الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Rift Valley Fever Virus (RVFV) is a zoonotic virus that is transmitted via arthropod - vector with high emergence in Africa and Arabian Peninsula. RVFV contributes to outbreaks in livestock and humans with a great incidence to cross borders and spread worldwide, which made RVFV a priority pathogen on the World Health Organization (WHO) list. The lack of countermeasures and accurate surveillance of RVFV incidence in humans, stresses the urgent need for new therapeutics against RVFV infection.Gene silencing mechanism introduced antiviral therapeutics utilizing a specific and conserved 21-nt known as small interfering RNA (siRNA) targeting RVFV nucleoprotein. Three different siRNA have been designed and evaluated as prophylactic and antiviral therapeutics against RVFV strain in the Vero cell line. The broad - spectrum antiviral efficiency of the host defense peptides (HDP) encourages us to investigate the activity of human cathelicidin peptide (LL-37) against RVFV and evaluate its possible mechanisms in the Vero cell line. Real-time PCR besides Endpoint log reduction assay was used to determine the silencing activity of different siRNAs and LL-37 antiviral activity,inhibition in nucleoprotein gene expression was evaluated. Western blot analysis was utilized for protein abundance detection after 48 hours. All siRNAs showed superior antiviral and prophylactic activity against RVFV at 30 nM and 10 nM concentrations with anapproximate complete abrogation of virus replication especially in 30 nM concentrations in all designs when used individually or pooledas antiviral therapeutics when evaluated by Endpoint and realtime RT- PCR. Post-transfection of siRNAs with Vero cells had superior silencing activity over pre- transfected of siRNAs with Vero cells. However, pre – treated cells with different siRNAs reduced RVFV N by more than 92 % in all deigns at 30 nM concentration and more than 88 % at 10 nM concentration. LL-37 antiviral activity was evaluated at different mechanisms as LL-37 introduced 28.6 % and 21.4 % loss in virus titer in direct and simultaneous treatment at 2.5 µg / ml respectively. About7.4 % was introduced as prophylactic measurement at a concentration 1.25 of µg / ml,while in post-treatment of Vero cells with LL-37 virus inhibited by about 28.6%1.25 of µg / ml. The same results were obtained when RVFV N protein was quantified with RT-PCR. We concluded that both the siRNA silencing pathway and LL-37 had superior antiviral and prophylactic activity against RVFV that can be used during, after, and before outbreaks to prevent RVFV spread and prevent the production of new infectious particles.