Synergistic effect of two Toxoplasma gondii proteins on dendritic cell activation

ARCÓN, N; PRATO, CA; A SOTO; M PERRONE SIBILIA; V TRIBULATTI; A GOLDMAN; V MARTÍN

Tucumán

Congreso; reunión anual SAI LXVII; 2019

SAI

Toxoplasma gondii profilin protein (TgPF) is a TLR ligand. We previously evaluated the ability of this protein as an adjuvant in a vaccine formulation when co-administered with the GRA7 antigen (T. gondii dense granule protein) in BALB/c mice. TgPF increased GRA7-specific cellular and humoral responses, sufficient to enhance animal protection upon parasite challenge. OBJECTIVE: The purpose of the present work was to evaluate the activation level of antigen presenting cells by the vaccine GRA7+TgPF formulation using murine bone marrow-derived dendritic cells (BMDC) and compare with the individual protein treatments. METHODS: Generation of BMDCs: bone marrow collected from femurs of naive BALB/c mice, was resuspended in complete medium (CM) and cultured with GM-CSF. On day 8, non-adherent and loosely attached cells were transferred into 24 well plates and stimulated with TgPF, GRA7, TgPF+GRA7, LPS or CM for 24 h.RESULTS: BMDCs (CD11c+/MHCII+) stimulated with TgPF showed an increase in the co-stimulatory protein CD80, and significant levels of IL-6 and IL-12 cytokines were detected in cell supernatants. Surprisingly, GRA7 stimulation increased CD80 and CD86 expression, and induced the production of IL-6 and IL-10. When cells were cultured with GRA7+TgPF, CD80 and CD86 expression resulted greater than rGRA7-treated cells and additionally, significant levels of IL-6, IL-12 and IL-10 were detected.CONCLUSION: The mix GRA7+TgPF was able to promote higher levels of antigen-presenting cell activation. These findings may account for the elicitation of a stronger immune response upon immunization that results in protection against infection.