NKT Cell Infiltration Research Articles

Abstract PO2-24-10: Anti-Tumorigenic Immuno-Microenvironment by AB-329, a Potent and Selective AXL inhibitor, combined with paclitaxel in Triple-Negative Breast Cancer Preclinical Model

Abstract BACKGROUND The Gas6/AXL signaling pathway plays a substantial role in cancer cell survival, proliferation, immunosuppression, and metastasis. Elevated AXL expression is associated with advanced cancer stages and decreased overall survival rates, underscoring its potential as a therapeutic target for metastatic cancers. We investigated this possibility by utilizing AB-329, a selective small molecule AXL kinase inhibitor, to treat triple-negative breast cancer (TNBC). TNBC, typified by the lack of ER, PR, and HER2 expression, frequently displays mesenchymal characteristics and carries a significant risk of metastasis and an immunosuppressive tumor microenvironment. METHODS We assessed AXL protein expression in 28 human and 11 mouse breast cancer cell lines using Western blotting. The Microarray database was utilized to examine AXL gene expression in 40 human breast cancer cells. The Sulforhodamine B proliferation and soft agar assays measured the antiproliferative effect of AB-329 in TNBC cell lines. The in vitro anti-metastatic impact of AB-329 was evaluated through migration and invasion assays. We appraised the anti-tumor effects of AB-329 in combination with paclitaxel using 4T1 and E0771-LMB mouse TNBC xenograft models. We used FACS and CIBERSORTx to perform immune cell type profiling in E0771-LMB xenograft tumor tissues. To understand AB-329’s immunomodulatory effects in tumors, single-cell RNA sequencing was conducted in a humanized mouse model with SUM149 human TNBC xenografts. RESULTS Microarray data revealed higher AXL expression in TNBC cells compared to non-TNBC cells. Western blotting supported this, showing higher AXL protein expression, particularly in basal and mesenchymal subtypes of TNBC cells, compared to luminal breast cancer cells. AB-329 presented moderate antiproliferative effects as a monotherapy in the TNBC cell lines tested, with half-maximal inhibitory concentrations exceeding 5 µM. Nevertheless, combining AB-329 with paclitaxel resulted in significant growth inhibition in all tested TNBC cell lines (p < 0.05). Importantly, AB-329 alone could inhibit TNBC migration and invasion at a concentration of 1 µM (p < 0.01) and showed enhanced inhibition rates when paired with paclitaxel (p < 0.05). The combination of AB-329 and paclitaxel considerably reduced tumor growth in the 4T1 and E0771-LMB xenograft models compared to paclitaxel or AB-329. Total RNA sequencing and CIBERSORTx analysis indicated that the AB-329 and paclitaxel combination increased Natural Killer (NK) cells’ infiltration into E0771-LMB mouse TNBC xenograft tumors compared to single agent-treated tumors. A nearly 2.5-fold increase in NKT cell infiltration was also detected with AB-329 treatment compared to Control in SUM149 human TNBC xenografts. CONCLUSIONS Our preclinical data suggest that AB-329, an AXL inhibitor, could synergize effectively with paclitaxel in TNBC treatment, notably inhibiting tumor cell proliferation and migration while enhancing NK cell infiltration. Intriguingly, we observed an increased infiltration of NKT cells into tumors following AB-329 treatment, which may promote an anti-tumorigenic immuno-microenvironment. These results underscore the necessity for further investigation into the role of AB-329 in modulating the tumor immuno-microenvironment through AXL pathway inhibition and accentuate the potential for combining AB-329 with immunotherapy. Citation Format: Dileep Reddy Rampa, Jon Fuson, Huey Liu, Max Pan, Naoto Ueno, Jangsoon Lee. Anti-Tumorigenic Immuno-Microenvironment by AB-329, a Potent and Selective AXL inhibitor, combined with paclitaxel in Triple-Negative Breast Cancer Preclinical Model [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-24-10.

Building an Immune-Related Genes Model to Predict Treatment, Extracellular Matrix, and Prognosis of Head and Neck Squamous Cell Carcinoma.

Due to the considerable heterogeneity of head and neck squamous cell carcinoma (HNSCC), individuals with comparable TNM stages who receive the same treatment strategy have varying prognostic outcomes. In HNSCC, immunotherapy is developing quickly and has shown effective. We want to develop an immune-related gene (IRG) prognostic model to forecast the prognosis and response to immunotherapy of patients. In order to analyze differential expression in normal and malignant tissues, we first identified IRGs that were differently expressed. Weighted gene coexpression network analysis (WGCNA) was used to identify modules that were highly related, and univariate and multivariate Cox regression analyses were also used to create a predictive model for IRGs that included nine IRGs. WGCNA identified the four most noteworthy related modules. Patients in the model's low-risk category had a better chance of survival. The IRGs prognostic model was also proved to be an independent prognostic predictor, and the model was also substantially linked with a number of clinical characteristics. The low-risk group was associated with immune-related pathways, a low incidence of gene mutation, a high level of M1 macrophage infiltration, regulatory T cells, CD8 T cells, and B cells, active immunity, and larger benefits from immune checkpoint inhibitors (ICIs) therapy. The high-risk group, on the other hand, had suppressive immunity, high levels of NK and CD4 T-cell infiltration, high gene mutation rates, and decreased benefits from ICI therapy. As a result of our research, a predictive model for IRGs that can reliably predict a patient's prognosis and their response to both conventional and immunotherapy has been created.

Comprehensive pan-cancer analysis reveals NUSAP1 is a novel predictive biomarker for prognosis and immunotherapy response.

Nucleolar and spindle-associated protein 1 (NUSAP1) is a microtubule-associated protein that plays a crucial role in mitosis. Despite initial reports suggesting a potential involvement of NUSAP1 in tumor progression and malignant cell regulation, there has been no systematic analysis of its role in the tumor immune microenvironment, nor its predictive value for prognosis and immunotherapy response across different cancer types. In this study, we analyze NUSAP1 mRNA and protein expression levels in various human normal and tumor tissues, using data from TCGA, GTEx, CPTAC, HPA databases, and clinical samples. Our findings reveal that NUSAP1 is highly expressed in multiple tumor tissues across most cancer types and is primarily expressed in malignant and immune cells, according to single-cell sequencing data from the TISCH database. Prognostic analysis based on curated survival data from the TCGA database indicates that NUSAP1 expression levels can predict clinical outcomes for 26 cancer types. Furthermore, Gene Set Enrichment Analysis (GSEA) suggests that NUSAP1 promotes cell proliferation, tumor cell invasion, and regulation of anti-tumor response. Analysis of immune score, immune cell infiltration, and anti-cancer immunity cycle using ESTIMATE, TIMER, and TIP databases show that high NUSAP1 levels are associated with low CD4+T and NKT cell infiltration but high Th2 and MDSC infiltration, inversely correlated with antigen-presenting molecules and positively correlated with a variety of immune negative regulatory molecules. Notably, patients with melanoma, lung, and kidney cancer with high NUSAP1 expression levels have shorter survival times and lower immunotherapy response rates. Using Cmap analysis, we identify Entinostat and AACOCF3 as potential inhibitors of NUSAP1-mediated pro-oncogenic effects. In vitro and in vivo experiments further confirm that NUSAP1 knockdown significantly reduces the proliferation ability of A549 and MCF-7 cells. Overall, our study highlights the potential of NUSAP1 expression as a novel biomarker for predicting prognosis and immuno-therapeutic efficacy across different human cancers and suggests its potential for developing novel antitumor drugs or improving immunotherapy.

An association of iNKT+/CD3+/CD161+ lymphocytes in ovarian cancer tissue with CA125 serum concentration

The purpose of this study was to investigate the association of iNKT (human invariant natural killer T) cells with the key marker of ovarian cancer (OC) - CA125 (cancer antigen125) in serum. The study reports the assessment of iNKT cells in peripheral blood and tissue of benign and borderline ovarian tumors (BOTs) and in the advanced-stage ovarian cancer. The study groups were as follows: 25 women with benign ovarian tumors, 11 women with BOTs, and 24 women with primary advanced-stage ovarian cancers. The control group consisted of 20 patients without the ovarian pathology. The rates of iNKT lymphocytes in the peripheral blood and tissue specimens were evaluated by a flow cytometry. Significant differences in the percentage of iNKT+/CD3+ of CD3+ lymphocytes, iNKT+/CD3+/CD161+ among CD3+ and iNKT+/CD3+/CD161+ among CD3+/iNKT+ between the control group and patients with ovarian tumors in the peripheral blood and tumor tissue were identified. Significant correlations were noticed between the proportion of lymphocytes iNKT+/CD3+/CD161+ among CD3+/iNKT cells in blood and in cancer tissue of both benign and malignant tumors. In the OC group, neither the ratio of iNKT cells in the blood (P = 0.07), nor the intra-tumor NKT-cell infiltration (P = 0.5) were independent prognostic factors for the follow-up. An increased rate of iNKT cells was detected in benign ovarian tumors compared to OCs. In patients with ovarian cancer, a higher rate of iNKT cells in tumor tissue was present related to that noted in the patient’s blood. In addition, a correlation was discovered between the CA125 serum marker and NKT cells from the ovarian cancer tissue. This article has for the first time demonstrated a negative relationship between serum levels and NKT lymphocyte count from ovarian tissue. The inflammatory process in ovarian cancer tissue and the potential infiltration of endothelial immune cells, may result in a reduced number of NKT cells in the tumor microenvironment and increased circulation of the CA125 marker. Presented findings underscore new aspects of the iNKT cells involvement in the ovarian cancer development.

Abstract 6679: Immunophenotypic and transcriptome analyses of CT26 and 4T1 murine tumor models following anti-CTLA-4 treatment

Abstract Model selection for evaluation of immuno-oncology agents is often aided by both response to therapy and changes in immune cell subsets following treatment. To identify underlying factors that influence differences in therapeutic response, CT26 colorectal and 4T1-Luc (4T1) breast tumor models, which are immunologically warm and cold, respectively, were treated with anti-cytotoxic T-lymphocyte associated protein 4 (CTLA-4). Flow cytometry and transcriptome analysis were used to describe treatment-related changes in immune cell infiltrate, TIL activation status, cytokine/granzyme B production, and overall changes in gene expression. Response to anti-CTLA-4 therapy was distinct between these models. Tumor growth inhibition was observed in CT26 (74%), but not 4T1. In CT26, CD8+ and NK T cell infiltration increased, while M2 macrophages decreased. In 4T1 tumors, only increased NKT cell infiltration was noted after treatment, and no demonstrable changes were observed in any other cell type or activation marker. Several pharmacodynamic changes in immune cell activation were observed in CT26. Notably, CT26-derived CD4+, CD8+, and NK T cell subsets had increased IFNγ production (70%, 25%, and 17%, respectively, versus control). An increase in polyfunctional T cells producing both IFNγ and TNFα was also noted for CT26 and was correlated with slower tumor growth. Granzyme B was reduced and CD107a was increased in CT26-derived NK T cells, suggesting functionally active T cells. This was also supported by upregulation of genes in the cytotoxicity, antigen presentation, and NFkappaB pathways. Following CT26 treatment with anti-CTLA-4, transcriptome analysis with the nCounter® Mouse PanCancer IO 360 Panel (NanoString) showed an 8-10 fold induction of several T cell-related genes as well as an 8-14 fold induction of several chemokines and their receptors. These data complement the flow cytometry data and support stimulation of T cell activation and recruitment to CT26 tumors following anti-CTLA-4 treatment. In contrast, analysis of 4T1 tumors indicated only a 2 to 3-fold induction of CCL4, CCL11, and Granzyme A after treatment. Interestingly, genes in the matrix remodeling pathway were upregulated in 4T1 tumors upon anti-CTLA-4 treatment. In summary, CT26 tumors were responsive to anti-CTLA-4 treatment, showing increased polyfunctional T cell recruitment, NK T cell activity, and reduced M2 macrophage infiltration, as well as marked upregulation of several genes involved in T cell recruitment and activation in tumor. In contrast, 4T1 tumors did not display any remarkable response to therapy, changes to TIL infiltrates, and only limited changes to gene expression with treatment. Collectively, these results suggest tumor profiles following treatment can provide insight into potential targets of interest and are important for preclinical model selection. Citation Format: Sheri R. Barnes, David Draper, Sarah E. Church, Maryland Rosenfeld Franklin. Immunophenotypic and transcriptome analyses of CT26 and 4T1 murine tumor models following anti-CTLA-4 treatment [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6679.

Abstract A86: Comparative immunophenotypic analysis of immunogenically warm and cold syngeneic tumor models at baseline and after anti-mCTLA-4 treatment

Abstract To examine how baseline tumor immunophenotyes can influence therapeutic outcome, we used the CT26 colorectal and 4T1-Luc (4T1) breast cancer models, which are immunologically warm and cold tumors, respectively. We treated tumor-bearing mice with control or anti-mCTLA-4 antibodies (anti-CTLA-4), or left them untreated, and excised tumors to measure immune cell infiltrates, TIL cytokine/granzyme B production, and activation marker expression. Baseline analysis in untreated mice revealed that CD8+ T-cell infiltrates were similar between models (5-6% of total CD45+ cells). NKT cells were reduced in CT26 (0.5% vs. 1.2%). The myeloid compartment in CT26 was mostly M2 macrophages (43% of CD45+ cells), whereas G-MDSCs dominated in 4T1 (40% of CD45+ cells). CD69 and PD-1 activation markers were expressed on >90% of CD8+ T cells from CT26 tumors compared to 4T1, which were <40% positive for both markers. Following ex vivo stimulation, the IFNγ response in CD8+ T cells was higher in CT26-derived cells. Treatment with anti-CTLA4 triggered distinct responses in the two models. Delayed tumor growth was observed in CT26 (74% TGI), but no effect in 4T1 was shown. In CT26 tumors, CD8+ T-cell and NKT cell infiltration increased, with a corresponding decrease in M2 macrophages. In 4T1 tumors, only increased NKT cell infiltration occurred. Several pharmacodynamic changes were observed in immune cell activation in CT26 but absent in 4T1. IFNγ production increased in CT26-derived CD4+ and CD8+ T cells, as well as NKT cell subsets (70%, 25%, and 17%, respectively compared to control). This included an increase in polyfunctional T cells that produced both IFNγ and TNFα. Moreover, we found that tumors with the highest frequency of IFNγ/TNFα double positive T cells had slower growth, suggesting that polyfunctional T-cell differentiation correlates with tumor growth delay. Granzyme B was 31% reduced in NKT cells in CT26. Together with increased CD107a expression on these cells, the observed granzyme B reduction was likely due to treatment-induced degranulation. Notably, a correlation between granzyme B expression and delayed tumor growth was also observed, albeit indirect. In summary, untreated CT26 tumors contained TILs that expressed high levels of CD69/PD-1 and moderately expressed IFNγ, and subsequently responded to anti-CTLA-4 treatment with increased polyfunctional T-cell recruitment, NKT cell activity, and reduced M2 macrophage infiltration. In contrast, 4T1 tumors contained low levels of both CD69/PD-1 expression and TIL cytokine expression, which is characteristic of an immunosuppressive tumor microenvironment, and did not display any remarkable response to therapy. Collectively, these results suggest baseline tumor profiles can provide insight into responsiveness to therapy and assist in model selection for preclinical research. Future studies to more broadly profile baseline TIL functional states across different syngeneic models should prove valuable during study design for targeted I/O therapy development. Citation Format: David Draper, Philip Lapinski, Stacey Roys, Scott Wise, Maryland Rosenfeld Franklin. Comparative immunophenotypic analysis of immunogenically warm and cold syngeneic tumor models at baseline and after anti-mCTLA-4 treatment [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr A86.

Intravesical Mycobacterium brumae triggers both local and systemic immunotherapeutic responses against bladder cancer in mice

The standard treatment for high-risk non-muscle invasive bladder cancer (BC) is the intravesical administration of live Mycobacterium bovis BCG. Previous studies suggest improving this therapy by implementing non-pathogenic mycobacteria, such as Mycobacterium brumae, and/or different vehicles for mycobacteria delivery, such as an olive oil (OO)-in-water emulsion. While it has been established that BCG treatment activates the immune system, the immune effects of altering the mycobacterium and/or the preparation remain unknown. In an orthotopic murine BC model, local immune responses were assessed by measuring immune cells into the bladder and macromolecules in the urine by flow cytometry and multiplexing, respectively. Systemic immune responses were analyzed by quantifying sera anti-mycobacteria antibody levels and recall responses of ex vivo splenocytes cultured with mycobacteria antigens. In both BCG- and M. brumae-treated mice, T, NK, and NKT cell infiltration in the bladder was significantly increased. Notably, T cell infiltration was enhanced in OO-in-water emulsified mycobacteria-treated mice, and urine IL-6 and KC concentrations were elevated. Furthermore, mycobacteria treatment augmented IgG antibody production and splenocyte proliferation, especially in mice receiving OO-in-water emulsified mycobacteria. Our data demonstrate that intravesical mycobacterial treatment triggers local and systemic immune responses, which are most significant when OO-in-water emulsified mycobacteria are used.

Paeoniflorin protects against concanavalin A-induced hepatitis in mice.

Paeoniflorin (PF) is one of the main effective components of the total glucosides of peony, which has been reported to have anti-inflammatory ability. However, the effects of paeoniflorin on concanavalin A (Con A)-induced hepatitis have not been carefully examined. The aim of this study was to investigate the protective effect of paeoniflorin and elucidate potential mechanisms of paeoniflorin on Con A-induced hepatitis. C57BL/6 mice were divided randomly into the following four experimental groups: PBS group, PF group, Con A group, and Con A+PF group. Mice received paeoniflorin (50mg/kg) by tail vein before Con A intravenous administration. We found that paeoniflorin pretreatment can significantly reduce the elevated plasma aminotransferase levels and liver necrosis in Con A-induced hepatitis. Also, paeoniflorin pretreatment suppressed the secretion of proinflammatory cytokines (TNF-α, INF-γ, IL-6), compared with Con A group. Meanwhile, paeoniflorin pretreatment decreased CD4(+), CD8(+) and NKT cell infiltration in the liver. Besides, we observed that paeoniflorin pretreatment can decrease the expression level of Toll-like receptor (TLR) 4 mRNA or protein in liver tissues. Further results showed that paeoniflorin pretreatment was capable of suppressing the activation of the NF-κB pathway by inhibiting IκBα kinase and p65 phosphorylation in Con A-induced liver injury. These results suggest that paeoniflorin pretreatment protects mice against Con A-induced liver injury via inhibition of several inflammatory mediators and, at least in part, by suppressing CD4(+), CD8(+) and NKT cell infiltration in liver. The beneficial effect of paeoniflorin may be related to the downregulation of TLR4 expression and the inhibition of NF-κB activation.

MRNA-based vaccines synergize with radiation therapy to eradicate established tumors.

BackgroundThe eradication of large, established tumors by active immunotherapy is a major challenge because of the numerous cancer evasion mechanisms that exist. This study aimed to establish a novel combination therapy consisting of messenger RNA (mRNA)-based cancer vaccines and radiation, which would facilitate the effective treatment of established tumors with aggressive growth kinetics.MethodsThe combination of a tumor-specific mRNA-based vaccination with radiation was tested in two syngeneic tumor models, a highly immunogenic E.G7-OVA and a low immunogenic Lewis lung cancer (LLC). The molecular mechanism induced by the combination therapy was evaluated via gene expression arrays as well as flow cytometry analyses of tumor infiltrating cells.ResultsIn both tumor models we demonstrated that a combination of mRNA-based immunotherapy with radiation results in a strong synergistic anti-tumor effect. This was manifested as either complete tumor eradication or delay in tumor growth. Gene expression analysis of mouse tumors revealed a variety of substantial changes at the tumor site following radiation. Genes associated with antigen presentation, infiltration of immune cells, adhesion, and activation of the innate immune system were upregulated. A combination of radiation and immunotherapy induced significant downregulation of tumor associated factors and upregulation of tumor suppressors. Moreover, combination therapy significantly increased CD4+, CD8+ and NKT cell infiltration of mouse tumors.ConclusionOur data provide a scientific rationale for combining immunotherapy with radiation and provide a basis for the development of more potent anti-cancer therapies.Electronic supplementary materialThe online version of this article (doi:10.1186/1748-717X-9-180) contains supplementary material, which is available to authorized users.

Immune response to RB1-regulated senescence limits radiation-induced osteosarcoma formation

Ionizing radiation (IR) and germline mutations in the retinoblastoma tumor suppressor gene (RB1) are the strongest risk factors for developing osteosarcoma. Recapitulating the human predisposition, we found that Rb1+/- mice exhibited accelerated development of IR-induced osteosarcoma, with a latency of 39 weeks. Initial exposure of osteoblasts to carcinogenic doses of IR in vitro and in vivo induced RB1-dependent senescence and the expression of a panel of proteins known as senescence-associated secretory phenotype (SASP), dominated by IL-6. RB1 expression closely correlated with that of the SASP cassette in human osteosarcomas, and low expression of both RB1 and the SASP genes was associated with poor prognosis. In vivo, IL-6 was required for IR-induced senescence, which elicited NKT cell infiltration and a host inflammatory response. Mice lacking IL-6 or NKT cells had accelerated development of IR-induced osteosarcomas. These data elucidate an important link between senescence, which is a cell-autonomous tumor suppressor response, and the activation of host-dependent cancer immunosurveillance. Our findings indicate that overcoming the immune response to senescence is a rate-limiting step in the formation of IR-induced osteosarcoma.

Positioning Ganglioside D3 as an Immunotherapeutic Target in Lymphangioleiomyomatosis

Tumors that develop in lymphangioleiomyomatosis (LAM) as a consequence of biallelic loss of TSC1 or TSC2 gene function express melanoma differentiation antigens. However, the percentage of LAM cells expressing these melanosomal antigens is limited. Here, we report the overexpression of ganglioside D3 (GD3) in LAM. GD3 is a tumor-associated antigen otherwise found in melanoma and neuroendocrine tumors; normal expression is largely restricted to neuronal cells in the brain. We also observed markedly reduced serum antibody titers to GD3, which may allow for a population of GD3-expressing LAM cells to expand within patients. This is supported by the demonstrated sensitivity of cultured LAM cells to complement mediated cytotoxicity via GD3 antibodies. GD3 can serve as a natural killer T (NKT) cell antigen when presented on CD1d molecules expressed on professional antigen-presenting cells. Although CD1d-expressing monocyte derivatives were present in situ, enhanced NKT-cell recruitment to LAM lung was not observed. Cultured LAM cells retained surface expression of GD3 over several passages and also expressed CD1d, implying that infiltrating NKT cells can be directly cytotoxic toward LAM lung lesions. Immunization with antibodies to GD3 may thus be therapeutic in LAM, and enhancement of existing NKT-cell infiltration may be effective to further improve antitumor responses. Overall, we hereby establish GD3 as a suitable target for immunotherapy of LAM.

A humanized anti-osteopontin antibody protects from Concanavalin A induced-liver injury in mice

Osteopontin has been implicated in various inflammatory diseases including rheumatoid arthritis, multiple sclerosis, Crohn's disease, and fulminant hepatitis. Increased expression of osteopontin has been detected in pathological foci of these diseases. RA and fulminant hepatitis have been successfully treated by administration of neutralizing anti-osteopontin antibody in mice. However, rodent antibodies are highly immunogenic in humans and therefore limited in their clinical application. Here, a murine monoclonal antibody 23C3 against human osteopontin, was humanized by complementarity-determining region grafting method based on computer-assisted molecular modeling. The humanized version of 23C3, denoted as Hu23C3, was shown to possess affinity comparable to that of its parental antibody. Hu23C3 could also inhibit monocyte migration in response to osteopontin in vitro. Furthermore, in vivo data showed that Hu23C3 significantly protects mice from Concanavalin A (Con A) induced-liver injury in association with the reduction of transaminase activities and improvement of liver injury. Mechanistic studies demonstrated that Hu23C3 inhibited T and NKT cell infiltration, and activation of nuclear factor κB (NF-κB) in the liver, resulting in reduction of TNF-α and IFN-γ production. Thus, our data strongly support that the humanized anti-osteopontin antibody, Hu23C3, may have a potential for the treatment of T cell mediated-hepatitis in human.

IFN Regulatory Factor 3 Contributes to the Host Response during Pseudomonas aeruginosa Lung Infection in Mice

Pseudomonas aeruginosa is a major opportunistic pathogen. However, host defense mechanisms involved in P. aeruginosa lung infection remain incompletely defined. The transcription factor IFN regulatory factor 3 (IRF3) is primarily associated with host defense against viral infections, and a role of IRF3 in P. aeruginosa infection has not been reported previously. In this study, we showed that IRF3 deficiency led to impaired clearance of P. aeruginosa from the lungs of infected mice. P. aeruginosa infection induced IRF3 translocation to the nucleus, activation of IFN-stimulated response elements (ISRE), and production of IFN-beta, suggesting that P. aeruginosa activates the IRF3-ISRE-IFN pathway. In vitro, macrophages from IRF3-deficient mice showed complete inhibition of CCL5 (RANTES) and CXCL10 (IP-10) production, partial inhibition of TNF, but no effect on CXCL2 (MIP-2) or CXCL1 (keratinocyte-derived chemokine) in response to P. aeruginosa stimulation. In vivo, IRF3-deficient mice showed complete inhibition of CCL5 production and partial or no effects on production of other cytokines and chemokines in the bronchoalveolar lavage fluids and lung tissues. Profiling of immune cells in the airways revealed that neutrophil and macrophage recruitment into the airspace was reduced, whereas B cell, T cell, NK cell, and NKT cell infiltration was unaffected in IRF3-deficient mice following P. aeruginosa lung infection. These data suggest that IRF3 regulates a distinct profile of cytokines and chemokines and selectively modulates neutrophil and macrophage recruitment during P. aeruginosa infection. Thus, IRF3 is an integral component in the host defense against P. aeruginosa lung infection.

Prevention of NKT Cell Activation Accelerates Cutaneous Wound Closure and Alters Local Inflammatory Signals

We previously reported that in the absence of NKT cells, wound closure was accelerated in a murine excisional punch wound model. Here, we explored whether purposefully inhibiting NKT cell activation had similar effects on wound closure and the dermal inflammatory response to injury. We found that prevention of NKT cell activation accelerated wound closure in a dose-responsive manner. If anti-CD1d was administered before wounding, NKT cell infiltration into cutaneous wounds was diminished without quantitative changes in cellular infiltrates. Furthermore, prevention of NKT cell activation transiently enhanced the local production of a subset of chemokines, including MIP-2, MCP-1, MIP-1α, and MIP-1β, and altered the relative expression of CD69 and CXCR2 on the surface of both circulating and wound NKT cells. Taken together, these findings suggest that wounding activates NKT cells via CD1d presentation of glycolipid antigen and help further define a role for NKT cells in the regulation of wound inflammation and closure. Many soluble factors have been targeted as potential wound healing therapies, but their clinical success has been limited. Given our findings, the NKT cell may be an attractive target for wound healing therapies.

Pathological role of CD44 on NKT cells in carbon tetrachloride‐mediated liver injury

CD44 has a variety of functions in immune regulation and signal transduction. Although CD44 is involved in the induction of several inflammatory diseases, it remains unknown whether CD44-targeting therapies are useful for liver diseases. Here, we examined whether CD44 blockade is effective in a chemical-induced liver injury model. We injected CD44 knock out (KO) or wild type mice with carbon tetrachloride (CCl(4)) and examined the difference of liver injury by immunological or histological analysis. Although CD44KO mice exhibited suppressed liver injury at 6 h after CCl(4) injection with decreased inflammatory cell numbers and cytokine production, these mice showed severe liver injury at 24 h. We found that NKT cells played an important role in liver injury with increased infiltration of theliver after migration, which was independent of the CD44 pathway. In CD44NKT double-KO mice, liver injury was suppressed with reduced cytokine production and macrophage infiltration compared with CD44KO mice. Furthermore, MIP-2 derived from NKT cells or tumor necrosis factor alpha from macrophages contributed to exacerbation of the liver injury, since neutralization of MIP-2 provided significant protection against liver injury in CD44KO mice. Finally, we found that CD44KO mice exhibited excessive liver fibrosis compared with wild-type mice after repeated CCl(4) injections. We found that CD44 has unique characteristics for inflammatory liver diseases associated with NKT cell infiltration and activation. Furthermore, CD44-targeting therapies may need to be viewed with caution for liver diseases due to the actions of the liver immune system.

S1898 Hepatic Steatosis Is Associated with Increased Intrahepatic NKT Cell Infiltration

S1898 Hepatic Steatosis Is Associated with Increased Intrahepatic NKT Cell Infiltration

Increased Intratumor Vα24-Positive Natural Killer T Cells: A Prognostic Factor for Primary Colorectal Carcinomas

Human invariant natural killer T (NKT) cells are novel, distinct lymphocyte populations with a restricted T-cell receptor repertoire (Valpha24-Vbeta11). They play a pivotal role in immunoregulation and in antitumor activities. This study focused on Valpha24+ NKT cells in colorectal carcinomas and their clinicopathologic significance. Valpha24+ NKT-cell infiltration immunohistochemistry was studied in a total of 103 colorectal carcinoma cases. The degree of NKT-cell infiltration in tumors was evaluated as low (<7 NKT cells/5 HPF) or high (> or =7 NKT cells/5 HPF). The correlation between the degree of infiltrated Valpha24+ NKT cells and clinicopathologic variables was studied statistically. A small number of Valpha24+ NKT cells were found in the normal colorectal mucosa (2.6 +/- 3.7 cells/5 HPF); however, their number increased remarkably in colorectal carcinomas (15.2 +/- 16.3 cells/5 HPF; P = 0.0003) and a majority showed phenotype of activation. Higher NKT-cell infiltration was more frequent in women than in men (P = 0.034) and correlated with fewer lymph node metastases (P = 0.042). Patients with high NKT-cell infiltration showed higher overall (P = 0.018) as well as disease-free (P = 0.0006) survival rates. Intratumor NKT-cell infiltration was an independent prognostic factor for the overall (P = 0.033) and disease-free (P = 0.0064) survival rates. Increased infiltration of Valpha24+ NKT cells was observed in colorectal carcinomas. Higher Valpha24+ NKT-cell infiltration in colorectal carcinomas was an independent prognostic factor for favorable prognosis.