en مقاله کامل Full Length/Original Article The Immunogenicity of γ-irradiated tachyzoites of a highly virulent strain of Toxoplasma gondii (RH strain) was investigated. Immunized mice survived challenge infection and displayed increased interferon gamma (INF-γ ) production. On the other hand, nonimmunized controls died after 10 days and displayed a significantly decreased lymphoproliferative response to Concanavalin A (Con A). No tachyzoites were detected in peritoneal exudates of the immunized mice 10 days after challenge. These results indicate that the vaccination with γ-irradiated tachyzoites not only protects the mice against challenge infection, but may circumvent the danger of the vaccine being life-threatening because of remaining tachyzoites inside macrophages posing as a latent infection. Gamma-irradiated tachyzoites, Toxoplasma gondii, immunization 93 97 http://ibj.pasteur.ac.ir/browse.php?a_code=A-10-1-409&slc_lang=en&sid=1 Mehdi Assmar مهدی آسمار Yes Masoud Hajizadeh Manjili مسعود حاجی زاده منجیلی No Ahmad R. Esmaeili-Rastaghi احمد رضا اسماعیلی رستاقی No Mahin Farahmand مهین فرهمند No Nourair Piazak نورایر پیازک No Sima Rafati سیما رافتی No Saied Reza Naddaf Dezfooli سعید رضا نداف دزفولی No