Background: Dendritic Cell (DC) is an important antigen-presenting cell that present tumor antigen to CD8⁺ and CD4⁺ T- Lymphocytes and induce specific anti-tumor immunity. In order to induce effective anti-tumor response, an option is increasing the efficiency of antigen presentation of dendritic cells and T cell activation capacity. The aim of the present study was to investigate the effect of dendritic cell maturation with protein components of toxoplasma gondii on cytotoxic T lymphocyte activity and their infiltration in to the tumor.
Methods: For DC generation, bone marrow cells were cultured in the presence of GM-CSF and IL-4 for five days. After that, LPS, protein components and whole extract of toxoplasma gondii were added to the culture media and incubated for another two days for DC maturation. To generate tumor, mices were injected subcutaneously with WEHI-164 cell line. For immunotherapy 10⁶ DCs matured with different compounds were injected around the tumor site. Infiltration of CD8⁺ T cells were determined by flow cytometry and cytotoxic activity was measured by LDH detection kit.
Results: Immunotherapy with DCs treated with protein components of toxoplasma gondii led to a significant increase in the activity of cytotoxic T cells and infiltration of CD8⁺ T cells in to the tumor. Immunotherapy using protein components of toxoplasma gondii significantly improved the survival of the mice compared with other groups (p<0.0001).
Conclusion: Protein components of toxoplasma are able to increase DC capability in induction of CTL-mediated anti-tumor response and increase infiltration of these cells in to the tumor.