Higher mass meningococcal group C-tetanus toxoid vaccines conjugated with carbodiimide correlate with greater immunogenicity

To examine the link between meningococcal C (MenC) vaccine size and immunogenic response, a panel of MenC glycoconjugate vaccines were prepared differing in chain length, molar mass and hydrodynamic volume. The preparations consisted of different lengths of MenC polysaccharide (PS) covalently linked to monomeric purified tetanus toxoid (TT) carrier protein using the coupling reagent ethylcarbodiimide hydrochloride (EDC). Size exclusion chromatography with multi-angle light scattering (SEC-MALS) and viscometry analysis confirmed that the panel of MenC-TT conjugates spanned masses of 191,500 to 2,348,000 g/mol, and hydrodynamic radii ranging from 12.1 to 47.9 nm. The two largest conjugates were elliptical in shape, whereas the two smallest conjugates were more spherical. The larger conjugates appeared to fit a model described by multiple TTs with cross-linked PS, typical of lattice-like networks described previously for TT conjugates, while the smaller conjugates were found to fit a monomeric or dimeric TT configuration. The effect of vaccine conjugate size on immune responses was determined using a two-dose murine immunization. The two larger panel vaccine conjugates produced higher anti-MenC IgG1 and IgG2b titres after the second dose. Larger vaccine conjugate size also stimulated greater T-cell proliferative responses in an in vitro recall assay, although cytokines indicative of a T-helper response were not measurable. In conclusion, larger MenC-TT conjugates up to 2,348,000 g/mol produced by EDC chemistry correlate with greater humoral and cellular murine immune responses. These observations suggest that conjugate size can be an important modulator of immune response.     

Effective vaccine management through social behavior change communication: Exploring solutions using a participatory action research approach in the Solomon Islands

Addressing vaccine management bottlenecks, including high vaccine wastage rates, has traditionally been addressed through health worker training and other didactic methods of technical assistance or support as required. It has been shown, though, that the high level of technical skills, expertise, and responsibility required in vaccine handling and management cannot be achieved by mere didactic learning. While gains have been made in vaccine management and handling with these approaches, there remain challenges of high vaccine wastage rates and poor vaccine management practices across the board. Interestingly, approaching vaccine management through social behavior change has not been documented. Through Participatory Action Research (PAR), which is increasingly being used in health sciences, we explore an attempt at strengthening vaccine management and thus reducing high vaccine wastage rates by working together with health workers to identify plausible, realistic solutions to vaccine management through social behavior change. Select health workers directly involved with the immunization program in the four major provinces of the Solomon Islands were identified purposively to use action media and come up with concepts and materials for social behavior change communication that will have an impact on effective vaccine management and reducing wastages. This is the first documented use of such methodology in addressing vaccine management issues.     

Vaccination against cocaine using a modifiable dendrimer nanoparticle platform

Pharmacological therapies for the treatment of cocaine addiction have had disappointing efficacy, and the lack of recent developments in the clinical care of cocaine-addicted patients indicates a need for novel treatment strategies. Recent studies have shown that vaccination against cocaine to elicit production of antibodies that reduce concentrations of free drug in the blood is a promising method to protect against the effects of cocaine and reduce rates of relapse. However, the poorly immunogenic nature of cocaine remains a major hurdle to active immunization. Therefore, we hypothesized that strategies to increase targeted exposure of cocaine to the immune system may produce a more effective vaccine. To specifically direct an immune response against cocaine, in the present study we have conjugated a cocaine analog to a dendrimer-based nanoparticle carrier with MHC II-binding moieties that previously has been shown to activate antigen-presenting cells necessary for antibody production. This strategy produced a rapid, prolonged, and high affinity anti-cocaine antibody response without the need for an adjuvant. Surprisingly, additional evaluation using multiple adjuvant formulations in two strains of inbred mice found adjuvants were either functionally redundant or deleterious in the vaccination against cocaine using this platform. The use of conditioned place preference in rats after administration of this vaccine provided proof of concept for the ability of this vaccine to diminish cocaine reward. Together these data demonstrate the intrinsic efficacy of an immune-targeting dendrimer-based cocaine vaccine, with a vast potential for design of future vaccines against other poorly immunogenic antigens by substitution of the conjugated cargo.     

Evaluation of the impact of HIV-1 infection and density of common nasopharyngeal bacterial colonizers in South African children immunized with 7-valent pneumococcal conjugate vaccine

BackgroundDue to limitations in standard culture methods, the impact of pneumococcal conjugate vaccine (PCV) immunization on nasopharyngeal bacterial carriage density is unclear, including among HIV-infected children.MethodsThe prevalence and density of serotype/serogroup-specific pneumococcal and other nasopharyngeal colonizing bacteria were investigated in archived swabs of HIV-infected and HIV-uninfected, PCV-7 immunized (at 6, 10 and 14 weeks of age) South African children collected at 9 and 16 months of age. During the course of the study, PCV-immunization of children in Soweto was limited to study-participants, as the vaccine had not been introduced into the public immunization program.ResultsAt 9 months of age, the prevalence of overall pneumococcal colonization was lower in HIV-infected (58.6%) than HIV-uninfected children (69.9%, p = 0.02), mainly due to lower prevalence of non-vaccine-serotype colonization (27.8% vs. 40%, respectively; p = 0.047). The mean-log₁₀ density of pneumococcal colonization was, however, higher in HIV-infected (4.81 CFU/ml) than HIV-uninfected pneumococcal colonized children (4.44 CFU/ml; p = 0.014); mainly due to higher mean-log₁₀ density of PCV7-serotype colonization (4.21 vs. 3.72 CFU/ml; p = 0.014). No difference in the prevalence or density of overall pneumococci was found at 16 months of age. The prevalence of non-vaccine serotype colonization remained 1.7 fold higher in HIV-uninfected (60.4%) than HIV-infected children (50.9%, p = 0.049). Other differences included a lower prevalence of H. influenzae colonization in HIV-infected (42.3% and 56%) than HIV-uninfected children (64.2% and 73.4%) at both 9 and 16 months of age respectively; however, the density of colonization was similar.ConclusionIncreased carriage density of residual PCV7-serotypes might cause HIV-infected children to have a higher risk of pneumococcal disease. The higher carriage density observed in HIV-infected children could be attributed to a combination of factors, including HIV treatment and impaired host immunity. Additional studies are needed.     

Effectiveness of a single dose of the quadrivalent meningococcal conjugate vaccine,MenACWY-CRM,in the Korean Armed Forces

Conjugate vaccines are widely used to overcome the disadvantages of polysaccharide vaccines in the prevention of meningococcal disease. However, limited studies have examined the clinical effectiveness of single-dose meningococcal quadrivalent conjugate vaccines in adults. We assessed the effectiveness of the meningococcal vaccination program in the Republic of Korea Armed Forces, since 2013. Following vaccination program implementation, meningococcal disease cases decreased from 0.52/100,000 to 0.06/100,000 and the number of deaths declined from four to zero. Two meningococcal cases that developed post-implementation were identified as serotype B and X. The effectiveness of single-dose conjugate vaccination in recruits, expressed as the incidence rate ratio, was 0.88 during a 19–23-month observation period. These results indicate that meningococcal infections can be prevented by single-dose administration of the quadrivalent conjugate vaccine in at-risk groups, such as soldiers, travelers, and students in dormitories. Continuous investigation is needed to determine serogroup change, including B serogroups.     

肺炎球菌荚膜多糖和溶血素结合疫苗的制备及其免疫原性的研究

目的 研制肺炎球菌荚膜多糖（PS）与肺炎球菌溶血素（蛋白）偶联结合疫苗.方法 用PCR扩增肺炎球菌溶血素（Pn）基因,将其克隆入表达载体pET-28a质粒中,然后转化大肠杆菌JM109（DE3）宿主细胞,并以IPTG诱导进行蛋白质表达,对所得蛋白质用固相Ni-NTA树脂作纯化,再用SDS-PAGE鉴定表达的纯化蛋白（rPn）.以福尔马林脱毒rPn,去除其溶血活性,然后用氨基还原法将脱毒的rPn与PS（19F血清型）偶联结合,加入铝佐剂制备成疫苗.以该疫苗腹腔注射接种小鼠,用ELISA法检测小鼠血清中抗PS及抗Pn的体水平.结果 成功扩增和克隆了Pn基因,经诱导表达得到rPn蛋白,纯化后纯度达90%以上.PS与Pn结合物经凝胶层析柱分离,其洗脱峰较PS与Pn二峰明显前移.用该结合疫苗免疫的小鼠血清中抗PS（19F）抗体及抗Pn抗体的效价均明显高于阴性对照组（P＜0.01）.结论 用基因工程技术制备的肺炎球菌溶血素作为蛋白载体,脱毒后与肺炎球菌多糖偶联而成的结合疫苗能在小鼠体内诱导出明显的免疫应答反应.     

14型肺炎球菌荚膜多糖-破伤风类毒素结合疫苗研究

目的：探讨制备肺炎球菌荚膜多糖（PNCPS）－蛋白结合疫苗适宜条件。方法：采用碳二亚胺法将14型PNCPS与破伤风类毒素（TT）结合，将结合物免疫NIH小鼠，用ELISA法检测小鼠血清中抗14例PNCPS的IgG抗体滴度。结果：结合反应产率和结合物中多糖，蛋白含量的测定显示试验成功合成了14型PNCPS－TT结合物，该结合物具有14型PNCPS的血清学特异性，将之免疫小鼠诱生的抗14型PNCPS特异性IgG抗水平显著高于单纯14型PNCPS。结论：试验成功地合成了14型PNCPS－TT结合物，本试验采用的结合方法可行。     

Identification of glutathione conjugates of 1-bromopentane and its hepatotoxicity in female BALB/c mice

Halogenated organic compounds, such as 1-bromopentane (1-BPT), are used as cleaning agents, synthesis agents, or extraction solvents in the workplace. In the present study, glutathione (GSH) conjugation and hepatotoxicity induced by 1-BPT were investigated in female BALB/c mice. S-Bromopentyl GSH, S-bromopentyl cysteine, and mono-hydroxypentyl mercapturic acid were identified in liver by liquid chromatography-electrospray ionization tandem mass spectrometry. Oral treatment of mice with 1-BPT at 1500 mg/kg produced maximum GSH conjugates at 6 h after treatment. For hepatotoxicity tests, the animals were treated orally with 1-BPT at 375, 750, or 1500 mg/kg in corn oil once for a dose response study or at 1500 mg/kg for 6, 12, 24, or 48 h for a time course study. 1-BPT dose-dependently increased serum activity of ALT and AST and decreased hepatic GSH levels, peaking at 6 and 12 h after treatment. 1-BPT (750 and 1500 mg/kg) also significantly increased the hepatic content of malondialdehyde. Thus, 1-BPT could cause hepatotoxicity and depletion of GSH content by forming GSH conjugates, presenting a toxicity mechanism and potential biomarkers for low molecular weight haloalkanes.     

通过CDAP活化多糖制备b型流感嗜血杆菌荚膜多糖-D蛋白疫苗初探

目的 用CDAP活化b型流感嗜血杆菌（Hib）荚膜多糖,制备b型流感嗜血杆菌荚膜多糖及D蛋白疫苗.方法 采用CDAP法在不同pH值条件下活化Hib荚膜多糖,再通过乙二酰肼（ADH）与D蛋白共价结合,制备Hib荚膜多糖与其D蛋白结合物原液,并对三批结合物原液的各项指标进行检测.获得的结合物原液免疫BALB/c小鼠,应用ELISA法检测血清中的IgG抗体水平,评价其免疫原性.结果 三批结合物原液以上检测指标均符合药典要求,衍生物中ADH含量对结合物的免疫原性有重要影响.结论 用CDAP活化工艺制备的Hib荚膜多糖-D蛋白结合物适宜制备结合疫苗,为以D蛋白为载体的Hib结合疫苗的制备及五价联苗的研制奠定实验基础.