Study of different routes of immunization using outer membrane vesicles of Neisseria meningitidis B and comparison of two adjuvants

Outer membrane vesicles (OMVs) of Neisseria meningitidis contain important antigens to trigger an immune response against meningococci and have been studied as vaccines compounds. The immune response to a vaccine may be affected by its constitution and route of administration. Therefore, Swiss mice were immunized by different routes with OMVs of N. meningitidis B with dimethyl dioctadecyl ammonium bromide in bilayer fragments (DDA-BF) or aluminum hydroxide (AH) as adjuvants. The adjuvants and different routes were compared regarding the immune responses by ELISA, western blot, delayed type hypersensitivity (DTH) and histopathologic analysis. The antigenic preparation generated humoral and cellular immune responses. In quantitative analyzes, in general, AH was superior to DDA-BF. However, analysis such as IgG avidity index, bactericidal activity and immunoblot, revealed no important differences regarding the adjuvant or route of immunization. Regarding the parameters tested, it was not possible to define a superiority between the adjuvants and routes of immunization proposed by this study.     

A novel liposome adjuvant DPC mediates Mycobacterium tuberculosis subunit vaccine well to induce cell-mediated immunity and high protective efficacy in mice

Tuberculosis (TB) is a serious disease around the world, and protein based subunit vaccine is supposed to be a kind of promising novel vaccine against it. However, there is no effective adjuvant available in clinic to activate cell-mediated immune responses which is required for TB subunit vaccine. Therefore, it is imperative to develop new adjuvant. Here we reported an adjuvant composed of dimethyl dioctadecylammonium (DDA), Poly I:C and cholesterol (DPC for short). DDA can form a kind of cationic liposome with the ability to deliver and present antigen and can induce Th1 type cell-mediated immune response. Poly I:C, a ligand of TLR3 receptor, could attenuate the pathologic reaction induced by following Mycobacterium tuberculosis challenge. Cholesterol, which could enhance rigidity of lipid bilayer, is added to DDA and Poly I:C to improve the stability of the adjuvant. The particle size and Zeta-potential of DPC were analyzed in vitro. Furthermore, DPC was mixed with a TB fusion protein ESAT6-Ag85B-MPT64(190-198)-Mtb8.4-Rv2626c (LT70) to construct a subunit vaccine. The subunit vaccine-induced immune responses and protective efficacy against M. tuberculosis H37Rv infection in C57BL/6 mice were investigated. The results showed that the DPC adjuvant with particle size of 400 nm and zeta potential of 40 mV was in good stability. LT70 in the adjuvant of DPC generated strong antigen-specific humoral and cell-mediated immunity, and induced long-term higher protective efficacy against M. tuberculosis infection (5.41 ± 0.38 log₁₀ CFU) than traditional vaccine Bacillus Calmette–Guerin (BCG) (6.01 ± 0.33 log₁₀ CFU) and PBS control (6.53 ± 0.26 log₁₀ CFU) at 30 weeks post-vaccination. In conclusion, DPC would be a promising vaccine adjuvant with the ability to stimulate Th1 type cell-mediated immunity, and could be used in TB subunit vaccine.     

Nasal delivery of H5N1 avian influenza vaccine formulated with GenJet™ or in vivo-jetPEI® induces enhanced serological,cellular and protective immune responses

Avian influenza virus infection is a serious public health threat and preventive vaccination is the most cost-effective public health intervention strategy. Unfortunately, currently available unadjuvanted avian influenza vaccines are poorly immunogenic and alternative vaccine formulations and delivery strategies are in urgent need to reduce the high risk of avian influenza pandemics. Cationic polymers have been widely used as vectors for gene delivery in vitro and in vivo. In this study, we formulated H5N1 influenza vaccines with GenJet? or in vivo-jetPEI^®, and showed that these formulations significantly enhanced the immunogenicity of H5N1 vaccines and conferred protective immunity in a mouse model. Detailed analyses of adaptive immune responses revealed that both formulations induced mixed T_H1/T_H2 antigen-specific CD4 T-cell responses, antigen-specific cytotoxic CD8 T-cell and memory B-cell responses. Our findings suggest that cationic polymers merit future development as potential adjuvants for mucosal delivery of poorly immunogenic vaccines.     

Cationic liposomes formulated with a novel whole Leishmania lysate (WLL) as a vaccine for leishmaniasis in murine model

Although there have been numerous attempts to develop a successful vaccine against leishmaniasis, based on the clinical trial in this field, no vaccine against Leishmania in routine way can be found for globally effective vaccination in human. Amongst, first generation vaccines consisting of parasite fractions or whole killed Leishmania showed more successful results in clinical trials. It seems that the main reason for the low efficacy of these vaccines is lack of a suitable adjuvant. In this study, a crude extract of detergent-solubilized L. major promastigotes as a novel developed antigen (whole Leishmania lysate (WLL)) was formulated in liposomal form. The cationic liposomes consisting of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) were used to deliver WLL. Liposomes formulations containing different WLL concentrations (prepared from 10³, 10⁴, 10⁵, 10⁶ and 10⁷ parasites) were prepared and characterized for particle size, surface charge, proteins, DNA and phospholipids contents. Moreover, to explore the type of immune response generated and extend of immunization, in vivo and in vitro tests including evaluation of lesion development, parasite burden in the foot and spleen, Th1 and Th2 cytokine analysis, and titration of IgG isotypes before and after the challenge were used. The maximum immunization was provided by WLL06 as depicted by the reduction of footpad swelling andparasite load, increase in anti-Leishmania IgG2a production, though no significant difference was observed between mice which received WLL05 vs WLL06. While maximum immunization was seen in WLL06 group, most of the liposomal WLL formulations induced a mixed Th1/Th2 response. Hence, a more protective immune response is expected to be induced when an immune potentiator adjuvant such as CpG ODNs would be co-deliverd in WLL liposomal formulations.     

超声复合微泡促进骨髓间充质干细胞归巢对大鼠前列腺炎的治疗作用

目的 研究静脉注射骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSCs)对大鼠前列腺炎的治疗作用.方法 贴壁法分离、培养、扩增BMSCs.将50只SD大鼠按随机数字表法分为慢性细菌性前列腺炎(chronic bacterial prostatitis,CBP)组、CBP+BMSCs组、CBP+超声复合微泡(microbubble-enhanced therapeutic ultrasound,MEUS)组、CBP+ MEUS+ BMSCs组和正常对照组,每组10只.在小动物超声引导下向大鼠前列腺两侧叶内注射大肠埃希菌建立前列腺炎症模型,注入细菌1～14 d为急性炎症期,4～ 12周为慢性炎症期,对照组注入等量PBS.建模28 d后经静脉单纯注入BMSCs、单纯行MEUS及行MEUS+注入BMSCs,活体成像观察BMSCs向前列腺归巢情况.观察移植BMSCs 2周后大鼠前列腺组织病理学变化并作炎症评分,RT-PCR检测炎症因子IL-1β、TNF-α mRNA,ELISA检测IL-1β、TNF-α蛋白含量,统计分析各组表达差异.结果 前列腺组织病理学提示CBP组、CBP+ BMSCs组、CBP+ MEUS组前列腺呈典型炎症病理变化,腺管上皮增生,层次增加,炎细胞浸润,纤维组织增生,而CBP+ MEUS+ BMSCs组大鼠前列腺炎症明显减轻.RT-PCR检测结果提示CBP组炎症因子IL-1β(0.282±0.067)、TNF-α(0.631 ±0.116),CBP+BMSCs组IL-1[β(0.893 ±0.117)、TNF-α(0.876 ±0.137),CBP+ MEUS组IL-1β(0.683 ±0.097)、TNF-α(0.814±0.127)高于正常对照组IL-1β(0.282±0.067)、TNF-α(0.256±0.059)和CBP+MEUS+BMSCs组IL-1β(0.322±0.086)、TNF-α(0.313 ±0.079) (P ＜0.05);ELISA检测结果显示CBP组炎症因子IL-1β[(315.14±86.08) pg/mL]、TNF-α[(86.41 ±24.32) pg/mL],CBP+BMSCs组IL-1 β[(278.87±72.04) pg/mL]、TNF-α[(67.77±16.98) pg/mL],CBP+ MEUS组IL-1 β[(321.24 ±93.12) pg/mL]、TNF-α[(79.14±19.17) pg/mL]含量均显著高于正常对照组[IL-1β(43.36±11.35) pg/mL、TNF-α(13.26±3.97) pg/mL]和CBP+MEUS+BMSCs组[IL-1 β (65.34±17.23) pg/mL、TNF-α(19.94±5.37) pg/mL],差异有统计学意义(P＜0.01),而CBP+ MEUS+ BMSCs组与正常对照组比较差异无统计学意义(P＞0.05).结论 超声复合微泡促进BMSCs向前列腺归巢,能够减轻前列腺炎症反应,可能为前列腺炎的治疗带来新策略.     

The antimicrobial peptide LL37 and its truncated derivatives potentiates proinflammatory cytokine induction by lipoteichoic acid in whole blood

Abstract

Interactions of bacterial and host products in activating the innate immune system is an important area to address. The role of lipoteichoic acid (LTA) in these interactions is particularly important because it is understudied in comparison to other factors. This study evaluated the effect of cationic peptides (CPs) on LTA-induced proinflammatory cytokine production in human whole blood and on purified leukocytes. Four different CPs of truncated derivatives from the known peptides LL37, BPI, and CP207 were used. Two of the CPs (IG33 and LL33), derivatives from LL37, potentiated S. aureus LTA induced TNFα, IL-6 and IL-1β production in whole blood. The release of TNFα was increased 30-fold after 16 hours incubation. Intact LL37 also increased LTA-induced TNFα and IL-1β in a time dependent manner. LTA in combination with either LL33 or IG23 demonstrated a synergistic enhanced TNFα and IL-1β secretion on isolated leukocytes but not on purified monocytes. When complexed with IG23 and LL33, the electrophoretic mobility of LTA was altered in a non-denaturating gel electrophoresis. LTA was disaggregated and migrated more rapidly, suggesting an amphiphilic effect of CPs on LTA. In conclusion, LTA synergizes with LL37 and its truncated derivatives and this may lead to proinflammatory cytokine production and cause problems in sepsis therapy.     

The application of microbubbles for targeted drug delivery

Interest in microbubbles as vehicles for drug delivery has grown in recent years, due in part to characteristics that make them well suited for this role and in part to the need the for localized delivery of drugs in a number of applications. Microbubbles are inherently small, allowing transvascular passage, they can be functionalized for targeted adhesion, and can be acoustically driven, which facilitates ultrasound detection, production of bioeffects and controlled release of the cargo. This article provides an overview of related microbubble biofluid mechanics and reviews recent developments in the application of microbubbles for targeted drug delivery. Additionally, related advances in non-bubble microparticles for drug delivery are briefly described in the context of targeted adhesion.     

LPS interactions with immobilized and soluble antimicrobial peptides

Abstract

A promising approach in sepsis therapy is the use of peptides truncated from serum- and membrane-proteins with binding domains for LPS: antimicrobial peptides (AMPs). AMPs can be useful in combination with conventional antibiotics to increase killing and neutralize LPS. Although many AMPs show a high specificity towards bacterial membranes, they can also exhibit toxicity, i.e. non-specific membrane lysis, of mammalian cells such as erythrocytes and therefore, unsuitable as systemic drugs. A way to overcome this problem may be an extracorporeal therapy with immobilized peptides. This study will compare neutralization of LPS using different AMPs in solution and when immobilized on to solid phases. The peptides ability to neutralize LPS-induced cytokine release in whole blood will also be tested. The peptides are truncated derivates from the known AMPs LL-37, SC4, BPI, S3Δ and CEME. Two different methods were used to immobilize peptides, biomolecular interaction analysis, and Pierce SulfoLink Coupling Gel. To investigate LPS binding in solution the LAL test was used. After whole blood incubation with LPS and AMPs ELISA was used to measure TNFα, IL-1β and IL-6 production. The results suggest that immobilization of antimicrobial peptides does not inhibit their capacity to neutralize LPS, although there are differences between the peptides tested. Thus, peptides derived from LL-37 and CEME were more efficient both in LPS binding and neutralizing LPS-induced cytokine production.     

Irregular Defects in Hepatocellular Carcinomas During the Kupffer Phase of Contrast-Enhanced Ultrasonography with Perfluorobutane Microbubbles: Pathological Features and Metastatic Recurrence After Surgical Resection

The present study aimed to elucidate the association between post-vascular–phase (Kupffer-phase) images from contrast-enhanced ultrasonography (CEUS) with perfluorobutane microbubbles and metastatic recurrences after the resection of hepatocellular carcinoma (HCC). The study examined 73 patients with solitary HCC ≤5 cm in diameter who underwent CEUS before resection. HCC was defined as irregular type (including an irregular defect on Kupffer-phase images) or non-irregular type. Intrahepatic metastatic recurrence was defined as >3 intrahepatic recurrences. Metastatic recurrence included both extrahepatic and intrahepatic recurrences. Frequencies of microscopic portal invasion and intrahepatic metastasis were significantly higher in the irregular group than in the non-irregular group. Cumulative 5-y metastatic recurrence rates in the irregular and non-irregular groups were 43% and 7% (p = 0.028), respectively. Multivariate analyses identified Kupffer-phase findings as a factor significantly related to metastatic recurrence. In conclusion, HCCs with an irregular defect during Kupffer-phase CEUS are characterized by more frequent microscopic vascular invasion and intrahepatic metastasis and are significantly associated with metastatic recurrence after resection.     

Combination of MIDGE-Th1 DNA vaccines with the cationic lipid SAINT-18: Studies on formulation,biodistribution and vector clearance

We have previously shown that the combination of MIDGE-Th1 DNA vectors with the cationic lipid SAINT-18 increases the immune response to the encoded antigen in mice. Here, we report on experiments to further optimize and characterize this approach. We evaluated different formulations of MIDGE-Th1 vectors with SAINT-18 by assessing their influence on the transfection efficiency in cell culture and on the immune response in mice. We found that high amounts of SAINT-18 in formulations with a w/w ratio MIDGE Th1/SAINT-18 of 1:4.8 are beneficial for cell transfection in vitro. In contrast, the formulation of HBsAg-encoding MIDGE-Th1 DNA vectors with the lowest amount of SAINT-18 (w/w ratio MIDGE Th1/SAINT-18 of 1:0.5) resulted in the highest serum IgG1 and IgG2a levels after intradermal immunization of mice. Consequently, latter formulation was selected for a comparative biodistribution study in rats. Following intradermal administration of both naked and formulated MIDGE-Th1 DNA, the vectors localized primarily at the site of injection. Vector DNA levels decreased substantially over the two months duration of the study. When administered in combination with SAINT-18, the vectors were found in significantly higher amounts in draining lymph nodes in comparison to administration of naked MIDGE-Th1 DNA. We propose that the high immune responses induced by MIDGE-Th1/SAINT-18 lipoplexes are mediated by enhanced transfection of cells in vivo, resulting in stronger antigen expression and presentation. Importantly, the combination of MIDGE-Th1 vectors with SAINT-18 was well tolerated in mice and rats and is expected to be safe in human clinical applications.