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Immunotherapies targeting truly tumor-specific targets focus on the expansion and activation of T cells against neoantigens or oncogenic viruses. One target is the human papilloma virus type 16 (HPV16), responsible for several anogenital cancers and oropharyngeal carcinomas. Spontaneous and vaccine-induced HPV-specific T cells have been associated with better clinical outcome. However, the epitopes and restriction elements to which these T cells respond remained elusive. To identify CD8

PURPOSE Genetically engineered T-cell therapy is an emerging treatment of hematologic cancers with potential utility in epithelial cancers. We investigated T-cell therapy for the treatment of metastatic human papillomavirus (HPV)–associated epithelial cancers. METHODS This phase I/II, single-center trial enrolled patients with metastatic HPV16-positive cancer from any primary tumor site who had received prior platinum-based therapy. Treatment consisted of autologous genetically engineered T cells expressing a T-cell receptor directed against HPV16 E6 (E6 T-cell receptor T cells), a conditioning regimen, and systemic aldesleukin. RESULTS Twelve patients were treated in the study. No dose-limiting toxicities were observed in the phase I portion. Two patients, both in the highest-dose cohort, experienced objective tumor responses. A patient with three lung metastases experienced complete regression of one tumor and partial regression of two tumors, which were subsequently resected; she has no evidence of disease 3 years after treatment. All patients demonstrated high levels of peripheral blood engraftment with E6 T-cell receptor T cells 1 month after treatment (median, 30%; range, 4% to 53%). One patient’s resistant tumor demonstrated a frameshift deletion in interferon gamma receptor 1, which mediates response to interferon gamma, an essential molecule for T-cell–mediated antitumor activity. Another patient’s resistant tumor demonstrated loss of HLA-A*02:01, the antigen presentation molecule required for this therapy. A tumor from a patient who responded to treatment did not demonstrate genetic defects in interferon gamma response or antigen presentation. CONCLUSION Engineered T cells can induce regression of epithelial cancer. Tumor resistance was observed in the context of T-cell programmed death-1 expression and defects in interferon gamma and antigen presentation pathway components. These findings have important implications for development of cellular therapy in epithelial cancers.

7010 Background: Brexucabtagene autoleucel (KTE-X19) is an autologous anti-CD19 CAR T-cell therapy approved in the US to treat adult R/R B-ALL based on the ZUMA-3 study. The overall complete remission (CR) rate (CR + CR with incomplete hematologic recovery [CRi]) was 71% (95% CI, 57-82) after 16.4 mo median follow-up (N = 55; Shah et al. Lancet 2021). Here, we report updated outcomes with longer follow-up in these pts and in a larger pooled analysis of Phase (Ph) 1 and 2 pts who received the pivotal dose of KTE-X19. Methods: Eligible adults (≥18 years) had R/R B-ALL and received a single infusion of KTE-X19 at the pivotal dose (1×106 CAR T cells/kg) following leukapheresis and conditioning chemotherapy. The primary endpoint was CR/CRi rate by central review. Results: As of 23 July 2021, median follow-up was 26.8 mo (range, 20.7-32.6) for treated Ph 2 pts (N = 55). The CR/CRi rate per central review was 71% (95% CI, 57-82; 56% CR; 15% CRi). Eleven pts (20%; 8 CR and 2 CRi) proceeded to subsequent allogeneic stem cell transplant (alloSCT). Median duration of remission (DOR) censored at subsequent alloSCT was 14.6 mo (9.4-not estimable [NE]); not censored: 18.6 mo (9.6-NE); 6/39 responders (15%) had ongoing responses at data cutoff. Median (95% CI) relapse-free survival (RFS) was 11.6 mo (2.7-20.5) censored at subsequent alloSCT and 11.7 mo (2.8-20.5) not censored at subsequent alloSCT; 18-mo RFS rates (95% CI) were 35% (20.5-50.6) and 42% (28.0-55.0), respectively. Median (95% CI) overall survival (OS) was 25.4 mo (16.2-NE) among all KTE-X19-treated pts and not reached (25.4-NE) in pts with CR (n = 31). For Ph 1/2 pts (N = 78) who received the pivotal KTE-X19 dose (median follow-up: 29.7 mo; range 20.7-58.3), the CR/CRi rate by independent review was 73% (95% CI, 62-82). Medians (95% CI) for DOR, RFS, and OS were 18.6 mo (9.6-NE), 11.7 mo (6.1-20.5), and 25.4 mo (16.2-NE), respectively. A subgroup analysis revealed that in pts aged 18-39 (n = 36), 40-59 (n = 27), and ≥60 (n = 15) years, the CR/CRi rates (95% CI) were 69% (52-84), 70% (50-86), and 87% (60-98); 24-mo OS rates (95% CI) were 48% (30-64), 54% (33-71), and 57% (28-78), respectively. In pts with pre-KTE-X19 infusion marrow blast percentages > 25 to ≤50 (n = 12), > 50 to ≤75 (n = 14), and > 75 to 100 (n = 30), CR/CRi rates (95% CI) were 83% (52-98), 86% (57-98), and 57% (37-75); 24-mo OS rates (95% CI) were 58% (27-80), 55% (26-77) and 37% (19-55), respectively. There were no new safety signals; the proportion of treated Ph 2 pts with Gr ≥3 treatment emergent adverse events was unchanged since prior data cutoff. One pt had an ongoing neurologic event of Gr 1 finger numbness. Conclusions: With longer follow-up and an expanded data set by independent review, outcomes remain durable in adults with R/R B-ALL, most of whom were heavily pretreated, with median OS not yet reached in pts with CR. Long-term safety was favorable. Clinical trial information: NCT02614066.

TPS3149 Background: Human papillomavirus 16 (HPV16) is the most prominent subtype across invasive head and neck cancers, as well as cervical cancer and other anogenital cancers (Saraiya M, et al. J Natl Cancer Inst. 2015). The HPV16 E7 (E7) viral antigen is important for the survival of HPV-positive tumor cells but is absent from normal human tissue, making it an attractive target for anti-cancer therapy. Preclinical efficacy has been observed with MHC class I-restricted T cell receptor (TCR)-engineered T cells targeting E7 on HPV16-positive tumor cells (Jin BY, et al. JCI Insight. 2018). This Phase 1, first-in-human, open-label, multicenter study (NCT03912831) will evaluate the safety and efficacy of KITE-439, an autologous TCR-engineered T cell therapy targeting E7, in HLA-A*02:01–positive patients with relapsed/refractory HPV16-positive cancers. Methods: A single-patient dose-escalation schema will be used in Phase 1A of the study, enrolling up to 30 patients. Phase 1A will evaluate safety and inform the recommended dose of KITE-439 for Phase 1B. Approximately 45 patients with squamous cell cancer of the head and neck, cervical cancer, and other HPV16-positive tumors will be included in Phase 1B. Patients in Phase 1A and Phase 1B may receive optional bridging therapy followed by cyclophosphamide and fludarabine conditioning chemotherapy. Patients will then receive an infusion of KITE-439 at 1 × 106 up to 1 × 108 TCR-transduced T cells/kg along with daily subcutaneous IL-2 therapy for a maximum of 14 doses post-infusion. The primary endpoint for Phase 1A is the incidence of adverse events defined as dose-limiting toxicities. The primary endpoint for Phase 1B is investigator-assessed objective response rate per modified RECIST v1.1 criteria (Eisenhauer EA, et al. Eur J Cancer. 2009). Secondary endpoints for Phase 1B include duration of response, progression-free survival, overall survival, and safety. Patients ≥ 18 years must be HLA-A*02:01–positive and have relapsed/refractory HPV16-positive cancer, an ECOG PS of ≤ 1, and adequate bone marrow and organ function. Key exclusion criteria include a history of stroke, myocardial infarction, or symptomatic deep vein thrombosis/pulmonary embolism, known infection with human immunodeficiency virus, detectable hepatitis C, or detectable hepatitis B. This study is currently open and accruing patients. Clinical trial information: NCT03912831 .

101 Background: Genetically engineered T-cell therapy has shown remarkable clinical activity in hematologic malignancies. It is not known if this type of treatment can be applied effectively to epithelial cancers, which account for 80% to 90% of human malignancies. Methods: We conducted a phase I clinical trial with a 3 + 3 dose escalation in which patients with metastatic HPV-16+ epithelial cancers were treated with a one-time infusion of genetically engineered T cells expressing a T-cell receptor targeting an HLA-A*02:01-restricted epitope of HPV-16 E7 (E7 TCR-T cells). A lymphocyte-depleting conditioning regimen was administered before cell infusion, and high-dose systemic aldesleukin was administered after cell infusion. Results: Twelve patients, previously treated with a median of 4 (range, 3 to 7) anticancer agents, were treated. The cell dose was not limited by toxicity. Six patients demonstrated objective clinical responses, which included regression of bulky tumors and complete elimination of some tumors. Responses occurred in patients with vulvar, anal, head and neck, and cervical cancer. Four patients who previously received PD-1-based therapy responded. Response duration ranged from 3 to 9 months. Sustained, high-level engraftment of E7 TCR-T cells in peripheral blood was observed (median after approximately 6 weeks, 66% of total T cells, range 1% to 88%) and correlated with cell dose but not with clinical response. Infused T cell characteristics did not correlate strongly with response. Of the 4 resistant tumors that were studied, 3 demonstrated genetic defects in HLA-A*02:01 or B2M (necessary components of the target complex) and 1 demonstrated copy loss with decreased expression of antigen presentation and interferon response molecules (i.e. TAP1, TAP2, IFNGR1, IFNGR2). Of the 3 sensitive tumors studied, 0 showed genetic defects in these molecules. Conclusions: E7 TCR-T cells demonstrated safety and clinical activity in the treatment of highly refractory metastatic HPV-16+ cancers. Treatment resistance was linked to definitive genetic defects in the targeted peptide-HLA complex and to manifold defects in antigen processing and interferon response. Clinical trial information: NCT02858310.

433 Background: MAGE is an attractive target for IO given its expression restricted to carcinomas and the testes. Engineered T-cell targeting MAGE A3/6 has shown promise. However, successful treatment is dependent on circumventing the potentially hostile immune microenvironment in metastatic tumors. In this study, we aim to assess the effects of ICI on the immune microenvironment in patients who progressed on ICI. Methods: We obtained FFPE tissue from 16 patients with mUC across 3 institutions. Samples from the primary or metastatic tumor prior to treatment with PD1/PD-L1 inhibitors (ICI) were paired with samples from metastatic sites post-treatment. Differential mRNA expression was assessed using NanoString PanCancerIO360 panel for the main genes of interest ( MAGEA3/6, CD274, HLADP, HLAA, B2M and PDCD1) in addition to immune profiling of the tumor samples. Also, IHC was done on the paired samples to assess DE for the genes of interest using an H-score analyzed via the paired T-test. p-values

Administration of cannabinoid receptor 2 (CB2R) agonists in inflammatory and autoimmune disease and CNS injury models results in significant attenuation of clinical disease, and reduction of inflammatory mediators. Previous studies reported that CB2R signaling also reduces leukocyte migration. Migration of dendritic cells (DCs) to various sites is required for their activation and for the initiation of adaptive immune responses. Here, we report for the first time that CB2R signaling affects DC migration in vitro and in vivo, primarily through the inhibition of matrix metalloproteinase 9 (MMP-9) expression. Reduced MMP-9 production by DCs results in decreased migration to draining lymph nodes in vivo and in vitro in the matrigel migration assay. The effect on Mmp-9 expression is mediated through CB2R, resulting in reduction in cAMP levels, subsequent decrease in ERK activation, and reduced binding of c-Fos and c-Jun to Mmp-9 promoter activator protein 1 sites. We postulate that, by dampening production of MMP-9 and subsequent MMP-9–dependent DC migration, cannabinoids contribute to resolve acute inflammation and to reestablish homeostasis. Selective CB2R agonists might be valuable future therapeutic agents for the treatment of chronic inflammatory conditions by targeting activated immune cells, including DCs.

We reported previously that prostaglandin E2 (PGE2) up-regulates IL-23 in vitro in bone marrow-derived dendritic cells and in vivo in models of collagen-induced arthritis and inflammatory bowel disease, leading to preferential Th17 development and activity. There is very little information on the molecular mechanisms involved in the PGE2-induced up-regulation of Il23a gene expression. In this study we investigated the signaling pathways and transcription factors involved in the stimulatory effect of PGE2. Although PGE2 does not induce IL-23p19 expression by itself, it synergizes with both extra- and intracellular Toll-like receptor ligands and with inflammatory cytokines such as TNFα. We established that the effect of PGE2 in conjunction with either LPS or TNFα is mediated through the EP4 receptor and the cAMP-dependent activation of both protein kinase A (PKA) and exchange protein activated by cAMP (EPAC). Using the EP4 agonist PGE(1)OH in conjunction with TNFα, we found that PKA-induced phosphorylation of cAMP-response element-binding protein ((P)CREB) and EPAC-induced phosphorylation of C/AATT enhancer-binding protein β ((P)C/EBPβ) mediate the stimulatory effect of PGE2 on IL-23p19 expression. This is the first report of CREB and C/EBPβ involvement in Il23a promoter activation. Mutation within the putative CREB and C/EBP sites combined with in vivo DNA binding (ChIP) assays identified the distal CREB site (-1125) and the two proximal C/EBP sites (-274 and -232) as essential for PKA-activated CREB and EPAC-activated C/EBPβ-induced IL-23p19 expression.

The goal of the current investigation was to evaluate the mechanisms through which administration of a selective cannabinoid-2 (CB2) agonist (O-1966) modifies inflammatory responses and helps to improve function following spinal cord injury. A comparison of motor function, autonomic function, and inflammatory responses was made between animals treated with O-1966 (5 mg/kg IP) and animals treated with vehicle 1 h and 24 h following contusion injury to the spinal cord. Motor function was significantly improved in the treated animals at each time point during the 14 days of evaluation. The percentage of animals able to spontaneously void their bladder was also greater over the entire study period in the group treated with the selective CB2 agonist. Seven days following injury there was a significant reduction in both hematopoietic and myeloid cell invasion of the spinal cord, and a reduction in the number of immunoreactive microglia. The results of the evaluation of chemokine/cytokine expression and inflammatory cell invasion also demonstrated a significant effect of treatment on inflammatory reactions following injury. Two days after injury, animals treated with O-1966 had significant reductions in CXCL-9 and CXCL-11, and dramatic reductions in IL-23p19 expression and its receptor IL-23r. Treatment with O-1966 also caused inhibition of toll-like receptor expression (TLR1, TLR4, TLR6 and TLR7) following injury. These results demonstrate that the improvement in motor and autonomic function resulting from treatment with a selective CB2 agonist is associated with a significant effect on inflammatory responses in the spinal cord following injury.

Background: Adoptive T cell therapy with gene-engineered T cells is an emerging cancer treatment strategy that has been applied successfully to the treatment of hematological cancers. We conducted a clinical trial to test proof of principle for this type of treatment in an epithelial cancer. Patients with human papillomavirus (HPV) 16-associated cancers were treated with gene-engineered T cells targeting HPV16 E7. Methods: The clinical trial was a phase I study with a 3 + 3 design and three dose levels (DL) of gene-engineered T cells (DL1: 1 x 109, DL2: 1 x 1010, DL3: 1 x 1011). Patients had metastatic HPV-16+ cancers from any primary tumor site. Treatment consisted of a one-time infusion of autologous T cells that were gene-engineered to express an HLA-A*02:01-restricted T-cell receptor (TCR) that targets HPV-16 E7 (E7 T cells). A lymphocyte-depleting conditioning regimen was administered before treatment. E7 T cell infusion was followed by high-dose systemic aldesleukin. Results: Twelve patients were treated (DL1, n=3; DL2, n=3; DL3, n=6). The age range was 31 to 59 years. The site of the primary cancer was vulva (n=1), head and neck (n=4), uterine cervix (n=5), and anus (n=2). Each patient had multiple metastases and had previously received 3 to 7 anti-cancer agents. The conditioning regimen consisted of cyclophosphamide 30 mg/Kg (n=6) or 60 mg/Kg (n=6) iv daily for 2 days overlapping with fludarabine 25 mg/m2 iv daily for 5 days. The E7 TCR was expressed by 90-99% of the infused T cells for each patient. E7 T cell cross-reactivity against healthy tissues was not identified. Cytokine-release syndrome was not observed. A single patient, at DL3, experience dose-limiting toxicity. Four patients experienced confirmed responses, and two patients experienced unconfirmed responses (i.e. met criteria for response at only one assessment) (Figure 1). Confirmed responses occurred in patients with cervical cancer, oropharyngeal cancer, vulvar cancer, and anal cancer. The duration of responses was 3 months (ongoing), 4 months, 8 months, and 9 months, respectively. These patients had previously received 7, 4, 7 and 3 prior anti-cancer agents, respectively. Three patients with confirmed responses had previously received PD-1 or PD-L1 checkpoint blockade. Four patients whose cancer progressed after E7 T cells received PD-1 or PD-L1 checkpoint blockade; none responded. Conclusions: Tumor regression can occur following treatment of an epithelial cancer with gene-engineered T cells. These findings support continued study of E7 T cells and possibly other types of gene-engineered T cells in epithelial cancers. Disclosures Adhikary: Kite Pharma: Employment. Schweitzer:Kite Pharma: Employment. Astrow:Kite Pharma: Employment. Hinrichs:Kite Pharma: Research Funding; NIH: Patents & Royalties: NIH patents related to cell therapy.

3043Background: Adoptive T-cell therapy with gene-engineered T cells is an emerging cancer treatment strategy. Study of this approach in epithelial cancers, the most common types of malignancies, h...

3019Background: Engineered T-cell therapy is an emerging treatment for hematological cancers. In epithelial cancers, its study has been limited. Human papillomavirus (HPV)-16+ epithelial cancers co...

3009 Background: Engineered T-cell therapy has shown promise in B-cell malignancies and melanoma, but clinical investigation in epithelial cancers has been limited. Methods: We conducted a phase I/II clinical trial of T cells genetically engineered to express a T-cell receptor that targets an HLA-A*02:01-restricted epitope of E6 (E6 TCR T Cells) for patients with metastatic HPV-16+ carcinoma. The cell dose was escalated in cohorts of single patients (1 x 109, 1 x 1010, and 1-2 x 1011cells). Patients received a nonmyeloablative conditioning regimen of cyclophosphamide and fludarabine, a single infusion of E6 TCR T Cells, and systemic high-dose aldesleukin. Results: Twelve patients were treated, 9 at the highest cell dose, plus one retreatment. The cancer types were 6 cervical, 4 anal, 1 oropharyngeal, and 1 vaginal. No dose-limiting toxicity, autoimmune adverse events, or cytokine storm were observed. Two patients with anal cancer treated at the highest cell dose experienced partial tumor responses lasting 6 and 3 months after treatment. The patient with a 6-month response had complete regression of one tumor and partial regression of two tumors that were resected upon progression; she has no evidence of disease 22 months after treatment. T-cell receptor gene transfer efficiency was 45 and 51% in the responding patients, and 47-76% (median 61%) in the non-responding patients. Responding patients showed robust levels of E6 TCR T cell memory (30 and 46% of circulating T cells 1-month after treatment). Non-responding patients showed wide-ranging levels of E6 TCR T cell memory (range 4-53%, median 29%). Expression of programmed cell death protein 1 (PD-1) by circulating E6 TCR T Cells 1-month after treatment was low in all patients ( < 5%). The patient with a 6-month response had 7% E6 TCR T Cells in a resected tumor 10 months after treatment, 25% of which expressed PD-1. A patient with no response had no detectable E6 TCR T Cells in a resected tumor 3 months after treatment. Conclusions: E6 TCR T-cell therapy was safe at doses up to 2 x 1011 cells. Regression of metastatic HPV+ carcinoma occurred in two patients following treatment, suggesting that TCR T-cell therapy can mediate epithelial cancer regression. Clinical trial information: NCT02280811.

The proinflammatory cytokine IL-23 emerged recently as a key player in autoimmune diseases. Production of IL-23 by pathogen-activated dendritic cells (DC) is regulated by endogenous mediators such as prostaglandin E2 (PGE2) and interferon-γ (IFN-γ). PGE2 stimulates IL-23 and inhibits IL-12 production. In contrast, IFN-γ inhibits IL-23 and stimulates IL-12. In the presence of both PGE2 and IFN-γ, TLR-stimulated DC produce higher levels of both cytokines. Here we analyze the signaling pathways involved in this complex regulation. IRF1, induced by LPS and at high levels by IFN-γ, acts as a positive transcription factor for IL-12p40, and as a negative regulator for IL-23p19. The potent effect of IFN-γ on IRF1 correlates with the inhibition of IL-23 and stimulation of IL-12 in LPS-activated DC. In contrast, PGE2 abolishes IRF1 expression in LPS-stimulated DC, resulting in the inhibition of IL-12 and stimulation of IL-23 production. When both PGE2 and IFN-γ are present, the IRF1 levels are similar to LPS controls, allowing for both IL-23p19 and IL-12p40 expression. In addition, as previously reported by us, the stimulatory effect of PGE2 on p19 transcription is also mediated through the activation of the positive transcription factors CREB and C/EBP. Our findings suggest that the combined presence of PGE2 and IFN-γ in autoimmune conditions results in sustained production of both IL-12 and IL-23, which contribute to the maintenance of a proinflammatory environment.

In murine models of multiple sclerosis (experimental autoimmune encephalomyelitis or EAE), cannabinoid receptor 2 (CB2) agonists have been shown to be beneficial, reducing the number of CNS infiltrating leukocytes. Adhesion molecules, chemokines, and matrix metalloproteinases (MMPs), particularly MMP-9, play important roles in migration to the CNS. Antigen presenting cells such as dendritic cells (DC) and macrophages, as well as activated microglia are major producers of MMP-9. In this study, we investigated the effects of CB2 receptor agonists on DC migration and MMP-9 production utilizing both in vitro and in vivo migration assays. DC activated with cytokine cocktail (TNFα+IL-1β+IL-6+PGE2) in the presence or absence of CB2R agonist exhibited similar migratory capacity in transwell migration assays. However, the CB2R agonist treated cells migrated less in matrigel migration assays as compared to untreated cells. We found that this effect was due to reduced MMP-9 production in CB2R agonist treated cells. Also, in the in vivo migration assay using cytokine cocktail-activated DCs injected into mice footpads, we found significantly fewer CB2R agonist-treated DCs in the draining lymph nodes. Our data indicate that one of the mechanisms by which CB2R agonists attenuate inflammation is the inhibition of MMP-9 release which results in decreased migration of activated dendritic cells.

Previous studies showed that cannabinoids have anti-inflammatory effects in experimental autoimmune encephalomyelitis (EAE), but the mechanism is elusive. In the present study, we investigated the effects of Gp1a (a new CB2 selective agonist) in EAE. EAE developed in a similar way in both vehicle and Gp1a treatment group, but mice treated with Gp1a recovered faster than the vehicle group. Cellular analysis was performed in spleen, brain and spinal cord. In spleen, there was no difference in numbers of CD3+ T cells, Th1 and Th17 cells, or macrophages. In contrast, CNS mononuclear cell analysis showed fewer CD3+ T cells, Th1 and Th17 cells, macrophages and activated microglia in spinal cord but not in brainin the Gp1a treatment group. Accordingly, for the Gp1a-treated group, histology studies also showed fewer CD3+ T cells, CD11b+ macrophages/microglia and less Iba-1 expression in spinal cord but not in brain. In vivo cell proliferation as measured through BrdU incorporation in CD3+CD45hi, CD11b+CD45hi and CD11b+CD45int mononuclear cells was not affected by Gp1a treatment. We hypothesize that Gp1a inhibits cell migration to the CNS. We also analyzed gene expression in brain and spinal cord following EAE development and found lower levels of VCAM-1, CXCL-10 and MMP9 in spinal cord. We also found that Gp1a inhibits MMP9 and TNFα production in BV.2 cells (a microglia cell line). We conclude that Gp1a improves EAE recovery through inhibiting immune cell migration into CNS.

Protective anti-inflammatory effects of DHA were reported in clinical studies and animal models of colitis, sepsis, and stroke. In the present study, we investigated the effects of DHA on the function of bone marrow-derived dendritic cells (DC) in CD4+ T cell stimulation and differentiation. Pretreatment of DC with DHA prevented LPS-induced DC maturation, maintaining an immature phenotype characterized by low expression of costimulatory molecules and lack of proinflammatory cytokine production (IL-12p70, IL-6 and IL-23). DHA-treated DC were poor stimulators of antigen-specific T cells in terms of proliferation and Th1/Th17 differentiation. This was associated with an increase in p27(kip1), a cell cycle arresting agent. In contrast, T cells co-cultured with DC-DHA express higher levels of TGFβ and Foxp3, without exhibiting a functional Treg phenotype. In addition, DHA prevents up-regulation of VCAM-1 and ICAM-1 in bEND.3 cells (mouse brain microvascular endothelial cell line). Here we report for the first time a beneficial effect of dietary n-3 fatty acids in experimental autoimmune encephalomyelitis (EAE), a model for human multiple sclerosis. The beneficial effect of DHA in EAE was associated with reduced numbers of IFNγ- and IL-17-producing CD4+ T cells in both spleen and CNS.

We reported previously that PGE2 promotes IL-23p19 expression in dendritic cells (DC) treated with LPS. The effect is mediated through EP4 through the induction of cAMP. This study is focused on the signaling pathways involved in PGE1OH (an EP4 agonist)-induced p19 expression. EP4 activates adenylate cyclase and increases intracellular cAMP which leads to activation of PKA and EPAC. We found that adenylate cyclase, cAMP, and EPAC play a role in IL-23p19 induction. Using chemical inhibitors of PKA, PI3K, MAPK, and GSK3, we did not see a decrease in IL-23p19 expression. Previous studies reported the involvement of NFkB/c-Rel, ATF-2, SMAD-3 and AP-1 in p19 expression. Since two CRE-binding sites have been identified in the p19 promoter, we focused on CREB as a potential transcription factor activated by PGE1OH. Luciferase experiments including vectors containing mutated CRE sites and expressing dominant negative versions of CREB demonstrated the essential role CREB plays in IL-23p19 expression. In a transcription factor assay we found increased CREB binding activity in nuclear extracts from cells treated with PGE1OH. In addition, a ChIP assay confirmed CREB binding to the p19-promoter in the presence of PGE1OH. Overall, we identified CREB as a new transcription factor required for PGE1OH induction of IL-23p19 expression.

Recently cannabinoids are being studied in treatment of various animal models of CNS disorders such as MS, AD, PD and stroke. They are also being used in treating neuropathic pain in patients with spinal cord injury (SCI). Two cannabinoid receptors have been cloned; CB1, mainly expressed in the CNS and CB2, predominantly expressed in the periphery including immune cells. Previous studies from our laboratory showed that treatment with the CB2 specific agonist O-1966 improved recovery of motor and bladder function in mouse model of acute spinal cord injury. In SCI, increased infiltration and activation of inflammatory immune cells that follow the initial injury exacerbate neuronal damage. In this study we analyzed expression of inflammatory molecules that serve as markers for activation and infiltration of immune cells and their modulation by the CB2 agonist treatment. A murine thoracic spinal cord contusion model of SCI was used and spinal cords were analyzed for expression of various cytokines and chemokines. We found suppression of a number of molecules in spinal cords that were subjected to the CB2 agonist treatment. There was decreased expression of the CXCL family chemokine members CXCL1, 2, 3, 9 and 11, the CC family chemokine members CCL 8, 11, 20, T cell activation cytokines: IFN-γ, IL-23, IL-22 and some of the Toll-like receptors such as TLR1, 4, 6, and 7. Thus, it appears that CB2 agonist treatment may aid in recovery in acute SCI via its immunomodulating effects.

Previously, we have shown that PGE2 inhibits IL-12p35 expression & promotes IL-23p19 expression in dendritic cells (DC) treated with LPS or Poly I:C. The effect is mediated through EP4 and to a lesser degree EP2 receptors and induction of cAMP. This study is focused on essential transcriptional factors and signaling pathways involved in PGE1-OH (EP4 agonist) induced p19 expression. Previous studies reported involvement of NFkB (c-Rel), ATF-2, SMAD-3 & AP-1. CREB is a target of cAMP-activated PKA and two CREB binding sites have been identified in the p19 promoter. Therefore, CREB is a potential transcription factor activated by PGE. Experiments with p19-luciferase constructs containing wt & CREB-mutated sites indicate the importance of CREB sites in p19 transcriptional activity. PGE2/PGE1-OH also induced STAT-3 tyrosine phosphorylation in DC and in the DC cell line. Blocking STAT-3 phosphorylation with the chemical inhibitor S3I-201 and the specific peptide inhibitor PpYLKTK-mts reduced p19 expression in DC. Although no STAT-3 binding site was found in the p19 promoter, STAT-3 was proposed to act as a co-activator for c-Rel to induce p19 expression. These data show for the first time that CREB and STAT-3 are important regulators of PGE2-induced p19 expression in DC. These observations show the versatility that prostaglandins have to differentially regulate expression patterns of cytokines that orchestrate an immune response.

Protective anti-inflammatory effects of the n-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were reported in clinical studies and animal models of colitis, sepsis, and stroke. In the present study we investigated the effects of DHA on the function of bone marrow-derived dendritic cells (DC) and CD4+ T cells. Our studies show that pretreatment with DHA prevents LPS-induced DC maturation, maintaining an immature phenotype characterized by low expression of MHCII and costimulatory molecules, and high levels of endocytosis. Exposure to DHA inhibits the production of proinflammatory cytokines and chemokines such as IL-6, TNFα, CCL-4, and IL-12p70. In addition, we report here for the first time that DHA has a similar inhibitory effect on IL-23 and IL-27, two other members of the IL-12 family. DHA exerted a similar inhibitory effect on IL-12 and IL-23 expression in vivo in LPS-inoculated mice maintained on a DHA-enriched diet. We also investigated the effects of DHA on T cells and found that DC treated with DHA (DC-DHA) have poor stimulatory capacity for T cells. T cells activated by DC-DHA also showed low levels expression of IFNα and IL-17, and high levels of Foxp3. Based on the inhibition of proinflammatory cytokine release and reduction in T cell stimulatory capacity, we conclude that DC are important targets for the anti-inflammatory activity of n-3 fatty acids.

A few studies have been published showing effects of cannabinoids in modulating immune response from T helper cell type 1 (Th1) to T helper cell type 2 (Th2) in a model of Legionella pneumophila infection. Cannabinoids act through two cloned receptors, CB1 and CB2. The CB1 receptor is expressed primarily in the CNS, whereas the CB2 receptor is highly expressed in immune cells in the periphery. Previous results from our laboratories indicated that the CB2 agonist had an anti-inflammatory effect on dendritic cells (DCs) and T cells. DCs differentiated in the presence of CB2 agonist produced less IL-12 upon LPS stimulation and T cells produced less IFN-gamma when co-cultured with these DCs in syngeneic culture in the presence of specific antigen. Here, we report that CB2 agonist treatment of DCs resulted in reduced STAT-1 phosphorylation. Also, treatment of polyclonally activated CD4+ T cells resulted in reduced expression of IL-12 receptor beta 2 chain, which correlated with decreased IFN-gamma production. Our data lead us to believe that CB2 agonists can modulate immune responses by acting directly on CD4+ T cells or through their effects on DCs. This work is supported by NIH/NIAID R01AI05230, and training grant T32 DA07237 (SA)

Background Acute and chronic inflammation play essential roles in inflammatory/autoimmune conditions. Protective anti-inflammatory effects of the n-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were reported in animal models of colitis, sepsis, and stroke. Since dendritic cells (DC) represent the essential cellular link between innate and adaptive immunity and have a prominent role in tolerance for self-antigens, we sought to investigate the impact of DHA on DC maturation and proinflammatory cytokine production. Methods Murine bone marrow-derived DC were treated with DHA and stimulated with various toll-like receptor (TLR) ligands. Flow cytometry was used to determine the levels of surface maturation markers and endocytic activity. Cytokine expression and secretion were measured by real-time RT-PCR and ELISA assays. PPARγ and NFκB activity in nuclear extracts were determined by binding to specific oligonucleotide sequences using ELISA-based assays. In vivo effects of DHA were assessed in splenic DC from LPS-inoculated mice maintained on a DHA-enriched diet. Results DHA maintained the immature phenotype in bone marrow-derived DC by preventing the upregulation of MHCII and costimulatory molecules (CD40, CD80 and CD86) and maintaining high levels of endocytic activity. DHA inhibited the production of pro-inflammatory cytokines, including the IL-12 cytokine family (IL-12p70, IL-23, and IL-27), from DC stimulated with TLR2, 3, 4, and 9 ligands. DHA inhibition of IL-12 expression was mediated through activation of PPARγ and inhibition of NFκBp65 nuclear translocation. DHA exerted a similar inhibitory effect on IL-12 and IL-23 expression in vivo in LPS-inoculated mice maintained on a DHA-enriched diet. Conclusions Exposure of bone marrow-derived DC to DHA resulted in the maintenance of an immature phenotype and drastic reduction in proinflammatory cytokine release. DHA inhibited the expression and secretion of the IL-12 cytokine family members (IL-12p70, IL-23 and IL-27), which play essential roles in the differentiation of the proinflammatory Th1/Th17 effector cells. The effect of DHA on IL-12 expression was mediated through activation of PPARγ and inhibition of NFκB. Inhibition of IL-12 and IL-23 expression was also evident in splenic DC from mice fed a DHA-enriched diet, suggesting that dietary DHA acts as an anti-inflammatory agent in vivo.