The use of Gecko cell line in the cultivation and preparation oflive attenuated Toxoplasma gondii strain

Background and Aim : Toxoplasma gondii is an obligate intracellular parasite that causesToxoplasmosis. Until now, no cost-effective treatment method has been found to deal withToxoplasma and the best way to deal with the infection is vaccination. Live vaccines compared toother vaccine platforms against pathogenic protozoa have had successful results so far. In thisstudy, the efficacy of a live attenuated experimental vaccine through long-term passages on a cellline of reptilian origin (Z۱) has been evaluated in inducing a protective immune response in aBalb/c mouse model.Methods : Thirty mice divided into three equal groups including; Group one: nonimmunized/challenged as a control (injection of culture medium), group two:immunized/challenged (injection of attenuated strain) and group three: immunized/unchallenged(injection of attenuated strain). One month after immunization, the studied mice were challengedwith ۱ₓ۱۰۳ live tachyzoites of RH Toxoplasma acute strain. Serological investigations, includingevaluation of antibody, gamma interferon, interleukins ۲, ۴, ۱۰ and ۱۲ were performed. Also, atthe end of the study, a molecular test was performed on brain and liver tissues to check the presenceof parasites.Results : The results obtained from serological tests in the vaccinated group have a significantdifference with the control group (p<۰.۰۵); So that after the challenge in the vaccinated group, thesurvival rate of mice was ۵۰%. Also, the molecular results showed the absence of parasites in brainand liver tissues.Conclusion : Therefore, the use of the attenuated strain caused a significant humoral and cellularimmune response in the vaccinated groups. Also, in group three, the attenuated strain ofToxoplasma gondii had no pathogenicity and all mice survived until the end of the study. Inconclusion, the results of this study showed that this attenuated strain can promise new research inorder to achieve a promising vaccine against Toxoplasmosis, which is worth further evaluation inintermediate and definitive hosts.

کلیدواژه ها:

Toxoplasma gondii ، attenuated strain ، vaccine ، immunogenicity ، Gecko cell line