Harnessing anti-cytomegalovirus immunity for local immunotherapy against solid tumors.

Tumor infiltration by T cells profoundly affects cancer progression and responses to immunotherapy. However, the tumor immunosuppressive microenvironment can impair the induction, trafficking, and local activity of antitumor T cells. Here, we investigated whether intratumoral injection of virus-derived peptide epitopes could activate preexisting antiviral T cell responses locally and promote antitumor responses or antigen spreading. We focused on a mouse model of cytomegalovirus (CMV), a highly prevalent human infection that induces vigorous and durable T cell responses. Mice persistently infected with murine CMV (MCMV) were challenged with lung (TC-1), colon (MC-38), or melanoma (B16-F10) tumor cells. Intratumoral injection of MCMV-derived T cell epitopes triggered in situ and systemic expansion of their cognate, MCMV-specific CD4+ or CD8+ T cells. The MCMV CD8+ T cell epitopes injected alone provoked arrest of tumor growth and some durable remissions. Intratumoral injection of MCMV CD4+ T cell epitopes with polyinosinic acid:polycytidylic acid (pI:C) preferentially elicited tumor antigen-specific CD8+ T cells, promoted tumor clearance, and conferred long-term protection against tumor rechallenge. Notably, secondary proliferation of MCMV-specific CD8+ T cells correlated with better tumor control. Importantly, intratumoral injection of MCMV-derived CD8+ T cell-peptide epitopes alone or CD4+ T cell-peptide epitopes with pI:C induced potent adaptive and innate immune activation of the tumor microenvironment. Thus, CMV-derived peptide epitopes, delivered intratumorally, act as cytotoxic and immunotherapeutic agents to promote immediate tumor control and long-term antitumor immunity that could be used as a stand-alone therapy. The tumor antigen-agnostic nature of this approach makes it applicable across a broad range of solid tumors regardless of their origin.

Innate Immune Responses of Vaccinees Determine Early Neutralizing Antibody Production After ChAdOx1nCoV-19 Vaccination.

Background: Innate immunity, armed with pattern recognition receptors including Toll-like receptors (TLR), is critical for immune cell activation and the connection to anti-microbial adaptive immunity. However, information regarding the impact of age on the innate immunity in response to SARS-CoV2 adenovirus vector vaccines and its association with specific immune responses remains scarce. Methods: Fifteen subjects between 25-35 years (the young group) and five subjects between 60-70 years (the older adult group) were enrolled before ChAdOx1 nCoV-19 (AZD1222) vaccination. We determined activation markers and cytokine production of monocyte, natural killer (NK) cells and B cells ex vivo stimulated with TLR agonist (poly (I:C) for TLR3; LPS for TLR4; imiquimod for TLR7; CpG for TLR9) before vaccination and 3-5 days after each jab with flow cytometry. Anti-SARS-CoV2 neutralization antibody titers (surrogate virus neutralization tests, sVNTs) were measured using serum collected 2 months after the first jab and one month after full vaccination. Results: The older adult vaccinees had weaker vaccine-induced sVNTs than young vaccinees after 1st jab (47.2±19.3% vs. 21.2±22.2%, p value<0.05), but this difference became insignificant after the 2nd jab. Imiquimod, LPS and CpG strongly induced CD86 expression in IgD+CD27- naïve and IgD-CD27+ memory B cells in the young group. In contrast, only the IgD+ CD27- naïve B cells responded to these TLR agonists in the older adult group. Imiquimode strongly induced the CD86 expression in CD14+ monocytes in the young group but not in the older adult group. After vaccination, the young group had significantly higher IFN-γ expression in CD3- CD56dim NK cells after the 1st jab, whilst the older adult group had significantly higher IFN-γ and granzyme B expression in CD56bright NK cells after the 2nd jab (all p value <0.05). The IFN-γ expression in CD56dim and CD56bright NK cells after the first vaccination and CD86 expression in CD14+ monocyte and IgD-CD27-double-negative B cells after LPS and imiquimod stimulation correlated with vaccine-induced antibody responses. Conclusions: The innate immune responses after the first vaccination correlated with the neutralizing antibody production. Older people may have defective innate immune responses by TLR stimulation and weak or delayed innate immune activation profile after vaccination compared with young people.

Randomized trial of neoadjuvant vaccination with tumor-cell lysate induces T cell response in low-grade gliomas.

BACKGROUNDLong-term prognosis of WHO grade II low-grade gliomas (LGGs) is poor, with a high risk of recurrence and malignant transformation into high-grade gliomas. Given the relatively intact immune system of patients with LGGs and the slow tumor growth rate, vaccines are an attractive treatment strategy.METHODSWe conducted a pilot study to evaluate the safety and immunological effects of vaccination with GBM6-AD, lysate of an allogeneic glioblastoma stem cell line, with poly-ICLC in patients with LGGs. Patients were randomized to receive the vaccines before surgery (arm 1) or not (arm 2) and all patients received adjuvant vaccines. Coprimary outcomes were to evaluate safety and immune response in the tumor.RESULTSA total of 17 eligible patients were enrolled - 9 in arm 1 and 8 in arm 2. This regimen was well tolerated with no regimen-limiting toxicity. Neoadjuvant vaccination induced upregulation of type-1 cytokines and chemokines and increased activated CD8+ T cells in peripheral blood. Single-cell RNA/T cell receptor sequencing detected CD8+ T cell clones that expanded with effector phenotype and migrated into the tumor microenvironment (TME) in response to neoadjuvant vaccination. Mass cytometric analyses detected increased tissue resident-like CD8+ T cells with effector memory phenotype in the TME after the neoadjuvant vaccination.CONCLUSIONThe regimen induced effector CD8+ T cell response in peripheral blood and enabled vaccine-reactive CD8+ T cells to migrate into the TME. Further refinements of the regimen may have to be integrated into future strategies.TRIAL REGISTRATIONClinicalTrials.gov NCT02549833.FUNDINGNIH (1R35NS105068, 1R21CA233856), Dabbiere Foundation, Parker Institute for Cancer Immunotherapy, and Daiichi Sankyo Foundation of Life Science.

Selective deficits in attentional set-shifting in mice induced by maternal immune activation with poly(I:C).

Maternal immune activation has been identified as a significant risk factor for schizophrenia. Using rodent models, past work has demonstrated various behavioral and brain impairments in offspring after immune-activating events. We applied 5 mg/kg of poly(I:C) on gestation day 9 to pregnant mouse dams, whose offspring were then stressed during puberty. We show impairments in attentional set-shifting in a T-maze, and a decreased number of parvalbumin-positive interneurons in the hippocampus as a result of peripubertal stress specifically in females.

Insular cortex modulates social avoidance of sick rats.

Avoidance of sick individuals is vital to the preservation of one's health and preventing transmission of communicable diseases. To do this successfully, one must identify social cues for sickness, which include sickness behaviors and chemosignals, and use this information to orchestrate social interactions. While many social species are highly capable with this process, the neural mechanisms that provide for social responses to sick individuals are only partially understood. To this end, we used a task in which experimental rats were allowed to investigate two conspecifics, one healthy and one sick. To imitate sickness, one conspecific received the viral mimic Polyinosinic:polycytidylic acid (Poly I:C) and the other saline. In a 5-minute social preference test, experimental male and female adult rats avoided Poly I:C treated adult conspecifics but did not adjust social interaction in response to Poly I:C treated juvenile conspecifics. Seeking a neural locus of this behavior, we inhibited the insular cortex, a region necessary for social behaviors directed toward conspecifics in distress. Insular cortex inactivation via administration of the GABAA agonist muscimol to experimental rats prior to social preference tests eliminated the preference to avoid sick adult conspecifics. These results suggest that some aspect of conspecific illness may be encoded in the insular cortex which is anatomically positioned to coordinate a situationally appropriate social response.

Maoto, a traditional Japanese medicine, controls acute systemic inflammation induced by polyI:C administration through noradrenergic function.

Maoto, a traditional Japanese medicine (Kampo), is widely used to treat upper respiratory tract infections, including influenza virus infection. Although maoto is known to inhibit pro-inflammatory responses in a rodent model of acute inflammation, its underlying mechanism remains to be determined. In this study, we investigated the involvement of immune responses and noradrenergic function in the inhibitory action of maoto. In a mouse model of polyI:C-induced acute inflammation, maoto was administered orally in conjunction with intraperitoneal injection of PolyI:C (6 mg/kg), and blood was collected after 2 h for measurement of plasma cytokines by ELISA. Maoto significantly decreased PolyI:C-induced TNF-α levels and increased IL-10 production. Neither pretreatment with IL-10 neutralizing antibodies nor T-cell deficiency using nude mice modified the inhibitory effect of maoto, indicating that the anti-inflammatory effects of maoto are independent of IL-10 and T cells. Furthermore, the inhibitory effects of maoto on PolyI:C-induced TNF-α production were not observed in ex vivo splenocytes, suggesting that maoto does not act directly on inflammatory cells. Lastly, pretreatment with a ß-adrenergic receptor antagonist partially cancelled the anti-inflammatory effects of maoto. Collectively, these results suggest that maoto mediates its anti-inflammatory effects via ß-adrenergic receptors in vivo.

Antigen Delivery to DEC205+ Dendritic Cells Induces Immunological Memory and Protective Therapeutic Effects against HPV-Associated Tumors at Different Anatomical Sites.

The generation of successful anticancer vaccines relies on the ability to induce efficient and long-lasting immune responses to tumor antigens. In this scenario, dendritic cells (DCs) are essential cellular components in the generation of antitumor immune responses. Thus, delivery of tumor antigens to specific DC populations represents a promising approach to enhance the efficiency of antitumor immunotherapies. In the present study, we employed antibody-antigen conjugates targeting a specific DC C-type lectin receptor. For that purpose, we genetically fused the anti-DEC205 monoclonal antibody to the type 16 human papillomavirus (HPV-16) E7 oncoprotein to create a therapeutic vaccine to treat HPV-associated tumors in syngeneic mouse tumor models. The therapeutic efficacy of the αDEC205-E7 mAb was investigated in three distinct anatomical tumor models (subcutaneous, lingual and intravaginal). The immunization regimen comprised two doses of the αDEC205-E7 mAb coadministered with a DC maturation stimulus (Polyinosinic:polycytidylic acid, poly (I:C)) as an adjuvant. The combined immunotherapy produced robust antitumor effects on both the subcutaneous and orthotopic tumor models, stimulating rapid tumor regression and long-term survival. These outcomes were related to the activation of tumor antigen-specific CD8+ T cells in both systemic compartments and lymphoid tissues. The αDEC205-E7 antibody plus poly (I:C) administration induced long-lasting immunity and controlled tumor relapses. Our results highlight that the delivery of HPV tumor antigens to DCs, particularly via the DEC205 surface receptor, is a promising therapeutic approach, providing new opportunities for the development of alternative immunotherapies for patients with HPV-associated tumors at different anatomical sites.

TLR ligand loaded exosome mediated immunotherapy of established mammary Tumor in mice.

Tumor-derived exosomes (TEXs) could be harnessed as an immunotherapeutic cancer vaccine. These nanovesicles are inherently possesses rich tumor antigen reservoirs. Due to their undesirable features such as poor or limited immunogenicity as well as facilitation of cancer development via mediating communication between tumor cells TEXs could be transformed into an effective immune adjuvant delivery system that initiates a strong humoral and cell-mediated tumor-specific immune response. Engineering TEXs to harbor immunostimulatory molecules still remains a challenge. Previously, we demonstrated that nucleic acid ligand encapsulated liposomes could trigger synergistic strong humoral, and cell mediated immune responses and provokes tumor regression to that of their standalone counterparts. In this study, we evaluated to immunogenicity of 4T1/Her2 cell-derived exosomes upon loading them with two potent immuno adjuvant, a TLR9 ligand, K-type CpG ODN and a TLR3 ligand, p(I:C). Engineered TEXs co-encapsulating both ligands displayed boosted immunostimulatory properties by activating antigen-specific primary and memory T cell responses. Furthermore, our exosome-based vaccine candidate elicited robust Th1-biased immunity as evidenced by elevated secretion of IgG2a and IFNγ. In a therapeutic cancer model, administration of4T1 tumor derived exosomes loaded with CpG ODN and p(I:C) to animals regress tumor growth in 4T1 tumor-bearing mice. Taken together this work implicated that an exosome-based therapeutic vaccine promoted strong cellular and humoral anti-tumor immunity that is sufficient to reverse established tumors. This approach offers a personalized tumor therapy strategy that could be implemented in the clinic.

Co-administration of toll-like receptor (TLR)-3 agonist Poly I:C with different infectious bursal disease (IBD) vaccines improves IBD specific immune response in chicken.

Toll-like receptor (TLR) agonists are emerging as promising vaccine adjuvants and immunomodulators in poultry against many diseases. Infectious bursa disease (IBD) still remains as a major threat to poultry industry. Improving the vaccine mediated immune response would help in better protection against IBD virus infection. Adjuvant potential of TLR3 agonist, Polinosinic polycytidylic acid (Poly I:C) with different IBD vaccines has been analyzed in chicken in the present study. Intermediate, intermediate plus IBD vaccine, bursaplex vaccine and their respective poly I:C combinations were used for immunization of chicken. IBD specific antibody titers, bursa to body weight ratio, body weight gain and bursal lesion scores were evaluated at weekly interval in different immunization groups. Fold changes in cytokines IL-1ß and IFN-γ mRNA expression levels in spleen were also analyzed in different groups. Intermediate plus IBD vaccine induced significantly (P ≤ 0.05) higher IBD specific antibody response at 35 days of age than other groups with comparatively lower body weight gain and moderate bursal lesion score. Poly I:C co-administration with intermediate IBD vaccine and bursaplex vaccine improved the IBD specific antibody titers, better body weight gain and moderately less bursal lesion score. However, Poly I:C combination with intermediate plus IBD vaccine did not improve the specific immune response. IL-1ß levels were up-regulated in intermediate plus and bursaplex group, whereas IFN-γ m RNA expression levels were upregulated in intermediate IBD with Poly I:C group. In conclusion, poly I:C co-administration with intermediate IBD and bursaplex vaccine was beneficial and improved the specific immune response with least immunosuppression and bursal damage.

STAT1 potentiates oxidative stress revealing a targetable vulnerability that increases phenformin efficacy in breast cancer.

Bioenergetic perturbations driving neoplastic growth increase the production of reactive oxygen species (ROS), requiring a compensatory increase in ROS scavengers to limit oxidative stress. Intervention strategies that simultaneously induce energetic and oxidative stress therefore have therapeutic potential. Phenformin is a mitochondrial complex I inhibitor that induces bioenergetic stress. We now demonstrate that inflammatory mediators, including IFNγ and polyIC, potentiate the cytotoxicity of phenformin by inducing a parallel increase in oxidative stress through STAT1-dependent mechanisms. Indeed, STAT1 signaling downregulates NQO1, a key ROS scavenger, in many breast cancer models. Moreover, genetic ablation or pharmacological inhibition of NQO1 using ß-lapachone (an NQO1 bioactivatable drug) increases oxidative stress to selectively sensitize breast cancer models, including patient derived xenografts of HER2+ and triple negative disease, to the tumoricidal effects of phenformin. We provide evidence that therapies targeting ROS scavengers increase the anti-neoplastic efficacy of mitochondrial complex I inhibitors in breast cancer.

Ligilactobacillus salivarius Strains Isolated From the Porcine Gut Modulate Innate Immune Responses in Epithelial Cells and Improve Protection Against Intestinal Viral-Bacterial Superinfection.

Previously, we constructed a library of Ligilactobacillus salivarius strains from the intestine of wakame-fed pigs and reported a strain-dependent capacity to modulate IFN-ß expression in porcine intestinal epithelial (PIE) cells. In this work, we further characterized the immunomodulatory activities of L. salivarius strains from wakame-fed pigs by evaluating their ability to modulate TLR3- and TLR4-mediated innate immune responses in PIE cells. Two strains with a remarkable immunomodulatory potential were selected: L. salivarius FFIG35 and FFIG58. Both strains improved IFN-ß, IFN-λ and antiviral factors expression in PIE cells after TLR3 activation, which correlated with an enhanced resistance to rotavirus infection. Moreover, a model of enterotoxigenic E. coli (ETEC)/rotavirus superinfection in PIE cells was developed. Cells were more susceptible to rotavirus infection when the challenge occurred in conjunction with ETEC compared to the virus alone. However, L. salivarius FFIG35 and FFIG58 maintained their ability to enhance IFN-ß, IFN-λ and antiviral factors expression in PIE cells, and to reduce rotavirus replication in the context of superinfection. We also demonstrated that FFIG35 and FFIG58 strains regulated the immune response of PIE cells to rotavirus challenge or ETEC/rotavirus superinfection through the modulation of negative regulators of the TLR signaling pathway. In vivo studies performed in mice models confirmed the ability of L. salivarius FFIG58 to beneficially modulate the innate immune response and protect against ETEC infection. The results of this work contribute to the understanding of beneficial lactobacilli interactions with epithelial cells and allow us to hypothesize that the FFIG35 or FFIG58 strains could be used for the development of highly efficient functional feed to improve immune health status and reduce the severity of intestinal infections and superinfections in weaned piglets.

Adjuvant oncolytic virotherapy for personalized anti-cancer vaccination.

By conferring systemic protection and durable benefits, cancer immunotherapies are emerging as long-term solutions for cancer treatment. One such approach that is currently undergoing clinical testing is a therapeutic anti-cancer vaccine that uses two different viruses expressing the same tumor antigen to prime and boost anti-tumor immunity. By providing the additional advantage of directly killing cancer cells, oncolytic viruses (OVs) constitute ideal platforms for such treatment strategy. However, given that the targeted tumor antigen is encoded into the viral genomes, its production requires robust infection and therefore, the vaccination efficiency partially depends on the unpredictable and highly variable intrinsic sensitivity of each tumor to OV infection. In this study, we demonstrate that anti-cancer vaccination using OVs (Adenovirus (Ad), Maraba virus (MRB), Vesicular stomatitis virus (VSV) and Vaccinia virus (VV)) co-administered with antigenic peptides is as efficient as antigen-engineered OVs and does not depend on viral replication. Our strategy is particularly attractive for personalized anti-cancer vaccines targeting patient-specific mutations. We suggest that the use of OVs as adjuvant platforms for therapeutic anti-cancer vaccination warrants testing for cancer treatment.

The possible role of catalase in innate immunity and diminution of cellular oxidative stress: Insights into its molecular characteristics, antioxidant activity, DNA protection, and transcriptional regulation in response to immune stimuli in yellowtail clownfish (Amphiprion clarkii).

Catalase, a key enzyme in the antioxidant defense grid of organisms, scavenges free radicals to curtail their harmful effects on the host, supporting proper immune function. Herein, we report the identification and characterization of a catalase homolog from Amphiprion clarkii (ClCat), followed by its functional characterization. An open reading frame was identified in the cDNA sequence of ClCat at 1581 bp, which encodes a protein of 527 amino acids (aa) with a molecular mass of 60 kDa. In silico analyses of ClCat revealed characteristic features of the catalase family and a lack of a signal peptide. Multiple sequence alignment of ClCat indicated the conservation of functionally important residues among its homologs. According to phylogenetic analysis, ClCat was of vertebrate origin, positioned within the teleost clade. During native conditions, ClCat mRNA was highly expressed in blood, followed by the liver and kidney. Moreover, significant changes in ClCat transcription were observed after stimulation with LPS, poly I:C, and Vibrio harveyi, in a time-dependent manner. Recombinant ClCat (rClCat) was characterized, and its peroxidase activity was determined. Furthermore, the optimum temperature and pH for rClCat were determined to be 30-40 °C and pH 7, respectively. Oxidative stress tolerance and chromatin condensation assays indicated enhanced cell survival and reduced apoptosis, resulting from reactive oxygen species scavenging by rClCat. The DNA-protective function of rClCat was further confirmed via a metal-catalyzed oxidation assay. Taken together, our findings propose that rClCat plays an essential role in maintaining cellular oxidative homeostasis and host immune protection.

Skin dendritic cells in melanoma are key for successful checkpoint blockade therapy.

BACKGROUND: Immunotherapy with checkpoint inhibitors has shown impressive results in patients with melanoma, but still many do not benefit from this line of treatment. A lack of tumor-infiltrating T cells is a common reason for therapy failure but also a loss of intratumoral dendritic cells (DCs) has been described. METHODS: We used the transgenic tg(Grm1)EPv melanoma mouse strain that develops spontaneous, slow-growing tumors to perform immunological analysis during tumor progression. With flow cytometry, the frequencies of DCs and T cells at different tumor stages and the expression of the inhibitory molecules programmed cell death protein-1 (PD-1) and T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) on T cells were analyzed. This was complemented with RNA-sequencing (RNA-seq) and real-time quantitative PCR (RT-qPCR) analysis to investigate the immune status of the tumors. To boost DC numbers and function, we administered Fms-related tyrosine 3 ligand (Flt3L) plus an adjuvant mix of polyI:C and anti-CD40. To enhance T cell function, we tested several checkpoint blockade antibodies. Immunological alterations were characterized in tumor and tumor-draining lymph nodes (LNs) by flow cytometry, CyTOF, microarray and RT-qPCR to understand how immune cells can control tumor growth. The specific role of migratory skin DCs was investigated by coculture of sorted DC subsets with melanoma-specific CD8+ T cells. RESULTS: Our study revealed that tumor progression is characterized by upregulation of checkpoint molecules and a gradual loss of the dermal conventional DC (cDC) 2 subset. Monotherapy with checkpoint blockade could not restore antitumor immunity, whereas boosting DC numbers and activation increased tumor immunogenicity. This was reflected by higher numbers of activated cDC1 and cDC2 as well as CD4+ and CD8+ T cells in treated tumors. At the same time, the DC boost approach reinforced migratory dermal DC subsets to prime gp100-specific CD8+ T cells in tumor-draining LNs that expressed PD-1/TIM-3 and produced interferon γ (IFNγ)/tumor necrosis factor α (TNFα). As a consequence, the combination of the DC boost with antibodies against PD-1 and TIM-3 released the brake from T cells, leading to improved function within the tumors and delayed tumor growth. CONCLUSIONS: Our results set forth the importance of skin DC in cancer immunotherapy, and demonstrates that restoring DC function is key to enhancing tumor immunogenicity and subsequently responsiveness to checkpoint blockade therapy.

Effect of lipopolysaccharide and polyinosinic:polycytidylic acid in a murine model of nasal polyp.

Several factors, including bacterial and viral infections, have been associated with rhinosinusitis and nasal tissue remodelling that may result in nasal polyp formation. However, the potential role of bacterial or viral stimuli triggering polyp development is unclear. Here, we used lipopolysaccharide (LPS) and polyinosinic:polycytidylic acid [poly(I:C)] in a murine model of allergic rhinosinusitis to compare different effects of bacterial- and virus-derived stimuli in the pathogenesis of nasal polyp formation. Briefly, BALB/c mice were sensitised and challenged with ovalbumin and staphylococcal enterotoxin, with or without LPS or poly(I:C), and the consequent histopathological profiles, cytokines, and systemic humoral responses were studied. While no significant differences in polyp formations and epithelial disruptions were observed among the experimental groups, the local cell recruitment patterns slightly differed in animals that received either LPS or poly(I:C). Additionally, the local immune environments generated by LPS or poly(I:C) stimulation varied. LPS stimulation induced a marked Th1/Th17 response and predominantly neutrophilic nasal polyp formations, whereas poly(I:C) induced a Th2-skewed environment in neutrophilic nasal polyp development. Overall, our findings show that both cell recruitment patterns and local immune environments induced by these two stimuli differ, which may have implications in the physiopathology of rhinosinusitis with nasal polyp.

Trial to evaluate the immunogenicity and safety of a melanoma helper peptide vaccine plus incomplete Freund's adjuvant, cyclophosphamide, and polyICLC (Mel63).

BACKGROUND: Peptide vaccines designed to stimulate melanoma-reactive CD4+ T cells can induce T cell and antibody (Ab) responses, associated with enhanced overall survival. We hypothesized that adding toll-like receptor 3 agonist polyICLC to an incomplete Freund's adjuvant (IFA) would be safe and would support strong, durable CD4+ T cell and Ab responses. We also hypothesized that oral low-dose metronomic cyclophosphamide (mCy) would be safe, would reduce circulating regulatory T cells (T-regs) and would further enhance immunogenicity. PARTICIPANTS AND METHODS: An adaptive design based on toxicity and durable CD4+ T cell immune response (dRsp) was used to assign participants with resected stage IIA-IV melanoma to one of four study regimens. The regimens included a vaccine comprising six melanoma peptides restricted by Class II MHC (6MHP) in an emulsion with IFA alone (Arm A), with IFA plus systemic mCy (Arm B), with IFA+ local polyICLC (Arm C), or with IFA+ polyICLC+ mCy (Arm D). Toxicities were recorded (CTCAE V.4.03). T cell responses were measured by interferon γ ELIspot assay ex vivo. Serum Ab responses to 6MHP were measured by ELISA. Circulating T-regs were assessed by flow cytometry. RESULTS: Forty-eight eligible participants were enrolled and treated. Early data on safety and dRsp favored enrollment on arm D. Total enrollment on Arms A-D were 3, 7, 6, and 32, respectively. Treatment-related dose-limiting toxicities (DLTs) were observed in 1/7 (14%) participants on arm B and 2/32 (6%) on arm D. None exceeded the 25% DLT threshold for early closure to enrollment for any arm. Strong durable T cell responses to 6MHP were detected ex vivo in 0%, 29%, 67%, and 47% of participants on arms A-D, respectively. IgG Ab responses were greatest for arms C and D. Circulating T-regs frequencies were not altered by mCy. CONCLUSIONS: 6MHP vaccines administered with IFA, polyICLC, and mCy were well tolerated. The dRsp rate for arm D of 47% (90% CI 32 to 63) exceeded the 18% (90% CI 11 to 26) rate previously observed with 6MHP in IFA alone. Vaccination with IFA+ polyICLC (arm C) also showed promise for enhancing T cell and Ab responses.

Combined Intranasal Nanoemulsion and RIG-I Activating RNA Adjuvants Enhance Mucosal, Humoral, and Cellular Immunity to Influenza Virus.

Current influenza virus vaccines are focused on humoral immunity and are limited by the short duration of protection, narrow cross-strain efficacy, and suboptimal immunogenicity. Here, we combined two chemically and biologically distinct adjuvants, an oil-in-water nanoemulsion (NE) and RNA-based agonists of RIG-I, to determine whether the diverse mechanisms of these adjuvants could lead to improved immunogenicity and breadth of protection against the influenza virus. NE activates TLRs, stimulates immunogenic apoptosis, and enhances cellular antigen uptake, leading to a balanced TH1/TH2/TH17 response when administered intranasally. RIG-I agonists included RNAs derived from Sendai and influenza viral defective interfering RNAs (IVT DI, 3php, respectively) and RIG-I/TLR3 agonist, poly(I:C) (pIC), which induce IFN-Is and TH1-polarized responses. NE/RNA combined adjuvants potentially allow for costimulation of multiple innate immune receptor pathways, more closely mimicking patterns of activation occurring during natural viral infection. Mice intranasally immunized with inactivated A/Puerto Rico/8/1934 (H1N1) (PR/8) adjuvanted with NE/IVT DI or NE/3php (but not NE/pIC) showed synergistic enhancement of systemic PR/8-specific IgG with significantly greater avidity and virus neutralization activity than the individual adjuvants. Notably, NE/IVT DI induced protective neutralizing titers after a single immunization. Hemagglutinin stem-specific antibodies were also improved, allowing recognition of heterologous and heterosubtypic hemagglutinins. All NE/RNAs elicited substantial PR/8-specific sIgA. Finally, a unique cellular response with enhanced TH1/TH17 immunity was induced with the NE/RNAs. These results demonstrate that the enhanced immunogenicity of the adjuvant combinations was synergistic and not simply additive, highlighting the potential value of a combined adjuvant approach for improving the efficacy of vaccination against the influenza virus.

Fever Induced by Zymosan A and Polyinosinic-Polycytidylic Acid in Female Rats: Influence of Sex Hormones and the Participation of Endothelin-1.

Sex differences in the immune response can also affect the febrile response, particularly the fever induced by lipopolysaccharide (LPS). However, other pathogen-associated molecular patterns, such as zymosan A (Zym) and polyinosinic-polycytidylic acid (Poly I:C), also induce fever in male rats with a different time course of cytokine release and different mediators such as endothelin-1 (ET-1). This study investigated whether female sex hormones affect Zym- and Poly I:C-induced fever and the involvement of ET-1 in this response. The fever that was induced by Zym and Poly I:C was higher in ovariectomized (OVX) female rats compared with sham-operated female rats. Estrogen replacement in OVX females reduced Zym- and Poly I:C-induced fever. The ETB receptor antagonist BQ788 reversed the LPS-induced fever in cycling females but not in OVX females. BQ788 did not alter the fever that was induced by Zym or Poly I:C in either cycling or OVX females. These findings suggest that the febrile response in cycling females is lower, independently of the stimulus that is inducing it and is probably controlled by estrogen. Also, ET-1 seems to participate in the febrile response that was induced by LPS in males and cycling females but not in the LPS-induced fever in OVX females. Additionally, ET-1 was not involved in the febrile response that was induced by Zym or Poly I:C in females.

Inhibition of adjuvant-induced TAM receptors potentiates cancer vaccine immunogenicity and therapeutic efficacy.

Analyzing immunomodulatory elements operating during antitumor vaccination in prostate cancer patients and murine models we identified IL-10-producing DC as a subset with poorer immunogenicity and clinical efficacy. Inhibitory TAM receptors MER and AXL were upregulated on murine IL-10+ DC. Thus, we analyzed conditions inducing these molecules and the potential benefit of their blockade during vaccination. MER and AXL upregulation was more efficiently induced by a vaccine containing Imiquimod than by a poly(I:C)-containing vaccine. Interestingly, MER expression was found on monocyte-derived DC, and was dependent on IL-10. TAM blockade improved Imiquimod-induced DC activation in vitro and in vivo, resulting in increased vaccine-induced T-cell responses, which were further reinforced by concomitant IL-10 inhibition. In different tumor models, a triple therapy (including vaccination, TAM inhibition and IL-10 blockade) provided the strongest therapeutic effect, associated with enhanced T-cell immunity and enhanced CD8+ T cell tumor infiltration. Finally, MER levels in DC used for vaccination in cancer patients correlated with IL-10 expression, showing an inverse association with vaccine-induced clinical response. These results suggest that TAM receptors upregulated during vaccination may constitute an additional target in combinatorial therapeutic vaccination strategies.