bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving the immunogenicity of dendritic cell-derived exosome-based vaccines for the immunotherapy of melanoma
Authors: Damo Martina , Wilson D. Scott , Simeoni Eleonora , Hubbell Jeffrey A.
Published: January 2023

Dendritic cell (DC)-derived exosomes (Dexo) are promising vaccine candidates for the treatment of cancer.

We aimed at identifying a Dexo formulation with stronger immune stimulatory properties and efficacy as compared to the Dexo vaccines previously tested in pre-clinical and clinical settings of cancer immunotherapy. We therefore produced Dexo from DCs loaded with specific antigens and matured with the Toll-like receptor (TLR)-3 ligand poly(I:C) as danger signal.

In vivo, Dexo produced from DCs loaded with OVA and stimulated with poly(I:C) could induce efficient activation of endogenous OVA-specific CD4+ and CD8+ T cells, leading to pro-inflammatory Th1 immune responses.

We subsequently produced Dexo from DCs matured with poly(I:C) and cultured in the presence of oxidized B16F10 cell lysates (Dexo(B16+pIC)) as a source of B16F10 antigens.

Mice bearing subcutaneous B16F10 tumors were vaccinated intradermally to target tumor-draining lymph nodes (tdLN), resulting in reduced tumor growth, limited metastasis burden and, most importantly, in prolonged survival of the mice vaccinated with Dexo(B16+pIC). Such benefits were associated with increased frequencies of effector CD8+ T cells in the tdLNs, spleen and tumor masses, reduced frequencies of tumor-infiltrating exhausted PD-1+ CD8+ T cells and increased frequencies of tumor-infiltrating NK and NK-T cells obtained upon vaccination with Dexo(B16+pIC) as compared to Dexo(B16), which instead are devoid of poly(I:C) and resemble the Dexo vaccines previously tested in human patients.

Our results demonstrate that poly(I:C) is a promising candidate for the production of Dexo vaccines with improved immune stimulatory properties suitable for the immunotherapy of cancer.
Naturally-derived bacterial nano-particles engage diverse innate receptors, driving the activation of dendritic cells and leading to the establishment of potent adaptive immune responses.
Authors: Davitt Christopher JH , Petersen Hailey E , Kikendall Nicole L , Lavelle Edward C , Morici Lisa A
Published: January 2023

Most non-living vaccines in clinical use are thought to mediate protection primarily via antibody responses; however, many intracellular bacterial infections require cell-mediated immunity (CMI) for protection. This renders traditional strategies insufficient and drives a need for new approaches to elicit CMI. Outer-membrane vesicles (OMVs) derived from Gram-negative bacteria are an effective vaccine platform with precedence for safe use in humans. Unlike most subunit antigens and synthetic nano-particles, OMVs contain endogenous immunostimulatory ligands and deliver antigens in their native orientation. We hypothesized that OMVs could activate antigen presenting cells through the engagement of various innate receptors and drive CMI through the three key activation steps: antigen-presentation, co-stimulation and cytokine production. Following OMV uptake in vitro and in vivo, dendritic cells (DCs) increased surface MHC class I and II (MHCcII), CD80, and CD86 expression. OMV-stimulated DCs produced significantly more of the key T cell polarizing cytokines IL-1β, IL-6, IL-18 and IL-12p70 compared to DCs treated with heat-killed (HK) bacteria. TLR-4 contributed to OMV-mediated expression of MHCcII, CD80, and IL-1β, IL-6, IL-18 and IL-12p70, while the NLRP3 inflammasome was required for OMV-induced production of IL-1β and IL-18. Following vaccination of mice, Th1- and Th17-type T cell responses were observed after ex vivo restimulation with OMVs and HK bacteria. In addition, OMV vaccination produced functional CD8+ T cells capable of killing bacteria-infected cells. Collectively these results support the utility of the OMV platform as a non-living vaccine that can lead to protective CMI against bacterial pathogens.
Collection and characterization of potentially novel antimicrobial peptides from Japanese medaka plasma
Authors: Dong Miao , Lei Haipeng , Humble Joseph L , Liang Yimin , Shen Wei , Au Doris W.T. , Sun Hongyan , Lam Yun Wah
Published: January 2023

The excessive use of antibiotics in aquaculture contributes to the uprising of antibiotic resistance that threatens human health. We explore the innate immunity of fish for naturally occurring antimicrobial factors that can be developed into potential antibiotic agents. Antimicrobial peptides (AMPs) have been studied in many organisms but efforts on the systematic identification of AMPs in fish have been lacking. In this study, we systematically identified naturally occurring peptides in medaka plasma. Blood collected from medaka of different gender, age and infection status were combined. Peptides under the molecular weight of 3kDa were fractionated and purified, followed by mass spectrometry analysis. In total, 6483 unique peptides were identified against the medaka genome, constituting a database of circulating peptides in this organism. After evaluation with a combination of web-based prediction tool and conserved physicochemical properties of AMPs, 83 potential antimicrobial peptides were predicted. One of them, a 13-residue peptide named VPS13D3241–3253, showed a broad-spectrum toxicity on fish and human pathogenic bacteria (gram+ or gram−) without significant cytotoxicity on mammalian cell lines. Scanning electron microscopy indicated that VPS13D3241–3253 disrupted the cell wall of both gram+ and gram− bacteria. SOS response assay showed that this peptide efficiently induced DNA damage in bacteria. The identification of VPS13D3241–3253 illustrates the feasibility of the proteomic approach in the discovery of potentially novel AMPs from fish. These AMPs will form an important basis for the development of new antibacterial agents in the fish farming industries.
Sterilizing immunity to influenza virus infection requires local antigen-specific T cell response in the lungs
Authors: Dutta Avijit , Huang Ching-Tai , Chen Tse-Ching , Lin Chun-Yen , Lin Yung-Chang , Chang Chia-Shiang , He Yueh-Chia , Huang Yu-Lin
Published: January 2023

Pre-infection induces sterilizing immunity to homologous influenza virus challenge in ferret. In our antigen-specific experimental system, mice pre-infected with PR8 influenza virus through nasal route are likewise resistant to reinfection of the same strain of virus. The virus is cleared before establishment of effective infection. Intramuscular influenza virus injection confers protection against re-infection with facilitated virus clearance but not sterilizing immunity. Pre-infection and intramuscular injection generates comparable innate immunity and antibody response, but only pre-infection induces virus receptor reduction and antigen-specific T cell response in the lung. Pre-infection with nH1N1 influenza virus induces virus receptor reduction but not PR8 specific T cell immune response in the lung and cannot prevent infection with PR8 influenza virus. Pre-infection with PR8 virus induced PR8-specific T cell response in the lung but cannot prevent infection with nH1N1 virus either. Antigen specific T cell immunity is required for sterilizing immunity. We discuss the potential implications of these findings in vaccination strategy for effectual protection comparable to pre-infection.
Antigen presenting cell subsets in the lung and draining lymph nodes affect granzyme B-expressing CD4+ T cells in the lung during influenza A infection
Authors: Price Jeffrey D. , Brown Deborah M.
Published: January 2023

Influenza A virus (IAV) is a global health burden that evades vaccine responses and can present as a pandemic threat. Innate immune cells are the first line of defense at the mucosal site of entry and drive adaptive responses that provide immunity. Therefore, we examined the distinct antigen-presenting cell (APC) populations in the lung and draining lymph nodes that respond to IAV infection. When mice are treated intranasally with PR8, a highly inflammatory H1N1 IAV, the populations of APCs in the lung change, inducing infiltration of a large population of inflammatory macrophages and a concomitant decrease in dendritic cells. These inflammatory macrophages express increased levels of TLR9 after infection, corresponding with our previous work demonstrating the efficacy of CpG DNA in driving anti-IAV responses. These changes in APC subsets do not occur in a similar fashion after infection with X31, a low inflammation H3N2 virus, or in the lymph nodes. One significant response is the production of granzyme B (GzB) in CD4+ T cells that infiltrate the lung after IAV infection. APC populations were sorted after PR8 infection and used to stimulate DO11.10 T cells in vitro. CD11b+ APCs were most efficient at inducing GzB in CD4+ T cells in steady-state, while after infection both CD11b+ and CD11b+CD11c+ APCs induced strong GzB expression, while all APC subsets induced IL-2 and IFN-gamma release from CD4+ T cells. These results have implications for vaccine design and we are currently utilizing chimeric antibodies to target antigen to APC populations in the lung and lymph nodes to induce anti-IAV CD4+ T cell responses.
West Nile virus infection in the Collaborative Cross mouse model recapitulates unique human disease states
Authors: Graham Jessica B , Swarts Jessica , Thomas Sunil , Wilkins Courtney , Ferris Martin , Gale Michael J , Lund Jennifer M
Published: January 2023

West Nile Virus (WNV) is a cytopathic neurotropic flavivirus that causes a wide range of infection states in humans, ranging from asymptomatic to severe neuroinvasive disease. This variation supports the idea that host genetics play an important role in immunity to WNV infection. The significant individual to individual variation in immune responses within the human population can not be fully captured in single laboratory inbred strains, so a systems genetic approach requires the use of the Collaborative Cross (CC) mouse system to identify polymorphic host genes and networks that control the regulation of adaptive immunity to WNV infection. The CC is a panel of lines with over 40 million single nucleotide polymorphisms evenly distributed throughout the genome, providing the statistical power to map multiple genetic factors with small to moderate effect. In the CC model we have identified lines with unique human phenotypes that have not previously been captured in laboratory inbred strains, such as severe neuroinvasive disease and chronic WNV infection. Our use of the CC model shows differing immune responses to WNV in terms of T cell frequency and activation, antigen-specific CD8 T cell frequency, memory precursor cells, and T cell cytokine production between CC strains after WNV infection. A distinct immune signature is present in the chronic line, characterized by a strong systemic regulatory T cell response and late virus-specific response in the CNS due to viral persistence. Microarray analysis on spleen and CNS tissue reveals expression changes correlated with extreme immune phenotype responses within and between organ compartments, allowing for identification of correlates of protection and susceptibility to WNV infection.
HVEM regulates effector versus memory cell fate decisions following respiratory poxvirus infection
Authors: Desai Pritesh , Abboud Georges , Dastmalchi Farhad , Stanfield Jessica , Ware Carl F , Croft Michael , Song Jianxun , Hutchinson Tarun E , Salek-Ardakani Shahram
Published: January 2023

During an acute respiratory viral infection, effector CD8 T cells differentiate into short-lived effector cells (SLECs) that are destined to die and memory precursor effector cells (MPECs) that give rise to long-lived memory cells. Defining the precise molecular cues that regulate the survival of MPECs is of great interest. HVEM (Herpes Virus Entry Mediator) is a member of tumor necrosis factor receptor (TNF) superfamily that acts as a molecular switch between pro-inflammatory and inhibitory signaling by respectively binding with its endogenous ligand (LIGHT) from the TNF family and with (BTLA) from the Ig like CD28/B7 family. Using respiratory vaccinia virus (VACV) infection in mice, we found that HVEM was selectively expressed on MPECs but not on SLECs. Lack of HVEM on Ag-specific CD8 T cells resulted in an altered SLEC/MPEC ratio, with effector cells skewing more towards SLEC phenotype. Adoptive transfer of HVEM-deficient MPECs showed markedly increased contraction after viral clearance, leading to nearly complete loss of lung-resident CD8 memory T cells. Similar to CD8 T cells lacking HVEM, WT CD8 T cells failed to accumulate in LIGHT-deficient host but not BTLA-deficient host upon VACV infection. Collectively, these results reveal that HVEM expression on MPECs is critical for the development of long-lived memory cells and suggests that strategies targeting HVEM signaling might be beneficial in augmenting CD8 T cell immunity against respiratory viruses.
The influence of genetic diversity on neonatal respiratory syncytial virus disease
Authors: Siefker David , Williams Robert W. , Lu Lu , You Dahui , Cormier Stephania
Published: January 2023

Respiratory syncytial virus (RSV) is the number one cause of lower respiratory infections in children. Although most children are infected with RSV in their first year of life, 40% have severe disease suggesting a genetic component in addition to age. This collaborative project aims to identify genetic determinants associated with RSV infectivity during the neonatal period. Recombinant inbred strains of mice such as the BXD family have been extensively typed for both genetic polymorphisms (5 million variants) and a wide range of phenotypes, including influenza and other pathogens. Here, we infected different BXD strains with RSV at five days of age and evaluated pulmonary viral load. We show a difference in viral burden in the lungs of neonatal mice between different BXD strains, suggesting a role for genetic variation in RSV infectivity. Therefore, we have a novel system to identify genetic loci involved in the development of RSV disease. These results will be critical in the development of specific antivirals and vaccines against RSV.
Membrane-based immunotherapy with immune checkpoint blockade antibodies confers protection against metastatic breast cancer
Authors: Bommireddy Ramireddy , Pack Christopher D , Bozeman Erica N , Patel Jaina M , Vartebedian Vincent F , Munoz Luis E , Shafizadeh Yalda , Menon Ashwathi P , Lakshmanan Ramana , Reddy Shaker JC , Selvaraj Periasamy
Published: January 2023

Objective

The 4T1 triple negative breast cancer (TNBC) model resembles many of the hallmarks of advanced TNBC in humans. In this study we investigate if combining a membrane-based immunotherapy with immune checkpoint blockade antibodies in a metastatic tumor model could effectively generate protective immunity. This personalized strategy is applicable to indications such as TNBC that exhibit a high degree of heterogeneity and do not respond to approved cancer therapies.

Methods

4T1 tumor tissue was harvested from BALB/c mice and processed to generate tumor membrane vesicles (TMVs). TMVs were then incorporated with GPI-B7-1 and GPI-IL-12 by protein transfer and used for immunization in conjunction with immune checkpoint inhibitors. Survival was assessed using a Kaplan-Meier survival curve and significance determined using a Log-rank test for comparison analysis. Metastasis was assessed by clonogenic assay. Immune response was assessed by IFN-γ ELISPOT. Cell depletion studies were performed with anti-CD4 and anti-CD8 antibodies. Significance was determined using a student’s t test to compare metastasis and immune responses.

Results

TMV-based immunotherapy in combination with anti-CTLA-4 antibody significantly improved survival, reduced pulmonary metastasis, and increased tumor-specific CD8 T cell responses. Interestingly, either treatment alone failed to have a significant impact on survival, metastasis, or immune response.

Conclusions

These results strongly suggest that a TMV-based immunotherapy in combination with anti-CTLA-4 antibody generates effective antitumor immunity. Such a combinatorial approach could potentially translate into an effective treatment for patients with metastatic TNBC.
Role of miR-142 in regulatory T cell development and regulating immune responses
Authors: Bhela Siddheshvar , Rouse Barry T
Published: January 2023

Regulatory T cells (Treg) are essential for maintenance of self-tolerance and prevention of autoimmune diseases. Although, Treg have been known to be regulated by the transcription factor Foxp3 but role of miRNAs that control Treg is still not yet completely understood. Here, we report that miR-142-deficient mice have reduced number of Treg, but normal development of CD4+Foxp3− T cells both in the thymus and periphery. Interestingly, reduced number of Treg was accompanied by increased frequencies and numbers of Th1 cell responses in the periphery. In addition, we found that miR-142KO T cells showed defective in-vitro Treg cell differentiation. Lastly, we compared the outcome of herpes simplex virus 1(HSV-1) induced immunopathology, Th1 cell orchestrated ocular lesions, in mice unable to express miR-142 because of gene knockout to that of wild-type mice. The miR-142KO mice developed more-severe and earlier stromal keratitis lesions than did infected wild-type animals. This increased disease severity was associated with increased Th1 cell responses in the cornea at day 7pi. Taken together our data suggests that miR-142 is required for normal Treg cell development and that proper regulation of miR-142 is crucial for immunological tolerance.
Modulation of the subcellular localization of T-bet and Eomes alters CD8 exhaustion during chronic LCMV infection
Authors: McLane Laura M , Attanasio John , Huang Alexander C. , Wherry E. John
Published: January 2023

Following acute viral infection, effector CD8 T-cells (TE) differentiate into long-lived memory cells (TMEM) required for secondary viral clearance. Due to persisting antigen in chronic infection, rather than differentiating into TMEM, TE progressively lose their functional abilities and become exhausted (TEX), expressing high levels of the inhibitory receptor PD1. Differentiation into TE, TMEM, and TEX is driven by transcription factors including T-bet and Eomes. In TMEM, T-bet represses PD1 while Eomes drives memory formation. In PD1+ TEX, T-betand Eomes are also expressed leading to the question of how these factors are able to play differing roles in TMEM and TEX. Using the LCMV infection model, we show that T-bet and Eomes are differentially localized during acute and chronic infection where T-bet is more cytoplasmic and Eomes is more nuclear during chronic Clone 13 infection compared to Armstrong. Additionally, nuclear T-bet in TMEM is associated with low PD1 and nuclear Eomes correlates with high PD1 in TEX. Interestingly, a higher Eomes to T-bet ratio in the nucleus correlates with TEX and blocking PD1 during chronic infection reverses this ratio. We also found that post aPD1-treated tumor-infiltrating lymphocytes from human melanoma patients have more T-bet in the nucleus compared to Eomes. Taken together, these data suggest the subcellular localization of T-bet and Eomes impacts exhaustion: nuclear Eomes is associated with high PD1 and nuclear T-bet correlates with low PD1. Importantly, these data also reveal the ratio of nuclear Eomes to T-bet influences CD8 TMEM and TEX formation and blocking PD1 signaling impacts T-bet and Eomes localization suggesting that dampening its expression might be key to reversing exhaustion.
The Influence of Genetic Diversity on Neonatal Respiratory Syncytial Virus Disease
Authors: Siefker David , Williams Robert , Lu Lu , You Dahui , Cormier Stephania
Published: January 2023

Respiratory Syncytial Virus (RSV) is the number one cause of lower respiratory infection in children and is linked to asthma development later in life. After acute infection, some infants develop severe lower respiratory disease that requires hospitalization and can even cause death. This collaborative project aims to identify genetic determinants associated with susceptibility to RSV infection during the neonatal period. Our laboratory has developed a neonatal mouse model of RSV infection to study immunopathology in an age-appropriate manner. Recombinant inbred strains of mice have been extensively sequenced for genetic polymorphisms and are used as a forward genetics approach to identify groups of genes involved in phenotypes of interest, such as disease susceptibility. Here, we utilize the BXD family of recombinant inbred strains of mice with our neonatal RSV infection model to discover genetic loci involved in the susceptibility of neonates to RSV. We show a difference in viral burden in the lungs of neonatal mice between different BXD strains, suggesting a role for genetic variation in RSV susceptibility. Therefore, we have a novel system to identify genetic loci involved in the development of RSV disease. These results will be critical in the development of specific antivirals and vaccines against RSV, which remain elusive despite five decades of research.
Type I interferon suppresses neutralizing antiviral B cell responses by modulating CD8+ T cell differentiation
Authors: Moseman E. Ashley , Wu Tuoqi , de la Torre Juan Carlos , Schwartzberg Pamela L. , McGavern Dorian B
Published: January 2023

Studies have established a role for T cells in resolving persistent viral infections, yet emerging evidence indicates that both T and B cells are required to control some viruses. During persistent infection, a marked lag or failure to generate neutralizing antibodies is commonly observed and likely contributes to an inability to control certain pathogens. Using lymphocytic choriomeningitis virus (LCMV) as a model, we have examined how a persistent viral infection can suppress neutralizing humoral immunity. By tracking the fate of virus-specific B cells in vivo, we report that LCMV-specific B cells were rapidly deleted within a few days of persistent infection, and this deletion was completely reversed by blockade of type I interferon (IFN-I) signaling. Early interference with IFN-I signaling promoted survival and differentiation of LCMV-specific B cells, which accelerated the generation of neutralizing antibodies. This marked improvement in antiviral humoral immunity did not rely on the cessation of IFN-I signaling in B cells but on alterations in the virus-specific CD8+ T cell response. Using two-photon microscopy and in vivo calcium imaging, we observed that cytotoxic T lymphocytes (CTLs) productively engaged and killed LCMV-specific B cells in a perforin-dependent manner within the first few days of infection. Blockade of IFN-I signaling protected LCMV-specific B cells by promoting CTL dysfunction. Therapeutic manipulation of this pathway may facilitate efforts to promote humoral immunity during persistent viral infection in humans. Our findings illustrate how events that occur early after infection can disturb the resultant adaptive response and contribute to viral persistence.
Antibody responses induced to the C1 region of HIV-1 gp120 in acute HIV-1 infection and after vaccination
Authors: Trinh Hung Viet , Pham Peter , Hamlin Christopher , Bose Meera , Tovanabutra Sodsai , Kijak Gustavo , Sanders-Buell Eric , Eller Leigh A. , Alving Carl R. , Kim Jerome H. , Michael Nelson L. , Robb Merlin L. , Rao Mangala
Published: January 2023

Based on the analysis of secondary immune correlates, the RV144 phase III trial demonstrated a reduced risk of infection in vaccine recipients with high levels of ADCC activity and low HIV-1 Env specific plasma IgA antibodies (Abs). Ab responses to the HIV-1 Env constant 1 (C1) region constituted the dominant ADCC Ab response. To further explore the binding Ab profiles and determine differences in the Ab responses to the C1 region (100 amino acids) induced by vaccine versus natural HIV-1 infection, plasma samples from an early acute HIV-1 infection Thai cohort (RV217) and a phase II clinical trial, RV135 (ALVAC prime and gp120 SF2/CM235 boost adjuvanted with MF59) were evaluated by Biacore. Based on the sequencing data from 16 RV217 individuals at 3 time points (week 1, weeks 4–6 and weeks 21–27 post infection), consensus 40-mer C1 peptides with 10-mer-overlapping amino acid sequences were initially screened for binding responses in RV217 and RV135 plasma samples. This was then followed with 16-mer peptides with 8-mer overlapping amino acid sequences to match the viral sequences in individual RV217 patients at these 3 time points. Vaccinees (RV135) induced Ab responses that recognized linear C1 peptides spanning amino acids 31-46, 55-70, 61-76, 77-92, and 85-100, whereas HIV-1 infected individuals (RV217) recognized linear C1 peptides spanning amino acids 1-16, 55-70, and 77-92. Future experiments will examine the functional role of these C1-specific Abs, in particular ADCC activity.
Docosahexaenoic acid improves the decrement in antibody production upon influenza infection in murine obesity through the production of pro-resolving lipid mediators
Authors: Guesdon William , Crouch Miranda , Kosaraju Rasagna , Armstrong Mike , Reisdorph Nichole , Shaikh Saame Raza
Published: January 2023

Obesity is associated with diminished antibody production against influenza infection. Therefore, therapeutic strategies are needed to enhance humoral immunity. We previously demonstrated that essential long-chain n-3 polyunsaturated fatty acids (PUFA) enhance humoral responses to a T-independent antigen. Thus, here we hypothesized that the n-3 PUFA docosahexaenoic acid (DHA) could improve antibody production upon influenza infection in obese mice. To test the hypothesis, mice were fed for 15 weeks with a control or a Western diet with or without DHA supplementation followed by infection with influenza A/Puerto Rico/8/34. The data show that DHA supplementation improved antibody titers, as measured by HAI and microneutralization assays, in obese mice after influenza infection. Mechanistically, DHA did not target B-cell PPARγ or the DHA-sensing G-protein coupled receptor 120 to boost antibody levels. Instead, DHA increased the levels of downstream D-series specialized pro-resolving lipid mediators (SPMs), which are known to increase antibody production through the generation of CD138+ antibody secreting cells. Specifically, LC/MS analyses showed 14-HDHA to be elevated upon DHA intervention, which elevated antibody levels upon infection and increased the frequency of CD138+ cells. Overall, the results suggest that DHA may have potential therapeutic applications for improving humoral immunity, potentially through an SPM mediated mechanism.
B cell response to parvovirus B19 despite abnormal splenic architecture and cytokine/chemokine profiles in patients and animal models with sickle cell disease (SCD)
Authors: Penkert Rhiannon , Hankins Jane S , Dormitzer Philip R , Settembre Ethan C , Tang Li , Sun Yilun , Thomas Paul G , Chandramouli Sumana , Hayden Randall , Wong Susan , Surman Sherri L , Sealy Robert E , Rosch Jason , Dowdy Jola , Young Neal S , Hurwitz Julia L
Published: January 2023

Sickle cell disease (SCD) is caused by a mutant β-globin gene and affects more than 100,000 individuals in the USA alone. Sickled RBCs and ischemic events cause tissue damage, altered splenic architecture, and inflammation. When children are infected with parvovirus B19, they can develop life-threatening aplastic crisis. Previous reports have described immune defects among patients with SCD, and their potential correlations with splenic dysfunction or inflammation. In a multi-center study involving St. Jude, NIH, Novartis, and GlaxoSmithKline, we examined (i) inflammatory cytokines/chemokines in patients with SCD, treated or untreated with hydroxyurea (HU); (ii) immune responses toward parvovirus B19 infections in children with SCD; and (iii) immune responses in a mouse model for SCD against a candidate Saccharomyces cerevisiae-derived parvovirus B19 VLP vaccine. Results showed that HU treatment reduced serum cytokines/chemokines in patients with SCD (e.g. TGFα, TNFα, and sVCAM-1). Both HU-treated and untreated children, regardless of their cytokine/chemokine profile, responded to parvovirus B19. Binding antibodies were apparent in the nasal cavity (a common point-of entry for the pathogen) and sera by day 7 post-infection, and virus-specific neutralizing antibodies were induced. In transgenic mice with SCD (expressing human α, βS, and γ globin genes), we observed normal antibody activities toward the VLP vaccine. Together, data show that parvovirus B19 -specific B cells withstand the aberrant SCD environment better than their previously-described Streptococcus pneumonia-specific B cell counterparts. Data encourage rapid development of the VLP vaccine to prevent aplastic crises in children with SCD.
Acute phase human B cell response after ZIKV infection
Authors: Bhaumik Siddhartha Kumar , Priyamvada Lalita , Kauffman Robert , Mulligan Mark , Wrammert Jens
Published: January 2023

Prior to its emergence in Brazil in 2015, Zika virus (ZIKV) was mainly reported to cause either asymptomatic infections or mild, self-limiting illness. However, the disease pathology of recent epidemics includes neurological complications such as Guillain-Barré Syndrome in adults and congenital microcephaly in neonates. Consequently, there is a pressing need to understand ZIKV pathogenesis and the immunology of ZIKV infections. To this end, we have studied the B cell response in acutely-infected ZIKV patients, both at the serum and at the monoclonal level. Of the several plasmablast-derived mAbs generated, most were specific to the ZIKV envelope. Given the immunological cross-reactivity between ZIKV and dengue virus (DENV), we tested the panel for reactivity against DENV1-4 and found that all ZIKV-reactive mAbs also bound DENV antigens. Interestingly, even though the patients was infected with ZIKV, more mAbs neutralized DENV than ZIKV in vitro. Patient serum showed high ZIKV and DENV IgG binding titers, illustrating that this cross-reactivity was evident at the serum level as well. At the cellular level, the plasmablasts isolated from these patients exhibited high levels of somatic hypermutation, comparable to frequencies seen in secondary dengue cases. Together, these data suggest that the patients may have previously been exposed to DENV, and that the poorly neutralizing mAbs generated after ZIKV infection could be the product of a DENV-derived memory response, suggesting evidence of original antigenic sin (OAS). These findings have important implications from a public health viewpoint, given that a majority of areas currently experiencing ZIKV outbreaks are also DENV endemic.
Autoreactive T-bet+ B-cells promote pathological anemia during infection
Authors: Rivera-Correa Juan , Pardo-Ruge Maria , Gonzalez Sandra , Rodriguez Ana
Published: January 2023

Malaria is still one of leading infectious diseases in the world being a great global health burden. Pathological anemia is one of the most common malaria-associated complications, which accounts to both great morbidity and mortality of the infection. Our lab has recently identified autoantibodies that target the membrane lipid phosphatidylserine (PS) on uninfected erythrocytes as a major promoter of malarial anemia both in a rodent model and correlating with P. falciparum malarial anemia in patients. The aim of this work was to identify the population of B-cells that are responsible for the production of these autoantibodies as well as characterizing the mechanism by which they arise during malarial infection. Our results have identified an atypical population of B-cells expressing the transcription factor T-bet as being major producers of anti-PS antibodies during malarial anemia. Additionally we have identified parasite DNA along with inflammatory cytokine IFNγ as essential signals that synergize to promote the development and appearance of these autoreactive T-bet+ B-cells. Similarly, the lack of any of these signals ameliorated severe anemia during a rodent malarial infection model. We have also identified both expansion of T-bet+ B-cells and production of anti-PS antibodies in ex-vivo cultures of naïve human PBMCs exposed to P. falciprum infected erythrocyte lysates. Lastly, we have also observed the expansion of T-bet+ B-cells correlating with both anti-PS antibodies and anemia during rodent trypanosoma (T. brucei) infection. These results provide mechanistic insights about the appearance of autoimmunity during infection and attribute a role for autoimmunity in contributing to pathology during parasitic infections.
Using magnetic resonance imaging to elucidate the mechanism of experimental cerebral malaria rescue by 6-diazo-5-oxo-norleucine
Authors: Riggle Brittany Anne , Sinharay Sanhita , Hammoud Dima , Munasinghe Jeeva , Slusher Barbara , Powell Jonathan D , Seydel Karl , Taylor Terrie , Miller Louis H. , Pierce Susan K
Published: January 2023

We have previously demonstrated the efficacy of 6-diazo-5-oxo-L-norleucine (DON), a glutamine analog, as a possible adjunctive therapy to mitigate the clinical severity of human cerebral malaria (HCM) (Gordon et al. PNAS 2016). The pathology of HCM is heterogeneous, but generally includes the accumulation of infected red blood cells in the brain vascular endothelium, cerebral microhemorrhages, compromised blood-brain barrier and brain swelling. These changes manifest in severe neurologic symptoms including headache, fever, ataxia, seizures, retinopathy, and coma. The mouse model of CM, experimental cerebral malaria (ECM), approximates the main characteristics of HCM when susceptible C57BL/6 mice are infected with Plasmodium berghei ANKA (PbA) parasites. Studies in these mice found that treatment with DON, even in late stage ECM, rescued animals and increased survival while mitigating and reversing blood-brain barrier dysfunction and brain swelling. Recently, Seydel et al. (NEJM 2015) used magnetic resonance imaging (MRI) to characterize HCM pathology and correlate it to disease severity in children in Malawi. They observed increased brain volume in children that died from HCM that was uncommon in children that survived HCM. Herein, we perform MRI studies in the mouse model to determine if the disease course effectively recapitulates that of HCM, based on morphological changes in MRI. These studies may help elucidate the mechanisms underlying CM pathology, aiding the development of effective treatments. Furthermore, we utilize MRI to probe the mechanisms of action of recovery with DON treatment in order to evaluate the drug for possible clinical trials in HCM.
Constitutive Transcription of the ProIL-1β Gene in Human CCR5+ CD4 T Cells is Distinct from that of Monocytes
Authors: Pulugulla Sree H , Packard Thomas A , Galloway Nicole l.K. , Doitsh Gilad , Adamik Juraj , Galson Deborah L , Greene Warner C , Auron Philip E
Published: January 2023

Transcription of IL-1β activity has been extensively studied in stimulated myeloid cells, but not in lymphoid-derived CD4 T cells, the primary cellular target for infection by HIV. Most CCR5+ CD4 T cells in lymphoid tissues are non-permissive for productive HIV infection and die by Caspase-1-mediated pyroptosis, in which proInterleukin 1β (proIL-1β) precursor is converted to highly active mature IL-1β. It is unclear whether expression of proIL-1β protein in CCR5+ CD4 T cells is derived from active transcription of the IL1B gene, or from previously transcribed mRNA and/or stored protein. Our results reveal that despite very low amounts of IL1B mRNA, CCR5+ CD4 T cells accumulate intracellular proIL-1β protein at levels higher than that of both unstimulated myeloid THP-1 cells and CCR5− CD4 T cells. Further, we observe that the chromatin from CCR5+, but not CCR5− CD4 T cells, contain RNA polymerase II and bivalent H3K4me3 and H3K27me3 nucleosomes at the IL1B promoter, consistent with developmentally regulated constitutive gene expression. This observation contrasts with the rapidly activated and extremely robust H3K4me3 monovalent IL1B gene promoter in TLR4-activated monocytes. This unique phenomenon of CCR5+ CD4 T cells is important to understanding how non-myeloid lineage cells express and release significant levels of IL-1β in the apparent absence of transcription induction.
STAT1 activation represses IL-22 gene expression and psoriasis pathogenesis.
Authors: Bai Li , Xia Sisi , Ochando Jordi , Li Liwu , Xu Jiangnan , Ding Yaozhong
Published: January 2023

IL-22 plays an important role in modulation of tissue repair and inflammatory responses and is implicated in psoriasis, ulcerative colitis, as well as liver and pancreas damage. The molecular mechanisms of its regulation have been actively studied. In our study, STAT1 but not T-bet deficiency resulted in higher levels of IL-22 expression and severer acanthosis in imiquimod-induced mouse psoriasiform skin inflammation, which indicates a critical role of STAT1 in repressing IL-22 gene expression and psoriasis pathogenesis. Quantitative RT-PCR data showed that high levels of IL-22 production were only observed in STAT1 but not T-bet deficient T cells stimulated with anti-CD3 and anti-CD28 in combination with or without IL-6 plus IL-23, further demonstrating that STAT1 but not T-bet is crucial to suppress IL-22 gene expression. There was no difference between STAT1 and T-bet deficiency in activation of transcription factors RORγt, c-Maf, ICOS or AhR, suggesting they do not play significant roles in STAT1 mediated IL-22 inhibition. A STAT binding motif was identified within IL-22 promoter, and CHIP assay showed direct interaction between STAT1 and IL-22 promoters, revealing a novel regulatory mechanism of IL-22 suppression by STAT1. Additional molecular mechanisms of STAT1 mediated IL-22 regulation are currently under investigation.
Transient FOXP3 upregulation protects human conventional T cells from restimulation-induced cell death during activation-induced proliferation
Authors: Voss Kelsey , Snow Andrew L
Published: January 2023

An efficient adaptive immune response relies on the rapid clonal expansion of effector T cells, followed by timely disposal of those cells in order to avoid damage to host tissues. Effector T cell proliferation is constrained by the action of forkhead box P3 (FOXP3)+ regulatory T cells (Tregs) and restimulation-induced cell death (RICD), an apoptotic pathway triggered by repeated stimulation through the T cell receptor (TCR) in the presence of interleukin-2 (IL-2). Constitutive FOXP3 expression renders Tregs resistant to RICD, in part through repression of the signaling adaptor molecule SLAM-associated protein (SAP) and FAS ligand (FASL). Interestingly, FOXP3 is also expressed transiently in human conventional T cells (Tcons) during initial rounds of activation-induced proliferation, but its function in this context remains unclear. Here we uncover a new role for FOXP3 induction in protecting both CD4+ and CD8+ human Tcons from premature RICD during the expansion phase. SiRNA-mediated silencing of FOXP3 sensitized early effector Tcons to RICD. This increase in RICD was completely dependent on de novo transcription, but FOXP3 knockdown did not alter SAP or FASL expression in these cells. Instead, FOXP3 silencing increased glycolysis and reduced autophagy in Tcons, which we and others have linked to changes in apoptosis sensitivity. Surprisingly, FOXP3-dependent autophagy specifically protected CD4+ but not CD8+ Tcons from RICD. Our results suggest a fundamentally different mechanism connecting transient FOXP3 expression to metabolic activity and RICD resistance in CD4+ versus CD8+ T cells.
Influence of age on mycobacterial myocarditis and heart failure
Authors: Rajaram Murugesan , Headley Colwyn , Murphy Nathaniel , Schlesinger Larry S , Mohler Peter J , Turner Joanne
Published: January 2023

Mycobacterium avium complex (MAC) consists of M. avium and M. intracellulare and enters the host primarily through the gastrointestinal track and pulmonary route. MAC is a common cause of mycobacterial infection in immune compromised individuals including, the elderly and those with COPD, HIV/AIDS or cystic fibrosis. The disease symptoms are reminiscent of tuberculosis (TB). Mycobacterium can infect every organ in the body including the heart causing carditis (pericarditis, myocarditis and endocarditis). Myocardial TB is difficult to diagnose and treat and can cause heart failure and ventricular tachyarrhythmia which can ultimately lead to sudden cardiac arrest. Very little is known regarding cardiac dysfunction during mycobacterial infection in the elderly. In this study we examined cardiac electrical activity, cardiac inflammation and fibrosis in young and old mice after 32 days of M. avium infection. The electrocardiogram of old mice shows abnormalities that include sinus node pause and first degree heart block. Thus, we hypothesize that mycobacterial infection leads to increased cardiac inflammation, fibrosis and necrosis which lead to significant electrical disturbances in old mice. The proposed work will identify new molecular mechanisms and key factors that cause sudden cardiac arrest during mycobacterial infection and will thereby provide us with additional strategies to protect the heart from cardiac damage during infection.
Immunologic non-response during HIV infection is characterized by systemic immune activation
Authors: Rousseau Rodney , Choi Yoojin , Lau Elizabeth , Kim Connie J , Benko Erika , Huibner Sanja , Kovacs Colin , Kaul Rupert
Published: January 2023

Introduction

Despite effective treatment HIV infection is characterized by non-AIDS health burdens, linked to immune activation, gut damage and microbial translocation. Some HIV+ individuals achieve viral suppression but do not recover blood CD4 T cells; these immunologic non-responders (INRs) are at elevated disease risk. We hypothesized that INRs have higher immune activation and markers related to gut damage, as compared to HIV+ treatment responders (TRs).

Methods

Thirty-six men who have sex with men (MSM) were recruited through the Maple Leaf Medical Clinic in Toronto. INRs (n=15) were defined as having a CD4 T cell count <350/μl, despite >2 years of HIV suppression. TRs (n=15) had a nadir CD4 T cell count <350/μl, but restored blood CD4 T cell count >350/μl. HIV-negative MSM (n=6) were also recruited. T cell activation (%HLA-DR+CD38+) and other cellular markers were assessed by flow cytometry. Plasma markers of coagulation (D-Dimer), and microbial translocation-associated immune activation (sCD14) were quantified by immunosorbent assay.

Results

INRs had elevated levels of CD8 and CD4 T cell activation compared to TRs (p<0.05). INRs had a reduced CD4/CD8 ratio compared to TRs (p<0.001), and lower CD4 T cell count was associated with elevated CD8 T cell activation (p<0.05). There was a trend towards higher plasma D-dimer levels in INRs compared to TRs (p=0.12).

Conclusion

INR men had a reduced CD4/CD8 ratio, higher levels of systemic immune activation, and a trending elevation in markers of coagulation. These data highlight a need for characterization of tissue-specific gut immune function in the INR context. Ultimately gut-targeted clinical interventions may be useful to mitigate adverse health outcomes in INR individuals.
miR-155 and let-7a potentiate auto-inflammatory and tumor-like proliferative dysregulation in post-infectious Lyme arthritis synovial tissue
Authors: Lochhead Robert B , Strle Klemen , Steere Allen
Published: January 2023

Post-infectious Lyme arthritis (LA) is a model for testing the causal relationship between infection and autoimmunity. The initial trigger for LA, Borrelia burgdorferi infection, is known with certainty, but it is unclear why some patients have persistent synovitis after completion of antibiotic therapy. To elucidate the inflammatory nature of post-infectious LA, whole transcriptome sequencing was performed on synovial tissue from 14 patients with post-infectious LA and compared with that from patients with other forms of inflammatory arthritis or degenerative arthritis. LA patient synovial tissue had a highly inflammatory expression signature, similar to patients with other immune disorders including Type IV hypersensitivity and autoimmune diseases. This profile included upregulation of IFN-responsive genes and genes associated with MHC Class II antigen processing and presentation, T cell activation, and cell-mediated cytotoxicity; and down-regulation of genes involved in tissue repair and cell metabolism. Fibroblasts isolated from synovial tissue and primary fibroblasts in vitro expressed markers of inflammation and active proliferation, consistent with the tumor-like proliferative nature of the synovial lesion. miR-155, a proinflammatory and oncogenic microRNA, was highly expressed and positively correlated with markers of inflammation and Class II antigen presentation. Expression of tumor suppressor let-7a was downregulated, negatively correlated with markers of inflammation, and positively correlated with markers of appropriate wound repair. We postulate that these two microRNAs potentiate epigenetic transformation of synovial fibroblasts into an auto-inflammatory and proliferative phenotype.
Trauma, stress, and HIV-associated immune cell levels in women
Authors: Kohlmeier Alison , Haddad Lisa B , Haaland Richard E , Brown Nakita L , Lupo L. Davis , Mehta Christina B , Sheth Anandi N , Titanji Kehmia , Hart Clyde E , Ofotokun Igho
Published: January 2023

Lifetime trauma, stress exposure, and current perceived stress are believed to lower immune responsiveness to infections but their effect on immune cell targets of HIV infection and pathogenesis are not known. We examined lifetime trauma and current perceived stress for associations with HIV target cells in genital mucosa and PBMC from 50 STI negative women of reproductive age. Validated scores for the number of traumatic exposures on the lifetime trauma and victimization history (LTVH) instrument, the 51-item Chronic Stress Scale (CSS) and the 10-item current perceived stress scale (PSS) were compiled. Paired cervicovaginal lavage (CVL) and blood samples were analyzed for T cell expression of CCR5 and activation markers (CD38, HLA-DR). Spearman correlations were used to evaluate associations between T cell subsets and LTVH, CSS, and PSS scores. LTVH number correlated with PBMC CD4/CD8 ratios and CCR5+ expression on CCR7+ CD4 T cells, but were inversely correlated with effector memory T cell frequency; CSS score was correlated CCR5+ expression on CCR7+ CD4 T cells. PSS scores were not correlated with T cell phenotypes. Genital tract T cell subsets were highly variable and not correlated with LTVH, CSS, or PSS scores. These findings suggest that increased lifetime trauma and chronic stress exposure is associated with shifts in circulating T cell populations that influence HIV susceptibility and its long-term pathogenesis. A better understanding of how lifetime trauma/stress exposure may affect immunologic mediators of HIV susceptibility, biomedical prevention efficacy, and HIV disease progression is warranted.