadly neutralizing monoclonal Abs (bNAbs) targeting the conserved stalk region of hemagglutinin (HA) required interactions between the Ab Fc and Fcγ-receptors for IgG (FcγR) to confer protection from lethal H1N1 challenge, three strain-specific monoclonal Abs (mAbs) against the variable head domain of HA were equally protective in the presence or absence of FcγR interactions. Although all Abs blocked infection, only anti-stalk bNAbs were able to mediate cytotoxicity of infected cells, which accounts for their FcγR dependence. Immune complexes generated with anti-HA stalk mAb efficiently interacted with FcγRs, but anti-HA head immune complexes did not. These results suggest that FcγR binding capacity by anti-HA Ab was dependent on the interaction of the cognate Fab with antigen. We exploited these disparate mechanisms of mAb-mediated protection to reengineer an anti-stalk bNAb to selectively enhance FcγR engagement to augment its protective activity. These findings reveal a previously uncharacterized property of bNAbs and guide an approach toward enhancing mAb-mediated anti-viral therapies.
Vaccine-mediated B cell responses to Staphylococcus aureus alpha-Hemolysin (Hla) and effect of different boosting intervals on functional antibodies (VAC7P.979)
Authors: Lofano Giuseppe , Fiorillo Maria Teresa , Bagnoli Fabio , Bertholet Sylvie 
Published: January 2023

Abstract
Primary exposure to an antigen generates, along with antibody-secreting cells (ASCs), a heterogeneous B-cell memory compartment that changes over time and that may respond in different ways when re-encountering the cognate antigen. The goal of this study is to characterize B-cell responses after priming and the effect of different boosting intervals on the differentiation and function of ASCs and memory B cells. We used an immunization strategy based on the Hla protein from S. aureus, adjuvanted with Alum, as it was previously reported to induce protective antibodies in several animal infection models. In this study we performed a time course analysis following one or two immunizations, two weeks apart. Mice immunized twice had increased magnitude and quality of the Hla-specific humoral responses compared to mice immunized once. Increasing the boosting interval from two weeks to 1 month or 4 months, Hla-specific humoral responses increased in term of total IgG, affinity, and Hla-neutralizing titers. Hla-specific ASCs and memory B cells persisted for 4 months after the last immunization. We recently set up a method to identify Hla-specific B cells by flow cytometry (FACS).In the future we intend to further characterize their phenotype and to extend these analyses to Hla-specific memory B cells induced by different adjuvant formulations. This work will provide new insights in the memory B-cell compartment that might benefit the design of new vaccination strategies.
PLGA nanoparticle-entrapped inactivated porcine reproductive and respiratory syndrome virus vaccine coadministered intranasally with a potent adjuvant elicits cross-protective immunity in the pig respiratory system (VAC7P.981)
Authors: Binjawadagi Basavaraj , Dwivedi Varun , Manickam Cordelia , Ouyang Kang , Torrelles Jordi , Gourapura Renukaradhya 
Published: January 2023

Abstract
Porcine reproductive and respiratory syndrome (PRRS) is caused by a highly mutagenic RNA virus, PRRS virus (PRRSV). Currently used vaccines have failed to prevent PRRS outbreaks induced losses of estimated one billion dollar annually to the US pig farmers. The PRRSV infects primarily the lung macrophages. Because of safety advantage, we attempted to strengthen the immunogenicity of killed PRRSV vaccine antigens (KAg) in the pig respiratory system. We entrapped the KAg in biodegradable PLGA nanoparticles (NP-KAg) and coadministered the NP-KAg with a potent mucosal adjuvant, whole cell lysate of Mycobacterium tuberculosis (M. tb WCL), twice intranasally to growing pigs and challenged with a heterologous virus. Our results indicated that formulation of NP-KAg and unentrapped soluble M. tb WCL significantly cleared detectable replicating infective PRRSV with a 10-fold reduction in viral RNA load in the lungs, associated with substantially reduced microscopic lung pathology. Immunologically, enhanced virus neutralizing antibody titers by high avidity antibodies and augmented populations of IFN-γ secreting CD4+ and CD8+ lymphocytes, and reduced secretion of TGFbeta was detected in the lungs. Currently, we are in the process of identifying PRRSV epitope-specific T-cell response and frequency of apoptotic/necrotic immune cells in the lungs of vaccinated pigs. In conclusion, our vaccine formulation elicited broadly cross-protective anti-PRRSV immunity in the pig respiratory system.
HLA restricted CD8+ T cell responses following vaccination with monovalent and tetravalent dengue live attenuated vaccines (VAC7P.983)
Authors: Weiskopf Daniela , Angelo Michael , Bangs Derek , Sidney John , de Silva Aruna , Lindow Janet , Durbin Anna , Whitehead Stephen , Kirkpatrick Beth , Sette Alessandro 
Published: January 2023

Abstract
The frequency of infection with any of the four dengue viruses (DENV 1-4) has increased dramatically in the last few decades, and the lack of a vaccine has led to significant morbidity and mortality worldwide. Correlates of protection from severe dengue disease and vaccine efficacy have not yet been established. A recent comprehensive analysis of T cell response against dengue virus suggested an HLA-linked protective role for CD8+ T cells, predominantly targeting the non-structural (NS) proteins. Here, we characterize for the first time CD8+ T cell responses after experimental vaccination and compare it to responses observed in natural infection with dengue virus (DENV). We have collected full blood donations from study participants receiving a dose of the monovalent or tetravalent live attenuated DENV vaccine (DLAV) developed by the NIH. CD8+ T cell responses in vaccinees were readily detectable with magnitude and breadth similar to natural dengue infection. Interestingly, while broad responses to all proteins have been observed after monovalent vaccination we have observed a dramatic focus of the T cell responses to the highly conserved proteins NS3 and NS5. Epitopes from these proteins are highly represented in a vast variety of field isolates and are able to elicit multifunctional T cell responses. Detailed knowledge of the T cell response may contribute to identify robust correlates of protection in natural immunity and vaccination against DENV.
Bivalent gp120/mAb complex vaccines to induce broadly reactive antibody response against HIV-1 (VAC7P.987)
Authors: Kumar Rajnish , Tuen Michael , Hioe Catarina 
Published: January 2023

Abstract
HIV-1 envelope gp120 is a key target for neutralizing antibodies (NAbs) against the virus. Our work focuses on improving immunogenicity of cross-reactive neutralizing epitopes on gp120 antigen. We demonstrated that immunogenicity of gp120 and especially its neutralizing V3 epitopes was enhanced when gp120 was administered with the anti-CD4 binding site monoclonal antibody (mAb) 654 as immune complex (IC) vaccine. The enhanced V3 immunogenicity correlated with greater V3 antigenicity and was mediated mainly by the Fab activity of mAb 654. Here, we further explored the use of gp120/654 to elicit V3 Ab responses with greater breadth. A bivalent IC vaccine made of two gp120 proteins with immunogenically distinct V3 loops, gp120JRFL and gp120LAI-N448Q (a LAI derivative), were compared with the individual ICs. Individually, these ICs elicited V3 Abs with complementary reactivity: gp120JRFL/654 induced V3 Abs reactive with many subtypes B and subtype C viruses but not LAI, whereas gp120LAI-N448/654 induced V3 Abs specific for LAI. Administration of the ICs as a mixture or sequentially did not expand the breadth of Ab response. However, injection of the ICs s.c. at different sites resulted in induction of Abs reactive to LAI and the other subtype B viruses. Neutralization was also detected against Tier I subtype B HIV-1 pseudoviruses. These results demonstrate the potential of multi-valent vaccines and the importance of the delivery methods to broaden Ab responses against HIV-1.
Immunogenicity of Clostridium difficult DNA-based vaccine in an aging mouse model (VAC7P.959)
Authors: Bernui Mariana , Baliban Scott , Jacobson Jeffrey , Sardesai Niranjan , Weiner David , Kutzler Michele 
Published: January 2023

Abstract
Clostridium difficile infection (CDI) is a major source of morbidity and mortality, costing our healthcare system ~ $1 billion/year. Over 90% of CDI-related deaths occur in individuals &gt;85yrs. Protection against severe C. difficile-associated disease and recurrent CDI is mediated by host antibody responses against C. difficile toxins. Our goal is to determine the immunogenicity of a DNA based anti-toxin vaccine in an aging mouse model. Young (4 mo.) and old (&gt;18mo.) mice were immunized with our optimized DNA vaccine encoding toxin A and toxin B receptor-binding domain of C. difficile (A-RBD; B-RBD). Day 12 after the first immunization the younger mice had significantly higher IgG titers against A-RBD than older mice (25 ug/ul vs. 5 ug/ul anti-toxin serum IgG). However 10 days post second immunization the both groups had comparable IgG titers (~500 ug/ul IgG) against A-RBD. Anti toxin B-RBD IgG responses in older mice remained lower when compared to young following the second immunization. This suggests our DNA vaccine platform can generate an antibody response against C. difficile toxin in older mice but defects in vaccine priming may be occurring leading to lower titers. Day 14 post second immunization, mice cellular responses were analyzed. Higher frequencies of CD4+/CD44+ (activated) T cells and toxin-specific CD4+ T cells secreting pro-inflammatory cytokines (IFN-gamma, IL2) and Th2 cytokines (IL4, IL10) were generated in older mice.
FcγRIIB limits protection against F. tularensis LVS challenge induced by inactivated F. tularensis (VAC7P.964)
Authors: Franz Brian , Li Ying , Bitsaktsis Constantine , Iglesias Bibiana , Pham Giang , Gosselin Edmund 
Published: January 2023

Abstract
We have previously demonstrated that intranasal (i.n.) immunization with inactivated Francisella tularensis (Ft) live vaccine strain (LVS) targeted to Fcγ receptors (FcγR) can induce partial protection against a lethal mucosal challenge with Ft SchuS4. This protection is antibody (Ab) and interferon gamma (IFNγ) dependent. FcγRIIB is the only inhibitory Fc receptor (FcR) in the FcγR family, and has been reported to regulate IgG production, which plays a significant role in protection against Ft LVS and Ft SchuS4 challenge. Thus, we sought to determine the impact of FcγRIIB on immune protection against Ft infection. We utilized inactivated Ft (iFt) as an immunogen. Naïve or iFt-immunized FcγRIIB knockout (KO) versus wildtype (WT) C57BL/6 mice were challenged with varying doses of Ft LVS. We observed no significant difference in survival between naïve KO versus WT mice or in basal levels of Ft-specific IgG or IgM. However, KO mice immunized with iFt showed significantly increased survival as compared to iFt-immunized WT mice. Furthermore, Ft-specific IgG and IgA production were elevated in the serum from iFt-immunized KO versus WT mice. IFNγ levels were also enhanced in iFt-immunized KO versus WT mice. In summary, our studies demonstrate that FcγRIIB influences the level of protection against Ft challenge generated by iFt immunization by limiting the production of Ft-specific Ab and IFNγ, which have been shown to play significant roles in protection against Ft infection.