Development of a latex agglutination method for diagnosis of rotavirus infections

Background: Rotavirus is a major cause of morbidity and mortality among children with gastroenteritis. Since the discovery of rotaviruses, several techniques have been used for their laboratory diagnosis; those included Electron Microscopy (EM) and enzyme immunoassay. These methods, however, are expensive and not readily available everywhere. We have developed a technique which can be used for routine diagnosis of rotavirus gastroenteritis. Methods: Purified simian rotavirus, SA11, was injected into rabbits and the γ-globulin fraction of antisera was purified and used for coating of latex beads. The prepared sensitizied latex was then used for agglutination test on fecal samples. 94 stool samples from infants with acute gastroenteritis were tested by (EM), enzyme immunoassay and Latex Agglutination (LA) method. Results: The sensitivity of enzyme immune assay and (LA) were 92.5 and 90, respectively; the specificity of both tests was 98.1 as compared with (EM). Conclusion: Latex Agglutination Test (LAT) is a simple and relatively inexpensive test which can be used for diagnosis of rotavirus gastroenteritis in diagnostic laboratories and health centers

Buthionine sulfoximine inhibits cytopathic effects and apoptosis induced by infection with AIK-HDC strain of measles virus

Background: Measles virus (MV) is a highly contagious agent which causes a major health problem in developing countries. We studied the effect of buthionine sulfoximine (BSO) on the replication of an AIK-HDC strain of MV and its induced apoptosis in Vero cell lines. Methods: In this study, toxicity of BSO on Vero cells was investigated first, resulted in determination of sub-lethal or non-toxic concentration zone of BSO for cells. Next, anti-viral effect of BSO at various time limits was evaluated and virus titer was determined at each stage either as 50 tissue culture infective dose (TCID) 50 or by plaque assay method. Using specific anti-measles IgG, anti-viral effect of BSO on MV replication cycle was evaluated through indirect immunofluorescence assay, meanwhile presence of viral RNA was investigated by RT-PCR and gel electrophoresis. Results: According to the experiments, BSO, at concentration of 50 μM, markedly inhibited the cytopathic effect (CPE) induced by MV. BSO also significantly inhibited apoptosis induced by MV. BSO either influences replication of MV genome, or may inhibit virion formation. Conclusion: These results suggest that the inhibition of CPE and apoptosis by BSO induced by MV may be associated with the effect of BSO on viral RNA genome. Therefore, it is suggested that MV infections can induce apoptosis through the activation of a common pathway that can be inhibited by BSO

Reovirus inhibits poliovirus replication upon superinfection

Objective: Viral interference has been demonstrated in different systems, such as the effect of enterovirus infection on live-attenuated oral polio vaccine. In this study, the effect of reovirus which could exist in the human intestinal tract on poliovirus vaccine strains was investigated and could be an important factor to consider in oral polio vaccination. Methods: Cells were infected with reovirus, then superinfected with poliovirus. The amount of viral yields was measured by the TCID 50 and plaque assay methods. Polioviral RNA synthesis was studied by real-time RT-PCR and the viral RNA load was calculated. Viral protein synthesis was determined using the techniques of immunoflourescent staining and PAGE followed by the immunoblotting experiment. Results: Poliovirus superinfection of reovirus-infected cells resulted in inhibition of poliovirus replication. It was found that the inhibitory effect of reovirus was after establishment of its infection (2 h postinfection). There was no competition between the two viruses for cell attachment but poliovirus RNA and protein synthesis were inhibited. Conclusion: Infection of cells with reovirus could interfere with the growth of poliovirus upon superinfection. This phenomenon could be important to consider when using attenuated poliovirus vaccine. Copyright © 2011 S. Karger AG, Basel

Expression of biologically active measles virus hemagglutinin glycoprotein by a recombinant baculovirus

In this study, one of the measles virus membrane proteins, named hemagglutinin (H) which has a key role in tropism, receptor binding, hemagglutinating activity and also induction of protective immunity against viral infection, was expressed by the baculovirus expression system using specific plasmid (pDONR221) to produce entry clone. Measles Virus (AIK-C strain) genome was extracted from infected Vero cells. H gene was amplified by specific primers during RT-PCR reaction and inserted into the specific plasmid (pDONR221) using BP recombination reaction. Recombinant baculovirus harboring H gene was consequently constructed by LR reaction. Insect cells (Sf9) were infected with recombinant baculovirus. In order to increase viral titer, recombinant baculoviruses were passaged four times in Sf9 cells. Synthesis of H protein was verified by SDS-PAGE, western-blot and indirect immunoflourescene using goat polyclonal antibody against Measles Virus. The results showed that H protein was partially glycosylated but it appeared to be active in hemagglutination assay. © 2008 Asian Network for Scientific Information

Effects of morphine on replication of herpes simplex virus type 1 and 2

Several drugs are being used in treatment of HSV (Herpesviridae) infection in human but still introducing an effective safe drug is desirable. We investigated the inhibitory effect of morphine on replication of HSV in vitro. The results indicated that a concentration of up to 200 pg/ml morphine had a limited effect on Vero cell viability. At this concentration, the growth of HSV was inhibited considerably and after the third passage in presence of morphine it was completely eliminated. The presence of viral antigens in infected cells in presence of morphine by immunoflourescent staining showed that after the first passage a small number of infected cells contained viral proteins and at the third passage no cells with viral antigen was observed. This was confirmed by page and immunobloting techniques. Electron microscopy observation in cellular section indicated that there was no virus present in treated cells as compared with control untreated infected cells. © 2009 Academic Journals

The study of antiviral effects of Glycyrrihza Glabra extract on HSV

Backround: Recently, resistance to anti viral drugs has been reported. Hence, study of other components for obtaining new treatment approaches is necessary. Objective: The main objective of this study is to determine the inhibitory effect of Glycyrrihza Glabra on HSV replication. Methods: The first step was to evaluate the concentration of Glycyrrihza Glabra which was non toxic for Vero cells. Then, antiviral effects of Glycyrrihza Glabra in non toxic concentration zone were determined through TCID50 Method. IF method was also used in order to determine the reduction of viral proteins. Results: The results indicated that inhibitory effects of Glycyrrihza Glabra on replication of HSV are related to primary time of replication cycle. Conclusion: Glycyrrihza Glabra extract can be a suitable choice for treatment due to HSV infection