Iranian Journal of Virology
Volume:3 Issue: 1, 2009

Coxsackievirus B3 (CVB3) is the most common agent known to cause viral myocarditis. The viral genome encodes a single polyprotein that is cleaved to produce several proteins by virally encoded proteases. Most of this proteolytic processing is catalyzed by a cysteine protease called 3C. The 3C protease plays major role in viral replication and cellular damage. To understand the mechanism of 3C function in virus infected cells and also development of antiviral agents against the virus, a 3C expressing plasmid was constructed. The cDNA of 3C protease was synthesized using CVB3 infected cells through reverse transcription process and was cloned in pcDNA3.1-. The constructed plasmid was confirmed by sequencing and restriction enzyme analysis. By transfection of the constructed plasmid into HeLa and MCF-7 cells. We showed that 3C protease induced cell death through multiple converging pathways, such as down regulation of cellular factors and decreasing of mRNA transcripts. This affect on HeLa cells as stronger than MCF-7 cells. This study, suggests that 3C protease is thought to be a suitable target for antiviral chemotherapy.

Viroids are smallest known plant pathogens and cause several economically significant diseases. Until recently, viroid detection relied mainly on biological tests and indexing. Today various diagnostic techniques such as nucleic acid hybridization, southern blot and reverse transcription coupled with polymerase chain reaction (RT-PCR) are being used for detection and diagnosis of viroids. This paper describes a new method for detection of citrus viroids, based on a combination of RT-PCR and dot blot hybridization (RT-PCR-DBH). In this method instead of using nucleic acid extracted directly from the plants, RT-PCR products are subjected to dot-blot hybridization. The results showed that the above mentioned method has some advantages compared with the other methods. It is more sensitive, relatively simple, cost-effective, rapid and easy to apply. It was about 1000 times more sensitive than southern blot and about 100 times more sensitive than PCR in detecting hop stunt viroid in citrus. The introduced method here has a high potential in diagnosis of viroids and is suitable for detection of low concentrations of the agent.

Herpes simplex virus type 1 (HSV1) remains a potentially serious health problem world wide. All infected people, including asymptomatic ones, are potential sources for virus transmission. Virus envelope contains at least 13 glycoproteins, which glycoprotein D is the major target of immune responses. The aim of this study was development of a specific method that is a more rapid, sensitive and specific test compared to the virus neutralization test which is applied as gold standard test. In this study, the Western blot technique using crude HSV1 whole particle and baculovirus derived glycoprotein D of HSV1 as antigens was set. Human sera were analyzed by virus neutralization test and then serum samples with reciprocal virus neutralization antibody titers of 32, 64, and 128 were taken to be analyzed by Western blotting. It was shown that there was a very good correlation between results obtained from virus neutralization antibody titers and those of Western blotting. Western blotting using recombinant glycoprotein D of HSV1 as an antigen showed positive results similar to the whole HSV1 antigen. Our study showed the Western blotting using recombinant glycoprotein D can replace virus neutralization test in diagnosis of HSV1 infections.

Influenza virus is the most important cause of annual morbidities and mortalities worldwide with numerous antigenic drifts and shifts. Inaccessibility to effective drugs and vaccines has made world health authorities to be interested in traditional medicine in order to prevent spread of the infectious agent. Garlic is one of the most famous of all plants in human history. It has been shown that garlic extract has various effects on different diseases. The aim of this study was to evaluate garlic extract antiviral activity against influenza virus in cell culture. To study the potential antiviral activity, MDCK (Madin-Darbey Canine Kidney) cells were treated with effective minimal cytotoxic concentration of the extract and 100 TCID50 (50% Tissue Culture Infectious Dose) of the virus during infection at different time periods. The viral titers were determined by hemagglutination (HA) and TCID50 assays. The antiviral effect of the extract was studied at 1, 8 and 24 hours after treatment on the culture. To measure the amount of the viral genome synthesized at different times after treatment, RNA extraction, Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and free band densitometry software were performed. Although the precise mechanism has not been defined yet, it was found that garlic extract with a good selectivity index (SI) has inhibitory effect on the virus penetration and proliferation in cell culture. The biochemical and molecular methods used to evaluate the antiviral activity of Garlic extract demonstrated that this compound could be suggested as a suitable potent antiseptic agent.

The safe, potent and effective live vaccines against Measles, Mumps and Rubella as important childhood diseases have been available for several decades. Several factors can affect the thermal stability of lyophilized vaccine. In this study, the effect of residual moisture on thermal stability of 61 batches of MMR vaccine was investigated using an accelerated method that has been recommended by World Health Organization (WHO). Our results suggest that the best thermal stability for the lyophilized MMR vaccine is in a range of 1.51 to 2.00% of residual moisture with the minimum decrease in the all three components of the vaccines. It is suggested that the lyophilizators of MMR vaccine production lines should be programmed in a manner that the best range of residual moisture achieves.

Recently, a novel DNA virus was isolated from the serum of a patient with post-transfusion non A-G hepatitis and named TT virus. The aim of this study was to determine the prevalence TT virus among cirrhotic patients due to hepatitis B & C in infection Ahwaz. The prevalence of TTV infection was studied in 41 patients with liver cirrhosis. TTV DNA was detected by semi-nested PCR. The plasma samples were tested for marker hepatitis B & C by ELISA test. TT virus was detected in 17(41.46%) of the 41 patients with cirrhotic liver disease. There were no significant difference between the subject TTV DNA in relation to sex and age. TTV positivity in cirrhotic patient infected with hepatitis B (52.9%) was higher than in similar patients infected with hepatitis C (47.1%). TTV infection was highly prevalence in patient with cirrhotic hepatitis, especially in those with hepatitis B virus infection.