Immunogenomic signatures to predict outcome in ovarian and endometrial cancers: Potential strategies in targeting the tumor immune microenvironment to improve response to immunotherapy.

2020 ◽  
Vol 38 (5_suppl) ◽  
pp. 4-4
Author(s):  
Haider Mahdi ◽  
Ying Ni
Keyword(s):  
Endometrial Cancer ◽  
Immune Cells ◽  
Transforming Growth Factor ◽  
Immune Cell ◽  
Checkpoint Inhibitors ◽  
Individual Gene ◽  
Cell Abundance ◽  
Ifn Γ ◽  
Endometrial Cancers ◽  
The Impact

4 Background: Ovarian and MSS endometrial cancers are characterized by immunosuppressive microenvironment (TME) and low response to immunotherapy with checkpoint inhibitors (CPI). Targeting immunosuppressive factors within TMErepresents an attractive approach to enhance response to CPI. Therefore, we sought to investigate different immunogenomic signatures and immune cells within TME and correlate them with survival. Methods: We used whole transcriptome sequencing of matched tumor-normal samples from 38 uterine serous cancer and TCGA data of ovarian (n = 374) and endometrial cancers (n = 541). Immunogenomic signatures focusing on Transforming Growth Factor (TGFβ), 18-genes IFN-γ and myeloid signatures (CD47 and B7H4 expressions) and immune cell abundance were investigated. Gene expression score was calculated by averaging the normalized and log transformed individual gene read counts. The optimized score cut off was selected to best separate the survival in the pilot cohort. Then the score was tested in TCGA RNAseq datasets. Population abundance of tissue-infiltrating immune cells were estimated using MCPcounter R package from bulk transcriptome data. Results: Higher IFN-γ and lower TGF-β signatures predicted better survival for endometrial and ovarian cancers (p < 0.05). The impact of TGF-β was higher in MSI-H vs. MSS cancers (p = 0.013 vs. 0.09). High CD47 predicted poor survival in endometrial cancer. Combined IFN-γ and TGF-β signatures predicted survival in the ovarian and endometrial cohorts (p < 0.001). Combined IFN-γ and CD47 expression predicted survival in endometrial cancer (p = 0.033). Analysis of immune cell abundance revealed enrichment of monocytic lineage and neutrophils but paucity of cytotoxic T-cells, NK cells, dendritic cells and B-cells. Immune cell abundance is being correlated with survival. Conclusions: Our data support the role of immunogenomic markers in predicting survival. We are evaluating these markers in predicting response to CPI in a pilot cohort. Immunogenomic markers represent the tumor microenvironment, can potentially guide rationale combination immunotherapy.

scholarly journals Oxidative Stress Compromises Lymphocyte Function in Neonatal Dairy Calves

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 255
Author(s):  
Wilmer Cuervo ◽  
Lorraine M. Sordillo ◽  
Angel Abuelo
Keyword(s):  
Oxidative Stress ◽  
Immune Responses ◽  
Immune Cell ◽  
Lymphocyte Activation ◽  
Dairy Calves ◽  
Lymphocyte Function ◽  
Newborn Calves ◽  
Ifn Γ ◽  
The Impact

Dairy calves are unable to mount an effective immune response during their first weeks of life, which contributes to increased disease susceptibility during this period. Oxidative stress (OS) diminishes the immune cell capabilities of humans and adult cows, and dairy calves also experience OS during their first month of life. However, the impact that OS may have on neonatal calf immunity remains unexplored. Thus, we aimed to evaluate the impact of OS on newborn calf lymphocyte functions. For this, we conducted two experiments. First, we assessed the association of OS status throughout the first month of age and the circulating concentrations of the cytokines interferon-gamma (IFN-γ) and interleukin (IL) 4, as well as the expression of cytokine-encoding genes IFNG, IL2, IL4, and IL10 in peripheral mononuclear blood cells (PBMCs) of 12 calves. Subsequently, we isolated PBMCs from another 6 neonatal calves to investigate in vitro the effect of OS on immune responses in terms of activation of lymphocytes, cytokine expression, and antibody production following stimulation with phorbol 12-myristate 13-acetate or bovine herpesvirus-1. The results were compared statistically through mixed models. Calves exposed to high OS status in their first month of age showed higher concentrations of IL-4 and expression of IL4 and IL10 and lower concentrations of IFN-γ and expression of IFNG and IL2 than calves exposed to lower OS. In vitro, OS reduced lymphocyte activation, production of antibodies, and protein and gene expression of key cytokines. Collectively, our results demonstrate that OS can compromise some immune responses of newborn calves. Hence, further studies are needed to explore the mechanisms of how OS affects the different lymphocyte subsets and the potential of ameliorating OS in newborn calves as a strategy to augment the functional capacity of calf immune cells, as well as enhance calves’ resistance to infections.

scholarly journals 492 Integration of high dimensional datasets in an immunocompetent mammary mouse model reveals pathways of tolerance and resistance to immune checkpoint blockade

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A528-A528
Author(s):  
Lin Ma ◽  
Jian-Hua Mao ◽  
Mary Helen Barcellos-Hoff ◽  
Jade Moore
Keyword(s):  
Tumor Microenvironment ◽  
Immune Cells ◽  
Transforming Growth Factor ◽  
Immune Cell ◽  
Systemic Disease ◽  
Ct Imaging ◽  
High Dimensional ◽  
Cytokine Signaling ◽  
Immune Infiltrate ◽  
Pet Ct

BackgroundCheckpoint inhibitors can induce robust and durable responses in a subset of patients. Extending this benefit to more patients could be facilitated by better understanding of how interacts with immune cells with the tumor microenvironment, which is a critical barrier to control both local and systemic disease. The composition and pattern of the immune infiltrate associates with the likelihood of response to immunotherapy. Inflamed tumors that exhibit a brisk immune cell infiltrate are responsive, while those in which immune cells are completely or partially excluded are not. Transforming growth factor β (TGFβ) is immunosuppressive and associated with the immune excluded phenotype.MethodsUsing an immune competent mammary tumor derived transplant (mTDT) model recently developed in our lab, exhibits inflamed, excluded or deserts immune infiltrate phenotypes based on localization of CD8 lymphocytes. Using whole transcriptome deep sequencing, cytof, and PET-CT imaging, we evaluated the tumor, microenvironment, and immune pathway activation among immune infiltrate phenotypes.ResultsThree distinct inflamed tumors phenotypes were identified: ‘classically’ inflamed characterized by pathway evidence of increased CD8+ T cells and decreased PD-L1 expression, inflamed tumors with pathways indicative of neovascularization and STAT3 signaling and reduced T cell mobilization, and an inflamed tumor with increased immunosuppressive myeloid phenotypes. Excluded tumors were characterized by TGFβ gene expression and pro-inflammatory cytokine signaling (e.g. TNFα, IL1β), associated with decreased leukocytes homing and increased immune cell death of cells. We visualized and quantified TGFβ activity using PET-CT imaging of 89Zr-fresolimumab, a TGFβ neutralizing antibody. TGFβ activity was significantly increased in excluded tumors compared to inflamed or desert tumors, which was supported by quantitative pathology (Perkin Elmer) of its canonical signaling target, phosphorylated SMAD2 (pSMAD2). pSMAD2 was positively correlated with PD-L1 expression in the stroma of excluded tumors. In contrast, in inflamed tumors, TGFβ activity positively correlated with increased F4/80 positive macrophages and negatively correlated with expression of PD-L1. CyTOF analysis of tumor and spleen immune phenotypes revealed increased trafficking of myeloid cells in mice bearing inflamed tumors compared to excluded and deserts.ConclusionsThe immunocompetent mTDT provides a model that bridges the gap between the immune landscape and tumor microenvironment. Integration of these high-dimensional data with further studies of response to immunotherapies will help to identify tumor features that favor response to treatment or the means to convert those that are unresponsive.

scholarly journals When Cells Suffocate: Autophagy in Cancer and Immune Cells under Low Oxygen

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Katrin Schlie ◽  
Jaeline E. Spowart ◽  
Luke R. K. Hughson ◽  
Katelin N. Townsend ◽  
Julian J. Lum
Keyword(s):  
Tumor Microenvironment ◽  
Cancer Cells ◽  
Immune Cells ◽  
Immune Cell ◽  
Treatment Strategies ◽  
Patient Treatment ◽  
Low Oxygen ◽  
Tumor Environment ◽  
And Function ◽  
The Impact

Hypoxia is a signature feature of growing tumors. This cellular state creates an inhospitable condition that impedes the growth and function of all cells within the immediate and surrounding tumor microenvironment. To adapt to hypoxia, cells activate autophagy and undergo a metabolic shift increasing the cellular dependency on anaerobic metabolism. Autophagy upregulation in cancer cells liberates nutrients, decreases the buildup of reactive oxygen species, and aids in the clearance of misfolded proteins. Together, these features impart a survival advantage for cancer cells in the tumor microenvironment. This observation has led to intense research efforts focused on developing autophagy-modulating drugs for cancer patient treatment. However, other cells that infiltrate the tumor environment such as immune cells also encounter hypoxia likely resulting in hypoxia-induced autophagy. In light of the fact that autophagy is crucial for immune cell proliferation as well as their effector functions such as antigen presentation and T cell-mediated killing of tumor cells, anticancer treatment strategies based on autophagy modulation will need to consider the impact of autophagy on the immune system.

scholarly journals Search for receptors in immune cells that bind cancer cell antigens and their activation in silent cases

2019 ◽  
Author(s):  
Wenfa Ng
Keyword(s):  
Immune System ◽  
Amino Acid ◽  
Cancer Cells ◽  
Cell Lines ◽  
Cancer Cell ◽  
Immune Cells ◽  
Immune Cell ◽  
Checkpoint Inhibitors ◽  
Host Cells ◽  
Immune Receptor

The immune checkpoint plays an important role in keeping immune cells in check for protecting tissues and organs from attack by the body’s own immune system. Similar concepts also apply in how cancer cells managed to fool immune cells through the surface display of particular antigens that mimic those exhibited by normal body cells. Specifically, cancer cells display antigens that bind to receptors on immune cells that subsequently prevent an attack on the cancer cells. Such binding between cancer antigens and immune cell receptors can be prevented through the use of checkpoint inhibitors antibodies specific for particular receptors on immune cells; thereby, unleashing immune cells to mount an immune response against cancer cells. While demonstrating good remissions in many patients where tumours shrunk substantially after administration of checkpoint inhibitors, cases exist where an overactivated immune system cause harm to organs and tissues culminating in multiple organ failure. Analysis of such toxicity effects of checkpoint inhibitors revealed that generic nature of targeted immune receptor plays a pivotal role in determining extent of side effects. Specifically, if the target immune receptor participates in checkpoints that prevent immune cells from attacking host cells, unleashing such receptors in cancer therapy may have untoward effects on patient’s health. Hence, the goal should be the selection of immune cell receptor specific to cancer cell antigens and which does not bind antigens or ligands displayed by the body’s cells. Such receptors would provide ideal targets for the development of checkpoint inhibitor antibodies for unleashing immune cells against cancer cells. To search for non-generic receptors that bind cancer cell antigens only, a combined computational and experimental approach could be used where ensemble of surface antigens on cancer cells and available receptors on immune cells could be profiled by biochemical assays. Downstream purification of ligands and receptors would provide for both structural elucidation and amino acid sequencing useful for bioinformatic search of homologous sequences. Knowledge of the antigens’ and receptors’ structures and amino acid sequence would subsequently serve as inputs to computational algorithms that models molecular docking events between receptor and antigen. This paves the way for heterologous expression of putative ligand and receptor in cell lines cultured in co-culture format for assessing binding between ligand and receptor, and more importantly, its physiological effects. Ability of immune receptor to bind to ligands on normal cells could also be assessed. Similar co-culture studies could be conducted with cancer cells and different immune cell types to check for reproducibility of observed effect in cell lines. Finally, antibodies could be raised for candidate receptors whose inhibition would not result in systemic attack of immune cells on host cells.

scholarly journals Nutritional immunity: the impact of metals on lung immune cells and the airway microbiome during chronic respiratory disease

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Claire Healy ◽  
Natalia Munoz-Wolf ◽  
Janné Strydom ◽  
Lynne Faherty ◽  
Niamh C. Williams ◽  
...  
Keyword(s):  
Immune System ◽  
Trace Metals ◽  
Lung Disease ◽  
Chronic Lung Disease ◽  
Immune Cells ◽  
Immune Cell ◽  
Redox Activity ◽  
Nutritional Immunity ◽  
Airway Microbiome ◽  
The Impact

AbstractNutritional immunity is the sequestration of bioavailable trace metals such as iron, zinc and copper by the host to limit pathogenicity by invading microorganisms. As one of the most conserved activities of the innate immune system, limiting the availability of free trace metals by cells of the immune system serves not only to conceal these vital nutrients from invading bacteria but also operates to tightly regulate host immune cell responses and function. In the setting of chronic lung disease, the regulation of trace metals by the host is often disrupted, leading to the altered availability of these nutrients to commensal and invading opportunistic pathogenic microbes. Similarly, alterations in the uptake, secretion, turnover and redox activity of these vitally important metals has significant repercussions for immune cell function including the response to and resolution of infection. This review will discuss the intricate role of nutritional immunity in host immune cells of the lung and how changes in this fundamental process as a result of chronic lung disease may alter the airway microbiome, disease progression and the response to infection.

scholarly journals Mitosis in Cancer Cell Increases Immune Resistance via High Expression of HLA-G and PD-L1

Cancers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2661
Author(s):  
Matti Ullah ◽  
Warda Aoudjeghout ◽  
Cynthia Pimpie ◽  
Marc Pocard ◽  
Massoud Mirshahi
Keyword(s):  
Protein Expression ◽  
Cancer Cell ◽  
Immune Cells ◽  
Immune Cell ◽  
Leukemia Cell ◽  
Leukemia Cell Line ◽  
G1 Phase ◽  
G2 Phase ◽  
The Impact

Cancer is a result of “aggressive” division and uncontrolled proliferation of the abnormal cells that survive attack by immune cells. We investigated the expression of HLA-G and PD-L1 with the different stages of cancer cell division along with their role in the interaction of immune cells in vitro. Ovarian cancer (OVCAR-3) and chronic myeloid leukemia cell line (K-562) are used for this study. The correlation of protein expression with percentage of cells in each phase (G1, S and G2 phase) was evaluated through FACS. Cells were synchronized in G1, G2 and mitotic phase to evaluate gene (RT-qPCR) and protein expression (FACS). Real-time immune cell attack (RTICA) analysis with PBMCs (peripheral blood mono-nuclear cells) and cancer cells were performed. We found that cells expressing higher levels of HLA-G and PD-L1 are mainly in G2 phase and those expressing lower levels are mainly in G1 phase. Evidently, the higher expression of the two proteins was observed when synchronized in mitotic phase as compared to low expression when synchronized in G1 phase. RTICA analysis showed the presence of HLA-G delayed the lysis of the cells. In conclusion, the cancer cell can escape from immune cells in division stage that suggests the impact of mitosis index for cancer immunotherapy.

scholarly journals Concomitant or delayed anti-TNF differentially impact on immune-related adverse events and antitumor efficacy after anti-CD40 therapy

2020 ◽  
Vol 8 (2) ◽  
pp. e001687
Author(s):  
Celia Jacoberger-Foissac ◽  
Stephen J Blake ◽  
Jing Liu ◽  
Elizabeth McDonald ◽  
Hannah Triscott ◽  
...  
Keyword(s):  
Adverse Events ◽  
Mouse Model ◽  
Immune Cell ◽  
Checkpoint Inhibitors ◽  
Clinical Score ◽  
Antitumor Efficacy ◽  
Tumor Models ◽  
Colon Tissue ◽  
Treg Depletion ◽  
The Impact

BackgroundConcomitant tumor necrosis factor (TNF) neutralization in combination with immune checkpoint inhibitors (ICIs) reduces clinical immune-related adverse events (irAEs) and appears to improve antitumor efficacy in preclinical tumor models. Agonistic antibodies targeting costimulatory receptors such as CD40 represent an additional strategy to boost antitumor immune response and potentiate the activity of ICIs. However, the dose-limiting toxicities observed in anti-CD40-treated cancer patients have hindered its clinical development.MethodsWe previously described a mouse model to assess both antitumor activity and irAEs induced by various effective combination immunotherapies. Using the BALB/c and C57BL/6 strains of FoxP3-GFP-DTR (FoxP3DTR) mice, transient depletion of T regulatory cells (Tregs) prior to immunotherapy with additional immunomodulatory antibodies, lowered immune self-tolerance, resulting in the development of a spectrum of physical and biochemical irAEs similar to that reported clinically. In MC38 and 4T1.2 tumor models, following transient Treg depletion, we evaluated the impact of anti-CD40 on antitumor efficacy and the development of irAEs and the impact of concomitant or delayed TNF blockade on both these parameters. Physical irAEs were scored and biochemical irAEs were measured in the serum (ALT and cytokine levels). Histopathological liver and colon tissue analysis were performed to assess immune cell infiltration and tissue damage.ResultsSimilar to early clinical trials of CD40 agonists, in our tumor models we observed liver toxicities and rapid release of proinflammatory cytokines (TNF, interleukin 6, interferon-γ). In the BALB/c strain, anti-CD40 induced severe physical and biochemical irAEs. Concomitant anti-TNF treatment abrogated weight loss, liver damage and colitis, which consequently resulted in an improved clinical score. However, concomitant anti-TNF impaired antitumor response in a proportion of anti-CD40-treated C57BL/6 FoxP3DTR mice. Delaying TNF blockade in these mice reduced biochemical but not physical irAEs while preserving antitumor efficacy.ConclusionsOur results suggest concomitant rather than delayed anti-TNF is most effective in reducing biochemical and physical irAEs induced by anti-CD40, although it had the potential to negatively impact antitumor efficacy. Furthermore, our findings highlight the utility of our mouse model to assess the severity of irAEs induced by novel immunotherapeutic agents and evaluate whether their toxicity and antitumor efficacy can be uncoupled.

scholarly journals 3363 Prognostic Value of Immune-Related Biomarkers in Resected Non-Small Cell Lung Cancer

2019 ◽  
Vol 3 (s1) ◽  
pp. 153-153
Author(s):  
Rajwanth R Veluswamy ◽  
Stephanie Tuminello ◽  
Francesca Petralia ◽  
Wil Lieberman-Cribbin ◽  
Pei Wang ◽  
...  
Keyword(s):  
Nk Cells ◽  
Immune Cells ◽  
Immune Cell ◽  
Meta Analysis ◽  
Stage I ◽  
Resected Stage ◽  
Iiia Nsclc ◽  
Nsclc Patients ◽  
Lung Adenocarcinomas ◽  
The Impact

OBJECTIVES/SPECIFIC AIMS: Immune cells within the tumor microenvironment (TME) play an important role in the development and progression of non-small cell lung cancer (NSCLC). However, data evaluating the impact of individual immune cell types on NSCLC outcomes is limited and often conflicting. We performed a meta-analysis of existing data and used The Cancer Genome Atlas (TCGA) to evaluate the effect of several immune cells on surgical outcomes of stage I-IIIA NSCLC. METHODS/STUDY POPULATION: PubMed was searched to identify eligible studies evaluating survival of surgically resected stage I-IIIA NSCLC patients according to immune cell infiltration. Meta-analysis was performed using a linear mixed-effects model to determine overall, disease specific and progression free survival. We then used a similar patient subset found in the TCGA to validate the meta-analysis findings. For the TCGA analysis, sample-specific scores for different immune cells were computed via xCell using level three RNAseq data. After stratifying the cohort by histologic subtype, the association between each cell type and survival was assessed via Cox Regression, while adjusting for stage, gender and smoking status. RESULTS/ANTICIPATED RESULTS: From the meta-analysis (37 articles eligible; N = 8,162 patients), high levels of CD20+ B cells (hazard ratio [HR]: 0.36, 95% confidence interval [CI]: 0.15-0.85), natural killer (NK) cells (HR: 0.64, 95% CI: 0.41-1.0), and dendritic cells (0.34, 95% CI: 0.13-0.84) were significantly associated with better overall survival (OS); T regulatory cells (HR: 1.85, 95% CI: 1.35-2.54) were associated with worst OS. High CD8+ T cell infiltrates were associated with improved disease-free survival (DFS; HR: 0.85, 95% CI 0.73-0.99), while CD68+ macrophages (HR> 2.83, 95% CI: 1.28-6.24) were associated with worst DFS. In the TCGA cohort, lung adenocarcinomas rich in CD4 T cells, CD8 T cells, B cells, and NK cells were associated with improved OS in unadjusted analysis. In adjusted analysis, only NK cells were associated with improved OS (HR: 0.82, 95% CI: 0.69-0.98). There was no significant association of any immune cell type for DFS in lung adenocarcinomas and with both OS and DFS in Squamous Cell Lung Cancers (p>0.05 for all comparisons). DISCUSSION/SIGNIFICANCE OF IMPACT: The presence of tumor infiltration by specific immune cell subsets may potentially predict survival outcomes in resected stage I-III NSCLC patients. However, the impact of immune cells may not be similar in all histologic types and after adjusting for important clinical confounders.

scholarly journals A correlation-based network for biomarker discovery in obesity with metabolic syndrome

2019 ◽  
Vol 20 (S6) ◽  
Author(s):  
Pin-Yen Chen ◽  
Allan W. Cripps ◽  
Nicholas P. West ◽  
Amanda J. Cox ◽  
Ping Zhang
Keyword(s):  
Metabolic Syndrome ◽  
Immune Cells ◽  
Immune Cell ◽  
Healthy Weight ◽  
Network Approach ◽  
Serum Cytokine ◽  
Cytokine Concentration ◽  
Microbial Composition ◽  
Cell Abundance ◽  
Serum Cytokine Concentration

Abstract Background Obesity is associated with chronic activation of the immune system and an altered gut microbiome, leading to increased risk of chronic disease development. As yet, no biomarker profile has been found to distinguish individuals at greater risk of obesity-related disease. The aim of this study was to explore a correlation-based network approach to identify existing patterns of immune-microbiome interactions in obesity. Results The current study performed correlation-based network analysis on five different datasets obtained from 11 obese with metabolic syndrome (MetS) and 12 healthy weight men. These datasets included: anthropometric measures, metabolic measures, immune cell abundance, serum cytokine concentration, and gut microbial composition. The obese with MetS group had a denser network (total number of edges, n = 369) compared to the healthy network (n = 299). Within the obese with MetS network, biomarkers from the immune cell abundance group was found to be correlated to biomarkers from all four other datasets. Conversely in the healthy network, immune cell abundance was only correlated with serum cytokine concentration and gut microbial composition. These observations suggest high involvement of immune cells in obese with MetS individuals. There were also three key hubs found among immune cells in the obese with MetS networks involving regulatory T cells, neutrophil and cytotoxic cell abundance. No hubs were present in the healthy network. Conclusion These results suggest a more complex interaction of inflammatory markers in obesity, with high connectivity of immune cells in the obese with MetS network compared to the healthy network. Three key hubs were identified in the obese with MetS network, involving Treg, neutrophils and cytotoxic cell abundance. Compared to a t-test, the network approach offered more meaningful results when comparing obese with MetS and healthy weight individuals, demonstrating its superiority in exploratory analysis.

scholarly journals Binding of Excreted and/or Secreted Products of Adult Hookworms to Human NK Cells in Necator americanus-Infected Individuals from Brazil

2008 ◽  
Vol 76 (12) ◽  
pp. 5810-5816 ◽  
Author(s):  
Andréa Teixeira-Carvalho ◽  
Ricardo T. Fujiwara ◽  
Erik J. Stemmy ◽  
Denise Olive ◽  
Jesse M. Damsker ◽  
...  
Keyword(s):  
Nk Cells ◽  
Transforming Growth Factor ◽  
Nk Cell ◽  
Ex Vivo ◽  
Interleukin 10 ◽  
Receptor Expression ◽  
Necator Americanus ◽  
Ifn Γ ◽  
The Impact

ABSTRACT The impact of the interaction between excreted and/or secreted (ES) Necator americanus products and NK cells from Necator-infected individuals was analyzed. We investigated the binding of ES products to NK cells, the expression of NK cell receptors (CD56, CD159a/NKG2A, CD314/NKG2D, CD335/NKp46, and KLRF1/NKp80), the frequency of gamma interferon (IFN-γ)-producing NK cells after whole-blood in vitro stimulation, and the capacity of N. americanus ES products to induce NK cell chemotaxis. In contrast to those from noninfected individuals, NK cells from Necator-infected individuals demonstrated no binding with N. americanus ES products. This phenomenon was not due to alterations in NK cell receptor expression in infected subjects and could not be reproduced with NK cells from uninfected individuals by incubation with immunoregulatory cytokines (interleukin-10/transforming growth factor β). Further, we found that a significantly greater percentage of NK cells from infected subjects than NK cells from uninfected individuals spontaneously produced IFN-γ upon ex vivo culture. Our findings support a model whereby NK cells from Necator-infected individuals may interact with ES products, making these cells refractory to binding with exogenous ES products. During N. americanus infection, human NK cells are attracted to the site of infection by chemotactic ES products produced by adult Necator worms in the gut mucosa. Binding of ES products causes the NK cells to become activated and secrete IFN-γ locally, thereby contributing to the adult hookworm's ability to evade host immune responses.

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