Clostridium perfringens is a gram-positive bacterium divided into five major A, E, and iota toxins based on the four main toxins. Epsilon toxin is a potent clostridial toxin and a major toxin of Clostridium Perfringens B and D types, and is the cause of gangrene gas in humans and enterotoxemia in human. For safety assessment of the vaccine, which is important for prevention of this disease, has been proposed SN (serum neutralization test) method in the pharmacopoeia. The purpose of this study was to evaluate the ELISA as an alternative method for measuring of epsilon antitoxin. First, vaccine potency test was performed using conventional method and the sera obtained were measured using both conventional and ELISA methods. The negative control cut-off was calculated 0. 42 and cross-examination was shown that epsilon toxin had no cross reaction with other toxins of Clostridium spp. The results of this study showed that there is a significant agreement between two tests for serum samples of vaccinated rabbits by polyvalent vaccine. Linear regression analysis gave correlation coefficients of 0. 697 for the indirect ELISA, with a significance level of P<0. 01. Finally, ELISA test could be used as an alternative MNT test which used for detection antibody in laboratory animals. However, further research in this field is needed for target animals.

Abstract Background and Aims: Foot-and-mouth disease (FMD), is a highly infectious and contagious disease in livestock. An effective and efficient vaccine is needed to Control FMD and reduces the associated damage. The goal of this study was to find out if the protective dose or challenge (PD50%) could be used instead of the antibody titer method to measure the effectiveness of the FMD vaccine. To achieve this, several calves were selected and divided into four groups. The vaccine was administered in three doses: a full dose, a 1/3 dose and a 1/9 dose. Twenty-one days after vaccination, all animals were challenged with a 10,000 LID50% virus in the tongue epithelium. For 7 days after, the animals were evaluated and monitored for the appearance of FMD symptoms. The PD50% (Protective Dose) for each vaccine against the virus was determined in the experiment. After obtaining the VN results that indicated the antibody titer and the PD50% level, a comparison was made between these two parameters. By examining 5 test cases, a formula was derived that accurately determined the PD50% with a high degree of precision using the VN50% result. This study determined the constants for A and O types using the VN50% test results. By incorporating these values into the derived formula, the PD50% level could be determined.

Purpose: Mumps virus is the cause of a contagious disease mostly seen in children and young adults. Immunoglobulin G protects individuals from reinfection. Because of the broad range of incubation time in various individuals, the presence of the virus in saliva before the appearance of clinical symptoms and infection of many individuals without symptoms makes the control of the transmission of the disease difficult. Therefore, vaccination is the best way to control the disease and spread of the viral agent. In addition, laboratory methods with a high sensitivity are needed to determine vaccine efficiency and to identify susceptible groups and infected individuals.Materials & Methods: In this research, we used the viral neutralization test (VNT) and ELlSA to determine IgG titers. First, the VNT was performed for 400 cord blood samples from which, 91.7% were detected to be positive. A vero cell line was infected with Hushino strain of mumps virus. By the hemad sorption test, the virus propagation in the infected cell line was confirmed. Later, the cultured virus was concentrated by PEG 6000, then purified by sucrose gradient and the amount of the protein was determined. The purified virus was coated on the micotiter plates and an indirect ELlSA was performed. Weused the VNT as a golden standard to determine the efficiency of our designed ELlSA method.Results: The results demonstrated that the two methods have a good correlation. The sensitivity and specificity of our ELISA system was 100% and 97% respectively. Thus, our ELISA technique is a reliable method to determine mumps virus antibody titer.

Background and Aims: Herpes simplex virus (HSV) is responsible for several significant human viral diseases, with severity ranging from subclinical to fatal infection. Herpes simplex virus type 2 (HSV2) infections are more commonly seen in association with the genitalia and surrounding areas, and can be transmitted to newborns during childbirth.Generalized infections in newborns are also predominantly HSV2. Therefore, due to the increasing HSV2 infections especially subclinical in women, the need to diagnose herpes simplex virus infections has increased.Materials and Methods: In the present study, the passive haemagglutination (PHA) test was applied to determine the titer of Anti-HSV2 antibodies. Sheep red blood cells (SRBCs) were treated with tannic acid at concentration of 0.002% and sensitized with HSV2 that had been propagated in HeLa cells. The tannic acid treated and HSV2 sensitized SRBCs were added to U-shaped 96 wells microtiter plates which contained serial dilutions of patient’s sera.Furthermore, serum neutralization test (SNT) was applied as a gold standard to determine the specificity and sensitivity of PHA test.Results: The results of PHA were examined after one hour incubation at 37°C. The endpoint was the highest dilution of serum which gave positive agglutination and compaired with serum neutralization test (SNT as a gold standard to determine the specificity and sensitivity of PHA test. Peripheral blood samples were obtained from 100 pregnant women and evaluated by both SNT and PHA tests. The specificity and sensitivity of PHA test were 92.68%, and 100% respectively. The results indicated that PHA test was easy, rapid and inexpensive but also had acceptable sensitively and specificity.Conclusion: PHA test can be used to determine the level of Anti-HSV2 antibodies and the rate of infection in pregnant women which could be an indication of infection and the risk of transmitting herpes to the newborn.

Measles is one of the most contagious human diseases. Although mass vaccination programs have reduced the incidence of this disease, measles is still an important cause of morbidity and mortality among children in developing countries. Therefore the use of sensitive techniques to evaluate vaccine efficacy and level of immunity among members of susceptible communities is crucial. serum neutralization test (SNT) and Dot immunoassay (DIA) are among the best methods utilized for evaluating measles virus antibodies. In this study, DIA was applied for detection and titration of measles virus antibodies. This test was developed for the fIrst time in Iran in the Virology Department of the School of Medical Sciences, Tarbiat Modarres University. Viral antigen was first prepared and titrated. Then human IgG was isolated by affinity chromatography. Anti-human immunoglobulin was prepared by immunizing rabbits with human IgG and was later conjugated with peroxidase. DIA was applied using these reagents. The results indicated that the specifIcity and sensitivity of DIA in comparison with SNT was 96% and 89%, respectively. This study demonstrated that DIA is a rapid and simple test which can be applied for the detection of mass immunity against the measles virus.

Hyperimmune sera are used in diagnostic laboratories abundantly. Because of the imported antisera are expensive, the internal preparation with high quality, is very important. In this study, the hyperimmune serum against adaptated plowright rinderpest virus to primary rabbit kidney cell prepared and used in agar gel immunodiffusion test and serum neutralization test. Primary cell, prepared with enzymatic disaggregation method. The attenuated virus was inoculated and the cytopathic effect was seen in 7th blind passage and it's ideal assay (10-5) obtained in 18th passage. The antiserum prepared after injection to rabbit and created clear precipitation lines in agar immunodiffusion test. In SN, the 1: 64 titer in 100 TCID50 could neutralized the RPV. The sensitivity and specificity of this antiserum was 100% and 80%, that is suitable. At the end, the adaptated virus and hyperimmune serum lyophilized. This serum kept to delivering to the diagnostic laboratories.

Background and Aims: Canine distemper (CD) is a deadly infectious disease of Canidae family. CD is a multi-systemic viral disease and is specified by wide range of clinical symptoms. The manifestations are not always indicative of CD, therefore a laboratory confirmation is necessary for suspected cases.Materials and Methods: Different clinical specimens of 19 CD suspected unvaccinated dogs were examined for canine distemper virus (CDV) infection by reverse transcription polymerase chain reaction (RT-PCR), Nested-PCR, and serum neutralization (SN) test during 2008-2011. RT-nested PCR assay was adjusted for detection of CDV nucleoprotein (NP) in prepared samples.Results: In samples of 3 out of 19 (15%) dogs, CDV NP gene was confirmed by RT-PCR while RT-PCR and combination with Nested-PCR (RT-nested PCR) presence of CDV NP gene was detected in various samples of 14 (73%) dogs. So efficiency of RT-PCR along with Nested-PCR raised 58%. Among different kinds of obtained samples, conjunctival swabs and kidney tissue biopsies were found to be suitable for analysis of CDV RNA. Additionally CDV antibody was detected in 11 out of 18 serum samples (61%) by SN test, but detection of neutralizing antibodies didn't comply with RT-nested PCR results.Conclusion: Results of this study indicated that Nested-PCR is a sensitive and applicable method for the diagnosis of CDV.