Evaluation of Protective Immune Response Induced by a DNA Vaccine Encoding GRA8 against Acute Toxoplasmosis in a Murine Model

Toxoplasma gondii is an apicomplexan zoonotic protozoan parasite that infects most species of warm-blooded animals, including humans. The heavy incidence and severe or lethal damage caused by T. gondii infection clearly indicate a need for the development of an effective vaccine. T. gondii GRA8 is a member of the dense granules protein family and is used as a marker of acute infection. In the present study, we evaluated the protective immunity induced by DNA vaccination based on a recombinant eukaryotic plasmid, pDsRed2-GRA8, against acute toxoplasmosis in mice. BALB/c mice were intramuscularly immunized with the pDsRed2-GRA8 plasmid and then challenged by infection with the highly virulent GFP-RH strain of T. gondii. The specific immune responses and protective efficacy against T. gondii of this vaccine were analyzed by measuring cytokine and serum antibody titers, splenocyte proliferation assays, and the survival times of mice after challenge. Our results showed that mice immunized with pDsRed2-GRA8 demonstrated specific humoral and cellular responses, induced higher IgG antibody titers with predominant IgG2a production; increased levels of IL-10, IL-12 (p70), IFN-γ, TNF-α, and splenocyte proliferation; and prolonged survival times compared to those of control mice. The present study showed that DNA immunization with pDsRed2-GRA8 induced humoral and cellular immune responses, and all immunized mice showed greater Th1-type immune responses and longer survival times than those of control mice. These results indicated that T. gondii GRA8 DNA immunization induces a partial protective effect against acute toxoplasmosis.

Effects of nuclear factor-kappa B p65 ASODN on transforming growth beta-1 and intercellular adhesion molecule-1 of rat hepatic stellate cells / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To study the effects of nuclear factor (NF)-kappa B p65 ASODN on transforming growth factor beta-1 (TGF beta 1) and intercellular adhesion molecule-1 (ICAM-1) of rat hepatic stellate cells (HSC) and the mechanisms of NF-kappa B p65 ASODN in treating liver fibrosis.</p><p><b>METHODS</b>Type IV collagen enzyme digestion and density centrifugation methods were used to separate rat hepatic stellate cells. NF-kappa B p65 ASODN was manually synthesized and completely phosphorothioate-modified. The changes of TGF beta 1 and ICAM-1 mRNA were detected by RT-PCR and albumen of TGF beta 1 and ICAM-1 were detected by ELISA. The changes of NF-kappa B activity were determined by ELISA.</p><p><b>RESULTS</b>NF-kappa B activity and the expressions of ICAM-1 and TGF beta 1 increased after the HSC were treated by TNF alpha. NF-kappa B activity weakened after being treated with NF-kappa B p65 ASODN (0.001-1.000 micromol/L), P less than 0.05 in a dose dependent manner. Transferring NF-kappa B p65 ASODN (0.001-1.000 micromol/L) also weakened the expression of ICAM-1 and TGF beta 1 mRNA and the protein induced by TNF alpha in HSC. It was also in a dose dependent manner, P less than 0.05.</p><p><b>CONCLUSIONS</b>After transferring NF-kappa B p65 ASODN into HSC, their NF-kappa B activity decreased, and their mRNA and protein expressions of ICAM-1 and TGF beta 1 also decreased. This may serve as a new way in treating hepatic fibrosis.</p>