Cell Host Research Articles

Decreased serum levels of IL-4 correlate with the efficacy of the PAI-1 inhibitor TM5614 in patients with malignant melanoma refractory to anti-PD-1 antibodies: post hoc study of TM5614-MM trial.

We previously reported that a combination of the PAI-1 inhibitor TM5614 and nivolumab resulted in a 25.9% response rate in patients with anti-PD-1 antibody failure. We therefore comprehensively evaluated the serum levels of chemokines and cytokines in patients enrolled in the protocol per set cohort of the TM5614-MM clinical trial (jRCT2021210029). Our present study revealed significant reductions in IL-4, IL-16 and CXCL2 in the response group treated with TM5614. Our findings suggest that the induction of an antitumour response in our previous clinical trial was due to the activation of tumour-associated macrophages through the blockade of M2 polarization and the reduction of monocytic myeloid-derived suppressor cells in the tumour-bearing host.

A phase I/II study of adoptive SARS-CoV-2-specific T cells in immunocompromised hosts with or at risk of severe COVID-19 infection

BackgroundPost-transplant or hematological cancer patients have a higher risk of mortality after infection with ancestral and early variants of severe acute respiratory syndrome (SARS)-CoV-2. Adoptive cell therapy (ACT) with virus-specific T cells (VSTs) could augment endogenous T cell immunity to avoid disease deterioration before viral clearance. MethodsWe established a third-party SARS-CoV-2-specific T cell (COVID-T) bank in 2020 (NCT04351659) using convalescent and/or vaccinated donors. In a phase I/II study (NCT04457726), 13 adult and pediatric patients, acutely positive for SARS-CoV-2 and predicted to have a high chance of mortality, were recruited from September 2021 to February 2022. Twelve patients received a single dose of COVID-T cells, matched on at least 1 HLA. ResultsA dose of either 75,000 or 150,000 IFN-γ+CD3+ cells/m2 SARS-COV-2-specific T cells did not cause cytokine release syndrome, acute respiratory distress syndrome, or graft-versus-host disease. In the 8 patients who had detectable donor SARS-COV-2-specific T cells after ACT, none progressed to severe disease or died with COVID-19. In contrast, among the other four patients without evidence of donor micro-chimerism, two died of COVID-19. ConclusionsLong-acting third-party VSTs from convalescent or vaccinated donors could be expediently produced and might be clinically useful in future pandemics, particularly before global vaccination is implemented.

The hyphal-specific toxin candidalysin promotes fungal gut commensalism.

The fungus Candida albicans frequently colonizes the human gastrointestinal tract, from which it can disseminate to cause systemic disease. This polymorphic species can transition between growing as single-celled yeast and as multicellular hyphae to adapt to its environment. The current dogma of C. albicans commensalism is that the yeast form is optimal for gut colonization, whereas hyphal cells are detrimental to colonization but critical for virulence1-3. Here, we reveal that this paradigm does not apply to multi-kingdom communities in which a complex interplay between fungal morphology and bacteria dictates C. albicans fitness. Thus, whereas yeast-locked cells outcompete wild-type cells when gut bacteria are absent or depleted by antibiotics, hyphae-competent wild-type cells outcompete yeast-locked cells in hosts with replete bacterial populations. This increased fitness of wild-type cells involves the production of hyphal-specific factors including the toxin candidalysin4,5, which promotes the establishment of colonization. At later time points, adaptive immunity is engaged, and intestinal immunoglobulin A preferentially selects against hyphal cells1,6. Hyphal morphotypes are thus under both positive and negative selective pressures in the gut. Our study further shows that candidalysin has a direct inhibitory effect on bacterial species, including limiting their metabolic output. We therefore propose that C. albicans has evolved hyphal-specific factors, including candidalysin, to better compete with bacterial species in the intestinal niche.

Cerebrospinal fluid pH regulation.

The cerebrospinal fluid (CSF) fills the brain ventricles and the subarachnoid space surrounding the brain and spinal cord. The fluid compartment of the brain ventricles communicates with the interstitial fluid of the brain across the ependyma. In comparison to blood, the CSF contains very little protein to buffer acid-base challenges. Nevertheless, the CSF responds efficiently to changes in systemic pH by mechanisms that are dependent on the CO2/HCO3- buffer system. This is evident from early studies showing that the CSF secretion is sensitive to inhibitors of acid/base transporters and carbonic anhydrase. The CSF is primarily generated by the choroid plexus, which is a well-vascularized structure arising from the pial lining of the brain ventricles. The epithelial cells of the choroid plexus host a range of acid/base transporters, many of which participate in CSF secretion and most likely contribute to the transport of acid/base equivalents into the ventricles. This review describes the current understanding of the molecular mechanisms in choroid plexus acid/base regulation and the possible role in CSF pH regulation.

Non-professional efferocytosis of Salmonella-infected intestinal epithelial cells in the neonatal host.

The intestinal epithelium is the first line of defense against enteric pathogens. Removal of infected cells by exfoliation prevents mucosal translocation and systemic infection in the adult host, but is less commonly observed in the neonatal intestine. Instead, here, we describe non-professional efferocytosis of Salmonella-infected enterocytes by neighboring epithelial cells in the neonatal intestine. Intestinal epithelial stem cell organoid cocultures of neonatal and adult cell monolayers with damaged enterocytes replicated this observation, confirmed the age-dependent ability of intestinal epithelial cells for efferocytosis, and identified the involvement of the "eat-me" signals and adaptors phosphatidylserine and C1q as well as the "eat-me" receptors integrin-αv (CD51) and CD36 in cellular uptake. Consistent with this, massive epithelial cell membrane protrusions and CD36 accumulation at the contact site with apoptotic cells were observed in the infected neonatal host in vivo. Efferocytosis of infected small intestinal enterocytes by neighboring epithelial cells may represent a previously unrecognized mechanism of neonatal antimicrobial host defense to maintain barrier integrity.

Role of thymosin α1 in restoring immune response in immunological nonresponders living with HIV

BackgroundImmunological nonresponders (INRs) living with HIV are at increased risk of co-infection and multiple tumors, with no effective strategy currently available to restore their T-cell immune response. This study aimed to explore the safety and efficacy of thymosin α1 in reconstituting the immune response in INRs.MethodsINRs with CD4 + T cell counts between 100 and 350 cells/μL were enrolled and received two-staged 1.6 mg thymosin α1 subcutaneous injections for 24 weeks (daily in the first 2 weeks and biweekly in the subsequent 22 weeks) while continuing antiretroviral therapy. T cell counts and subsets, the expression of PD-1 and TIM-3 on T cells, and signal joint T cell receptor excision circles (sjTREC) at week 24 were evaluated as endpoints.ResultsTwenty three INRs were screened for eligibility, and 20 received treatment. The majority were male (19/20), with a median age of 48.1 years (interquartile range: 40.5–57.0) and had received antiretroviral therapy for 5.0 (3.0, 7.3) years. Multiple comparisons indicated that CD4 + T cell count and sjTREC increased after initiation of treatment, although no significant differences were observed at week 24 compared to baseline. Greatly, levels of CD4 + T cell proportion (17.2% vs. 29.1%, P < 0.001), naïve CD4 + and CD8 + T cell proportion (17.2% vs. 41.1%, P < 0.001; 13.8% vs. 26.6%, P = 0.008) significantly increased. Meanwhile, the proportion of CD4 + central memory T cells of HIV latent hosts (42.7% vs. 10.3%, P < 0.001) significantly decreased. Moreover, the expression of PD-1 on CD4 + T cells (14.1% vs. 6.5%, P < 0.001) and CD8 + T cells (8.5% vs. 4.1%, P < 0.001) decreased, but the expression of TIM-3 on T cellsremained unaltered at week 24. No severe adverse events were reported and HIV viral loads kept stable throughout the study.ConclusionsThymosin α1 enhance CD4 + T cell count and thymic output albeit as a trend rather than an endpoint. Importantly, it improves immunosenescence and decreases immune exhaustion, warranting further investigation.Trial registrationThis single-arm prospective study was registered with ClinicalTrials.gov (NCT04963712) on July 15, 2021.

Toxoplasma protein export and effector function.

Toxoplasma gondii is a single-celled eukaryotic parasite with a considerable host range that must invade the cells of warm-blooded hosts to survive and replicate. The challenges and opportunities that such a strategy represent have been met by the evolution of effectors that are delivered into host cells, counter host defences and co-opt host cell functions for their own purposes. These effectors are delivered in two waves using distinct machinery for each. In this Review, we focus on understanding the architecture of these protein-export systems and how their protein cargo is recognized and selected. We discuss the recent findings on the role that host manipulation has in latent Toxoplasma infections. We also discuss how these recent findings compare to protein export in the related Plasmodium spp. (the causative agent of malaria) and how this can inform our understanding of host manipulation in the larger Apicomplexa phylum and its evolution.

Legume nodulation and nitrogen fixation require interaction of DnaJ-like protein and lipid transfer protein.

The lipid transport protein (LTP) product of the AsE246 gene of Chinese milk vetch (Astragalus sinicus) contributes to the transport of plant-synthesized lipids to the symbiosome membranes (SMs) that are required for nodule organogenesis in this legume. However, the mechanisms used by nodule-specific LTPs remain unknown. In this study, a functional protein in the DnaJ-like family, designated AsDJL1, was identified and shown to interact with AsE246. Immunofluorescence showed that AsDJL1 was expressed in infection threads (ITs) and in nodule cells and that it co-localized with rhizobium, and an immunoelectron microscopy assay localized the protein to SMs. Via co-transformation into Nicotiana benthamiana cells, AsDJL1 and AsE246 displayed subcellular co-localization in the cells of this heterologous host. Co-immunoprecipitation assays confirmed that AsDJL1 interacted with AsE246 in nodules. The essential interacting region of AsDJL1 was determined to be the zinc finger domain at its C-terminus. Chinese milk vetch plants transfected with AsDJL1-RNAi had significantly decreased numbers of ITs, nodule primordia and nodules as well as reduced (by 83%) nodule nitrogenase activity compared with the controls. By contrast, AsDJL1 overexpression led to increased nodule fresh weight and nitrogenase activity. RNAi-AsDJL1 also significantly affected the abundance of lipids, especially digalactosyldiacylglycerol, in early-infected roots and transgenic nodules. Taken together, the results of this study provide insights into the symbiotic functions of AsDJL1, which may participate in lipid transport to SMs and play an essential role in rhizobial infection and nodule organogenesis.

The Histopathological &amp; Behavioral Changes on Mice Experimentally Infected with Toxoplasma Gondii

Toxoplasmosis is one of the most important and common zoonotic diseases worldwide with an infection rate ranging between 20-80% of the world’s population. The affecting in a wide range of mammals, including humans, causes significant disease effects on human health and economic animals. The parasite has an amazing ability to spread within the host’s body and uses various strategies to overcome the blood-brain barrier, with the ability to exist for life within the cells of the infected host. The current study aimed at following up the histopathological changes in the brain of mice experimentally infected with toxoplasmosis. A placenta samples were collected from Al-Salam Teaching Hospital in Mosul, and the parasite was isolated and injection of 100 tissue cyst into the peritoneal cavity of laboratory mice. The animals were divided into three groups, and the mice were dissected after 21, 30 and 40 days of infection period in order to study histopathological changes in the cortex, hippocampus and amygdala. The results of the numbers of parasite cysts in the hippocampus, amygdala and cortex showed an increase in the number of parasite cysts in the cortex compared with the hippocampus and amygdala, the histological sections showed in addition to vacuolar degenerative changes and Apoptosis. After 30 days of infection, the results showed a decrease in body weight in males. The histological sections showed necrosis of the granular cell layer, edema around the nerve axons. The results of the third group, after 40 days of infection, showed a decrease in body weight in males and females compared with the control group and an increase in brain weight in males. The histological sections showed the loss of nuclei in the cells of the basal medial nuclei, vacuolar degeneration, in addition to the presence of vacuolization.

Small EV in plasma of triple negative breast cancer patients induce intrinsic apoptosis in activated T cells

Small extracellular vesicles (sEV) in TNBC patients’ plasma promote T cell dysfunction and tumor progression. Here we show that tumor cell-derived exosomes (TEX) carrying surface PDL-1, PD-1, Fas, FasL, TRAIL, CTLA-4 and TGF-β1 induce apoptosis of CD8+T and CD4+T cells but spare B and NK cells. Inhibitors blocking TEX-induce receptor/ligand signals and TEX pretreatments with proteinase K or heat fail to prevent T cell apoptosis. Cytochalasin D, Dynosore or Pit Stop 2, partly inhibit TEX uptake but do not prevent T cell apoptosis. TEX entry into T cells induces cytochrome C and Smac release from mitochondria and caspase-3 and PARP cleavage in the cytosol. Expression of survival proteins is reduced in T cells undergoing apoptosis. Independently of external death receptor signaling, TEX entry into T cells induces mitochondrial stress, initiating relentless intrinsic apoptosis, which is responsible for death of activated T cells in the tumor-bearing hosts. The abundance of TEX in cancer plasma represents a danger for adoptively transferred T cells, limiting their therapeutic potential.

Abstract P1098: Molecular Maturation Of Engrafted Human Pluripotent Stem Cell-derived Cardiomyocytes

The transplantation of human pluripotent stem cell derived cardiomyocytes (hPSC-CMs) represents an attractive strategy to regenerate myocardium lost following injury and mitigate the pathological remodeling that ultimately leads to heart failure. However, in vitro hPSC-CMs have an immature phenotype that likely contributes to the transient arrhythmias observed during the initial weeks following hPSC-CM transplantation in large-animal models, hindering safe translation into the clinic. We hypothesized that maturational changes in hPSC-CMs in vivo facilitate the improved electrophysiological behavior of graft tissue observed at later time-points. Because the changing phenotype of hPSC-CM graft tissue remains largely unexplored, we used single nucleus RNA sequencing to evaluate the transcriptional dynamics and cell population heterogeneity of hPSC-CMs prior to transplantation and at 2- and 8-weeks following transplantation in a guinea pig cardiac cryoinjury model (n=3). We used methods based on the sorting of nuclei labeled by a genetically-encoded fluorescent reporter to enrich the proportion of human nuclei sequenced from the graft site and created a comprehensive atlas (&amp;gt; 20,000 cells) of host and graft cells present at the implantation site at both time-points. We identified an upregulation of genes involved in intracellular calcium handling, AMPK, and cAMP signaling pathways, as well as a metabolic shift in engrafted hPSC-CMs that we speculate supports their growth and enhanced electrophysiological function. Our study includes a comprehensive description of the temporal changes in hPSC-CM graft tissue at the single-cell resolution and provides unique insights into how these cells adapt to the injured heart environment and mature in vivo.

Vaccination with a ZNF2oe Strain of Cryptococcus Provides Long-Lasting Protection against Cryptococcosis and Is Effective in Immunocompromised Hosts.

Systemic cryptococcosis is fatal without treatment. Even with the current antifungal therapies, this disease kills 180,000 of 225,000 infected people annually. Exposure to the causative environmental fungus Cryptococcus neoformans is universal. Either reactivation of a latent infection or an acute infection after high exposure to cryptococcal cells can result in cryptococcosis. Currently, there is no vaccine to prevent cryptococcosis. Previously, we discovered that Znf2, a transcription factor that directs Cryptococcus yeast-to-hypha transition, profoundly affects cryptococcal interaction with the host. Overexpression of ZNF2 drives filamentous growth, attenuates cryptococcal virulence, and elicits protective host immune responses. Importantly, immunization with cryptococcal cells overexpressing ZNF2, in either live or heat-inactivated form, offers significant protection to the host from a subsequent challenge by the otherwise lethal clinical isolate H99. In this study, we found that the heat-inactivated ZNF2oe vaccine offered long-lasting protection with no relapse upon challenge with the wild-type H99. Vaccination with heat-inactivated ZNF2oe cells provides partial protection in hosts with preexisting asymptomatic cryptococcal infection. Importantly, once animals have been vaccinated with heat-inactivated or live short-lived ZNF2oe cells, they are protected against cryptococcosis even when their CD4+ T cells are depleted at the time of fungal challenge. Remarkably, vaccination with live, short-lived ZNF2oe cells in CD4-depleted hosts still provides strong protection to these hosts with preexisting immunodeficiency at the time of vaccination. This work raises hope for developing effective vaccines with long-lasting protection for individuals who are immunocompromised or could become immunocompromised later in life.

Inducing cell-intrinsic dysfunction in pregnancy-sensitized alloreactive B cells

Abstract Objective: Pregnancy is an immunological paradox where the maternal immune system develops tolerance to semi-allogeneic fetus yet is a sensitizing event that is detrimental to subsequent organ transplantation. Humoral sensitization by semi-allogeneic pregnancy in WT mice prevents anti-CD154-mediated tolerance to fetus matched allograft. In contrast, pregnancy in mice lacking secreted immunoglobulins (mIgM −/−AID −/−; SIgKO) permitted anti-CD154 mediated transplant tolerance, suggesting that fetus-specific antibodies (FSA) were mediating resistance to anti-CD154. Here, we tested whether pregnancy-induced memory B cells could be desensitized to acquire a state of cell-intrinsic dysfunction. Methods: Pregnancy-sensitized SIgKO or WT mice were subjected to fetus-matched heart transplant/anti-CD154 (PP-tolerant B) or not (PP-memory B). Enriched B cells were adoptively transferred (AdTr) into secondary hosts (MD4 mice) and challenged with fetus-matched splenocytes. Germinal center (GC) allo-reactive B cells from MD4 mice were identified with MHC tetramers, and Fas +GL7 +. Results: While SIgKO PP-memory B cells differentiated into GC-B cells in secondary hosts; this was significantly decreased by 7–10-fold in SIgKO PP-tolerant B cells. In contrast, WT PP-memory B cells and PP-tolerant B cells comparably differentiated into GC-B cells. Conclusions: In the absence of FSA, PP memory B cells can acquire a cell-intrinsic hypo-functional state. This suggests possible B cell desensitization for multiparous women, who are currently disadvantaged by pregnancy-induced humoral sensitization. R01AI42747, P01AI097113

NAC1 constrains CD4 +T cell memory formation through the ROCK1-mediated pathway

Abstract Nucleus accumbens-associated protein 1 (NAC1) is a transcriptional co-factor that has been extensively investigated in cancer biology. Our recent studies indicate that NAC1 can modulate the functional activity of regulatory T cells and tumoral expression of NAC1 restrains antitumor immunity. However, little is known about its regulation of memory T cells. In the current study, we analyzed CD4 +T cells from wild type (WT) and NAC1-decificient (−/−) mice and used the vaccinia virus (VACV) as the tool to investigate the precise role and mechanism of NAC1 in controlling CD4 +T cell memory. In vitro, we identified that NAC1 is essential for T cell metabolism, including both glycolysis and oxidative phosphorylation, which positively modulates CD4 +T cell survival. We also revealed that NAC1 deficiency has an interruption of the AMPK-mTOR pathway, resulting in decreased glycolysis and defective autophagy of CD4 +T cells. Mechanically, loss of NAC1 downregulates ROCK1 expression and reduces the phosphorylation and stabilization of BECLIN1. When overexpressing ROCK1 in NAC1 −/−CD4 +T cells, both the defective autophagy and the interrupted AMPK-mTOR pathway were restored. In vivo, when i.p.challenged with VACV, NAC1 −/−mice had improved VACV-specific CD4 +memory T cell formation at 35 days compared with WT mice. Furthermore, in adoptively transferred experiments when overexpressing ROCK1 of NAC1 −/−CD4 +T cells (Thy1.2 +) in congenic hosts (Thy1.1 +), the increased memory T cell formation of NAC1 −/−CD4 +T cells was reverted to a normal WT level. Conclusively, we define that NAC1 acts as a suppressor of CD4 +T cell memory formation through the ROCK1-mediated pathway, and targeting NAC1 may be adapted to promote memory CD4 +T cell development.

Acute and chronic viral infection generate brain-resident memory T cells with distinct phenotypic, functional, spatial, and metabolic profiles

Abstract The rising incidence of post-viral neurological sequelae represents a substantial burden on global public health. Therefore, there is an urgent need to investigate alterations in brain immune composition after acute and chronic viral infection. While virus-specific tissue-resident memory (T RM) CD8 +T cells are observed in human health and neurological disease, these populations remain understudied in the brain. Here, we leveraged the comparative model system of lymphocytic choriomeningitis virus (LCMV) strain Armstrong vs. Clone 13 infection in mice to generate brain T RMwith quiescent and exhausted profiles respectively. We then interrogated the 1) phenotype, 2) functionality, 3) localization, and 4) metabolism of anti-viral T RMin the brain. Importantly, brain T RMexhibit higher expression of exhaustion markers (PD-1, LAG-3, TIM-3, TOX) compared to T circulating memory (T CIRCM) cells in the same host. Furthermore, brain T RMin chronically infected hosts are functionally impaired in cytokine production and cytolytic capacity. Anti-viral brain T RMseed distinct neuroanatomical sites, such as the cerebrospinal fluid, parenchyma, and choroid plexus, often adopting aggregate-like structures in solid compartments. Compared to T CIRCM, quiescent and exhausted brain T RMalso demonstrate higher expression of surface amino acid transporters with disparate amino acid uptake. These findings are contextualized by whole brain metabolomic profiling indicating global perturbations in amino acid metabolism post-acute and chronic viral infection. Altogether, these data highlight brain-intrinsic memory T cell signatures and offer broad insight into how brain T RMmay influence post-viral neurological outcomes. Supported by grants from the NIH (AI042767, AI114543, AI167847, 5T32GM007337) and the University of Iowa Post-Comprehensive Research Fellowship.

Abstract 6414: Concomitant anti-tumor immunity and checkpoint blockade responses are restored by depletion of CD62L expressing cells

Abstract Studies have shown the importance of CD62L in leukocyte trafficking. However, the significance of CD62L-expressing cells in concomitant anti-tumor immunity has not been investigated. Using a model of post-surgical tumor immunity, we show that in vivo depletion of CD62L-expressing cells before or immediately after surgical tumor resection enabled the development of anti-tumor concomitant responses against poorly immunogenic B16 (melanoma) or MTE-Ras (head &amp; neck cancer) tumor cells. Anti-CD62L mAb administration depleted the cellular immune components that express CD62L, including NK, NKT, Mo, Ma, B, and T cells. Within the T cell compartment, naïve T cells (CD44lo CD62Lhi), effector (CD44hi CD62Llo), memory (CD44hi CD62Lhi) and regulatory T cells (Treg, CD4 CD25 Foxp3) were also depleted, while effector CD62L-negative T cells were spared in the TDLN. Tumor immunity did not occur in the absence of a primary tumor (sham surgery group) or after CD8 depletion. Whereas anti-CTLA-4 or anti-PD-1 mAbs failed as monotherapies, their administration during CD62L depletion restored their anti-tumor properties. The unified global gene expression analysis of the TDLN shows the significant enrichment of biological processes involved in the CD8 T cell effector phase, IL-2/IL-15, TNF-α, IFN-γ, IFN-α, IL-6, responses, mitotic cell division, glycolysis, and acetylation. Also, genes related to Treg responses were downregulated. These data point to a process in which depletion of CD62L cells in tumor-bearing hosts transforms the TDLN into a highly active immunological site in which tumor-reactive effector CD8 T cells (CD62L-negative) actively divide in the absence of Treg, accompanied by a cytokine response, glucose consumption, and acetylation of transcriptional factors and histones. These results identify an unrecognized role of CD62L-expressing cells in regulating concomitant anti-tumor immunity and restoring anti-tumor responses by checkpoint blockade inhibitors. Our study provides a new framework that could help understand how anti-tumor responses are limited. Citation Format: Brianna Burke, Lourdes Plaza-Rojas, Cynthia Perez, Elena Kostenko, Anna Austin, Justin Boucher, Kushal Prajapati, Michael Delos Reyes, Christine Chung, Jose-Alejandro Guevara-Patino. Concomitant anti-tumor immunity and checkpoint blockade responses are restored by depletion of CD62L expressing cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6414.

Pulmonary inflammation promoted by type-2 dendritic cells is a feature of human and murine schistosomiasis

Schistosomiasis is a parasitic disease affecting over 200 million people in multiple organs, including the lungs. Despite this, there is little understanding of pulmonary immune responses during schistosomiasis. Here, we show type-2 dominated lung immune responses in both patent (egg producing) and pre-patent (larval lung migration) murine Schistosoma mansoni (S. mansoni) infection. Human pre-patent S. mansoni infection pulmonary (sputum) samples revealed a mixed type-1/type-2 inflammatory cytokine profile, whilst a case-control study showed no significant pulmonary cytokine changes in endemic patent infection. However, schistosomiasis induced expansion of pulmonary type-2 conventional dendritic cells (cDC2s) in human and murine hosts, at both infection stages. Further, cDC2s were required for type-2 pulmonary inflammation in murine pre-patent or patent infection. These data elevate our fundamental understanding of pulmonary immune responses during schistosomiasis, which may be important for future vaccine design, as well as for understanding links between schistosomiasis and other lung diseases.

Focus on the Plant Endomembrane System in Molecular Plant-Microbe Interactions

Interactions between plants and microbes are ubiquitous. The outcomes of these interactions involve interkingdom communication, with myriad, diverse signals moving between microbes and their potential plant hosts. Years of biochemical, genetic, and molecular biology research have provided an overview of the landscape of the repertoires of effectors and elicitors encoded by microbes that allow them to stimulate and manipulate responses from their potential plant hosts. Similarly, considerable insight into the plant machinery and capacity for responding to microbes has been gained. The advent of new bioinformatics and modeling approaches has greatly contributed to our understanding of how these interactions occur, and it is expected that these tools, coupled with burgeoning genome sequencing data, will eventually allow the prediction of the outcome of these interactions and whether they will result in a relationship that benefits one or both partners. As a complement to these studies, cell biological studies are elucidating how cells in the plant hosts behave in response to microbial signals. Such studies have brought new attention to the indispensable role of the plant endomembrane system in determining the outcome of plant-microbe interactions. This Focus Issue addresses not only how the plant endomembrane acts locally to mediate responses to microbes but, also, the importance of the plant endomembrane beyond the plant cell borders for cross-kingdom effects. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 "No Rights Reserved" license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2023.

A male-killing Wolbachia endosymbiont is concealed by another endosymbiont and a nuclear suppressor.

Bacteria that live inside the cells of insect hosts (endosymbionts) can alter the reproduction of their hosts, including the killing of male offspring (male killing, MK). MK has only been described in a few insects, but this may reflect challenges in detecting MK rather than its rarity. Here, we identify MK Wolbachia at a low frequency (around 4%) in natural populations of Drosophila pseudotakahashii. MK Wolbachia had a stable density and maternal transmission during laboratory culture, but the MK phenotype which manifested mainly at the larval stage was lost rapidly. MK Wolbachia occurred alongside a second Wolbachia strain expressing a different reproductive manipulation, cytoplasmic incompatibility (CI). A genomic analysis highlighted Wolbachia regions diverged between the 2 strains involving 17 genes, and homologs of the wmk and cif genes implicated in MK and CI were identified in the Wolbachia assembly. Doubly infected males induced CI with uninfected females but not females singly infected with CI-causing Wolbachia. A rapidly spreading dominant nuclear suppressor genetic element affecting MK was identified through backcrossing and subsequent analysis with ddRAD SNPs of the D. pseudotakahashii genome. These findings highlight the complexity of nuclear and microbial components affecting MK endosymbiont detection and dynamics in populations and the challenges of making connections between endosymbionts and the host phenotypes affected by them.

The Role of NK Cells in EBV Infection and Related Diseases: Current Understanding and Hints for Novel Therapies

The Epstein-Barr virus (EBV) is a ubiquitous herpesvirus most often transmitted during infancy and infecting the vast majority of human beings. Usually, EBV infection is nearly asymptomatic and results in life-long persistency of the virus in a latent state under the control of the host immune system. Yet EBV can cause an acute infectious mononucleosis (IM), particularly in adolescents, and is associated with several malignancies and severe diseases that pose a serious threat to individuals with specific inborn error of immunity (IEI). While there is a general consensus on the requirement for functional CD8 T cells to control EBV infection, the role of the natural killer (NK) cells of the innate arm of immunity is more enigmatic. Here we provide an overview of the interaction between EBV and NK cells in the immunocompetent host as well as in the context of primary and secondary immunodeficiencies. Moreover, we report in vitro data on the mechanisms that regulate the capacity of NK cells to recognize and kill EBV-infected cell targets and discuss the potential of recently optimized NK cell-based immunotherapies for the treatment of EBV-associated diseases.