Immunization with a Toll-like receptor 7 and/or 8 agonist vaccine adjuvant increases protective immunity against Leishmania major in BALB/c mice

Chlorogenic acid alleviates crayfish allergy by altering the structure of crayfish tropomyosin and upregulating TLR8

Studies have shown that high hydrostatic pressure (HHP) processing and chlorogenic acid (CA) treatment can effectively reduce food allergenicity. We hypothesize that these novel processing techniques can help tackle crayfish allergy and examined the impact and mechanism of HHP (300 MPa, 15 min) and CA (CA:tropomyosin = 1:4000, 15 min) on the allergenicity of crayfish tropomyosin. Our results revealed that CA, rather than HHP, effectively reduced tropomyosin's allergenicity, as evident in the alleviation of allergic symptoms in a food allergy mouse model. Spectroscopy and molecular docking analyses demonstrated that CA could reduce the allergenicity of tropomyosin by covalent or non-covalent binding, altering its secondary structure (2.1 % decrease in α-helix; 1.9 % increase in β-fold) and masking tropomyosin's linear epitopes. Moreover, CA-treated tropomyosin potentially induced milder allergic reactions by up-regulating TLR8. While our results supported the efficacy of CA in alleviating crayfish allergy, further exploration is needed to determine clinical effectiveness.

Imiquimod Reverses Chronic Toxoplasmosis-Associated Behavioral and Neurocognitive Anomalies in a Rat Model

Toxoplasma gondii is the etiologic agent of toxoplasmosis, a highly prevalent parasitosis. Toxoplasma gondii (T. gondii) transits in the brain from acute (AT) to chronic toxoplasmosis (CT), under host immune control. In immunocompromised patients, reactivation of CT is potentially life-threatening. Behavioral and neurological complications have been associated with CT. Furthermore, an effective treatment targeting CT is still lacking. We previously reported the efficacy of imiquimod against CT. Here, we demonstrate the molecular effects of imiquimod or imiquimod followed by the clinically used combination of sulfadiazine and pyrimethamine (SDZ + PYR) on CT-associated behavior in a rat model. Imiquimod decreased the number of cysts in the brains of chronically infected rats due to an induced reactivation of bradyzoites into tachyzoites. Importantly, this decrease was more pronounced in rats treated with imiquimod followed by SDZ + PYR. Rats chronically infected with T. gondii exhibited an anxiety-like behavior. Notably, treatment with imiquimod reversed this behavior aberrancy, with even a more pronounced effect with imiquimod followed by SDZ/PYR. Similarly, rats chronically infected with T. gondii exhibited learning deficits, and imiquimod alone or followed by SDZ/PYR reversed this behavior. Our results enhance our knowledge of the implications of CT on behavioral aberrancies and highlight the potency of imiquimod followed by SDZ + PYR on these CT-associated complications.

Macromolecular Cargo Encapsulation via In Vitro Assembly of Two-Component Protein Nanoparticles

Self-assembling protein nanoparticles are a promising class of materials for targeted drug delivery. Here, the use of a computationally designed, two-component, icosahedral protein nanoparticle is reported to encapsulate multiple macromolecular cargoes via simple and controlled self-assembly in vitro. Single-stranded RNA molecules between 200 and 2500 nucleotides in length are encapsulated and protected from enzymatic degradation for up to a month with length-dependent decay rates. Immunogenicity studies of nanoparticles packaging synthetic polymers carrying a small-molecule TLR7/8 agonist show that co-delivery of antigen and adjuvant results in a more than 20-fold increase in humoral immune responses while minimizing systemic cytokine secretion associated with free adjuvant. Coupled with the precise control over nanoparticle structure offered by computational design, robust and versatile encapsulation via in vitro assembly opens the door to a new generation of cargo-loaded protein nanoparticles that can combine the therapeutic effects of multiple drug classes.

Lymph node targeting for immunotherapy

Immunotherapy that aims to boost the body's immune responses against pathogens or diseased cells has achieved significant progress for treating different diseases over the past several decades, especially with the success of checkpoint blockades, chimeric antigen receptor T therapy, and cancer vaccines in clinical cancer treatment. Effective immunotherapy necessitates the generation of potent and persistent humoral and T-cell responses, which lies in the ability of modulating and guiding antigen-presenting cells to prime antigen-specific T and B cells in the lymphoid tissues, notably in the lymph nodes proximal to the disease site. To this end, various types of strategies have been developed to facilitate the delivery of immunomodulatory agents to immune cells (e.g. dendritic cells and T cells) in the lymph nodes. Among them, intranodal injection enables the direct exposure of immunomodulators to immune cells in lymph nodes, but is limited by the technical challenge and intrinsic invasiveness. To address, multiple passive and active lymph node-targeting technologies have been developed. In this review, we will provide an overview of different lymph node-targeting technologies developed to date, as well as the mechanism and merits of each approach.

Optimized dithranol-imiquimod-based transcutaneous immunization enables tumor rejection

Introduction

Transcutaneous immunization (TCI) is a non-invasive vaccination method promoting strong cellular immune responses, crucial for the immunological rejection of cancer. Previously, we reported on the combined application of the TLR7 agonist imiquimod (IMQ) together with the anti-psoriatic drug dithranol as novel TCI platform DIVA (dithranol/IMQ based vaccination). In extension of this work, we further optimized DIVA in terms of drug dose, application pattern and established a new IMQ formulation.

Methods

C57BL/6 mice were treated on the ear skin with dithranol and IMQ-containing ointments together with ovalbumin-derived peptides. T cell responses were determined by flow cytometry and IFN-ɤ ELISpot assay, local skin inflammation was characterized by ear swelling.

Results

Applying the adjuvants on separate skin sites, a reduced number of specific CD8+ T cells with effector function was detectable, indicating that the local concurrence of adjuvants and peptide antigens is required for optimal vaccination. Likewise, changing the order of dithranol and IMQ resulted in an increased skin inflammatory reaction, but lower frequencies of antigen-specific CD8+ T cells indicating that dithranol is essential for superior T cell priming upon DIVA. Dispersing nanocrystalline IMQ in a spreadable formulation (IMI-Sol+) facilitated storage and application rendering comparable immune responses. DIVA applied one or two weeks after the first immunization resulted in a massive increase in antigen-specific T cells and up to a ten-fold increased memory response. Finally, in a prophylactic tumor setting, double but no single DIVA treatment enabled complete control of tumor growth, resulting in full tumor protection.

Discussion

Taken together, the described optimized transcutaneous vaccination method leads to the generation of a strong cellular immune response enabling the effective control of tumor growth and has the potential for clinical development as a novel non-invasive vaccination method for peptide-based cancer vaccines in humans.

Interplay of Chemokines Receptors, Toll-like Receptors, and Host Immunological Pathways

A comprehensive framework has been established for understanding immunological pathways, which can be categorized into eradicated and tolerable immune responses. Toll-like receptors (TLRs) are associated with specific immune responses. TH1 immunity is related to TLR7, TLR8, and TLR9, while TH2 immunity is associated with TLR1, TLR2, and TLR6. TH22 immunity is linked to TLR2, TLR4, and TLR5, and THαβ (Tr1) immunity is related to TLR3, TLR7, and TLR9. The chemokine receptor CXCR5 is a marker of follicular helper T cells, and other chemokine receptors can also be classified within a framework based on host immunological pathways. On the basis of a literature review on chemokines and immunological pathways, the following associations were identified: CCR5 with TH1 responses, CCR1 with TH1-like responses, CCR4 (basophils) and CCR3 (eosinophils) with TH2 and TH9 responses, CCR10 with TH22 responses, CCR6 with TH17 responses, CXCR3 with THαβ responses, CCR8 with regulatory T cells (Treg), and CCR2 with TH3 responses. These findings contribute to the identification of biomarkers for immune cells and provide insights into host immunological pathways. Understanding the chemokine and Toll-like receptor system is crucial for comprehending the function of the innate immune system, as well as adaptive immune responses.

The Use of an Adjuvant System Improves Innate and Adaptive Immune Response When Associated with a Leishmania (Viannia) braziliensis Antigen in a Vaccine Candidate against L. (Leishmania) infantum Infection

BACKGROUND

The adjuvants' optimal dose and the administration route can directly influence the epitope recognition patterns and profiles of innate response. We aimed to establish the effect and the optimal dose of adjuvant systems for proposing a vaccine candidate to be employed with Leishmania (Viannia) braziliensis.

METHODS

We evaluated the adjuvants saponin (SAP), monophosphoryl lipid A (MPL) and resiquimod (R-848) isolated and combined as adjuvant systems in a lower dose corresponding to 25%, 33%, and 50% of each adjuvant total dose. Male outbred BALB/c mice were divided into 13 groups, SAP, MPL, and R-848 isolated, and the adjuvant systems SAP plus MPL (SM), SAP plus R-848 (SR), and MPL plus R-848 (MR).

RESULTS

SM50 increased levels of all chemokines analyzed and TNF production, while it presented an increased inflammatory cell infiltrate in the skin with macrophage recruitment. Thus, we proposed a vaccine candidate employing L. (V.) braziliensis antigen associated with the SM adjuvant system against experimental L. (Leishmania) infantum challenge. We observed a significant increase in the frequency of cells expressing the central and effector memory CD4⁺ T cells phenotype in immunized mice with the LBSM50. In the liver, there was a decreased parasite load when mice received LBSM50.

CONCLUSIONS

When combined with L. (V.) braziliensis antigen, SM50 increases TNF and IFN-γ, which generates central and effector memory CD4⁺ T cells. Therefore, using an adjuvant system can promote an effective innate immune response with the potential to compose future vaccines.

Toll-like receptor (TLR) agonists as a driving force behind next-generation vaccine adjuvants and cancer therapeutics

Until recently, the development of new human adjuvants was held back by a poor understanding of their mechanisms of action. The field was revolutionized by the discovery of the toll-like receptors (TLRs), innate immune receptors that directly or indirectly are responsible for detecting pathogen-associated molecular patterns (PAMPs) and respond to them by activating innate and adaptive immune pathways. Hundreds of ligands targeting various TLRs have since been identified and characterized as vaccine adjuvants. This work has important implications not only for the development of vaccines against infectious diseases but also for immuno-therapies against cancer, allergy, Alzheimer's disease, drug addiction and other diseases. Each TLR has its own specific tissue localization and downstream gene signalling pathways, providing researchers the opportunity to precisely tailor adjuvants with specific immune effects. TLR agonists can be combined with other TLR or alternative adjuvants to create combination adjuvants with synergistic or modulatory effects. This review provides an introduction to the various classes of TLR adjuvants and their respective signalling pathways. It provides an overview of recent advancements in the TLR field in the past 2-3 years and discusses criteria for selecting specific TLR adjuvants based on considerations, such as disease mechanisms and correlates of protection, TLR immune biasing capabilities, route of administration, antigen compatibility, new vaccine technology platforms, and age- and species-specific effects.

Evaluating the Efficacy of Combined Intralesional Sodium Stibogluconate Plus Topical Imiquimod on Healing and Risk of Scarring of Cutaneous Leishmaniasis: A Case-Control Study

Background: A combination treatment of cutaneous leishmaniasis (CL) that hastens the healing and reduces the chance of scarring, especially in aesthetically receptive sites, is required.

Objectives: To evaluate if a combination of intralesional sodium stibogluconate (SSG) injection and topical imiquimod 5% cream (IMI) accelerates healing and improves the quality of scars from CL.

Patients and Methods: A prospective, placebo-controlled, randomized clinical trial was conducted at Basrah Teaching Hospital, Basrah, southern Iraq from 2017 to 2019 on a cohort of patients with CL. Eligible patients were injected intralesionally with sodium stibogluconate (SSG) weekly for six weeks and randomized to receive either topical imiquimod 5% cream (IMI group) or topical emollient cream (placebo group). The healing rate and scar quality were assessed at week six.

Results: One hundred twenty-one patients completed the trial (66 [55%] males, mean age SD: 34.1 years). The clinical healing rate was significantly higher in the IMI group than in the placebo group (94% versus 74%, p <0.05). A high rate of scars was noticed in both groups (66.6% in the IMI group and 91.2% in the placebo group). However, superficial non-atrophic scars were more frequent in the IMI group (40% versus 26%), while deep atrophic scars were more evident in the placebo group than in the IMI group (65.2% versus 26.6%, p<0.05).

Conclusions: Combined intralesional SSG plus topical imiquimod was beneficial in accelerating CL healing and improving scar quality, and should be considered when CL is located in aesthetically sensitive areas.

Imiquimod-gemcitabine nanoparticles harness immune cells to suppress breast cancer

Monotherapy with a single chemotherapeutic regimen has met with significant hurdles in terms of clinical efficacy. The complexity of cancer accentuates the need for an alternative approach with a combination of two or more therapeutic regimens to win the battle. However, it is still a challenge to develop a successful combination of drugs with high efficiency and low toxicity to control cancer growth. While gemcitabine monotherapy remains a choice of standard treatment for advanced breast cancer, the approach has not prolonged the median survival time of metastatic breast cancer patients. Here, we report a hyaluronic acid (HA)-based drug combination of gemcitabine (GEM) with imiquimod (IMQ) to stimulate immune cells for anticancer activity. Treatment of the drug combination (IMQ-HA-GEM) showed enhanced anticancer activity against 4T1 breast tumor cells in vitro. Our study with a microfluidics-based 3D, compartmentalized cancer model showed that infiltration of THP-1 monocytes occurred particularly at the site of cancer cells treated with IMQ-HA-GEM. Moreover, IMQ-HA-GEM significantly suppressed the volume of 4T1 breast tumor of mice in vivo. Flow cytometry study displayed a significantly higher activation of CD11b⁺ immune cells in the blood of mice treated with IMQ-HA-GEM, whereas immunohistochemistry study revealed greater prevalence of CD68⁺ tumor-associated macrophages in the tumor. Histological examination of isolated tumors of mice treated with IMQ-HA-GEM further confirmed the efficacy of drug combination on cancer cells. This study supports the conclusion that imiquimod potentiates the effect of gemcitabine by activating immune cells to suppress tumors in the form of combination nanoparticles.

Evaluation of Cellular Immune Responses in Dogs Immunized with Alum-Precipitated Autoclaved Leishmania major along with BCG and Imiquimod

Background:

We aimed to investigate the potential effects of BCG and imiquimod on improvement of current experimental L. major vaccine against dogs in an endemic area of Zoonotic visceral leishmaniasis (ZVL) in Iran.

Methods:

During 2012 till 2014, seven mixed-breed shepherd dogs with no anti-Leishmania antibodies and no response to Leishmanin reagent were immunized with 2 doses of alum-precipitated autoclaved L. major (Alum-AML) while BCG and imiquimod (for skin pre-treatment) were used as adjuvants. The productions of a few characteristic cytokines of T-helper immune responses and the development of delayed-type hypersensitivity (DTH) of the immunized animals were then evaluated, up to 300 days. Blood samples were collected at 0, 30, 80 and 300 d post-vaccination and the concentrations of IFN-γ, IL10, IL-12 and TGF-β cytokines secreted from PBMCs at these time-points were quantified by ELISA. DTH was evaluated by Leishmanin skin test (LST).

Results:

Although a similar LST conversion was observed at all time-points, the cytokine measurement results indicated significantly higher levels of IFN-γ at day 80 and elevated levels of IL-10 at days 80 and 300, post-vaccination. Moreover, a significantly higher IFN-γ/IL-10 ratio was observed at day 30 post-vaccination compared to the other time-points.

Conclusion:

Although a Th1-like response could be observed at day 30 post-vaccination, the development of cytokine profiles was inclined toward mixed Th1 and Th2 responses at days 80 and 300 post-vaccination. This situation may indicate the requirement of an additional boosting by this Alum-AML formula, in order to induce long-lasting protection against ZVL.

Toll-like receptor-7/8 agonist kill Leishmania amazonensis by acting as pro-oxidant and pro-inflammatory agent

OBJECTIVES

Evaluation of the anti-Leishmanial activity of imidazoquinoline-based TLR7/8 agonists.

METHODS

TLR7/8-active imidazoquinolines (2 and 3) were synthesized and assessed for activity against Leishmania amazonensis-intracellular amastigotes using mouse peritoneal macrophages. The production of reactive oxygen species (ROS), nitric oxide (NO) and cytokines was determined in infected and non-infected macrophages.

KEY FINDINGS

The imidazoquinolines, 2 and 3, were primarily agonists of TLR7 with compound 3 also showing modest TLR8 activity. Docking studies showed them to occupy the same binding pocket on TLR7 and 8 as the known agonists, imiquimod and resiquimod. Compounds 2 and 3 inhibited the growth of L. amazonensis-intracellular amastigotes with the most potent compound (3, IC50 = 5.93 µM) having an IC50 value close to miltefosine (IC50 = 4.05 µM), a known anti-Leishmanial drug. Compound 3 induced macrophages to produce ROS, NO and inflammatory cytokines that likely explain the anti-Leishmanial effects.

CONCLUSIONS

This study shows that activating TLR7 using compounds 2 or 3 induces anti-Leishmanial activity associated with induction of free radicals and inflammatory cytokines able to kill the parasites. While 2 and 3 had a very narrow cytotoxicity window for macrophages, this identifies the possibility to further develop this chemical scaffold to less cytotoxic TLR7/8 agonist for potential use as anti-Leishmanial drug.

Potential of TLR agonist as an adjuvant in Leishmania vaccine against visceral leishmaniasis in BALB/c mice

Morbid infection of leishmaniasis is posing threat to humankind due to its exacerbating prevalence in newer emerging areas. Moreover, the availability of limited drugs, their toxicity, limited efficacy, the emergence of drug resistance, and unavailability of vaccines are the major obstacles in its elimination. This implies the demand for a prophylactic vaccine candidate to prevent this infection and resulting fatal disease. We evaluated gardiquimod (a toll-like receptor-7 agonist) for its action as an adjuvant with the heat-killed antigen of Leishmania donovani. BALB/c mice were immunized with a vaccine either with or without adjuvant and given challenge infection. The results depicted the low parasite burden, higher delayed-type hypersensitivity response, and higher levels of IgG2a, Th1 cytokines, and NO in immunized mice in contrast to infected control mice. Low levels of Th2 cytokines and IgG1 were also noticed in the vaccinated mice than in infected mice. The mice immunized with a combination of gardiquimod and heat-killed antigen showed maximum efficacy. The results from the present study reflect the potential of tested vaccine candidate with gardiquimod as an adjuvant.

Adjuvant effects of TLR agonist gardiquimod admixed with Leishmania vaccine in mice model of visceral leishmaniasis

Tropical and subtropical areas of the world are affected by leishmaniasis, which is caused by Leishmania spp. It has been categorized as an NTD (neglected tropical disease) because of its negligence. The sand fly of genus Phlebotomus acts as the vector for the transmission of the promastigote form of this protozoan parasite to the mammalian host where it converts to amastigote form in the macrophages. Visceral form of leishmaniasis (VL) is a deadly infection in the endothelial system of the human and other mammals. Only a few chemotherapeutic agents are available for the treatment of this infectious disease whereas no vaccine is available for the control of leishmanial infection. Therefore in the current study, we have tested the effects of gardiquimod (a TLR agonist) as an adjuvant in combination with the formalin-killed antigen of L. donovani as a vaccine. The mice were vaccinated thrice at an interval of 2 weeks and challenged with L. donovani promastigotes after 2 weeks of the last vaccination. We assessed the parasite load, delayed-type hypersensitivity (DTH) responses, humoral and cell-mediated immune response in BALB/c mice before and after challenge infection with L. donovani. Immunized mice were found to have the least parasite load, high DTH response, elevated levels of Th1 cytokines, IgG2a, and nitric oxide than non-immunized and infected control mice. The efficacy of the vaccine was boosted with the use of adjuvant gardiquimod that depicts its potential as an adjuvant in this study. Our study is reporting the adjuvant effects of gardiquimod for the first time. Further studies using other Leishmania species can be performed to signify its role.

Immunotherapy in treatment of leishmaniasis

Leishmaniasis caused by various species of protozoan transmitted by sand fly vectors occurs as a spectrum of clinical features including cutaneous, mucocutaneous and visceral forms. It is a geographically distributed parasitic disease and a major public health problem in the world. The clinical syndromes are highly variable depending on the parasite species, host genetics, vectors and environment. To date, there is no effective vaccine and traditional treatments are toxic, expensive with long administration duration and many adverse side effects and/or drug resistance. Instead of treatments based on chemotherapy, certain strategies aim to recover leishmaniasis and reduce the parasitic burden. Immunotherapy has focused on the induction of effective immune response to rapidly control the disease. Recent studies have indicated that a single dose of a suitable therapeutic vaccine induces a quick and lasting recovery in patients. Immunotherapy reduces the toxicity of drug and the emergence of resistance dramatically. It could be an effective addition to chemotherapy with a safe and potent drug compared with monotherapy, resulting in a prophylactic and therapeutic cure of leishmaniasis. This review has focused on treatment of leishmaniasis with particular emphasis on immunotherapy as an alternative to conventional drug treatment.

A TLR7/8 Agonist-Including DOEPC-Based Cationic Liposome Formulation Mediates Its Adjuvanticity Through the Sustained Recruitment of Highly Activated Monocytes in a Type I IFN-Independent but NF-κB-Dependent Manner

Novel adjuvants, such as Toll-like receptors (TLRs) agonists, are needed for the development of new formulations able to circumvent limitations of current vaccines. Among TLRs, TLR7/8 agonists represent promising candidates, as they are well described to enhance antigen-specific antibody responses and skew immunity toward T helper (T_H) 1 responses. We find here that the incorporation of the synthetic TLR7/8 ligand 3M-052 in a cationic DOEPC-based liposome formulation shifts immunity toward T_H1 responses and elicits strong and long-lasting germinal center and follicular T helper cell responses in adult mice. This reflects the prolonged recruitment of innate cells toward the site of immunization and homing of activated antigen-loaded monocytes and monocyte-derived dendritic cells toward draining lymph nodes. We further show that this adjuvanticity is independent of type I IFN but NF-κB-dependent. Overall, our data identify TLR7/8 agonists incorporated in liposomes as promising and effective adjuvants to enhance T_H1 and germinal center responses.

Immunotherapy in clinical canine leishmaniosis: a comparative update

Leishmaniosis due to Leishmania infantum is a complex infection that can affect both humans and dogs, and present a wide range of clinical signs and clinicopathological abnormalities. The conventional treatment of this disease is challenging due to the fact that complete parasitological cure commonly does not occur. Furthermore, treatment of the disease with the conventionally used drugs has several shortcomings. These include the need for long-term treatment, side effects and the formation of drug resistance. Moreover, it is important to highlight that the host immune responses play a crucial role in the outcome of this infection. For this reason, the use of immunotherapy in clinical leishmaniosis to improve the result of treatment with the conventional anti-leishmanial drugs by enhancing the immune response is imperative. The aim of this review is to provide a comparative overview of the wide range of immunotherapeutical approaches and strategies for the treatment of L. infantum infection in animals focusing on dogs.

Protection induced by Leishmania Major antigens and the imiquimod adjuvant encapsulated on liposomes in experimental cutaneous leishmaniasis

There is a need for new, effective, and less expensive and toxic treatment for Leishmaniasis. It seems that the use of a suitable adjuvant and a delivery system is effective in inducing immune reactions for protection. Liposomes can be applied as immunoadjuvants to trigger immune reactions to different antigens. The adjuvant effects of imiquimod using DSPC liposomes containing SLA (soluble Leishmania antigens) were studied on the type and intensity of the produced immune reaction to the challenge of Leishmania major in BALB/c mice. Liposomes were produced by the lipid film procedure. BALB/C mice were immunized subcutaneously, three times at 2-week intervals and with various formulations. Lesion development and the parasite burden in the spleens and feet after the challenge with Leishmania major, Th1 cytokine (IFN-γ), and the IgG isotype titration were assessed to evaluate the induced immune reaction and the protection level. The group of mice immunized with Liposome DSPC +Imiquimod +SLA revealed less severe footpad swelling, being significantly different (P < .05) from other groups. A higher level of IgG2a and IFN-γ secretion was observed in the mice immunized with Liposome DSPC +Imiquimod +SLA than the control group. These observations imply that the DSPC liposome containing imiquimod induces the Th1 immune response that is protective against the challenge of Leishmania major.

EAPB0503: An Imiquimod analog with potent in vitro activity against cutaneous leishmaniasis caused by Leishmania major and Leishmania tropica

Cutaneous Leishmaniasis (CL) is a parasitic infection classified by the WHO as one of the most uncontrolled spreading neglected diseases. Syria is endemic for Leishmania tropica and Leishmania major, causing CL in the Eastern Mediterranean. The large-scale displacement of Syrian refugees exacerbated the spread of CL into neighboring countries. Therapeutic interventions against CL include local, systemic and physical treatments. The high risk for drug-resistance to current treatments stresses the need for new therapies. Imiquimod is an immunomodulatory drug with a tested efficacy against L. major species. Yet, Imiquimod efficacy against L. tropica and the molecular mechanisms dictating its potency are still underexplored. In this study, we characterized the effect of Imiquimod against L. tropica and L. major, and characterized the molecular mechanisms dictating its anti-leishmanial efficacy against both strains. We also investigated the potency and molecular mechanisms of an Imiquimod analog, EAPB0503, against these two strains. We have tested the effect of Imiquimod and EAPB0503 on macrophages infected with either L. major, L. tropica strains, or patient-derived freshly isolated L. tropica parasites. The anti-amastigote activity of either drugs was assessed by quantitative real time PCR (RT-PCR) using kinetoplast specific primers, confocal microscopy using the Glycoprotein 63 (Gp63) Leishmania amastigote antibody or by histology staining. The mechanism of action of either drugs on the canonical nuclear factor kappa- B (NF-κB) pathway was determined by western blot, and confocal microscopy. The immune production of cytokines upon treatment of infected macrophages with either drugs was assessed by ELISA. Both drugs reduced amastigote replication. EAPB0503 proved more potent, particularly on the wild type L. tropica amastigotes. Toll-Like Receptor-7 was upregulated, mainly by Imiquimod, and to a lesser extent by EAPB0503. Both drugs activated the NF-κB canonical pathway triggering an immune response and i-NOS upregulation in infected macrophages. Our findings establish Imiquimod as a strong candidate for treating L. tropica and show the higher potency of its analog EAPB0503 against CL.

Cutaneous Leishmaniasis (CL) is a parasitic infection caused by Leishmania (L.) parasites. In the Old World and the Near East, CL is mainly caused by L. major and L. tropica. The ongoing Syrian war and the resulting massive population displacement led to an alarming increase in the incidence of CL, in Syria and its surrounding countries. Current therapies against CL lead to partial or complete cure in L. major infections but are less effective against L. tropica. These therapies associate with several limitations, including patients’age, immune system, repetitive painful injections, high cost, poor availability, and mainly systemic toxicity. Therefore, it is of high interest to seek for novel drugs against CL. We assessed the activity of an immunomodulatory drug and its analog against L. major and L. tropica parasites and showed their potency. Importantly, the analog proved more efficient against the wild type L. tropica strain. These results highlight the promising efficacy of immuno-modulatory drugs against CL.

Cytokine Effect of TLR3, TLR4, and TLR7 Agonists Alone or Associated with Leishmania infantum Antigen on Blood from Dogs

Activation of toll-like receptors (TLRs) has been shown to play an important role in leishmaniosis by enhancing the parasite specific immune responses to control infection. However, the role of TLR agonists has not been studied in detail in dogs. The aim of this study was to determine the effect of TLR3, TLR4, and TLR7 agonists (TLR3a, TLR4a, and TLR7a) alone or in combination with Leishmania infantum antigen (LSA) on TNF-α and IL-6 production in blood from dogs living in endemic areas of canine leishmaniosis (CanL). Twenty-four healthy dogs from Catalonia (n=14) and Ibizan hound dogs from the island of Mallorca (n=10) were enrolled. Whole blood with TLR3a, TLR4a, and TLR7a alone or combined with LSA were cultured separately, and IFN-γ, TNF-α, and IL-6 were measured by ELISA. A significant increase of TNF-α was found for all conditions studied compared to medium alone. Stimulation with TLR4a (p=0.0001) and TLR7a (p=0.005) presented a significantly marked increase in TNF-α and IL-6 production compared to TLR3a. Importantly, significantly higher TNF-α production was found in LSA+TLR4a (p=0.0001) stimulated blood and LSA+TLR7a (p=0.005) compared to LSA alone. All dogs showed higher TNF-α production after LSA+TLR7a compared to TLR7a (p=0.047) and LSA+TLR3a compared to TLR3a (p=0.052). These data indicate a marked inflammatory cytokine effect of TLR4a and TLR7a on blood from healthy dogs living in endemic areas of CanL. Additionally, LSA+TLR7a promoted a synergistic proinflammatory effect with TNF-α in all dogs. Those findings suggest an active role of TLRs in proinflammatory responses, which might be strongly involved in the process of disease resolution.

The role of MPL and imiquimod adjuvants in enhancement of immune response and protection in BALB/c mice immunized with soluble Leishmania antigen (SLA) encapsulated in nanoliposome

Adjuvants play an essential role in the induction of immunity against leishmaniasis. In this study, monophosphoryl lipid A (MPL) and imiquimod (IMQ) were used as TLR ligands adjuvants to enhance immunogenicity and rate of protection against leishmaniasis. Nanoliposomes containing soluble Leishmania antigens (SLA) and adjuvants were consisted of DSPC, DSPG and Chol prepared by using lipid film method followed by bath sonication. The size of nanoliposomes was around 95 nm and their zeta potential was negative. BALB/c mice were immunized by liposomal formulations of lip/SLA, lip/MPL/SLA, lip/IMQ/SLA, lip/MPL/IMQ/SLA, lip/SLA + lip/IMQ, lip/SLA + lip/MPL, lip/SLA + lip/MPL/IMQ and five controls of SLA, lip/MPL, lip/IMQ, lip/MPL/IMQ and buffer by subcutaneously (SC) injections, three times in 2 weeks intervals. The synergic effect of two adjuvants when they are used in one formulation showed significantly (p < .001) smaller footpad swelling and the lowest parasite burden in lymph node and foot after the challenge. IgG2a in these groups showed the higher titre compared to control groups, which is compatible with the high IFN-γ production and lowest IL-4. Taken together the results indicated that co-delivery of MPL and IMQ adjuvants and antigen in nanoliposome carrier could be an appropriate delivery system to induce cellular immunity pathway against leishmaniasis.

Redundant and regulatory roles for Toll-like receptors in Leishmania infection

Toll-like receptors (TLRs) are germline-encoded, non-clonal innate immune receptors, which are often the first receptors to recognize the molecular patterns on pathogens. Therefore, the immune response initiated by TLRs has far-reaching consequences on the outcome of an infection. As soon as the cell surface TLRs and other receptors recognize a pathogen, the pathogen is phagocytosed. Inclusion of TLRs in the phagosome results in quicker phagosomal maturation and stronger adaptive immune response, as TLRs influence co-stimulatory molecule expression and determinant selection by major histocompatibility complex (MHC) class II and MHC class I for cross-presentation. The signals delivered by the TCR-peptide-MHC complex and co-stimulatory molecules are indispensable for optimal T cell activation. In addition, the cytokines induced by TLRs can skew the differentiation of activated T cells to different effector T cell subsets. However, the potential of TLRs to influence adaptive immune response into different patterns is severely restricted by multiple factors: gross specificity for the molecular patterns, lack of receptor rearrangements, sharing of limited number of adaptors that assemble signalling complexes and redundancy in ligand recognition. These features of apparent redundancy and regulation in the functioning of TLRs characterize them as important and probable contributory factors in the resistance or susceptibility to an infection.

The immune profile induced is crucial to determine the effects of immunocastration over gonadal function, fertility, and GnRH-I expression

PROBLEM

Immunocastration or vaccination against the GnRH-I hormone is a promising alternative to reproductive control in different animal species. Given the low immunogenicity of this hormone, the use of adjuvants becomes necessary.

METHOD OF STUDY

This study evaluated the effects of three adjuvants that induce different immune response profiles over gonadal function, fertility, and expression of GnRH-I. Female mice (n = 6) were vaccinated at days 1 and 30 with a recombinant antigen for immunocastration and different adjuvants that induced preferentially Th1/Th2, Th2, and Th1 immune profiles.

RESULTS

Th1/Th2 response is the most efficient to block reproductive activity in vaccinated animals, reducing the number of luteal bodies and pre-ovulatory follicles. Th2 and Th1/Th2 responses induced an increase in GnRH-I at the hypothalamus.

CONCLUSION

The immune profile induced by different adjuvants is essential on the effects over fertility, gonadal function, and hypothalamic GnRH-I expression in immunocastrated animals.

Evaluation of the adjuvant effect of agonists of toll-like receptor 4 and 7/8 in a vaccine against leishmaniasis in BALB/c mice

There is no effective vaccine against human leishmaniasis. Achieving successful vaccines seems to need powerful adjuvants. Separate or combined use of toll like receptor (TLR) agonists as adjuvant is a promising approach in Leishmania vaccine research. In present study, we evaluated adjuvant effect of separate or combined use of a TLR7/8 agonist, R848 and a TLR4 agonist, monophosphoryl lipid A (MPL) beside soluble Leishmania antigen (SLA) in BALB/c mice. Mice were vaccinated three times by SLA with separate or combined TLR7/8 and TLR4 agonists and were then challenged by Leishmania major. Delay type hypersensitivity, lesion development, parasite load, and cytokines (interferon gamma, and interleukin-10) response were assessed. Results showed: 1) MPL can slightly assist SLA in parasite load reduction, but it is not able to increase SLA ability in evoking DTH and cytokine responses or decreasing lesion diameter. 2) R848 does not affect the DTH response and parasite load of mice vaccinated with SLA, but it decreases/inhibits cytokine responses induced by SLA, leading to increase lesion diameter. 3) MPL neutralized inhibitory effect of R848. In overall, these data emphasize that MPL slightly assists SLA to make a more potent vaccine, but R848 is not a good adjuvant to induce T cell-dependent immune response in BALB/c mice, and therefore combination of these TLR agonists in the current formulation, is not recommended for making a more powerful adjuvant.

Addition of a TLR7 agonist to an acellular pertussis vaccine enhances Th1 and Th17 responses and protective immunity in a mouse model

A resurgence of whooping cough (pertussis) has been observed in recent years in a number of developed countries, despite widespread vaccine coverage. Although the exact reasons of the recurrence of pertussis are not clear, there are a number of potential causes, like antigenic variation in the circulating strains of Bordetella pertussis, changes in surveillance and diagnostic tools, and potential differences in protection afforded by current acellular pertussis (aP) vaccines compared to more reactogenic whole cell (wP) vaccines, which they replaced. Studies in animal models have shown that induction of cellular as well as humoral immune responses are key to conferring effective and long lasting protection against B. pertussis. wP vaccines induce robust Th1/Th17 responses, which are associated with good protection against lung infection. In contrast, aP vaccines induce mixed Th2/Th17 responses. One research option is to modify current aP vaccines with the intention of inducing protective T cell responses, without compromising on their low reactogenicity profile. Here we found that formulation of an aP vaccine with a novel adjuvant based on a Toll-like receptor 7 agonist (TLR7a) adsorbed to aluminum hydroxide (alum) enhanced B. pertussis-specific Th1 and Th17 responses and serum IgG2a/b antibodies, which had greater functional capacity than those induced by aP formulated with alum alone. Furthermore, addition of a TLR7a enhanced the protective efficacy of the aP vaccine against B. pertussis aerosol challenge; protection was comparable to that of a wP vaccine. These findings suggest that alum-TLR7a is a promising adjuvant for clinical development of next generation pertussis vaccines.

CD14 is critical for TLR2-mediated M1 macrophage activation triggered by N-glycan recognition

Agonist interaction with Toll-like receptors (TLRs) induces T cell-mediated immunity, which is effective against intracellular pathogens. Consequently, TLR agonists are being tried as immunomodulatory agents. The lectin ArtinM targets TLR2 N-glycans on macrophages, induces cytokines production, and promotes T helper-1 immunity, a process that culminates in resistance to several parasitic and fungal infections in vivo. Because co-receptors influence agonist binding to TLRs, we investigated whether CD14 is required for macrophage activation induced by ArtinM. Macrophages from wild-type mice stimulated by ArtinM not only produced cytokines but also had the following activation profile: (i) expression of M1 polarization markers; (ii) nitrite oxide production; (iii) cellular migration; (iv) enhanced phagocytic and fungicide activity; (v) modulation of TLR2 expression; and (vi) activation of NF-κB pathway. This activation profile induced by ArtinM was evaluated in macrophages lacking CD14 that showed none of the ArtinM effects. We demonstrated by immunoprecipitation and sugar inhibition assays the physical interaction of ArtinM, TLR2, and CD14, which depends on recognition of the trimannoside that constitutes the core of N-glycans. Thus, our study showed that CD14 is critical for ArtinM-induced macrophage activation, providing fundamental insight into the design of anti-infective therapies based on carbohydrate recognition.

Nanoformulation of synergistic TLR ligands to enhance vaccination against Entamoeba histolytica

Diarrheal infectious diseases represent a major cause of global morbidity and mortality. There is an urgent need for vaccines against diarrheal pathogens, especially parasites. Modern subunit vaccines rely on combining a highly purified antigen with an adjuvant to increase their efficacy. In the present study, we evaluated the ability of a nanoliposome adjuvant system to trigger a strong mucosal immune response to the Entamoeba histolytica Gal/GalNAc lectin LecA antigen. CBA/J mice were immunized with alum, emulsion or liposome based formulations containing synthetic TLR agonists. A liposome formulation containing TLR4 and TLR7/8 agonists was selected based on its ability to generate intestinal IgA, plasma IgG2a/IgG1, IFN-γ and IL-17A. Immunization with a mucosal prime followed by a parenteral boost generated a high mucosal IgA response that inhibited adherence of parasites to mammalian cells. Inclusion of the immune potentiator all-trans retinoic acid in the regimen further improved the mucosal IgA response. Immunization protected from infection with up to 55% efficacy. Our results show that a nanoliposome delivery system containing TLR agonists is a promising prospect for the development of vaccines against enteric pathogens, especially when a multifaceted immune response is desired.

Innate immunity based cancer immunotherapy: B16-F10 murine melanoma model

Background

Using killed microorganisms or their parts to stimulate immunity for cancer treatment dates back to the end of 19^th century. Since then, it undergone considerable development. Our novel approach binds ligands to the tumor cell surface, which stimulates tumor phagocytosis. The therapeutic effect is further amplified by simultaneous application of agonists of Toll-like receptors. We searched for ligands that induce both a strong therapeutic effect and are safe for humans.

Methods

B16-F10 murine melanoma model was used. For the stimulation of phagocytosis, mannan or N-formyl-methionyl-leucyl-phenylalanine, was covalently bound to tumor cells or attached using hydrophobic anchor. The following agonists of Toll-like receptors were studied: monophosphoryl lipid A (MPLA), imiquimod (R-837), resiquimod (R-848), poly(I:C), and heat killed Listeria monocytogenes.

Results

R-848 proved to be the most suitable Toll-like receptor agonist for our novel immunotherapeutic approach. In combination with covalently bound mannan, R-848 significantly reduced tumor growth. Adding poly(I:C) and L. monocytogenes resulted in complete recovery in 83% of mice and in their protection from the re-transplantation of melanoma cells.

Conclusion

An efficient cancer treatment results from the combination of Toll-like receptor agonists and phagocytosis stimulating ligands bound to the tumor cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2982-x) contains supplementary material, which is available to authorized users.

Triggering Intracellular Receptors for Vaccine Adjuvantation

Immune adjuvants are components that stimulate, potentiate, or modulate the immune response to an antigen. They are key elements of vaccines in both the prophylactic and therapeutic domains. In the past decade substantial progress in our understanding of innate immunity has paved the way for the design of next-generation adjuvants that stimulate a wide range of receptors. Within the framework of vaccine adjuvant design, this review outlines the interest of targeting endosomal and intracellular receptors to enhance and guide the immune response. We present and compare the molecules as well as potential combinations which are currently in the spotlight. We emphasize how targeting the appropriate receptor can direct immunity towards the appropriate response, such as a cytotoxic or mucosal response.

Lipid based delivery and immuno-stimulatory systems: Master tools to combat leishmaniasis

Disease management of leishmaniasis is appalling due to lack of a human vaccine and the toxicity and resistance concerns with limited therapeutic drugs. The challenges in development of a safe vaccine for generation and maintenance of robust antileishmanial protective immunity through a human administrable route of immunization can be addressed through immunomodulation and targeted delivery. The versatility of lipid based particulate system for deliberate delivery of diverse range of molecules including immunomodulators, antigens and drugs have essentially found pivotal role in design of proficient vaccination and therapeutic strategies against leishmaniasis. The prospects of lipid based preventive and curative formulations for leishmaniasis have been highlighted in this review.

Insights on adaptive and innate immunity in canine leishmaniosis

Canine leishmaniosis (CanL) is caused by the parasite Leishmania infantum and is a systemic disease, which can present with variable clinical signs, and clinicopathological abnormalities. Clinical manifestations can range from subclinical infection to very severe systemic disease. Leishmaniosis is categorized as a neglected tropical disease and the complex immune responses associated with Leishmania species makes therapeutic treatments and vaccine development challenging for both dogs and humans. In this review, we summarize innate and adaptive immune responses associated with L. infantum infection in dogs, and we discuss the problems associated with the disease as well as potential solutions and the future direction of required research to help control the parasite.

TLR9-deficiency reduces TLR1, TLR2 and TLR3 expressions in Leishmania major-infected macrophages

The parasite Leishmania major counteractively modulates TLR2 and TLR9 expression and their functions. Although TLR1, TLR3, TLR4, and TLR7 are also implicated in Leishmania infection, whether their expression was altered in TLR2 or TLR9 deficiency remained unknown. Therefore, we examined TLR1, TLR3, TLR4 and TLR7 expression in L. major infection in TLR2-deficient or TLR9-deficient macrophages. We observed that TLR9-deficiency reduced TLR1, TLR2 and TLR3 but not TLR7 expression in the macrophages treated with live or killed L. major promastigotes. TLR2-deficiency had little effects by comparison. TLR9-deficient macrophages had reduced CD40 expression and less IL-12 and TNF-α expression. Thus, we report that TLR9 modulates TLR1, TLR2 and TLR3, but not TLR7, expression in L. major-infected macrophages.

Double-Blind Randomized Efficacy Field Trial of Alum Precipitated Autoclaved Leishmania major (Alum-ALM) Vaccine Mixed With BCG Plus Imiquimod Vs. Placebo Control Group

BACKGROUND

Canine visceral leishmaniasis (CVL) is not only an emerging veterinary concern but also a public health threat in endemic areas. The aim of this study was to assess the efficacy, immunogenicity and safety of two doses of aluminum hydroxide (alum) precipitated Leishmania major (Alum-ALM) mixed with BCG plus imiquimod against CVL.

METHODS

A total of 560 ownership dogs were serologically tested and 234 healthy dogs with no clinical signs of CVL, no anti-Leishmania antibodies and negative leishmanin skin test were selected and double-blind randomly injected intradermally either with 0.1 ml Alum-ALM (200µg protein) mixed with BCG (2 × 10(6) CFUs) plus imiquimod (121 dogs) or with 0.1 ml of normal saline (113 dogs).

RESULTS

The follow-up examinations showed that there was no side effect associated with the vaccination except one case. Strong skin test conversion were seen in vaccinated group (30.3%) compared to the control group (6.6%) at 22-24 weeks after the booster injection (p<0.001). The seroconversion was 16.3% (18/110) in vaccinated group and 26.4% (28/106) in control group after two transmission cycles but the difference was not significant (P=0.095). The efficacy rate based on seroconversion was 40.4 %.

CONCLUSION

Two injections of Alum-ALM mixed with BCG and imiquimod is safe, although decreases the seroconversion rate of CVL, but the overall efficacy was low.

Isolation, characterization, and functional analysis of ferret lymphatic endothelial cells

The lymphatic endothelium (LE) serves as a conduit for transport of immune cells and soluble antigens from peripheral tissues to draining lymph nodes (LNs), contributing to development of host immune responses and possibly dissemination of microbes. Lymphatic endothelial cells (LECs) are major constituents of the lymphatic endothelium. These specialized cells could play important roles in initiation of host innate immune responses through sensing of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs), including toll-like receptors (TLRs). LECs secrete pro-inflammatory cytokines and chemokines to create local inflammatory conditions for recruitment of naïve antigen presenting cells (APCs) such as dendritic cells (DCs) to sites of infection and/or vaccine administration. In this study, we examined the innate immune potential of primary LEC populations derived from multiple tissues of an animal model for human infectious diseases - the ferret. We generated a total of six primary LEC populations from lung, tracheal, and mesenteric LN tissues from three different ferrets. Standard RT-PCR characterization of these primary LECs showed that they varied in their expression of LEC markers. The ferret LECs were examined for their ability to respond to poly I:C (TLR3 and RIG-I ligand) and other known TLR ligands as measured by production of proinflammatory cytokine (IFNα, IL6, IL10, Mx1, and TNFα) and chemokine (CCL5, CCL20, and CXCL10) mRNAs using real time RT-PCR. Poly I:C exposure induced robust proinflammatory responses by all of the primary ferret LECs. Chemotaxis was performed to determine the functional activity of CCL20 produced by the primary lung LECs and showed that the LEC-derived CCL20 was abundant and functional. Taken together, our results continue to reveal the innate immune potential of primary LECs during pathogen-host interactions and expand our understanding of the roles LECs might play in health and disease in animal models.

Macrophage- and neutrophil-derived TNF-α instructs skin langerhans cells to prime antiviral immune responses

Dendritic cells are major APCs that can efficiently prime immune responses. However, the roles of skin-resident Langerhans cells (LCs) in eliciting immune responses have not been fully understood. In this study, we demonstrate for the first time, to our knowledge, that LCs in cynomolgus macaque skin are capable of inducing antiviral-specific immune responses in vivo. Targeting HIV-Gag or influenza hemagglutinin Ags to skin LCs using recombinant fusion proteins of anti-Langerin Ab and Ags resulted in the induction of the viral Ag-specific responses. We further demonstrated that such Ag-specific immune responses elicited by skin LCs were greatly enhanced by TLR ligands, polyriboinosinic polyribocytidylic acid, and R848. These enhancements were not due to the direct actions of TLR ligands on LCs, but mainly dependent on TNF-α secreted from macrophages and neutrophils recruited to local tissues. Skin LC activation and migration out of the epidermis are associated with macrophage and neutrophil infiltration into the tissues. More importantly, blocking TNF-α abrogated the activation and migration of skin LCs. This study highlights that the cross-talk between innate immune cells in local tissues is an important component for the establishment of adaptive immunity. Understanding the importance of local immune networks will help us to design new and effective vaccines against microbial pathogens.

Topical resiquimod protects against visceral infection with Leishmania infantum chagasi in mice

New prevention and treatment strategies are needed for visceral leishmaniasis, particularly ones that can be deployed simply and inexpensively in areas where leishmaniasis is endemic. Synthetic molecules that activate Toll-like receptor 7 and 8 (TLR7/8) pathways have previously been demonstrated to enhance protection against cutaneous leishmaniasis. We initially sought to determine whether the TLR7/8-activating molecule resiquimod might serve as an effective vaccine adjuvant targeting visceral leishmaniasis caused by infection with Leishmania infantum chagasi. Resiquimod was topically applied to the skin of mice either prior to or after systemic infection with L. infantum chagasi, and parasite burdens were assessed. Surprisingly, topical resiquimod application alone, in the absence of vaccination, conferred robust resistance to mice against future intravenous challenge with virulent L. infantum chagasi. This protection against L. infantum chagasi infection persisted as long as 8 weeks after the final topical resiquimod treatment. In addition, in mice with existing infections, therapeutic treatment with topical resiquimod led to significantly lower visceral parasite loads. Resiquimod increased trafficking of leukocytes, including B cells, CD4(+) and CD8(+) T cells, dendritic cells, macrophages, and granulocytes, in livers and spleens, which are the key target organs of visceralizing infection. We conclude that topical resiquimod leads to systemic immune modulation and confers durable protection against visceralizing L. infantum chagasi infection, in both prophylactic and therapeutic settings. These studies support continued studies of TLR-modulating agents to determine mechanisms of protection and also provide a rationale for translational development of a critically needed, novel class of topical, preventative, and therapeutic agents for these lethal infections.

A nanoliposome delivery system to synergistically trigger TLR4 AND TLR7

Background

Recent reports that TLR4 and TLR7 ligands can synergistically trigger Th1 biased immune responses suggest that an adjuvant that contains both ligands would be an excellent candidate for co-administration with vaccine antigens for which heavily Th1 biased responses are desired. Ligands of each of these TLRs generally have disparate biochemical properties, however, and straightforward co-formulation may represent an obstacle.

Results

We show here that the TLR7 ligand, imiquimod, and the TLR4 ligand, GLA, synergistically trigger responses in human whole blood. We combined these ligands in an anionic liposomal formulation where the TLR7 ligand is in the interior of the liposome and the TLR4 ligand intercalates into the lipid bilayer. The new liposomal formulations are stable for at least a year and have an attractive average particle size of around 140 nm allowing sterile filtration. The synergistic adjuvant biases away from Th2 responses, as seen by significantly reduced IL-5 and enhanced interferon gamma production upon antigen-specific stimulation of cells from immunized mice, than any of the liposomal formulations with only one TLR agonist. Qualitative alterations in antibody responses in mice demonstrate that the adjuvant enhances Th1 adaptive immune responses above any adjuvant containing only a single TLR ligand as well.

Conclusion

We now have a manufacturable, synergistic TLR4/TLR7 adjuvant that is made with excipients and agonists that are pharmaceutically acceptable and will have a straightforward path into human clinical trials.

Topical CpG adjuvantation of a protein-based vaccine induces protective immunity to Listeria monocytogenes

Robust CD8(+) T cell responses are essential for immune protection against intracellular pathogens. Using parenteral administration of ovalbumin (OVA) protein as a model antigen, the effect of the Toll-like receptor 9 (TLR9) agonist, CpG oligodeoxynucleotide (ODN) 1826, as an adjuvant delivered either topically, subcutaneously, or intramuscularly on antigen-specific CD8(+) T cell responses in a mouse model was evaluated. Topical CpG adjuvant increased the frequency of OVA-specific CD8(+) T cells in the peripheral blood and in the spleen. The more effective strategy to administer topical CpG adjuvant to enhance CD8(+) T cell responses was single-dose administration at the time of antigen injection with a prime-boost regimen. Topical CpG adjuvant conferred both rapid and long-lasting protection against systemic challenge with recombinant Listeria monocytogenes expressing the cytotoxic T lymphocyte (CTL) epitope of OVA(257-264) (strain Lm-OVA) in a TLR9-dependent manner. Topical CpG adjuvant induced a higher proportion of CD8(+) effector memory T cells than parenteral administration of the adjuvant. Although traditional vaccination strategies involve coformulation of antigen and adjuvant, split administration using topical adjuvant is effective and has advantages of safety and flexibility. Split administration of topical CpG ODN 1826 with parenteral protein antigen is superior to other administration strategies in enhancing both acute and memory protective CD8(+) T cell immune responses to subcutaneous protein vaccines. This vaccination strategy induces rapid and persistent protective immune responses against the intracellular organism L. monocytogenes.

Old World cutaneous leishmaniasis: diagnosis and treatment

Cutaneous leishmaniasis is a major world health problem. Diagnosis is suspected on evocative clinical presentation in patients living in or coming from endemic areas. Several methods have been used. The smear is a simple investigation used in endemic regions. The culture enables to identify the specimen. PCR has a high sensitivity. Montenegro's reaction is used in the epidemiological study. Pentavalent antimony derivatives remain the mainstay of systemic treatment. Their efficiency is well established. Their toxicity should be researched. Other treatments can be utilized, such as miltefosine. Local therapy is used in uncomplicated lesions. Injections of the pentavalent antimony derivate, cryotherapy and paromomycin ointmentsis are important options and should be used more frequently in Old World leishmaniasis.