Assessment the Efficiency of the Constructed Minigenome of Rabies Virus using PV Strain as Helper Virus.

INTRODUCTION: Rabies is an acute viral disease that causes encephalomyelitis in mammals and human. The only way to prevent this disease is through vaccination before or after exposure. The aim of this study is to evaluate the efficiency of the Pasteur virus (PV) minigenome, using PV strain. MATERIALS AND METHODS: Enhanced Green Fluorescent Protein (EGFP) sequence was placed between the designed necessary elements (Hammerhead, HDV ribozyme, 3' Leader, and 5' Trailer sequences), which resemble the rabies virus PV strain (PV2061) genome and anti-genome. These constructs were placed between T7 polymerase promoter and T7 polymerase terminator sequences. The accuracy of the minigenome was confirmed by the expression of EGFP using the helper virus in T7-BHK cell line. RESULTS: The viral necessary elements of positive and negative sense strands were evaluated for the ability of EGFP expression in the presence of the helper virus. While the positive strand showed background results, no EGFP background was observed in the negative strand application. CONCLUSION: Establishment of minigenome system does not require advanced biosafety levels. Furthermore, using minigenome system eliminates many potential confounding factors that may be present in coding regions of the genome. Use of the minigenome system is easier and more feasible than the full genome rescue of the virus. This study successfully shows the efficiency of the constructed rabies virus minigenome in expression of inserted gene.

A comparative approach between heterologous prime-boost vaccination strategy and DNA vaccinations for rabies.

BACKGROUND AND AIM: Rabies is a widespread neurological zoonotic disease causing significant mortality rates, especially in developing countries. Although a vaccine for rabies is available, its production and scheduling are costly in such countries. Advances in recombinant DNA technology have made it a good candidate for an affordable vaccine. Among the proteins of rabies virus, the Glycoprotein (RVG) has been the major target for new vaccine development which plays the principal role in providing complete protection against RV challenge. The aim of this study is to produce recombinant RVG which could be a DNA vaccine candidate and to evaluate the efficiency of this construct in a prime-boost vaccination regimen, compared to commercial vaccine. METHODS: Cloning to pcDNA3.1(+) and expression of rabies virus glycoprotein gene in BSR cell  line were performed followed by SDS-PAGE and Western blot analysis of the expressed glycoprotein. The resulting genetic construct was used as a DNA vaccine by injecting 80 µg of the plasmid to MNRI mice twice. Prime-Boost vaccination strategy was performed using 80 µg plasmid construct as prime dose and the second dose of an inactivated rabies virus vaccine. Production of rabies virus neutralizing antibody (RVNA) titers of the serum samples were determined by RFFIT. RESULTS: In comparisons between heterologous prime-boost vaccination strategy and DNA vaccinations, the potency of group D that received Prime-Boost vaccine with the second dose of pcDNA3.1(+)-Gp was enhanced significantly compared to the group C which had received pcDNA3.1(+)-Gp as first injection. CONCLUSION: In this study, RVGP expressing construct was used in a comparative approach between Prime-Boost vaccination strategy and DNA vaccination and compared with the standard method of rabies vaccination. It was concluded that this strategy could lead to induction of acceptable humoral immunity.

The effect of childhood bilingualism on episodic and semantic memory tasks.

Kormi-Nouri, Moniri and Nilsson (2003) demonstrated that Swedish-Persian bilingual children recalled at a higher level than Swedish monolingual children, when they were tested using Swedish materials. The present study was designed to examine the bilingual advantage of children who use different languages in their everyday life but have the same cultural background and live in their communities in the same way as monolingual children. In four experiments, 488 monolingual and bilingual children were compared with regard to episodic and semantic memory tasks. In experiments 1 and 2 there were 144 boys and 144 girls in three school groups (aged 9-10 years, 13-14 years and 16-17 years) and in three language groups (Persian monolingual, Turkish-Persian bilingual, and Kurdish-Persian bilingual). In experiments 3 and 4, there were 200 male students in two school groups (aged 9-10 years and 16-17 years) and in two language groups (Persian monolingual and Turkish-Persian bilingual). In the episodic memory task, children learned sentences (experiments 1-3) and words (Experiment 4). Letter and category fluency tests were used as measures of semantic memory. To change cognitive demands in memory tasks, in Experiment 1, the integration of nouns and verbs within sentences was manipulated by the level of association between verb and noun in each sentence. At retrieval, a recognition test was used. In experiments 2 and 3, the organization between sentences was manipulated at encoding in Experiment 2 and at both encoding and retrieval in Experiment 3 through the use of categories among the objects. At retrieval, free recall or cued recall tests were employed. In Experiment 4, the bilingual children were tested with regard to both their first and their second language. In all four experiments, a positive effect of bilingualism was found on episodic and semantic memory tasks; the effect was more pronounced for older than younger children. The bilingual advantage was not affected by changing cognitive demands or by using first/second language in memory tasks. The present findings support the cross-language interactivity hypothesis of bilingual advantage.