Infection dynamics and virus-induced apoptosis in cell culture-based influenza vaccine production—Flow cytometry and mathematical modeling

Cell culture-based influenza vaccine manufacturing is of growing importance. Depending on virus strains, differences in infection dynamics, virus-induced apoptosis, cell lysis and virus yields are observed. Comparatively little is known concerning details of virus–host cell interaction on a cellular level and virus spreading in a population of cells in bioreactors. In this study, the infection of MDCK cells with different influenza A virus strains in lab-scale microcarrier culture was investigated by flow cytometry. Together with the infection status of cells, virus-induced apoptosis was monitored. A mathematical model has been formulated to describe changes in the concentration of uninfected and infected adherent cells, dynamics of virus particle release (infectious virions, hemagglutinin content), and the time course of the percentage composition of the cell population.     

Serum antibodies to structural proteins of Hantavirus arise at different times after infection.

An enzyme-linked immunosorbent assay (ELISA) was developed for the quantification of serum antibodies against group-specific epitopes of the glycoproteins (G1, G2) and nucleoprotein (NP) of the genus Hantavirus. This assay was used to study the kinetics of the development of serum antibodies after natural infection with Puumala-like virus in humans. To this end a panel of 34 serum samples collected from individuals at different times after natural infection was tested by the ELISA. The samples were also tested for specific IgM and IgG levels against Puumala-like virus, which provided confirmatory data about the presumed timing of infection. It was shown that serum antibodies against the G1 epitope were present in the acute and early convalescent period just before antibodies to the NP epitope could be demonstrated. In contrast, antibodies to two G2 epitopes were present not earlier than in the convalescent and late convalescent period. Since all these categories of antibodies seem to persist for long periods, antibodies against the G1 epitope and the NP epitope may be of specific diagnostic value. Furthermore, levels of G1-specific antibodies and antibodies to either NP or G2 may allow estimation of the time elapsed following initial infection.     

Tolerance in TCR/Cognate Antigen Double-Transgenic Mice Mediated by Incomplete Thymic Deletion and Peripheral Receptor Downregulation

Influenza nucleoprotein (NP)-specific T-cell receptor transgenic mice (F5) were crossed with transgenic mice expressing the cognate antigenic protein under the control of the H- 2K^b promoter. Double-transgenic mice show negative selection of thymocytes at the CD4⁺8⁺TCR¹⁰ to CD4⁺8⁺TCR^hi transition stage. A few CD8 T cells, however, escape clonal deletion, and in the peripheral lymphoid organs of these mice, they exhibit low levels of the transgenic receptor and upregulated levels of the CD44 memory marker. Such cells do not proliferate upon exposure to antigen stimulation in vivo or ex vivo, however, they can develop low but detectable levels of antigen-specific cytotoxic function after stimulation in vitro in the presence of IL-2.     

Role of viral RNA and lipid in the adverse events associated with the 2010 Southern Hemisphere trivalent influenza vaccine

In Australia, during the 2010 Southern Hemisphere (SH) influenza season, there was an unexpected increase in post-marketing adverse event reports of febrile seizures (FS) in children under 5 years of age shortly after vaccination with the CSL 2010 SH trivalent influenza vaccine (CSL 2010 SH TIV) compared to previous CSL TIVs and other licensed 2010 SH TIVs. In an accompanying study, we described the contribution to these adverse events of the 2010 SH influenza strains as expressed in the CSL 2010 SH TIV using in vitro cytokine/chemokine secretion from whole blood cells and induction of NF-κB activation in HEK293 reporter cells. The aim of the present study was to identify the root cause components that elicited the elevated cytokine/chemokine and NF-κB signature. Our studies demonstrated that the pyrogenic signal was associated with a heat-labile, viral-derived component(s) in the CSL 2010 SH TIV. Further, it was found that viral lipid-mediated delivery of short, fragmented viral RNA was the key trigger for the increased cytokine/chemokine secretion and NF-κB activation. It is likely that the FS reported in children <5 years were due to a combination of the new influenza strains included in the 2010 SH TIV and the CSL standard method of manufacture preserving strain-specific viral components of the new influenza strains (particularly B/Brisbane/60/2008 and to a lesser extent H1N1 A/California/07/2009). These combined to heighten immune activation of innate immune cells, which in a small proportion of children <5 years of age is associated with the occurrence of FS. The data also demonstrates that CSL TIVs formulated with increased levels of splitting agent (TDOC) for the B/Brisbane/60/2008 strain can attenuate the pro-inflammatory signals in vitro, identifying a potential path forward for generating a CSL TIV indicated for use in children <5 years.     

严重发热伴血小板减少综合征病毒核蛋白核酸疫苗的构建及免疫原性研究

目的:构建SFTSV的核蛋白核酸疫苗并探讨其免疫原性?方法:采用PCR方法扩增SFTSV核蛋白基因,并用引物引入限制性内切酶酶切位点,克隆入载体pJW4303?经酶切和测序鉴定正确的质粒,用PEI瞬时转染HEK293T细胞,用免疫印迹法鉴定核蛋白的表达?同时以质粒pJW4303作为阴性对照,免疫BALB/c小鼠,酶联免疫法验证其免疫原性?结果:成功构建质粒pJW4303-N,经Western blot证实SFTSV核蛋白能够在HEK293T细胞中表达?ELISA检测免疫后小鼠血清特异性IgG抗体及其亚型发现,IgG抗体及其亚型较免疫前明显升高,亚型中以IgG2a升高为主?结论:SFTSV核蛋白核酸疫苗pJW4303-N具有良好的免疫原性,为进一步研究SFTSV核蛋白奠定了基础?     

不同连翘制剂对甲型流感病毒NP基因转染后表达的影响

目的：观察连翘苷、连翘醇提液、连翘水煎剂等3种连翘制剂对甲型流感病毒甲1型流感病毒核蛋白（ nucleoprotein,NP）基因转染后表达的影响。方法：将甲型流感病毒NP基因转染Hela细胞,用甲型流感病毒胶体金检测3种连翘制剂对转染后细胞内和上清核蛋白表达情况,用RT_PCR检测转染后Hela细胞内NP基因的拷贝数。结果：NP重组质粒组上清胶体金检测为阳性,连翘苷组上清为阴性、细胞内为弱阳性;连翘水煎剂及连翘醇提物组上清均为弱阳性。连翘苷组NP基因表达量较NP重组质粒组减少（ P<0.05）。结论：连翘苷抑制甲型流感病毒NP基因转染后表达作用最强。     

精子DNA碎片率与体外受精实验室结局的关系

目的初步探讨精子DNA碎片率、精子核蛋白不成熟度与体外受精实验室结局的关系。方法对2013年5~7月在我院行IVF治疗的男性患者行精液常规、精子DNA碎片率及精子核蛋白不成熟度检查,利用spearman相关分析探讨它们与IVF受精率、优胚率的关系。结果精子DNA碎片碎与男方年龄正相关,与前向运动精子百分率、优胚率负相关,与IVF受精率无相关。精子核蛋白不成熟度与精子浓度、正常精子百分率负相关,与IVF受精率、优胚率无显著相关。结论精子DNA碎片率检测对预测IVF优胚率有一定的临床意义。     

CCHFV S基因的重组杆状病毒的构建及鉴定

目的　利用杆状病毒表达系统（baculovirus expression vector systems, BEVS）构建含有克里米亚-刚果出血热病毒（Crimean-Congo hemorrhagic fever virus, CCHFV）S基因的重组杆状病毒,并在sf9昆虫细胞中表达出核衣壳蛋白（nucleoprotein, NP）。方法　将合成的CCHFV S基因定向克隆入杆状病毒转移载体pFastBac? Dual,获得重组的转移载体pFastBac? Dual-CCHFV-S。将其转化到E. coli DH10Bac?感受态细胞中,筛选得到重组杆状病毒杆粒rBV-Bacmid-S。用Cellfectin? II试剂将rBV-Bacmid-S转染入sf9昆虫细胞获得重组杆状病毒rBV-CCHFV-S。通过IFA和Western blot检测CCHFV S基因的表达。结果　构建了含有S基因的rBV-CCHFV-S,在sf9昆虫细胞中成功表达CCHFV NP。结论　利用BEVS 可以成功表达CCHFV NP,这为研究CCHFV NP的生物学特性,研制特异性的治疗药物和预防控制疫苗奠定基础。     

Principles of creation of protein carriers of DNA new derivatives of human epidermal growth factor for gene therapy

We formulated a new approach to the creation of transport proteins for the delivery of foreign DNA to target cells and used it for obtaining a polypeptide PGEk. Structural and functional analysis of PGEk—DNA complexes demonstrated good prospects for the creation of a wide spectrum of targeted preparations for gene therapy. These approaches and regularities are necessary for construction of new DNA carriers selective for various cell types. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Supplement 2, pp. 87–93, April, 2007