A recombinant varicella vaccine harboring a respiratory syncytial virus gene induces humoral immunity

The varicella-zoster virus (VZV) Oka vaccine strain (vOka) is highly efficient and causes few adverse events; therefore, it is used worldwide. We previously constructed recombinant vOka (rvOka) harboring the mumps virus gene. Immunizing guinea pigs with rvOka induced the production of neutralizing antibodies against the mumps virus and VZV.Here, we constructed recombinant vOka viruses containing either the respiratory syncytial virus (RSV) subgroup A fusion glycoprotein (RSV A–F) gene or RSV subgroup B fusion glycoprotein (RSV B–F) gene (rvOka-RSV A–F or rvOka-RSV B–F). Indirect immunofluorescence and Western blot analyses confirmed the expression of each recombinant RSV protein in virus-infected cells. Immunizing guinea pigs with rvOka-RSV A–F or rvOka-RSV B–F led to the induction of antibodies against RSV proteins. These results suggest that the current varicella vaccine genome can be used to generate custom-made vaccine vectors to develop the next generation of live vaccines.     

Diagnostic tools for Toscana virus infection

Toscana virus (TOSV; Phlebovirus, Bunyaviridae) is an important etiological agent of acute meningitis and meningoencephalitis in Mediterranean countries. Laboratory diagnosis has been carried out in serological studies using ELISA, immunofluorescence and/or neutralization tests that are not influenced by the virus viability; however, in the acute phase of the infection, nucleic acid amplification techniques are the methods of choice to diagnose viral meningitis from cerebrospinal fluid samples. Molecular methods are rapid and sensitive and, unlike traditional methods, such as virus isolation by cell culture, they are not influenced by the viability of the virus in the clinical specimen; however, the RNA integrity is crucial for the success of these methods. Real-time PCR is the most important molecular method used in laboratories worldwide, since it is less time-consuming and it reduces the risk of contamination. Therefore, a sensitive real-time PCR has been developed for diagnosis of suspected cases of TOSV infection either autochthonous and/or imported, since a new lineage of TOSV, divergent from the Italian prototype, has recently been reported in Spain.     

Plasmodium falciparum synthetic LbL microparticle vaccine elicits protective neutralizing antibody and parasite-specific cellular immune responses

Epitopes of the circumsporozoite (CS) protein of Plasmodium falciparum, the most pathogenic species of the malaria parasite, have been shown to elicit protective immunity in experimental animals and human volunteers. The mechanisms of immunity include parasite-neutralizing antibodies that can inhibit parasite motility in the skin at the site of infection and in the bloodstream during transit to the hepatocyte host cell and also block interaction with host cell receptors on hepatocytes. In addition, specific CD4+ and CD8+ cellular mechanisms target the intracellular hepatic forms, thus preventing release of erythrocytic stage parasites from the infected hepatocyte and the ensuing blood stage cycle responsible for clinical disease. An innovative method for producing particle vaccines, layer-by-layer (LbL) fabrication of polypeptide films on solid CaCO₃ cores, was used to produce synthetic malaria vaccines containing a tri-epitope CS peptide T1BT* comprising the antibody epitope of the CS repeat region (B) and two T-cell epitopes, the highly conserved T1 epitope and the universal epitope T*. Mice immunized with microparticles loaded with T1BT* peptide developed parasite-neutralizing antibodies and malaria-specific T-cell responses including cytotoxic effector T-cells. Protection from liver stage infection following challenge with live sporozoites from infected mosquitoes correlated with neutralizing antibody levels. Although some immunized mice with low or undetectable neutralizing antibodies were also protected, depletion of T-cells prior to challenge resulted in the majority of mice remaining resistant to challenge. In addition, mice immunized with microparticles bearing only T-cell epitopes were not protected, demonstrating that cellular immunity alone was not sufficient for protective immunity. Although the microparticles without adjuvant were immunogenic and protective, a simple modification with the lipopeptide TLR2 agonist Pam₃Cys increased the potency and efficacy of the LbL vaccine candidate. This study demonstrates the potential of LbL particles as promising malaria vaccine candidates using the T1BT* epitopes from the P. falciparum CS protein.     

猴泡沫病毒间接免疫荧光检测方法的建立及初步应用

目的建立检测血清中猴泡沫病毒(SFV)抗体的间接免疫荧光方法,为检测实验用猴群中SFV的感染情况提供参考依据。方法用SFV-1病毒感染BHK-21细胞,待50%细胞出现病变时,用胰蛋白酶消化细胞后以2×107/mL浓度40μL的细胞滴到10孔镀膜的玻片上,丙酮固定。利用制备的抗原片通过间接免疫荧光法对34份猴血清标本进行检测。结果建立了检测SFV抗体的间接免疫荧光染色方法,SFV抗体阳性19例,15例血清检测为阴性。结论本方法具有良好的特异性,可作为SFV检测的可靠方法。     

卡氏肺孢子虫感染的免疫诊断研究

目的：探讨肺泡灌洗液、血清抗原及血清抗体检测诊断卡氏肺孢子虫感染的价值。方法：利用免疫抑制大鼠模型及双夹心ＥＬＩＳＡ法检测不同时期感染大鼠肺泡灌洗液和血清中肺孢子虫抗原，用ＩＦＡ法检测血清中的肺孢子虫ＩｇＧ抗体，并与病原学检查结果进行比较。结果：感染大鼠肺泡灌洗液的抗原检测于免疫抑制６－８ｗｋ后均呈阳性，而对照组大鼠均呈阴性；大多数感染大鼠血清抗原检测为阴性；正常大鼠血清中有低滴度肺孢子虫ＩｇＧ抗体，感染大鼠抗体滴度轻度升高或不升高，但中止免疫抑制后血清抗体滴度明显升高，而肺泡灌洗液中抗原逐渐阴转。结论：肺泡灌洗液抗原检测可用于肺孢子虫感染的诊断，但血清中很难检出这种抗原；血清ＩｇＧ抗体的上升并不表示为现症感染。     

哺乳动物细胞西尼罗病毒样颗粒表达、纯化及其鉴定

目的利用哺乳动物细胞表达含有西尼罗病毒(WNV)prM和E蛋白,形成病毒样颗粒(virus-like particles,VLPs),为西尼罗病毒感染的免疫诊断试剂的研制奠定基础。方法筛选典型西尼罗病毒株,构建重组质粒,转染293T细胞,表达并纯化西尼罗病毒prM-E蛋白,利用透射电镜、免疫印迹试验、间接免疫荧光实验(IFA)和酶链免疫吸附试验(ELISA)对表达产物进行鉴定。结果重组质粒转染细胞后产生病毒样颗粒(viruslike particles VLPs),转染细胞上清纯化物中透射电镜观察到重组蛋白形成的球型颗粒,免疫印迹试验和间接免疫荧光试验表明,表达的病毒样颗粒蛋白能够与抗西尼罗病毒抗体特异结合,具有良好的抗原性;间接ELISA证实,重组蛋白可以作为抗原用于检测患者血清特异性抗体。结论在哺乳动物细胞中表达的西尼罗病毒样颗粒具有良好的抗原性,为西尼罗病毒感染快速特异诊断试剂研制奠定了基础。     

徐州市1977—1993年疟疾IFA结果初析

本文报告了原间日疟流行区徐州市两个监测点居民和１５岁以下儿童用ＩＦＡ试验进行１７年疟疾抗体调查的结果。疟疾年带虫发病率与人群疟疾抗体阳性率呈正相关（ｒ＝０．７０，Ｐ＜０．０１），流动人口疟疾抗体阳性率和当地居民疟疾抗体阳性率有显著的差异（Ｕ＝１１．８７，Ｐ＜０．０１）。自１９８６年基本消灭疟疾后，每年流行季节末期人群抗体阳性率为０．０３％￣４．２６％，儿童抗体阳性率为０￣３．５％。显示疟疾传播已得     

马来丝虫感染沙鼠血清中特异性抗体水平的动态研究

应用马来丝虫和牛丝虫成虫冰冻切片抗原作IFAT和IEST检测马来丝虫感染长爪沙鼠血清中抗体IgG和IgM水平的动态变化,结果分别在感染后12～14周及2～6周达高峰。感染沙鼠IgG水平与感染时期长短密切相关,但与感染度无关。认为IFAT和IEST,特别是后者,可望成为丝虫病诊断中较为理想的方法;牛丝虫抗原可望能代替马来丝虫抗原用于丝虫病血清诊断中。     

Macrophages from disease resistant B2 haplotype chickens activate T lymphocytes more effectively than macrophages from disease susceptible B19 birds

Resistance to respiratory pathogens, including coronavirus-induced infection and clinical illness in chickens has been correlated with the B (MHC) complex and differential ex vivo macrophage responses. In the current study, in vitro T lymphocyte activation measured by IFNγ release was significantly higher in B2 versus B19 haplotypes. AIV infection of macrophages was required to activate T lymphocytes and prior in vivo exposure of chickens to NP AIV plasmid enhanced responses to infected macrophages. This study suggests that the demonstrated T lymphocyte activation is in part due to antigen presentation by the macrophages as well as cytokine release by the infected macrophages, with B2 haplotypes showing stronger activation. These responses were present both in CD4 and CD8 T lymphocytes. In contrast, T lymphocytes stimulated by ConA showed greater IFNγ release of B19 haplotype cells, further indicating the greater responses in B2 haplotypes to infection is due to macrophages, but not T cells. In summary, resistance of B2 haplotype chickens appears to be directly linked to a more vigorous innate immune response and the role macrophages play in activating adaptive immunity.