Role of AcMNPV IE0 in baculovirus very late gene activation

IE0 is the only known baculovirus protein that is produced by splicing. In this study, we have explored the role of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) IE0 and its interaction with IE1 in the activation of very late gene expression from the polyhedrin promoter using transient assays. IE0 is co-expressed with IE1 throughout infection up to late times post-infection (p.i.) but shows peak levels of expression at early times. Significant changes in the ratios of the relative levels of IE0 to IE1 were observed throughout the course of infection. To study IE0 in the absence of IE1, we constructed a plasmid pAc-IE0(M-->A) that expressed only IE0. This was due to a mutation of the internal AUG that prevented translation of IE1 from the ie0 mRNA. Both IE0 and IE0(M-->A) were able to replace IE1 in transient assays, showing that IE0 is functional for very late gene activation and should be considered the 20th late gene expression factor (lef). In transient assays, IE0 showed that maximum very late gene expression is achieved at very low relative levels of protein. In contrast, IE1 requires higher levels of protein to obtain maximum very late gene expression. Furthermore, when the levels of IE0 become too high, very late gene expression rapidly declines. Interestingly, co-expression of IE0 and IE1 results in a mutually antagonistic affect on very late gene expression.     

人巨细胞病毒IE1真核表达载体的构建与表达

目的构建人巨细胞病毒（HCMV）IEl真核表达载体，观察其在真核细胞内的表达，为HC—MVIEl核酸疫苗的相关研究奠定基础。方法将质粒pNEBl93-IEl用Sal I、BamH I双酶切与载体pEGFP—C1连接构建重组载体pEGFP—C1-IEl；双酶切鉴定后，取重组载体pEGFP—C1-IEl用EcoR I 、Hind Ⅲ／双酶切与载体pcDNA3．1（-）连接构建重组质粒pcDNA3．I（-）-IEl，双酶切和测序鉴定；将重组质粒pcDNA3．1（-）-IEl转染HeLa细胞，RT—PCR检测IElmRNA的表达。结果重组载体pEGFP—C1-IEl和pcDNA3．1（-）-IEl双酶切后均可切出约1476bp目的片段；重组载体pcDNA3．1（-）-IEI测序结果登录C,enBank，作BLAST分析，含有1476bp目的基因片段，无碱基错配和移码突变，与读码框完全-致；转染重组载体pcDNA3．1（-）-IEl的细胞中可扩增出约1476bp的目的条带。结论成功地构建了真核表达载体pcDNA3．1（-）-IEl，且其能在真核细胞内袁达。     

Effect of HCMV IE1 Protein on Cytokines Secretion and Apoptosis of Macrophages

Objective： To investigate the effect of human cytomegalovirus （HCMV） IE1 protein on the secretory activity and apoptosis of macrophages. Methods： The eukaryotic expression vector pEGFP-C1/IE1 was used to transfect THP-1-macrophages. 48 h after transfection, the expression and localization of GFP or GFP-IE1 was observed under fluorescent microscope. The levels of IL-1β and TNF-α in the culture media were examined by ELISA, and the mRNA expression of them was analyzed by RT-PCR. Cell undergoing apoptosis were determined by flow cytometry using the propidium iodide （PI） staining method. The data were analyzed by SPSSI3.0. Results： As observed under fluorescent microscope, the expressions of GFP-IEI and GFP by plasmid pEGFP-C1/IE1 or pEGFP-C1 in THP-1-macrophages could be found in nuclei or whole cells. Conclusion： As demonstrated by RT-PCR and ELISA, mRNA and protein expressions of IL-1β and TNF-α and promotes apoptosis in THP-1-macrophages.     

High efficacy of anti DBL4ɛ-VAR2CSA antibodies in inhibition of CSA-binding Plasmodium falciparum-infected erythrocytes from pregnant women

Malaria during pregnancy is a major cause of intra-uterine growth-retardation and infant death in sub-Saharan Africa. Ideally, this could be prevented by a vaccine delivered before the first pregnancy. Antibodies against domain DBL4? from VAR2CSA has been shown to inhibit adhesion of laboratory isolates to the placental receptor chondroitin sulfate A. In this study, the binding inhibitory efficacy of IgG elicited by two different DBL4? recombinant proteins was tested on a panel of fresh clinical isolates from pregnant women living in Benin and Tanzania. The most promising recombinant protein elicited antibodies with similar efficacy as pooled plasma from immune multi-gravid African women.