CONICET | Buscador de Institutos y Recursos Humanos

Aprobado para ser presentado en la reunión Anual de la Sociedad Argentina de Inmunología. Mar del Plata. Noviembre 2016.STUDY OF SPLENIC MYELOID-DERIVED SUPPRESSOR CELLS IN CpG-ODN+IFA-TREATED TUMOR BEARING MICEHarman, María F1; Castell, Sofía D1; Maletto, Belkys A1; Morón, Victor G1; Pistoresi, María C11CIBICI-CONICET- Facultad de Ciencias Químicas- UNC- Córdoba- Argentina Alike the aging microenvironment, tumor can be viewed as a chronic inflammatory condition characterized by increased levels of pro-inflammatory cytokines as well as an overall immunosuppressive state. Previously we demonstrated that aged CpG-ODN+IFA treated mice present an expansion of myeloid derived suppressor cells (MDSC) capable of suppressing T-cell proliferative response. To characterize the effect of CpG-ODN+IFA in splenic MDSC in a tumor model, BALB/c young mice were injected with 4T1 mammary carcinoma into the mammary fat pads. CpG-ODN+IFA was injected (s.c) weekly, starting on day 7. We observed delayed tumor progression in CpG-ODN+IFA-treated tumor bearing mice (p≤0.05). After 24 days of tumor growth there were no significant differences in CD11b+Gr1+ MDSC levels, although a lower frequency of granulocytic MDSC (CD11b+Ly6G+Ly6Clow) was observed (p≤0.05) while monocytic MDSC (CD11b+Ly6G-Ly6Chigh) levels were augmented compared to non-treated tumor bearing mice (p≤0.05). In line with this, we also found reduced levels of reactive oxygen species (ROS) in total MDSC (p≤0.05) and mainly in the granulocytic subset (p≤0.01) of CpG-ODN+IFA-treated tumor bearing mice, but no significant differences were observed in nitric oxide (NO) production. In conclusion, systemic treatment of 4T1 tumor bearing young mice with CpG-ODN+IFA leads to a change in the composition of splenic MDSC subsets and these changes could be playing a role in the tumor progression.