Combined microautoradiographic and histopathologic analysis of the fate of challenge Schistosoma mansoni schistosomula in mice immunized with irradiated cercariae.

Combined microautoradiographic and histopathologic methods were used to locate and examine schistosomula of Schistosoma mansoni in the lungs of irradiated cercaria-immunized mice 21 days after percutaneous challenge infection with 75Se-labeled cercariae. Of 75 schistosomula examined in serial sections, 53% were located in the pulmonary microvasculature, 23% in alveolar spaces, 3% with one end in a vessel and the other in an alveolar space, and the locations of 21% were not identified. Inflammatory reactions of variable intensity were observed around schistosomula in both vascular and alveolar sites, although the most intense category of reactions was associated almost entirely with alveolar larvae. All autoradiographic foci contained recognizable schistosomula. Although the concentration of reduced silver grains precluded cyto-structural analysis, observations on schistosomular contour and shape provided no evidence of larval damage. Our findings suggest that immune elimination of schistosomula in mice immunized with irradiated cercariae is partly or largely effected by a process of alveolar extrusion of viable parasites during their lung migration.     

The tuberculosis vaccine challenge

Although antibiotic treatments for tuberculosis are available, because of re-infection, drug resistance, AIDS, and economic reasons, it is unlikely that we will be able to control the global spread of tuberculosis without an effective vaccine. A number of new candidate vaccines for tuberculosis are under development and some are being evaluated for safety in normal human subjects in clinical trials. Additional vaccine candidates have been shown to be safe and effective when administered prior to infection in animal models. However, in areas of the world where tuberculosis is endemic, up to two thirds of the population are already infected with Mycobacterium tuberculosis, and it is unlikely that a new pre-exposure vaccine would have a substantial impact on disease for decades. In contrast, a vaccine that could be delivered to individuals already infected could reduce the disease burden. At this time, it is unclear whether the new TB vaccines can be safely and effectively used in populations already infected with M. tuberculosis, immunized with BCG vaccine or infected with HIV. This presents a major challenge to pre-clinical testing and clinical evaluation as well as eventual uptake of the new TB vaccines into areas of the world that are most at risk for tuberculosis.     

Matrix-M adjuvanted virosomal H5N1 vaccine confers protection against lethal viral challenge in a murine model

Please cite this paper as: Pedersen et al. (2011) Matrix‐M adjuvanted virosomal H5N1 vaccine confers protection against lethal viral challenge in a murine model. Influenza and Other Respiratory Viruses 5(6), 426–437. Background A candidate pandemic influenza H5N1 vaccine should provide rapid and long‐lasting immunity against antigenically drifted viruses. As H5N1 viruses are poorly immunogenic, this may require a combination of immune potentiating strategies. An attractive approach is combining the intrinsic immunogenicity of virosomes with another promising adjuvant to further boost the immune response. As regulatory authorities have not yet approved a surrogate correlate of protection for H5N1 vaccines, it is important to test the protective efficacy of candidate H5N1 vaccines in a viral challenge study. Objectives This study investigated in a murine model the protective efficacy of Matrix‐M adjuvanted virosomal influenza H5N1 vaccine against highly pathogenic lethal viral challenge. Methods Mice were vaccinated intranasally (IN) or intramuscularly (IM) with 7·5 μg and 30 μg HA of inactivated A/Vietnam/1194/2004 (H5N1) (NIBRG‐14) virosomal adjuvanted vaccine formulated with or without 10 μg of Matrix‐M adjuvant and challenged IN with the highly pathogenic A/Vietnam/1194/2004 (H5N1) virus. Results and conclusions IM vaccination provided protection irrespective of dose and the presence of Matrix‐M adjuvant, whilst the IN vaccine required adjuvant to protect against the challenge. The Matrix‐M adjuvanted vaccine induced a strong and cross‐reactive serum antibody response indicative of seroprotection after both IM and IN administration. In addition, the IM vaccine induced the highest frequencies of influenza specific CD4+ and CD8+ T‐cells. The results confirm a high potential of Matrix‐M adjuvanted virosomal vaccines and support the progress of this vaccine into a phase 1 clinical trial.     

The challenge of improving the efficacy of measles vaccine

Despite a safe and effective measles vaccine, measles still claims an estimated 800,000 lives per year mostly among children in developing countries. This paper deals with strategies to improve vaccine efficacy and prevent unnecessary deaths, including considerations of one dose at 9 months strategy for developing countries, strain of vaccine, potency and number of doses of measles vaccine. After more than 20 years of measles immunisation in the developing world, the epidemiology of measles is radically changed, and the absence of measles epidemics might lead to waning immunity due to less clinical and subclinical infections boosting the antibody level. An increasing proportion of mothers are vaccinated, thus transferring a lower maternal antibody level to their infants who will be susceptible to measles at a younger age. The strategies to limit nosocomial measles infection and spread of measles epidemics are reviewed. Though the measles elimination programmes have been very effective in the Americas, it seems unlikely that they will be equally effective in the rest of the world. Even if eradication should be possible, it might be unwise to stop measles vaccination because the vaccine apparently has beneficial effects and because it would make measles a likely weapon for bio-terrorism. If we are unlikely to get rid of measles and measles vaccine, it might be wise to study further some of the many unanswered questions regarding the long-term effects of measles and measles vaccination.     

The fate and uptake of murine epidermal growth factor in the sheep

125I-Labelled murine epidermal growth factor (EGF) was injected or infused into conscious ewes through the jugular vein. Its disappearance from the circulation and the pattern of its distribution in other body tissues and compartments were observed. Single bolus injections of 125I-labelled EGF resulted in a transient peak of radioactive EGF in the circulation which occurred within 1 min of the injection. This was followed by a very rapid fall in radioactivity in the plasma (t1/2 approximately 1 min) and the gradual appearance of 125I-labelled EGF in the urine. Immunoprecipitable 125I-labelled EGF could be detected in urine within 5 min of the start of the experiment. 125I-Labelled EGF accumulated in the urine for several hours following the injection, although with increasing time a substantial amount of non-immunoprecipitable iodide was also found. The rate of disappearance of the 125I-labelled EGF from the plasma of the ewe was found to be faster than the rate of disappearance of free [125I]iodide that had been injected into the ewe. 125I-Labelled EGF was also administered by a continuous infusion following an initial bolus injection. This again resulted in a rapid initial fall in radioactivity in blood, followed by a slow rise throughout the period of the infusion. When the infusion was stopped, there was a 15-min period of rapid readjustment, after which the radioactivity in the blood fell at a much slower rate (t1/2 approximately 70 min) than was seen initially. Again, intact 125I-labelled EGF was transferred to urine throughout the experiment. At autopsy, 125I-labelled EGF was increased in bile, liver, thyroid and kidney. Although most of the 125I found in the thyroid was free iodide, some EGF-like material was also present. There was also EGF-like material found in both the kidney cortex and the kidney medulla. These results indicate that complex multi-compartment pathways for the uptake, distribution and clearance of 125I-labelled EGF exist in the sheep.     

不同激发方式对小鼠过敏性支气管哮喘模型的影响

目的探讨不同激发方式对小鼠过敏性支气管哮喘（简称哮喘）模型的影响。方法模型组用卵清蛋白致敏和激发BalB/c小鼠,第0天、第7天、第14天腹腔注射致敏,从第28天开始分别给予不同次数和方式的激发。根据激发方式的不同,随机分为5组,包括三次滴鼻激发组、二次雾化20min激发组、三次雾化20min激发组、三次雾化30min激发组、四次雾化20min激发组,每组12只。激发后48h采用整体体积描记法检测小鼠气道反应性,结果以增强的呼气间歇（enhanced pause,Penh）表示,测定肺功能后再用磷酸盐缓冲液对全肺进行支气管肺泡灌洗,支气管肺泡灌洗液（BALF）进行细胞学分析。结果哮喘组气道反应性（Penh%）和BALF中嗜酸粒细胞比例（EOS%）与正常组相比差异均有统计学意义（P〈0.05）。三次滴鼻激发组EOS%和Penh%显著高于其他雾化激发组（P〈0.05）,其中BALF中EOS%三次滴鼻激发组（46.30±4.55）%,与二次雾化20min激发组（31.19±12.84）%、三次雾化20min激发组（29.00±12.33）%、四次雾化20min激发组（37.08±8.44）%相比有显著差异,与三次雾化30min激发组（41.17±8.78）%无显著差异。三次滴鼻激发组PC100[（3.75±1.79）g/L]和三次雾化30min激发组[（5.94±3.27）g/L]、四次雾化20min激发组[（5.19±1.88）g/L]有显著差异（P〈0.05）。三次滴鼻激发组激发过程中动物死亡2只,其余各组均无死亡。结论滴鼻和雾化激发均能成功建立哮喘模型,其中滴鼻激发建立的哮喘模型气道炎症及气道反应性升高更为显著。     

不同激发方式对小鼠过敏性支气管哮喘模型的影响

目的 探讨不同激发方式对小鼠过敏性支气管哮喘(简称哮喘)模型的影响.方法 模型组用卵清蛋白致敏和激发BalB/c小鼠,第0天、第7天、第14天腹腔注射致敏,从第28天开始分别给予不同次数和方式的激发.根据激发方式的不同,随机分为5组,包括三次滴鼻激发组、二次雾化20 min激发组、三次雾化20 min激发组、三次雾化30 min激发组、四次雾化20 min激发组,每组12只.激发后48 h采用整体体积描记法检测小鼠气道反应性,结果 以增强的呼气间歇(enhanced pause,Penh)表示,测定肺功能后再用磷酸盐缓冲液对全肺进行支气管肺泡灌洗,支气管肺泡灌洗液(BALF)进行细胞学分析.结果 哮喘组气道反应性(Penh%)和BALF中嗜酸粒细胞比例(EOS%)与正常组相比差异均有统计学意义(P<0.05).三次滴鼻激发组EOS%和Penh%显著高于其他雾化激发组(P<0.05),其中BALF中EOS%三次滴鼻激发组(46.30±4.55)%,与二次雾化20 min激发组(31.19±12.84)%,三次雾化20 min激发组(29.00±12.33)%、四次雾化20 min激发组(37.08±8.44)%相比有显著差异.与三次雾化30 min激发组(41.17±8.78)%无显著差异.三次滴鼻激发组PCI00[(3.75±1.79)g/L]和三次雾化30 min激发组[(5.94±3.27)g/L],四次雾化20 min激发组[(5.19±1.88)g/L]有显著差异(P<0.05).三次滴鼻激发组激发过程中动物死亡2只,其余各组均无死亡.结论 滴鼻和雾化激发均能成功建立哮喘模型,其中滴鼻激发建立的哮喘模型气道炎症及气道反应性升高更为显著.     

CTL responses to Leishmania mexicana gp63-cDNA vaccine in a murine model

Immunity to Leishmania is believed to be strongly dependent upon the activation of Th1 immune responses, although the exact role of cytotoxic T lymphocytes (CTLs) has not yet been determined. The aims of this study were to establish a suitable cytotoxicity assay to measure CTL activity and to compare immunity induced by Leishmania mexicana gp63 cDNA via i.m. injection and gene gun immunization in the BALB/c mouse model. The CTL activity was evaluated by short-term ⁵¹Cr-release cytotoxicity assays against CT26 tumour cells transfected with L. mexicana gp63 cDNA and dendritic cells (DCs) loaded with soluble Leishmania antigen (SLA) as targets. The results clearly demonstrated that higher protection to L. mexicana infection was induced by gene gun DNA-immunization vs. i.m. injection. Cytotoxic T lymphocyte activity of splenocytes was observed in mice immunized either with L. mexicana gp63 cDNA or SLA and long-lived CTL activity was observed in immunized and/or re-challenged mice but not naïve mice infected with the parasite.     

日本血吸虫病治疗后血清抗体消长观察

目的 分析人群日本血吸虫病治疗后抗体滴度变化,为制订监测巩固方案提供科学依据。方法 采用定群前瞻性研究法,以江陵县2014年检出的粪检阳性病人及血检阳性滴度1∶80以上（含1∶80）者为对象,先用吡喹酮2日疗法治疗,于治疗后半年、1年、2年分别采集血样、粪样,进行IHA抗体检测和集卵孵化法检测。结果 2014年粪检阳性病例251人,年龄以41岁以上为主,占93.23%（234/251）;IHA法检测抗体高滴度病例581人,年龄以41岁以上为主,占89.16%（518/581）。粪检阳性人群治疗后半年、1年、2年粪检转阴率分别为99.60%（250/251）、100%（239/239）、100%（234/234）,IHA法检测抗体转阴率分别是21.91%（55/251）、64.11%（156/239）和76.89%（193/234）;IHA法检测抗体高滴度人群治疗后半年、1年、2年转阴率分别为38.04%（221/581）、64.11%（359/560）、77.86%（429/551）;抗体转阴率进行[χ2] 检验,差异均有统计学意义（[χ2] = 77.538、183.412、25.469,P值均< 0.001）。分别对两组人群治疗前后不同时间段抗体滴度的几何均值进行t检验,治疗前两组人群的抗体滴度几何均值差异有统计学意义（t = 23.576,P < 0.01）;治疗后半年、1年、2年两组人群抗体滴度的几何均值差异均无统计学意义（t = -0.046、1.165、-0.132,P均> 0.01）。结论 日本血吸虫病治疗后人群血清中抗体水平消退缓慢,尚需开发特异的诊断技术以满足监测需求。     

Signatures of malaria vaccine efficacy in ageing murine immune memory

Malaria transmission occurs by mosquito bite. Thereafter, Plasmodium sporozoites specifically invade the liver, where they develop into thousands of merozoites that initiate blood‐stage infection and clinical malaria. The pre‐erythrocytic phase of a Plasmodium infection is the target of experimental whole‐parasite vaccines against malaria. Repeated immunizations with high doses of live, metabolically active sporozoites can induce protracted protection against Plasmodium reinfection. Parasites lacking a Plasmodium‐specific apicoplast protein, termed PALM, arrest very late during intrahepatic development just prior to liver merozoite release and can elicit sterile protection with two immunization doses only. In this report, we show in the robust Plasmodium berghei‐C57BL/6 model that partial protection extends beyond 1 year after the last immunization. In ageing mice, intracellular cytokine staining of Plasmodium peptide‐stimulated intrahepatic CD8⁺ T cells revealed elevated levels of interferon gamma in vaccinated mice. We conclude that antigen‐specific T cells persist in the target organ and are critical signatures of lasting protection. Our data also support the notions that memory T‐cell responses generated early in life remain largely intact well into old age and that murine Plasmodium vaccination and infection models are suitable to study the mechanisms of maintenance and efficiency of adaptive immunity during immunosenescence.     

Leukemia vaccine overcomes limitations of checkpoint blockade by evoking clonal T-cell responses in a murine acute myeloid leukemia model

We have developed a personalized vaccine in which patientderived leukemia cells are fused to autologous dendritic cells, evoking a polyclonal T-cell response against shared antigens and neoantigens. We postulated that the dendritic cell/acute myeloid leukemia fusion vaccine would demonstrate synergy with checkpoint blockade by expanding tumor antigen-specific lymphocytes that would provide a critical substrate for checkpoint blockade-mediated activation. Using an immunocompetent murine leukemia model, we examined the immunological response to and therapeutic efficacy of vaccination in conjunction with checkpoint blockade with respect to leukemia engraftment, disease burden, survival and the induction of tumor-specific immunity. Mice treated with checkpoint blockade alone had rapid progression of leukemia and only a modest extension of survival. Vaccination with dendritic cell/acute myeloid leukemia fusions resulted in the expansion of tumor-specific lymphocytes and disease eradication in a subset of animals, while the combination of vaccination and checkpoint blockade induced a fully protective tumor-specific immune response in all treated animals. Vaccination followed by checkpoint blockade resulted in upregulation of genes regulating activation and proliferation in memory and effector T cells. Long-term survivors exhibited increased T-cell clonal diversity and were resistant to subsequent tumor challenge. The combination of dendritic cell/acute myeloid leukemia fusion vaccine and checkpoint blockade treatment offers unique synergy, inducing durable activation of leukemia-specific immunity, protection from lethal tumor challenge and the selective expansion of tumor-reactive clones.     

Schistosoma haematobium infection levels determine the effect of praziquantel treatment on anti-schistosome and anti-mite antibodies

Field studies show an association between schistosome infection and atopy, but the effects of anti-helminthic treatment on this association have not yet been investigated in human populations with different schistosome endemicity levels. This study aimed to compare the effects of anti-helminthic treatment on responses directed against the house dust mite Dermatophagoides pteronyssinus (Derp1) and Schistosoma haematobium in Zimbabwean populations living in high and low schistosome infection areas. Derp1- and schistosome-specific IgE and IgG4 antibodies were quantified by ELISA before and 6 weeks after anti-helminthic treatment. Following treatment, there were changes in the immune responses, which varied with place of residence. After allowing for the effects of sex, age and baseline infection intensity, there was no significant treatment effect on the change in anti-schistosome IgE and IgG4 in the high infection area. However, the anti-schistosome IgE/IgG4 ratio increased significantly, while anti-Derp1 IgE responses decreased as a result of treatment. In the low infection area, treatment resulted in a significant increase in anti-worm IgE levels, but there was no significant treatment effect on anti-schistosome or anti-Derp1 IgE/IgG4 ratios. Thus, the study shows that the level of schistosome endemicity affects the host responses to schistosome and mite antigens following anti-helminthic treatment.     

The impact of vaccination on RBC alloimmunization in a murine model

Emerging data in animal models and humans suggest that pathogen‐associated and damage‐associated molecular patterns variably impact RBC alloantibody formation. In this study, we tested the hypothesis that vaccinations may enhance immune responses to transfused RBCs. The Pneumovax23 vaccine decreased the magnitude of anti‐KEL alloimmunization in a murine model, whereas the hepB vaccine did not impact the response; RBC transfusion did not alter immune responses to either vaccine. These data highlight the complexities of the intersection of innate and adaptive immunity and suggest that future studies investigating the pathways through which inflammation impacts alloimmunization are warranted.     

Down‐selecting circumsporozoite protein‐based malaria vaccine: A comparison of malaria sporozoite challenge model

Plasmodium falciparum circumsporozoite protein (PfCSP) is the main target antigen in development of pre‐erythrocytic malaria vaccines. To evaluate PfCSP vaccines in animal models, challenge by intravenous sporozoite injection is preferentially used. However, in clinical trials, vaccinated human volunteers are exposed to the bites of malaria‐infected mosquitoes. In this study, we down‐selected Escherichia coli‐produced full‐length PfCSP (PfCSP‐F) and its three truncated PfCSPs based on their abilities to elicit immune response and protection in mice against two challenge models. We showed that immunization with three doses of PfCSP‐F elicited high anti‐PfCSP antibody titres and 100% protection against the bites of infected mosquitoes. Meanwhile, three‐dose truncated PfCSP induced 60%‐70% protection after immunization with each truncated PfCSP. Heterologous prime‐boost immunization regimen with adenovirus‐PfCSP‐F and R32LR greatly induced complete protection against intravenous sporozoite injection. Our results suggest that Abs to both anti‐repeat and anti‐nonrepeat regions induced by PfCSP‐F are required to confer complete protection against challenge by the bites of infected mosquitoes, whereas anti‐repeat Abs play an important role in protection against intravenous sporozoite injection. Our findings provide a potential clinical application that PfCSP‐F vaccine induces potent Abs capable of neutralizing sporozoites in the dermis inoculated by infected mosquitoes and subsequently sporozoites in the blood circulation.