bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficacy evaluation of B cell targeting drugs and the involved mechanism of action study in humanized BAFF transgenic SLE mice model
Authors: Liang Juan , Xu Shuxin , Xu Qiuping , Zhang Yuxi
Published: November 2024

The B cell activating factor (BAFF) functions as a crucial factor in B cell survival, and heightened BAFF expression can augment the presence of autoreactive B cells, thereby fostering autoimmunity like Systemic Lupus Erythematosus (SLE). This study introduces transgenic mouse strains with human BAFF overexpression, offering insights into SLE mechanisms and B cell-targeting therapies.

Human BAFF overexpression in B6-hBAFF mice led to a substantial rise in Igs and anti-dsDNA levels from 6 weeks of age, persistently escalating with time compared to wild-type mice. A heightened population of B cells but a reduced ratio of T cells was observed. At week 25 of age, B6-hBAFF mice developed lupus nephritis.

Belimumab, a BAFF antibody administrated to BAFF transgenic mice demonstrated the effectively reduced serum antibody levels after 16 weeks of dosing. Belimumab ameliorated kidney function by decreasing urine albumin-to-creatinine ratio and IgA deposition after 20 weeks of treatment. Mice were also treated with Enpatoran (TLR7/8 inhibitors) and BTK inhibitor Orelabrutinib. Only the BTK inhibitor Orelabrutinib significantly eliminated serum Igs levels. Enpatoran exhibited a similar ability to Orelabrutinib in reducing T follicular helper cell and plasma cell populations spleen and lymph nodes.

In summary, the humanized BAFF transgenic SLE model proves to be a valuable tool for preclinical efficacy studies in SLE treatment and understanding pathogenesis.
Pharmacological activation of LANCL2 ameliorates disease severity and decreases inflammation in a preclinical model of rheumatoid arthritis
Authors: Tubau-Juni Nuria , Hontecillas Raquel , Leber Andrew , Bassaganya-Riera Josep
Published: November 2024

Lanthionine synthetase C-like 2 (LANCL2) is a novel immunoregulatory therapeutic target for the treatment of autoimmune diseases. Activation of LANCL2 enhances Treg responses through engagement of immunometabolic pathways and interactions with IL2/CD25 signaling, while downregulating effector cell subsets. An impaired Treg compartment has been proposed as one of the key contributors to the pathogenesis of rheumatoid arthritis (RA). We have developed NIM-1324, an oral, once-daily, highly systemically distributed small-molecule first-in-class therapeutic that selectively activates LANCL2 with a benign safety profile. We evaluated the therapeutic efficacy of oral NIM-1324 in a collagen-induced arthritis (CIA) mouse model of RA. Oral daily treatment with NIM-1324 significantly reduced disease activity, including paw redness and swelling, and pathology compared to the vehicle group. Furthermore, activation of LANCL2 by NIM-1324 decreased systemic inflammation, reducing IL-17+ and IL-21+ CD4+ T cells plus TNF-producing myeloid cells while the Tregs compartment was enhanced. LANCL2 deficiency in mice resulted in increased disease severity, inflammatory pathology and frequency of inflammatory subsets, including Th17 and Th1 cells. In human peripheral blood mononuclear cells, NIM-1324 decreased secretion of inflammatory mediators. This data supports that the pharmacological activation of LANCL2 by NIM-1324 is a promising therapeutic approach for the treatment of RA.
GAIA-102 cells, an off-the-shelf and highly activated NK-like cell product, elicit endogenous immune cell responses in solid tumor model
Authors: Zheng Situo , Harada Yui , Morodomi Yosuke , Yonemitsu Yoshikazu
Published: November 2024

[Background] We have developed a novel method for generating highly activated NK-like cells (GAIA-102) from mixed peripheral blood mononuclear cells. Currently, three Phase I clinical trials are being conducted on patients with solid tumors. In preclinical studies, GAIA-102 has demonstrated two anti-tumor mechanisms in preclinical studies: significant mass reduction and the establishment of anti-tumor-acquired immunity. However, the underlying mechanism remains to be elucidated. This study aims to understand the interaction between GAIA-102 and the host immune response. [Methods]CT26-GFP cells were intraperitoneally injected into Balb/c mice, followed by intraperitoneal administration of GAIA-102 with IL-2. After one or three treatment cycles, spleens were harvested and manually dissociated and then analyzed by flow cytometry to evaluate antigen-presenting cells(APCs) , including conventional dendritic cells (cDC) and macrophages. Additionally, CD4+ and CD8+T cells were isolated for CT26-specific T cell response Enzyme-Linked Immunospot (ELISPOT) assay. [Results]The treatment with GAIA-102 resulted in a substantial increase in cDC counts and induced a shift in the M1 macrophage phenotype. ELISPOT assays demonstrated dose-dependent enhancements in CT26-specific T lymphocytes(CTLs) response in GAIA-102 treated mice. [Conclusion] GAIA-102 therapy can stimulate the recruitment of effector APCs and enhance the CTLs response, aligning with our preclinical findings.
Complement signaling as a T-cell checkpoint in the ovarian cancer (OC) tumor microenvironment (TME)
Authors: Giridharan Thejaswini , Suzuki Sora , Khan ANM Nazmul , Emmons Tiffany , Yaffe Michael , Kolev Martin , Deschatelets Pascal , Kemper Claudia , McGray AJ Robert , Zsiros Emese , Segal Brahm
Published: November 2024

T cell checkpoint pathways are barriers to anti-tumor immunity and critical therapeutic targets. We use ascites fluid supernatants (ASC) from patients with newly diagnosed OC as an authentic component of the TME. We previously showed that complement activation is increased in ASC versus paired serum and induces a suppressor phenotype in normal neutrophils characterized by inhibition of critical proliferative, signaling and metabolic pathways in normal human T cells. ASC by itself dramatically inhibited CD3/CD28-stimulated T cell cytokine production (IL-2, IFN-γ, and IL-10) and glucose consumption, but not proliferation. We hypothesized that complement activation in the TME delivers an inhibitory stimulus to T cells that suppresses stimulated cytokine responses required for activation and expansion. Peptide C3 inhibitors (compstatins) restored CD3/CD28-stimulated T cell cytokine responses and glucose consumption. Inhibition of Factor B, a component of the alternative pathway (AP), also rescued cytokine responses, while inhibition of C3aR, C5aR, and C7 had no significant effect. C3b/iC3b deposition on T cells was increased with ASC exposure and reduced by C3 inhibition. Addition of recombinant complement receptor-1 (CR-1) as a decoy of C3b binding to membrane-bound CR-1 fully abrogated the suppressive effect of ASC, while recombinant CD46 had variable effects among different ASC samples. Our results show a novel AP- and CR1-dependent checkpoint of T cell activation in the TME.
Longitudinal Analysis of HIV-1 Fusion Peptide-Directed Neutralizing Response in a Vaccinated Macaque Following SHIV Infection
Authors: Hwang Juyun , Wang Hua , Dal Santo James , Howe Colin , Cheng Cheng , Doria-Rose Nicole , Shaw George , Koup Richard , Mascola John , Kwong Peter , Pierson Theodore
Published: November 2024

A promising direction of HIV-1 vaccine research has been eliciting fusion peptide (FP)-directed broadly neutralizing antibodies. To investigate if a potent FP-directed neutralizing response could be induced, 10 macaques were infected with simian-human immunodeficiency virus (SHIV) after immunization via FP priming and envelope trimer boosting. While the FP-directed neutralizing responses for some of the macaques dramatically increased within 8 weeks of SHIV infection, another macaque, JC69, displayed a potent cross-clade neutralizing response that grew in magnitude in the year following experimental SHIV infection. To characterize the immune response in JC69, anti-FP and -trimer ELISA, FP competition neutralization, and FP-specific B cell phenotyping analyses were performed longitudinally. FP-directed neutralizing response remarkably increased from week 32 to 68 post-SHIV infection and remained high until week 136. Furthermore, the proportion of FP-specific B-cells greatly expanded from week 32 to 68 post-SHIV infection. Overall, a potent cross-clade FP-directed neutralizing response was elicited in JC69 that peaked more than 1 year after SHIV infection. To better understand the mechanism of this late response, future directions will include the characterization of FP-directed monoclonal antibodies and viral RNA sequencing to map antibody-SHIV coevolution. Immunization to elicit site-specific neutralizing antibodies may be a key component of effective HIV vaccine strategies.
Exploring the spatiotemporal cellular dynamics of draining lymph nodes during primary and secondary SARS-CoV-2 infection recovery
Authors: Oh Taehwan , Woo YoungMin , Kim Green , Baek Seung Ho , Koo Bon-Sang , Hwang Eun-Ha , An You Jung , Kim Dong-Yeon , Kim Yujin , Hong Jung Joo
Published: November 2024

While lymph node structures may experience compromise in severe SARS-CoV-2 infections, the extent of recovery in convalescent individuals remains a critical exploration. Our study aims to unravel the nuances of structural recovery, germinal center (GC) dynamics, and their implications for long-term immune memory in non-human primates recovered from SARS-CoV-2. Here, we utilized a Xenium In-situ (10x Genomics) to delineate the immune cell composition and mediastinal lymph node architecture in COVID-19 macaque lungs across primary infection, convalescence, and secondary infection. Noteworthy findings include an increase in follicular helper T cells, GC B cells and plasmablasts within lymphoid follicles during convalescence. In the paracortex, secondary infection results in a decrease in cytotoxic T cells but an increase in follicular helper T cells. In the medulla, a reduction in macrophages is observed, accompanied by increased conventional and plasmacytoid dendritic cells, GC B cells and plasmablasts during secondary infection. This study not only enhances our understanding of GC formation during COVID-19 recovery but also provides insights into immune cell repopulations within draining lymph nodes following secondary infection. These findings have the potential to inform the optimization of vaccine strategies and the design of precise therapeutic interventions.
Humoral correlates of protection against influenza A H3N2 virus infection
Authors: Hoy Gregory , Stadlbauer Daniel , Balmaseda Angel , Kuan Guillermina , Lopez Roger , Ojeda Sergio , Sanchez Nery , Plazaola Miguel , Krammer Florian , Gordon Aubree
Published: November 2024

Background: Gaps remain in our knowledge of the humoral correlates of protection against influenza A/H3N2, including the role of antibodies against the hemagglutinin stalk, a highly conserved but immunologically sub-dominant region.

Methods: Two household studies were conducted in Managua, Nicaragua. Household contacts were tested for influenza using RT-PCR. We compared pre-existing antibody levels against full-length hemagglutinin (FLHA), HA stalk, and neuraminidase (NA) measured by ELISA, along with initial HA inhibition assay (HAI) titers, between infected and uninfected participants.

Results: A total of 899 individuals participated in household activation during three A/H3N2 seasons with 329 infections occurring. A four-fold increase in initial HA stalk titers was independently associated with an 18% decrease in the risk of infection (OR=0.82, 95%CI 0.68-0.98, p=0.04). In 0-14-year-olds, anti-NA antibodies (OR=0.67, 95%CI 0.53-0.85, p<0.01) were associated with protection, but anti-HA stalk antibodies were not. In adults, anti-HA stalk antibodies were independently associated with protection (OR=0.72, 95%CI 0.54-0.95,p=0.02).

Conclusions: The HA stalk is an independent correlate of protection against A/H3N2 infection, though this protection is age dependent. This supports the continued exploration of the HA stalk as a target for broadly protective influenza vaccines and suggests that the protective benefits may depend on age and influenza exposure history.
Sphingosine kinase 2 suppresses neutrophil responses while attenuating immune pathology during a persistent viral infection
Authors: Vijayamahantesh Vijayamahantesh , He Ying , Studstill Caleb , Jung Kwang Il , McKenna Savannah , Allen Lee-Ann , Hahm Bumsuk
Published: November 2024

During chronic virus infections, the functions of immune cells are often suppressed which may restrict immune pathology but lead to viral persistence. However, the underlying mechanisms are incompletely understood. Sphingosine kinase 2 (SphK2) generates sphingosine 1-phosphate, a bioactive lipid mediator, and mediates diverse cellular processes. We have recently found that SphK2-deficient mice succumb to infection by lymphocytic choriomeningitis virus (LCMV) clone 13 (Cl 13) due to immune pathology associated with nephropathy. Heightened T cell immunity was crucial for infection-induced mortality of SphK2 KO mice. However, in addition to T cell immunity, a notable increase of neutrophils was observed in multiple tissues as well as blood of LCMV-infected SphK2 KO mice. Importantly, SphK2-deficient neutrophils expressed substantially lower levels of the immune suppressive marker CD244 and produced higher amounts of ROS compared to SphK2-sufficient neutrophils upon infection. Depletion of neutrophils from SphK2 KO mice increased the viability of infected mice. Further, adoptively transferred SphK2-deficient neutrophils improved virus-specific T cell responses in wild type mice when compared to the transferred SphK2-sufficient neutrophils. The results indicate that SphK2 inhibits neutrophil expansion and function, contributing to the immune regulation during a persistent virus infection. The study may help to design new immune therapeutics to control viral diseases.
A virtual memory T cell–originated CD44s-hiCD49dlo CD8+ T cell subset confers immune protection against respiratory viral infections
Authors: Cho Sung-Dong , Choi Yunseo , Kim Hawon , Seok Joon , Shin Eui-Cheol , Park Su-Hyung
Published: November 2024

Virtual memory CD8+ T (TVM) cells, exhibiting a memory phenotype without foreign antigen exposure, exert protective immunity against viral and bacterial infections. However, a TVM-originated distinct CD8+ T cell subset (CD44super-hi (s-hi)CD49dlo CD8+ T cells) induces pathogenesis of a chronic inflammatory disease (alopecia areata (AA)) by NKG2D-mediated innate-like cytotoxicity (Nat. Immunol. 24(8):1308-17 (2023)). Notably, these pathogenic cells were also residing in the lungs. Therefore, in this study, we aimed to investigate the distinct immune characteristics of lung-infiltrated CD44s-hiCD49dlo CD8+ T cells in AA mice and their protective roles against respiratory viral infections.

In AA mice, the lung-infiltrated CD44s-hiCD49dlo CD8+ T cells exhibited tissue-resident features, lower NKG2D expression, and less cytotoxicity than those in the skin. In AA mice with influenza A virus infection, the lung CD44s-hiCD49dlo CD8+ T cells showed increased NKG2D expression and cytotoxicity. Finally, CD44s-hiCD49dlo CD8+ T cells in the lungs of AA mice conferred immune protection against influenza virus infection, evidenced by a significantly improved survival rate and less body-weight loss.

Collectively, our results elucidate the two-sided roles of TVM cells. The ambivalent aspects of CD44s-hiCD49dlo CD8+ T cells originated from TVM cells provide a solid rationale for the continuing investigation of TVM cells in immune protection and disease.
PD-1 mediates brain resident memory T cell formation and virus control
Authors: Butic Arrienne , Lauver Matthew , Lukacher Aron
Published: November 2024

Programmed cell death protein 1 (PD-1) is upregulated in T cells of patients with progressive multifocal leukoencephalopathy (PML), a demyelinating disease caused by infection of the central nervous system (CNS) by JC polyomavirus (JCPyV). Studies have exhibited variable success in treating PML with PD-1 blockade, denoting a need to understand the function of PD-1 in polyomavirus CNS infection. PD-1 is highly expressed on functional CD8 T cells in the brain after intracerebral inoculation of mouse polyomavirus (MuPyV), which we use to model JCPyV CNS infection. We hypothesized that PD-1 signaling on CD8 T cells regulates the differentiation of virus-specific brain resident-memory T cells (bTrm). Using an inducible global PD-1 knockout mouse model, we show that deleting PD-1 during acute MuPyV infection results in the transition of virus-specific CD8 T cells toward a more resident-memory-like phenotype. PD-1 deletion during persistent infection results in higher T cell counts as well as reduced viral loads. To clarify the effects of CD8 T cell-specific PD-1 signaling, we adoptively transferred inducible PD-1 knockout CD8 T cells into recipient mice. In contrast to global deletion, CD8 T cell-specific loss of PD-1 led to a lower frequency in resident-memory-like cells. These data suggest that acute global PD-1 loss promotes bTrm formation, which may be independent of PD-1 signaling on CD8 T cells, and that PD-1 loss during persistent infection may promote better viral control.
Molecular mechanism of CD14+ human monocyte/macrophage activation by Ebola virus protein VP40
Authors: Singh Karnail , Le Hung , Ding Lingmei , Waggoner Stephen , Spearman Paul
Published: November 2024

Impaired functions of many innate immune cells have been implicated in Ebola virus disease (EVD) pathogenesis. Previously, we reported that CD14+ accessory cells are required for the optimal Ebola virus protein VP40-induced activation of human natural killer (NK) cells. In the current study, we explored the molecular mechanism(s) of VP40-induced activation of CD14+ accessory cells and their role in triggering NK cell activation. Human PBMCs, purified CD14+ myeloid cells or CD14+ cell and CD56+ NK cell co-cultures were incubated with VP40, mCherry-VP40 fusion protein or virus-like particles (VLPs) containing it and binding, internalization, and distribution of VP40 analyzed by flow and confocal microscopy. Molecular pathway(s) triggered in CD14+ cells and the resulting gene expression changes were analyzed by flow, western blotting, luminex and RNA-Seq. Ebola VP40/VLPs bound to and were internalized by classical, intermediate and non-classical monocytes but to varying degrees. VP40 triggered activation of NF-kB and inflammatory pathways in CD14+ cells resulting in their enhanced secretion of multiple cytokines and factors. IL-12 or IL-18 blockade partially abrogated VP40-induced, CD14+ cell dependent activation of NK cells. Taken together, our data suggests that activation of CD14+ cell by Ebola VP40/VLPs can rapidly trigger NK cells that, in turn, may eliminate Ebola virus infected host cells, findings that may help in designing better anti-Ebola countermeasures.
T-bet+ B cell-deficiency enhances obesity-driven autoantigen- and T-dependent humoral immunity
Authors: Leadbetter Elizabeth , Vanz Carlo , Enslow Benjamin , Liendo Nathaniel , Dudley Elizabeth
Published: November 2024

The recent pandemic provided a stark example of the deadly consequences of humoral immune suppression during infection or following vaccination in obese patients. Unfortunately, the mechanism of this inhibition remains unknown. We recently showed that T-bet+ B cells increase in lymphoid organs and adipose tissue during obesity and exacerbate metabolic dysfunction through antibody production, especially in female mice. Here, we report that autoreactive IgG antibodies in obese mice exist largely as autoantigen-bound immune complexes. T-bet+ B cells express elevated levels of antigen presenting molecules and scavenger receptor CD36, positioning them to efficiently uptake lipid antigens and productively engage T helper cells. Flow cytometry shows that during obesity CXCR5+ TFH and CXCR5- TPH cells expand in the spleen and liver, respectively, providing a ready source of help. T-bet+ B cell-deficient obese mice lack IgG2a but have expanded IgG2b and IgG3 antibody titers. Unexpectedly, they also develop expanded GC B cells, class switched B cells, and antibody secreting B cells compared to intact obese or lean controls. Furthermore, T-bet+ B cell deficient mice also make an enhanced humoral GC B cell response to NP-KLH/alum vaccination, suggesting that obesity-expanded T-bet+ B cells skew the immune response away from protective immunity. This may provide a much-needed explanation for reduced humoral immunity observed in obese patients.
IL-22 binding protein promotes macrophage phagocytosis during lung injury.
Authors: Chakawa Mazvita , Zhang Zhe , Allen Michaela , Pociask Derek
Published: November 2024

Interleukin 22 binding protein (IL-22BP) is a soluble receptor predominantly produced by myeloid and epithelial cells. While the only documented function of IL-22BP is regulation of IL-22 activity, our new data suggests IL-22BP is involved in macrophage function and phagocytosis independent of IL-22.

We found that IL-22BP knock out (IL-22BPKO) mice had greater pulmonary injury and elevated inflammatory macrophages compared to wildtype mice in a bleomycin injury model. Clodronate ablation of macrophages demonstrate limited ablation in IL-22BPKO mice. In-vitro phagocytic assays using fluorescent beads revealed a phagocytic defect in IL-22BPKO macrophages. This defect appeared independent of IL-22 as there were no differences in bead uptake in macrophages derived from IL-22 receptor knock out mice. Immunohistochemistry showed less foamy macrophages in IL-22BPKO mice compared to wildtype mice. Foamy macrophages are important in clearance of cellular debris during lung injury. We assessed expression of lipid recognition receptors using RT-qPCR. Our data shows reduced expression of macrophage scavenger receptor 1, scavenger receptor 1, lectin type oxidized LDL receptor and transcription factor peroxisome proliferator-activated receptor gamma in IL22BPKO mice.

Taken together, these data suggest lipid uptake is compromised in IL-22BPKO-derived macrophages and demonstrates that IL-22BP may have a novel role in lipid recognition and macrophage function.
A novel lentiviral vector-based approach to generate CAR T cells targeting Aspergillus fumigatus
Authors: Kumaresan Pappanaicken , Wurster Sebastian , da Silva Thiago , Bavasi Karishma , Albert Nathaniel , Hauser Paul , Neelapu Sattva , Kontoyiannis Dimitrios
Published: November 2024

Invasive aspergillosis (IA) is a common and deadly mold infection in immunocompromised patients. As morbidity and mortality of IA are primarily driven by poor immune defense, adjunct immunotherapies, such as chimeric antigen receptor (CAR) T cells, are direly needed. Here, we propose a novel approach to generate Aspergillus fumigatus (AF)-CAR T cells using the scFv domain of AF-269-5 mAb and a lentiviral vector system. These cells successfully targeted mature hyphal filaments of representative clinical and reference AF isolates and elicited potent release of cytotoxic effectors and type 1 T-cell cytokines. Furthermore, AF-CAR T cells generated from peripheral blood mononuclear cells of four healthy human donors and expanded with cytokine stimulation (IL-2, IL-7+IL-15) regimens significantly suppressed mycelial growth of AF-293 after 18 h of co-culture. Moreover, cyclophosphamide-immunosuppressed NSG mice with invasive pulmonary aspergillosis that received two doses of 5 million AF-CAR T cells on days 0 and 2 after AF infection showed significantly reduced morbidity on day 4 post-infection (p<0.001) and significantly improved 7-day survival (p=0.049) compared to mice receiving non-targeting control T cells. In conclusion, we developed a novel lentiviral strategy to obtain AF-CAR T cells with high targeting efficacy, yielding significant anti-AF activity in vitro and short-term protection in vivo.
Novel highly immunogenic DNA vaccine regimen potently activates lymph nodes in macaques.
Authors: Felber Barbara , Moussa Maha , Karaliota Sevasti , Rosati Margherita , Devasundaram Santhi , Goldfarbmuren Katherine , Bear Jenifer , Burns Robert , Khandhar Amit , Reed Steven , Pavlakis George
Published: November 2024

Background

We evaluated a novel DNA vaccine delivery by LION™ nanoparticles for its ability to induce innate and adaptive immune responses in Rhesus macaques.

Methods

CoV-2 Spike or HIV Env DNA were formulated with a cationic nanocarrier (Lipid InOrganic Nanoparticle; LION™) administered via the IM route. Chemokine/cytokine and vaccine-specific responses were monitored in blood and lymph nodes (LN) by proteomics, flow, antibody assays.

Results

DNA/LION™ induced strong cellular and higher humoral responses than DNA/Electroporation and induced rapid (4-24hr) transient innate responses. Flow analysis showed activation of T, B, myeloid incl. dendritic cells in blood and their trafficking to LN with a strong increase of Tfh, Germinal Center Tfh CD4 and CD8 cells. Cell subsets were activated by cytokine networks incl. CXCL11, IL-7 and IL-15. GC-B cell activation directly correlated with increase of FLT3L and CXCL12 and importantly with antibody levels.

Conclusion

DNA/LION™ led to robust induction of cellular and humoral responses against different immunogens, serving as promising platform of effective nucleic acid vaccine delivery. Transient cytokine responses, incl. IL-15, resulted in strong activation of draining lymph nodes, and contributed to shaping adaptive (cellular and humoral) immunity. Our data showed rapid and coordinated cytokine responses to the vaccine and highlight the important role of innate responses to vaccination in modulating adaptive immunity.
Early life exposure to Candida albicans disrupts regulatory T cells
Authors: Crozier Shaunessey , Greenfield Kara , Avni Joshi , Knoop Kathryn
Published: November 2024

Fungal species are immunogenic members of the commensal microbiota, on the skin and the intestine. Opportunistic Candida albicans is associated with numerous allergic disorders, like atopic dermatitis, with ~90% of cases diagnosed by age 6. With an increased lifetime risk to other allergic disorders, C. albicans exposure in early life may contribute to the development of allergic-type responses. Premature infant stool sequencing found frequent C. albicans colonization suggesting colonization in the human GI tract. Previous observations found mice exposed to C. albicans prior to, but not post, weaning maintain colonization into adulthood. Neonatal colonization of C. albicans in the intestine, resulted in long term colonization and presented significantly decreased FoxP3+ T regulatory cells (Tregs) post-weaning in the mesenteric lymph nodes, small intestine, and colon lamina propria (LP). Additionally, RORγt+ and C-MAF+ Th17-cells were increased in the LP. By comparison, adult exposure to C. albicans through the skin or intestine, showed no disruption of FoxP3+ Tregs, suggesting neonatal exposure to C. albicans may be more disruptive to developing Tregs. Future research will focus on the impact of C. albicans presence to early microbiota complexity and diversity development. Treg establishment in early life is vital for tolerance and maintenance of commensal organisms, thus Treg disruption potentially links C. albicans colonization towards the development of allergic responses.
Mechanisms of TFR cell-mediated regulation of microbiota-reactive IgA responses
Authors: Abdi Abdullahi , Dent Alexander
Published: November 2024

The rising prevalence of food allergies impacting over 10% of the U.S. population requires innovative diagnostic approaches and therapeutic interventions. Gut microbiota alterations play a crucial role in food allergy development, with immunoglobulin IgA (IgA) actively regulating gut microbiome composition. While T follicular helper (TFH) cells aid in high-affinity antigen-specific IgA production, T follicular regulatory (TFR) cells' role in generating microbiota-specific IgA remains unclear. Using a unique TFR cell-deficient mouse model (Bcl6FC) and flow cytometry staining, we found increased fecal IgA-coated bacteria over time in Bcl6FC compared to WT mice after sensitization. IgA-seq revealed differential baseline microbiota IgA-coating in naïve Bcl6FC, displaying increased alpha diversity and more taxa with higher relative abundance than WT mice. Calculating the IgA-index demonstrated elevated IgA binding in Bcl6FC mice to specific taxa, primarily Firmicute members, indicating TFR cells' suppression of taxon-specific IgA in the peanut allergy model. Ongoing experiments, including the adoptive transfer of WT TFR cells into Bcl6FC mice and the assessment of IgA-coated biome function via Fecal Microbiota Transplantation (FMT) into germ-free mice in a peanut allergy model, aim to validate TFR cells' role in generating microbiota-specific IgA responses. This contributes essential insights for potential therapeutic antibodies targeting specific commensals.
The inhibitory effects of Hispidulin on mast cell-mediated allergic airway inflammation
Authors: Lee Soyoung , Jeong Seungwon , Park Chul-Kyu , Kim Sang-Hyun
Published: November 2024

Allergic asthma is a type 2 immune-response-mediated chronic respiratory disease. Recent studies have shown that mast cell activation influences the development and aggravation of allergic asthma. Therefore, the development of mast cell-targeting pharmacotherapy is important for regulating allergic airway inflammation. We investigated the efficacy of hispidulin (HPD) – natural flavone – in a mast cell-mediated ovalbumin (OVA)-induced allergic airway inflammation model. HPD alleviated symptoms of allergic asthma, mast cell infiltration, and reduced the levels of eosinophil peroxidase, β-hexosaminidase, and type 2 cytokines (IL-4, IL-5 and IL-13) in the bronchoalveolar fluid (BALF) and the level of immunoglobulins in serum. Furthermore, we confirmed the efficacy of HPD through the evaluation of IgE-mediated allergic responses in a mast cell line. HPD treatment inhibited mast cell degranulation through inhibition of the FcεRⅠ signaling pathway, and suppressed the expression of inflammatory cytokines (TNF-α, IL-4, IL-6, and IL-13) through suppression of the NF-κB signaling pathway. In addition, the antioxidant effects of HPD in activated mast cells were identified through modulation of antioxidant enzymes (SOD, Catalase) and the Nrf2/HO signaling pathway. In conclusions, HPD is a potential therapeutic candidate for allergic airway inflammation of asthma and acts by suppressing mast cell activation and oxidative stress.
SREBP signaling is important for pathogenic B cell responses in allergy.
Authors: Maldeney Alexander , Jiang Wenxia , Luo Wei
Published: November 2024

Severe IgE antibody-mediated allergic conditions impacts millions worldwide, significantly influencing both the survival and quality of life of those affected. Our previous research indicated the critical role of sterol regulatory element-binding protein (SREBP) signaling in mediating lipid homeostasis during B cell activation and the formation of germinal centers following immunization and viral infection. However, it remained unclear whether this pathway is also involved in the pathogenic B cell responses triggered by chronic allergen sensitization. Our latest findings show that ablation of SREBP signaling in B cells doesn't affect overall IgE levels in the serum. However, during chronic sensitization to house dust mites (HDM), SREBP signaling was essential for allergen-triggered germinal center responses and pathogenic antibody production. These results suggest the potential of targeting the B cell SREBP pathway as a treatment approach for allergies.
Peptide DMS-DA6 have immunomodulatory effects in a mouse model of actinomicetoma by N. brasiliensis
Authors: Duarte Diana , Rosenstein Yvonne , Vazquez-Marmolejo Anna , Mejia-Torres Manuel , Auvynet Constance , Salinas-Carmona Mario
Published: November 2024

Actinomycetoma is an infectious disease recognized by the World Health Organization as a neglected tropical disease. In the Americas, the most common etiologic agent is the Gram-positive bacteria, Nocardia brasiliensis. Current treatment is prolonged, toxic and resistant strains have emerged. A promising solution is the use of host defense peptides, which are recognized for their bactericidal activity and ability to control infection by modulating the host immune system. Recently, the peptide DMS-DA6, a dermaseptin from the skin of the frog Pachymedusa dacnicolor, was reported to be bactericidal against Gram-positive bacteria. However, the function of the DMS-DA6 in host defense against infection remains unknown. In this study, we investigated the in vivo properties and effects of DMS-DA6 in a mouse model of actinomicetoma by N. brasiliensis. After peptide administration, a significant reduction in the volume of the affected limb was observed; furthermore, flow citometry showed that DMS-DA6 modified systemic leukocyte populations, such as monocytes/macrophages, neutrophils and CD8+ T lymphocytes were significantly reduced in spleen and peripheral blood. Interestingly, the combination of DMS-DA6 with the antibiotic linezolid had the opposite effect, significantly inducing CD4+ and CD8+ T lymphocyte influx into the spleen. These results suggest that the peptide DMS-DA6 is a promising alternative approach and a valuable addition to the current anti-infective strategy.
A Role for NOD2 in Intestinal Memory T cell Formation and Function
Authors: Tsankov Boyan , Carr Charles , Nathan Nayanan , Bayer Giuliano , Philpott Dana
Published: November 2024

Aberrant resident memory T cell (TRM) responses have been associated with increased intestinal inflammation and Crohn’s disease (CD) pathology in humans. Genetic mutations in NOD2 are associated with the highest risk of CD development. NOD2 has been shown to be critical for initiating adaptive immune responses at systemic sites. However, the role of NOD2 in establishing memory T cell responses in the intestine remains unclear. Using an acute model of LCMV infection, we interrogated the role of NOD2 in intestinal memory T cell generation and function. Littermate wildtype or NOD2-deficient mice were infected intraperitoneally with LCMV-Armstrong, and the intestinal T cell priming, effector, and memory T cell responses were profiled in the mesenteric lymph nodes (mLN) and small intestinal lamina propria (SILP). Augmented NOD2 signalling at homeostasis and during infection increased endogenous and LCMV-specific CD4+ T cell numbers in the mLN, but not in the spleen. This effect was due to a NOD2-dependent increase in T cell homing to the mLN. Furthermore, NOD2-deficiency resulted in decreased effector and memory T cell numbers in the SILP. This effect was associated with decreased memory T cell functions in NOD2-deficient mice during ex vivo and in vivo recall experiments. Taken together, our experiments suggest a role for NOD2 in mediating optimal T cell priming in the mesenteric lymph nodes, which later affects effector and memory T cell functions in the intestine.
Host-pathogen interactions in Leptospirosis
Authors: Gupta Suman , Matsunaga James , Haake David , Sutterwala Fayyaz , Cassel Suzanne
Published: November 2024

Leptospirosis is an emerging zoonotic disease, predominant in tropical and sub-tropical climates, with increasing sporadic outbreaks worldwide causing around 60,000 deaths per year. The spirochetal bacteria Leptospira interrogans is the major causative agent of leptospirosis. Canines and livestock animals are particularly susceptible to Leptospira and develop acute symptoms. Rodents, on the other hand, serve as reservoir hosts in which the bacteria chronically colonize the kidneys and get excreted in the urine. Humans are incidental hosts but can develop fulminant disease which can prove fatal. The host immune response to Leptospira spp. remains poorly defined. Leptospiral lipopolysaccharide and lipoproteins can activate TLR4 and TLR2. In addition, leptospires have been shown to activate the NLRP3 inflammasome. However, we observed that L. interrogans induced a poor inflammasome response particularly in mouse macrophages when compared to other bacteria known to activate NLRP3 inflammasome. In contrast, L. interrogans induced robust type I IFN responses in both mouse macrophages and human monocytes. In vivo studies suggest a potential role of type I IFN response in controlling bacteria loads in mouse models. Interestingly, we found the type I IFN response to be dependent on both cGAS-STING and TLR4-TRIF pathways. Further, differences in disease susceptibility in mouse and humans, when infected with Leptospira, may be explained by differences in host-specific immune responses.
Cold-stored platelets do not potentiate detrimental monocyte and neutrophil proinflammatory responses in vitro
Authors: Chitrakar Alisha , Thomas Kimberly
Published: November 2024

Cold-stored platelets (CSP) have increased hemostatic function compared to room temperature-stored platelets (RTP), leading to recent FDA conditional approval for CSP transfusion in bleeding patients. However, the immune consequences of CSP transfusion are not well defined. CD62P and CD40L expression is increased in CSP, potentially enhancing interaction with neutrophils (PMN, CD62P:PSGL-1) and monocytes (Mo, CD40L:CD40). We hypothesized CSP would form aggregates with leukocytes more readily than RTP, thereby increasing tissue factor/CD142 expression, inflammasome assembly, and neutrophil extracellular trap (NET) formation – functions potentiated by native platelets. We stored apheresis platelets in plasma (PLT) for 7 days at 22oC (RT) or 4oC (CS), and incubated PLT with freshly isolated PBMC or PMN at a 1:14 ratio. We measured CD142 and Apoptosis-associated speck-like protein containing caspase activation and recruitment domain (ASC) expression by flow cytometry in Mo, and ASC specks and NET formation in PMN using fluorescent microscopy. We found no difference in CD142 or ASC GMFI expression in monocytes incubated with RT or CS PLT, and no difference in ASC specks or NET formation between neutrophils incubated with RT and CS PLT. Therefore, our in vitro study shows CSP do not potentiate detrimental acute proinflammatory responses by monocytes or neutrophils, further supporting CSP use in actively bleeding patients and paving the way for precision transfusion medicine.
NK-like CD8+ T cells in CMV-seronegative and -seropositive individuals
Authors: Kim Dong-Uk , Moon Bae-Hyeon , Koh June-Young , Shin Eui-Cheol
Published: November 2024

Human cytomegalovirus (CMV) infection is widespread, with a seroprevalence exceeding 50% globally. Although typically asymptomatic in healthy individuals, CMV establishes latent infection, which significantly impacts the immune system, particularly influencing T and NK cell compartments. Notably, the frequency of CD8+ T cells expressing natural killer (NK) receptors, such as NKG2C and KIR, is increased in CMV-seropositive individuals compared to CMV-seronegative individuals. In the current study, we aimed to examine the characteristics of the NK-like CD8+ T cell population in the context of CMV infection. Single-cell RNA sequencing analysis identified common transcription factor IKZF2 (Helios) expression in NK-like CD8+ T cells. Among 7 IKZF2 clusters, 2 IKZF2 clusters (CD56 IKZF2 and CD161 IKZF2 clusters) were found to be increased in CMV-seropositive individuals. The CD56 IKZF2 cluster exhibited a unique TCR repertoire and characteristics similar to stem-like IKZF2 clusters, which are similar to the thymus CD8αα T-cell population. In contrast, the CD161 IKZF2 cluster exhibited a TCR repertoire similar to IKZF2 TEMRA clusters, which in turn are akin to that of IKZF2(-) TEMRA clusters. Taken together, our study has identified characteristics of the NK-like CD8+ T cell population in the context of CMV infection.
∆9-THC attenuates neurodegeneration seen in HIV-gp120 transgenic mice through downregulation of microglial cell activation, astrocytosis and by reversing gut dysbiosis
Authors: Halder Urmi , Kakkar Khadija , Wilson Kiesha , Carter Tayler , Weyer Chloe , Mohammed Amira , Kaul Marcus , Nagarkatti Prakash , Nagarkatti Mitzi
Published: November 2024

The GFAP-gp120Tg mice express soluble HIV-envelope protein gp120 in astrocytes and share many neuropathological features observed in the CNS of AIDS patients. Here, we investigated the effect of a cannabinoid, ∆9-THC, on gp120-mediated neuroinflammation and progression of neurodegeneration. We treated groups of GFAP-gp120Tg and C57/BL6 WT mice with ∆9-THC or the vehicle. Immunofluorescence imaging, flow cytometry, snRNA-sequencing, and shotgun sequencing were performed to understand the cellular and molecular level incidents. ∆9-THC reduced the neuroinflammation driven by gp120 by down-regulating the inflammatory chemokine receptors such as CCR5, CXCR4 on immune cells that directly access the CNS. Pronounced astrocytosis and microglial activation seen in Tg mice was significantly reduced following treatment with ∆9-THC. Neuroglial gene expression was also reversed after ∆9-THC treatment. Tg mice exhibited significant gut microbiota dysbiosis which was reversed by ∆9-THC. Members of the genera Alistipes, Prevotella, Plasmodium, Helicobacter, Desulfovibrio had higher relative abundance in Tg mice but reduced after ∆9-THC treatment. Taken together, this study demonstrates that ∆9-THC treatment significantly improves HIV-gp120-mediated pathogenesis of neurodegeneration, neuroinflammation, and helps to reshape gut microbiota (This work was supported in part by NIH grants R01ES030144, P01AT003961, P20GM103641, and R01AI123947, R01AI160896).
Variation in HIV-1 Tat activity is a key determinant in the establishment of active versus latent infection
Authors: Gomez-Rivera Francisco , Terry Valeri , Collins Kathleen
Published: November 2024

Despite effective treatment, Human Immunodeficiency Virus (HIV) remains latent as a transcriptionally silent provirus. Latent cells can evade the immune system and the harmful effects of the virus, thereby creating a long-lasting reservoir of HIV. To gain a deeper insight into the molecular mechanisms of HIV latency establishment, it is crucial to create tools that can detect and isolate cells that are infected with the virus but remain latent. We established a series of HIV-1 reporter constructs to better understand the factors that lead to latency. All the reporters identified the latent cell subset by flow cytometric detection of fluorescent probe expressed from the constitutive promoter without expression of a second fluorescent probe from the HIV LTR. The reporters can distinguish active and latently infected T cell lines and primary cells, including CD4+ T cells, and hematopoietic stem and progenitor cells. We observed that the proportion of active-to-latent infection increased with increasing virus inoculum, shifting the balance towards active infection regardless of the total infection rate. This suggested the hypothesis that at low viral inoculum, the availability of a viral factor needed for active infection was limiting. We demonstrated a reduced effect of inoculum size when tat was overexpressed regardless of whether exogenous Tat was introduced before or after integration. These results provide new insight into the mechanisms that govern latency establishment.
Targeting microglia with mannose-coated nanoparticles to improve pathology and behavior in a mouse model of Alzheimer’s disease.
Authors: badr Asmaa , Daily Kylene , Amer Amal
Published: November 2024

Neuroinflammation is a hallmark of Alzheimer’s disease (AD) pathobiology. Microglia in AD brains show elevated levels of microRNA-17 (miR-17), which maintains a balance between pro- and anti-inflammatory cytokine production. Microglia play an essential role in the production of cytokines; however, the role of microglial miR-17 in controlling neuroinflammation is not clear. We hypothesized that targeting miR-17 in microglia in vivo will decrease neuroinflammation and dampen immune cell activation, reducing amyloid beta (Aβ) deposition and preventing behavioral changes in AD mice. We generated mannose-coated lipid nanoparticles (MLNPs) enclosing an inhibitor to miR-17 (Anti-17 MLNPs) as mannose binds receptors on microglia. We used a 5XFAD mouse model that recapitulates AD-related phenotypes observed in humans. Anti-17 MLNPs were delivered to 5XFAD mouse brains by intra-cisterna magna injection. Our results show that MLNPs specifically deliver Anti-17 to microglia in vivo and in vitro. Anti-17 MLNPs attenuated the microglial inflammatory response to Aβ. Also, the Aβ burden in the brains of Anti-17 MLNPs mice was significantly lowered. A significant decrease in immune cell activation and cytokine production pathways was also identified in the brains of Anti-17 MLNPs-injected mice. This reduced spatial memory deterioration and decreased anxiety-like behavior in 5XFAD mice. We concluded that specific targeting of microglia with miR-17 antagomir improves pathology in AD.
Whole-body irradiation impairs naïve CD4 T cell function
Authors: Kannan Shravan Kumar , Turner Ti-ara , Heidarian Mohammad , Shahi Shailesh , Kim Caleb , Griffith Thomas , Harty John , Mangalam Ashutosh , Badovinac Vladimir
Published: November 2024

Advancements in nuclear power and radiotherapy have expanded new avenues for whole-body irradiation (WBI) to humans, urging the need to understand its impact on immune cells. While most studies focus on the numerical recovery of naïve T cells post-WBI, less is known regarding its impact on their function. We subjected B6 SPF mice to 0/5Gy doses of WBI and used I-Ab tetramer enrichment to track the recovery of naïve CD4s of different antigen specificities post WBI. The number of MOG40 specific CD4 T cells is diminished 10 days post-irradiation (DPR), and recovered by 40DPR. To test if they are able to induce EAE post-WBI, we administered MOG+CFA, followed by pertussis toxin (PTX). The 10DPR mice showed delayed EAE development, likely due to diminished MOG40 naïve precursors. Interestingly, the 40DPR mice potentiated EAE compared to the 0Gy mice, evidenced by increased CD4 priming in the dLN, and spine infiltration. While WBI-mediated CD4 T cell-intrinsic changes could contribute to the timing/severity of EAE, T cell-extrinsic factors could also influence disease. To test if WBI compromises the blood-brain barrier (BBB) and facilitates EAE progression, EAE is induced in +/-WBI mice without PTX. In the absence of PTX, 0Gy mice did not develop EAE, while the 10- and 40DPR mice developed EAE suggesting BBB impairment. Overall, WBI directly impacts the number and function of autoreactive CD4 T cells, while helping them enter the spine by changing the environment.
Delineation of naïve CD8+ T cell loss and reconstitution following exposure to sublethal whole-boy irradiation
Authors: Heidarian Mohammad , Kumar Kannan Shravan , Swanson Whitney , Griffith Thomas , Harty John , Badovinac Vladimir
Published: November 2024

While the immunosuppressive effect of ionizing radiation (IR) is commonly used as a conditioning regimen of hematopoietic stem cell transplants, delayed immune reconstitution, mainly lymphocytes, remains a leading cause of morbidity and mortality. We have previously shown that memory CD8+ T (TMEM) lymphocytes, potent mediators of anti-tumor and intracellular re-infections, are permanently lost and exhibit subpar functionality long after sublethal whole-body irradiation (WBI). However, the long-term impact of WBI on naïve CD8+ T (TN) cells, a key component of immune response to new intracellular pathogens, remains poorly understood. Using P14 LCMV immune chimeric mice, we observed that although TN cells are more susceptible to radiation-induced cell loss than bona-fide TMEM cells, the number of TN cells gradually recovered in a thymus-dependent manner. Profiling the T cell receptor (TCR) beta-chain repertoire within total TN cells revealed altered TCR clonotype composition and diversity in lymphoreplete irradiated hosts. Additionally, the numerical recovery of TN cells was concomitant with an increased representation of virtual memory phenotype (CD11ahi, CD49dlo, CD62Lhi) in total and GAP5041-48, B8R20-27, and GP33-41 epitope-specific CD8+ T cells. Together, these data demonstrate lasting numerical and phenotypical changes to the TN compartment, which may influence the breadth of primary immune responses to newly encountered antigens or infections.