Host Immune Environment Research Articles

Herpes simplex virus-1 targets the 2′-3'cGAMP importer SLC19A1 as an antiviral countermeasure

The extracellular addition of the STING agonist, 2-3cGAMP, induces an antiviral state that inhibits HSV-1 replication in a cell type dependent manner via the transportation of the cyclic-dinucleotide through the folate antiporter SLC19A1. To establish a successful infection, herpes simplex virus-1 (HSV-1), a ubiquitous virus with high seropositivity in the human population, must undermine a multitude of host innate and intrinsic immune defense mechanisms, including key players of the STimulator of INterferon Genes (STING) pathway. Herein, we report that HSV-1 infection results in the reduction of SLC19A1 transcription, translation, and importantly, the rapid removal of SLC19A1 from the cell surface of infected cells. Our data indicate SLC19A1 functions as a newly identified antiviral mediator for extracellular 2′-3'cGAMP which is undermined by HSV-1 protein ICP27. This work presents novel and important findings about how HSV-1 manipulates the host's immune environment for viral replication and discovers details about an important antiviral mechanism.

Itaconate induces tolerance of Staphylococcus aureus to aminoglycoside antibiotics.

Staphylococcus aureus is one of the chief pathogens that cause chronic and recurrent infections. Failure of the antibiotics to curb the infections contributes to relapse and is an important reason for the high mortality rate. Treatment failure may also be due to antibiotic tolerance. Accumulating evidence suggests that t the host immune environment plays an important role in inducing antibiotic tolerance of S. aureus, but research in this area has been limited. In this study,the minimum inhibitory concentration (MIC) of the antibiotics against S. aureus was determined using the standard broth microdilution method.The study evaluated whether itaconate induces antibiotic tolerance in S. aureus through an antibiotic bactericidal activity assay.The effect of itaconate on the growth of S. aureus was evaluated by monitoring the growth of S. aureus in medium supplemented with itaconate. Additionally, RNA sequencing and metabolomics analyses were used to determine transcriptional and metabolic changes in S. aureus when exposed to itaconate. According to the study,we found that the immune metabolite itaconate can induce tolerance in both methicillin-resistant and -susceptible S. aureus to aminoglycosides. When S. aureus was exposed to itaconate, its growth slowed down and transcriptomic and metabolomic alterations associated with decreased energy metabolism, including the tricarboxylate cycle, glycolysis, pyruvate metabolism, and arginine biosynthesis, were observed. These changes are associated with aminoglycoside tolerance. This study highlights the role of immune signaling metabolites in bacterial antibiotic tolerance and suggests new strategies to improve antibiotic treatment by modulating the host immune response and stimulating the metabolism of bacteria.

Inter and intra-host diversity of RSV in hematopoietic stem cell transplant adults with normal and delayed viral clearance.

Respiratory syncytial virus (RSV) infection in immunocompromised individuals often leads to prolonged illness, progression to severe lower respiratory tract infection, and even death. How the host immune environment of the hematopoietic stem cell transplant (HCT) adults can affect viral genetic variation during an acute infection is not understood well. In the present study, we performed whole genome sequencing of RSV/A or RSV/B from samples collected longitudinally from HCT adults with normal (<14 days) and delayed (≥14 days) RSV clearance who were enrolled in a ribavirin trial. We determined the inter-host and intra-host genetic variation of RSV and the effect of mutations on putative glycosylation sites. The inter-host variation of RSV is centered in the attachment (G) and fusion (F) glycoprotein genes followed by polymerase (L) and matrix (M) genes. Interestingly, the overall genetic variation was constant between normal and delayed clearance groups for both RSV/A and RSV/B. Intra-host variation primarily occurred in the G gene followed by non-structural protein (NS1) and L genes; however, gain or loss of stop codons and frameshift mutations appeared only in the G gene and only in the delayed viral clearance group. Potential gain or loss of O-linked glycosylation sites in the G gene occurred both in RSV/A and RSV/B isolates. For RSV F gene, loss of N-linked glycosylation site occurred in three RSV/B isolates within an antigenic epitope. Both oral and aerosolized ribavirin did not cause any mutations in the L gene. In summary, prolonged viral shedding and immune deficiency resulted in RSV variation, especially in structural mutations in the G gene, possibly associated with immune evasion. Therefore, sequencing and monitoring of RSV isolates from immunocompromised patients are crucial as they can create escape mutants that can impact the effectiveness of upcoming vaccines and treatments.

Hookworms dynamically respond to loss of Type 2 immune pressure.

The impact of the host immune environment on parasite transcription and fitness is currently unknown. It is widely held that hookworm infections have an immunomodulatory impact on the host, but whether the converse is true remains unclear. Immunity against adult-stage hookworms is largely mediated by Type 2 immune responses driven by the transcription factor Signal Transducer and Activator of Transcription 6 (STAT6). This study investigated whether serial passage of the rodent hookworm Nippostrongylus brasiliensis in STAT6-deficient mice (STAT6 KO) caused changes in parasites over time. After adaptation to STAT6 KO hosts, N. brasiliensis increased their reproductive output, feeding capacity, energy content, and body size. Using an improved N. brasiliensis genome, we found that these physiological changes corresponded with a dramatic shift in the transcriptional landscape, including increased expression of gene pathways associated with egg production, but a decrease in genes encoding neuropeptides, proteases, SCP/TAPS proteins, and transthyretin-like proteins; the latter three categories have been repeatedly observed in hookworm excreted/secreted proteins (ESPs) implicated in immunosuppression. Although transcriptional changes started to appear in the first generation of passage in STAT6 KO hosts for both immature and mature adult stages, downregulation of the genes putatively involved in immunosuppression was only observed after multiple generations in this immunodeficient environment. When STAT6 KO-adapted N. brasiliensis were reintroduced to a naive WT host after up to 26 generations, this progressive change in host-adaptation corresponded to increased production of inflammatory cytokines by the WT host. Surprisingly, however, this single exposure of STAT6 KO-adapted N. brasiliensis to WT hosts resulted in worms that were morphologically and transcriptionally indistinguishable from WT-adapted parasites. This work uncovers remarkable plasticity in the ability of hookworms to adapt to their hosts, which may present a general feature of parasitic nematodes.

A phase 2 trial of mosunetuzumab with lenalidomide augmentation as first-line therapy for follicular (FL) and marginal zone lymphoma (MZL).

TPS7588 Background: First-line therapy for high-burden FL and MZL includes immunochemotherapy (most commonly rituximab with bendamustine), which is associated with toxicities, is not curative, and leads to a prolonged T-cell depletion. The alternative of rituximab with full-dose lenalidomide did not improve efficacy or toxicity [Morschhauser et al., NEJM 2018]. However, lower-dose, short-course lenalidomide (15mg) may enhance cytotoxic T-cell immunity and efficacy of rituximab [Zucca et al, Blood 2019]. Mosunetuzumab is a CD20xCD3-binding, T-cell-engaging bispecific antibody approved for relapsed/refractory FL after 2 lines of therapy. It results in a complete response (CR) rate of 60% in that setting [Budde et al., Lancet Oncol, 2022], despite prior exposure to immunosuppressive therapies. This trial proposes a novel therapeutic approach to first-line treatment of FL/MZL, exploring 3 hypotheses: 1) that mosunetuzumab will lead to a high rate of CR, and possibly eradication, of FL/MZL when applied before exposure to immunosuppressive modalities; 2) that low-dose lenalidomide can augment the cytotoxic T-cell response when CR is not achieved with mosunetuzumab alone, and 3) that baseline host immune environment measured in treatment-naïve state can predict CR to bispecific antibody therapy. Methods: The Brown University Oncology Research Group BrUOG-401/ML43251 ( NCT04792502 ) is an investigator-initiated, multi-center, single-arm, phase 2 clinical trial for patients (pts) with FL and MZL in need of first-line systemic therapy. Pts with FL must meet the Groupe d’Etude des Lymphomes Folliculaires (GELF) criteria of high-burden disease, whereas pts with MZL must require therapy in the investigators’ opinion. As of January 2023, 7 of the planned 52 pts have been enrolled. The trial uses a response-adapted design: pts start with 4 courses of subcutaneous mosunetuzumab monotherapy, using step-up dosing during Cycle 1 (5mg → 45mg → 45mg) to mitigate the risk of cytokine release syndrome (CRS). Pts attaining CR (by Lugano criteria) after Cycle 4 continue for a total of 8 cycles of mosunetuzumab monotherapy. Pts attaining partial response or stable disease receive 4 additional cycles of mosunetuzumab with low-dose lenalidomide augmentation (10mg daily), with further 4 cycles of mosunetuzumab/lenalidomide if CR after C8 is still not attained. The primary endpoints include the ORR and CR rate at final assessment, and rates of toxicities, particularly CRS, tumor flare, and immune-mediated events. PFS and rate of progression of disease at 24 months (POD24) are among secondary endpoints. The study uses Simon’s two-stage design, with the null hypothesis that the CR rate is 53% (based on prior RELEVANCE trial). Correlative studies aim at determining predictive biomarkers of response, including immune signatures and dynamics of circulating tumor DNA during study therapy. Clinical trial information: NCT04792502 .

Biocompatible Nano-Hydroxyapatites Regulate Macrophage Polarization.

Research on regulation of the immune microenvironment based on bioactive materials is important to osteogenic regeneration. Hydroxyapatite (HAP) is believed to be a promising scaffold material for dental and orthopedic implantation due to its ideal biocompatibility and high osteoconductivity. However, any severe inflammation response can lead to loosening and fall of implantation, which cause implant failures in the clinic. Morphology modification has been widely studied to regulate the host immune environment and to further promote bone regeneration. Here, we report the preparation of nHAPs, which have uniform rod-like shape and different size (200 nm and 400 nm in length). The morphology, biocompatibility, and anti-inflammatory properties were evaluated. The results showed that the 400 nm nHAPs exhibited excellent biocompatibility and osteoimmunomodulation, which can not only induce M2-phenotype macrophages (M2) polarization to decrease the production of inflammatory cytokines, but also promote the production of osteogenic factor. The reported 400 nm nHAPs are promising for osteoimmunomodulation in bone regeneration, which is beneficial for clinical application of bone defects.

Granulomatous Herpetic Encephalitis A Possible Role for Inflammasomes.

Granulomatous herpetic encephalitis is a rare inflammatory complication of acute herpes simplex encephalitis. We describe 3 cases of granulomatous herpetic encephalitis in children arising between 1 to 10 years after the initial presentation with acute herpes simplex encephalitis. We focus on the clinical course and neuroimaging phenotype with a discussion of possible mechanisms underpinning this entity. The clinical course was highly variable. However, the dominant neuroimaging phenotype in each of our cases was that of confluent gyriform cortical enhancement with predominantly solid foci of enhancement in the subjacent white matter +/- deep gray nuclei. Cerebrospinal fluid was negative for herpes simplex virus DNA in all cases. All 3 cases required brain biopsy to help establish the diagnosis. Increased recognition of granulomatous herpetic encephalitis in children will facilitate earlier diagnosis and treatment. Although the exact role played by the host immune response, genetics, and environment in determining the different outcomes of herpes simplex encephalitis remains to be determined, we postulate a role for inflammasome dysregulation in this entity.

Imagining the cell therapist: Future CAR T cell monitoring and intervention strategies to improve patient outcomes.

Chimeric antigen receptor (CAR) T cell therapy is now approved for the standard of care treatment of several types of relapsed or refractory hematologic malignancies. Future advances may extend cellular therapies to solid tumors or even non‐malignant diseases. As patient need grows, a clinical specialty of “cell therapy” may emerge. Here, we envision the needs of a clinical cell therapist to monitor and intervene upon patients receiving cell therapies. These include: (1) monitoring patient T cell quality and the host immune environment to ensure optimal timing for cell therapy. (2) Tumor antigen profiling to personalize CAR T cell targeting. (3) Real‐time monitoring of CAR T cells and circulating tumor DNA to modulate CAR T cell activity to maximize tumor eradication while mitigating toxicity. (4) Monitoring of CAR rejection and anti‐CAR immunity posttreatment to inform re‐dosing and subsequent cell therapy strategies. Armed with these tools, the future Cell Therapist may optimize and personalize treatment to avoid toxicity and improve efficacy universally across CAR designs.

Modulation of Cystatin C in Human Macrophages Improves Anti-Mycobacterial Immune Responses to Mycobacterium tuberculosis Infection and Coinfection With HIV.

Tuberculosis owes its resurgence as a major global health threat mostly to the emergence of drug resistance and coinfection with HIV. The synergy between HIV and Mycobacterium tuberculosis (Mtb) modifies the host immune environment to enhance both viral and bacterial replication and spread. In the lung immune context, both pathogens infect macrophages, establishing favorable intracellular niches. Both manipulate the endocytic pathway in order to avoid destruction. Relevant players of the endocytic pathway to control pathogens include endolysosomal proteases, cathepsins, and their natural inhibitors, cystatins. Here, a mapping of the human macrophage transcriptome for type I and II cystatins during Mtb, HIV, or Mtb-HIV infection displayed different profiles of gene expression, revealing cystatin C as a potential target to control mycobacterial infection as well as HIV coinfection. We found that cystatin C silencing in macrophages significantly improves the intracellular killing of Mtb, which was concomitant with an increased general proteolytic activity of cathepsins. In addition, downmodulation of cystatin C led to an improved expression of the human leukocyte antigen (HLA) class II in macrophages and an increased CD4+ T-lymphocyte proliferation along with enhanced IFN-γ secretion. Overall, our results suggest that the targeting of cystatin C in human macrophages represents a promising approach to improve the control of mycobacterial infections including multidrug-resistant (MDR) TB.

Abstract 619: Integrated multi-platform profiling of early-stage non-small cell lung cancer identifies relationship between disease recurrence and decreased native immune response in treatment-naïve resected NSCLC

Abstract Introduction: Differences in the host immune environment are thought to mediate heterogeneous treatment responses in non-small cell lung cancer (NSCLC). Unlike individual platform analyses, integrative analysis of multi-platform profiling allows for the discovery of novel interactions that expand our understanding of the disease. Utilizing the ImmunogenomiC prOfiling of NSCLC patient cohort (ICON), a prospective multi-omics protocol of operable early-stage NSCLC tumors with integrated immune, genomic, and clinical data, we hypothesized that multi-platform analyses would identify differences in the immune-genomic landscape that are associated with disease recurrence. Methods: Tumor and tumor-adjacent uninvolved lung was collected at resection; blood was collected before and after surgery. Tissue samples underwent WES, RNAseq, TCR sequencing (TCRseq), multiplex immunofluorescence (mIF), and RPPA profiling; tissue and blood (PBMC) samples were analyzed by flow cytometry. An integrated, inter-modality network was built using Spearman correlations between measurement pairs from different data modalities. Multivariate analysis was performed to adjust for stage and histology. Results: A total of 89 treatment-naïve patients with Stage 1-3 resected NSCLC (Squamous: 19; Non-squamous: 70) and 24 months of follow-up were analyzed (recurrence N = 24; no recurrence N = 65). The data network includes over 4,000 measurements linked by over 50,000 correlations. InfoMap, a community detection approach, was used to extract sub-network modules, which were used to contextualize the results of multivariate analysis. Tumors from patients with recurrence demonstrated decreased immune cell infiltration and activation including decreased cytotoxic CD8 T-cells (CD8+PD1+; fold-change (FC) = 0.898, p = 0.018; flow cytometry), decreased T-cell clonality (FC = 0.954, p = 0.017; TCRseq), and decreased tumor-associated macrophages (CD68+PD-L1+; FC = 0.426, p = 0.011; mIF). Furthermore, circulating CD8+ICOS+ activated T cells were decreased in patients with recurrence suggesting an impaired systemic anti-tumor immune response (FC = 0.552, p = 0.042; PBMC Flow). Finally, tumor-adjacent uninvolved lungs showed distinct T-cell phenotypes with accumulation of inactive CD8 T-cells (CD8+PD1-TIM3-) in patients with recurrence and increased populations of activated CD8 T-cells (CD8+PD1+) in patients without recurrence. Conclusion: Integrative multi-omic analysis suggests preserved anti-tumor immune surveillance in patients who are disease-free after 2 years from surgical resection with curative intent for treatment of NSCLC relative to patients with disease recurrence. Further analysis is ongoing to interrogate genomic and immune variables that are associated with disease recurrence. Citation Format: Neal Akhave, Stephanie Schmidt, Alexandre Reuben, Tina Cascone, Jianhua Zhang, Jun Li, Junya Fujimoto, Lauren A. Byers, Beatriz Sanchez-Espiridion, Lixia Diao, Jing Wang, Lorenzo Federico, Marie-Andree Forget, Daniel J. McGrail, Annikka Weissferdt, Shiaw-Yih Lin, Younghee Lee, Carmen Behrens, Ignacio I. Wistuba, Andrew Futreal, Ara Vaporciyan, Boris Sepesi, John V. Heymach, Chantale Bernatchez, Cara Haymaker, Jianjun Zhang, Christopher A. Bristow, Marcelo V. Negrao, Don L. Gibbons. Integrated multi-platform profiling of early-stage non-small cell lung cancer identifies relationship between disease recurrence and decreased native immune response in treatment-naïve resected NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 619.

Neoadjuvant SABR for Renal Cell Carcinoma Inferior Vena Cava Tumor Thrombus-Safety Lead-in Results of a Phase 2 Trial.

To evaluate the feasibility, safety, oncologic outcomes, and immune effect of neoadjuvant stereotactic radiation (Neo-SAbR) followed by radical nephrectomy and thrombectomy (RN-IVCT). These are results from the safety lead-in portion of a single-arm phase 1 and 2 trial. Patients with kidney cancer (renal cell carcinoma [RCC]) and inferior vena cava (IVC) tumor thrombus (TT) underwent Neo-SAbR (40 Gy in 5 fractions) to the IVC-TT followed by open RN-IVCT. Absence of grade 4 to 5 adverse events (AEs) within 90 days of RN-IVCT was the primary endpoint. Exploratory studies included pathologic and immunologic alterations attributable to SAbR. Six patients were included in the final analysis. No grade 4 to 5 AEs were observed. A total of 81 AEs were reported within 90 days of surgery: 73% (59/81) were grade 1, 23% (19/81) were grade 2, and 4% (3/81) were grade 3. After a median follow-up of 24 months, all patients are alive. One patient developed de novo metastatic disease. Of 3 patients with metastasis at diagnosis, 1 had a complete and another had a partial abscopal response without the concurrent use of systemic therapy. Neo-SABR led to decreased Ki-67 and increased PD-L1 expression in the IVC-TT. Inflammatory cytokines and autoantibody titers reflecting better host immune status were observed in patients with nonprogressive disease. Neo-SAbR followed by RN-IVCT for RCC IVC-TT is feasible and safe. Favorable host immune environment correlated with abscopal response to SABR and RCC relapse-free survival, though direct causal relation to SABR has yet to be established.

Trichinella spiralis Calreticulin S-Domain Binds to Human Complement C1q to Interfere With C1q-Mediated Immune Functions.

Helminths develop strategies to escape host immune responses that facilitate their survival in the hostile host immune environment. Trichinella spiralis, a tissue-dwelling nematode, has developed a sophisticated strategy to escape complement attack. Our previous study demonstrated that T. spiralis secretes calreticulin (TsCRT) to inhibit host classical complement activation through binding to C1q; however, the C1q binding site in TsCRT and the specific mechanism involved with complement-related immune evasion remains unknown. Using molecular docking modeling and fragment expression, we determined that TsCRT-S, a 153-aa domain of TsCRT, is responsible for C1q binding. Recombinant TsCRT-S protein expressed in Escherichia coli had the same capacity to bind and inhibit human C1q-induced complement and neutrophil activation, as full-length TsCRT. TsCRT-S inhibited neutrophil reactive oxygen species and elastase release by binding to C1q and reduced neutrophil killing of newborn T. spiralis larvae. Binding of TsCRT-S to C1q also inhibited formation of neutrophil extracellular traps (NETs), which are involved in autoimmune pathologies and have yet to be therapeutically targeted. These findings provide evidence that the TsCRT-S fragment, rather than the full-length TsCRT, is a potential target for vaccine or therapeutic development for trichinellosis, as well as for complement-related autoimmune disease therapies.

Macrophage Tropism in Pathogenic HIV-1 and SIV Infections.

Most myeloid lineage cells express the receptor and coreceptors that make them susceptible to infection by primate lentiviruses (SIVs and HIVs). However, macrophages are the only myeloid lineage cell commonly infected by SIVs and/or HIVs. The frequency of infected macrophages varies greatly across specific host and virus combinations as well as disease states, with infection rates being greatest in pathogenic SIV infections of non-natural hosts (i.e., Asian nonhuman primates (Asian NHPs)) and late in untreated HIV-1 infection. In contrast, macrophages from natural SIV hosts (i.e., African NHPs) are largely resistant to infection due to entry and/or post-entry restriction mechanisms. These highly variable rates of macrophage infection may stem from differences in the host immune environment, entry and post-entry restriction mechanisms, the ability of a virus to adapt to efficiently infect macrophages, and the pleiotropic effects of macrophage-tropism including the ability to infect cells lacking CD4 and increased neutralization sensitivity. Questions remain about the relationship between rates of macrophage infection and viral pathogenesis, with some evidence suggesting that elevated levels of macrophage infection may contribute to greater pathogenesis in non-natural SIV hosts. Alternatively, extensive infection of macrophages may only emerge in the context of high viral loads and immunodeficiency, making it a symptom of highly pathogenic infections, not a primary driver of pathogenesis.

Mycobacterium tuberculosis clinical isolates carry mutational signatures of host immune environments.

Mycobacterium tuberculosis (Mtb) infection results in a spectrum of clinical and histopathologic manifestations. It has been proposed that the environmental and immune pressures associated with different contexts of infection have different consequences for the associated bacterial populations, affecting drug susceptibility and the emergence of resistance. However, there is little concrete evidence for this model. We prospectively collected sputum samples from 18 newly diagnosed and treatment-naïve patients with tuberculosis and sequenced 795 colony-derived Mtb isolates. Mutant accumulation rates varied considerably between different bacilli isolated from the same individual, and where high rates of mutation were observed, the mutational spectrum was consistent with reactive oxygen species-induced mutagenesis. Elevated bacterial mutation rates were identified in isolates from HIV-negative but not HIV-positive individuals, suggesting that they were immune-driven. These results support the model that mutagenesis of Mtb in vivo is modulated by the host environment, which could drive the emergence of variants associated with drug resistance in a host-dependent manner.

The essential schistosome tegumental ectoenzyme SmNPP5 can block NAD-induced T cell apoptosis

ABSTRACT Infection with intravascular platyhelminths of the genus Schistosoma can result in the debilitating disease schistosomiasis. Schistosomes (blood flukes) can survive in the host for many years. We hypothesize that proteins on their host-interactive surface modify the worm’s external environment to help insure worm survival. Previously, we have shown that a surface ectoenzyme of Schistosoma mansoni, SmNPP5 – a nucleotide pyrophosphatase/phosphodiesterase – can cleave ADP and block platelet aggregation in vitro. In this work, we show that both adult schistosomes and recombinant SmNPP5 can cleave the exogenous purinergic signaling molecule nicotinamide adenine dinucleotide (NAD). In doing so, worms and rSmNPP5 can prevent NAD-induced apoptosis of T cells in vitro. Since regulatory T cells (Tregs) are especially prone to such NAD-induced cell death (NICD), we hypothesize that schistosome cleavage of NAD promotes Treg survival which creates a more immunologically hospitable environment for the worms in vivo. In addition to SmNPP5, schistosomes express another host-interactive NAD-degrading enzyme, SmNACE. We successfully suppressed the expression of SmNPP5 and SmNACE (singly or together) using RNAi. Only SmNPP5-suppressed worms, and not SmNACE-suppressed worms, were significantly impaired in their ability to cleave exogenous NAD compared to controls. Therefore, we contend that ectoenzyme SmNPP5 on the surface of the worm is primarily responsible for extracellular NAD cleavage and that this helps modulate the host immune environment by preventing Treg cell death.

Electronic Cigarette Aerosol Modulates the Oral Microbiome and Increases Risk of Infection.

SummaryThe trend of e-cigarette use among teens is ever increasing. Here we show the dysbiotic oral microbial ecology in e-cigarette users influencing the local host immune environment compared with non-smoker controls and cigarette smokers. Using 16S rRNA high-throughput sequencing, we evaluated 119 human participants, 40 in each of the three cohorts, and found significantly altered beta-diversity in e-cigarette users (p = 0.006) when compared with never smokers or tobacco cigarette smokers. The abundance of Porphyromonas and Veillonella (p = 0.008) was higher among vapers. Interleukin (IL)-6 and IL-1β were highly elevated in e-cigarette users when compared with non-users. Epithelial cell-exposed e-cigarette aerosols were more susceptible for infection. In vitro infection model of premalignant Leuk-1 and malignant cell lines exposed to e-cigarette aerosol and challenged by Porphyromonas gingivalis and Fusobacterium nucleatum resulted in elevated inflammatory response. Our findings for the first time demonstrate that e-cigarette users are more prone to infection.

Modulation of host immune status by cryptococcus co-infection during HIV-1 pathogenesis and its impact on CD+4 cell and cytokines environment

BackgroundCryptococcus infection is the second most common opportunistic infection in HIV patients with an increased rate of morbidity and mortality. Altered immune system during HIV- Cryptococcus co-infection is yet to be explored by laboratory. This study evaluates pro- and the anti-inflammatory cytokines in HIV patients with Cryptococcus co-infection and correlate them with CD4+T cell counts as well as viral loads before the initiation of drug therapy. This information would enable to understand host immune modulation and cellular environment during co-infection and understand its impact on HIV pathogenesis. MethodologyThe study comprised four categories of patients with cryptococcosis, HIV, HIV-cryptococcosis co-infected and asymptomatic Healthy volunteers. All the patients and healthy individuals were subjected to CD4+T cells count by FACS using monoclonal antibody cocktail CD4+T cell count (counts per mm3) which was counted using multiSET software on FACS caliber. The viral loads were counted in terms of viral RNA copy numbers which was estimated by real-time PCR using by Artus HIV-1 RG. The sensitivity of kit was >70 IU/ml. ELISA was performed for IL-12 p70, IL-12, IL-4, IL-10, IL-6, TNF-α and IFN-Y using commercially kits (BD Biosciences, USA). Significant variations were assayed by Student's t-test and P values ≤ 0.05 were considered statistically significant. ResultsReduction in CD+4 cell counts was highly significant in HIV patients with or without cryptococcosis. CD4+T cell counts were inversely proportional to viral load. TNF-α levels were raised in cryptococcosis patients significantly higher than healthy individuals. TNF-α was more or less not dependent on viral load but it was more related to the cryptococcosis IL-12 levels were increased in patients with infection and was highest in the HIV infected group. Level of IL-4 was similar in healthy and patients with cryptococcosis but it was elevated in HIV-Crypto co-infected patients. HIV infected patients showed a significant increase in IL-4 level and it was elevated higher in co-infected patients. IL-10 and IL-6 were significantly higher in HIV patients. The fungal infection did not influence the levels of IL-10 in HIV group but IL-6 was low in fungal infected patients. ConclusionThere are very limited studies related to the immune modulation status of HIV co-infected with Cryptococcus before the initiation of any drug therapy. Such information might through in-depth light to understand the initial state of the immune environment which certainly would play a pivotal role in the outcome of the immune modulation.

The Deconstructed Granuloma: A Complex High-Throughput Drug Screening Platform for the Discovery of Host-Directed Therapeutics Against Tuberculosis.

Mycobacterium tuberculosis (Mtb) continues to be a threat to Global Public Health, and its control will require an array of therapeutic strategies. It has been appreciated that high-throughput screens using cell-based assays to identify compounds targeting Mtb within macrophages represent a valuable tool for drug discovery. However, the host immune environment, in the form of lymphocytes and cytokines, is completely absent in a chemical screening platform based on infected macrophages alone. The absence of these players unnecessarily limits the breadth of novel host target pathways to be interrogated. In this study, we detail a new drug screening platform based on dissociated murine TB granulomas, named the Deconstructed Granuloma (DGr), that utilizes fluorescent Mtb reporter strains screened in the host immune environment of the infection site. The platform has been used to screen a collection of known drug candidates. Data from a representative 384-well plate containing known anti-bacterial compounds are shown, illustrating the robustness of the screening platform. The novel deconstructed granuloma platform represents an accessible, sensitive and robust high-throughput screen suitable for the inclusive interrogation of immune targets for Host-Directed Therapeutics.

Neutrophil programming dynamics and its disease relevance.

Neutrophils are traditionally considered as first responders to infection and provide antimicrobial host defense. However, recent advances indicate that neutrophils are also critically involved in the modulation of host immune environments by dynamically adopting distinct functional states. Functionally diverse neutrophil subsets are increasingly recognized as critical components mediating host pathophysiology. Despite its emerging significance, molecular mechanisms as well as functional relevance of dynamically programmed neutrophils remain to be better defined. The increasing complexity of neutrophil functions may require integrative studies that address programming dynamics of neutrophils and their pathophysiological relevance. This review aims to provide an update on the emerging topics of neutrophil programming dynamics as well as their functional relevance in diseases.

Plastic and micro-evolutionary responses of a nematode to the host immune environment

Parasitic organisms have to cope with the defences deployed by their hosts and this can be achieved adopting immune evasion strategies or optimal life history traits according to the prevailing pattern of immune-mediated mortality. Parasites often encounter variable immune environments both within and between hosts, promoting the evolution of plastic strategies instead of fixed responses. Here, we explored the plasticity and micro-evolutionary responses of immunomodulatory mechanisms and life history traits to the immune environment provided by the host, using the parasitic nematode Heligmosomoides polygyrus. To test if the parasite responds plastically to the immune environment, we stimulated the systemic inflammatory response of mice and we assessed i) the expression of two genes with candidate immunomodulatory functions (Hp-Tgh2 and Hp-CPI); ii) changes in the number of eggs shed in the faeces. To test if the immune environment induces a micro-evolutionary response in the parasite, we maintained the nematode in mice whose inflammatory response was up- or down-regulated during four generations. We found that H. polygyrus plastically responded to a sudden rise of pro-inflammatory cytokines, up-regulating the expression of two candidate genes involved in the process of immune modulation, and enhancing egg output. At the micro-evolutionary level, parasites maintained in hosts experiencing different levels of inflammation did not have differential expression of Hp-Tgh2 and Hp-CPI genes when infecting unmanipulated, control, mice. However, parasites maintained in mice with an up-regulated inflammation shed more eggs compared to the control line. Overall, our study shows that H. polygyrus can plastically adjust the expression of immunomodulatory genes and life history traits, and responds to selection exerted by the host immune system.