IMMUNOSUPPRESSIVE MECHANISMS IN MURINE SPONTANEOUS LMM3 MAMMARY TUMOR

DANIELA MONTAGNA; JULIETA ALCAIN ; RAÚL RUGGIERO; MARÍA FLORENCIA TODERO; BÁRBARA REARTE ; PAULA CHIARELLA; MÓNICA VERMEULEN

Mar del Plata

Congreso; REUNIÓN CONJUNTA SAIC SAI SAFIS 2018; 2018

Different schedules of immunotherapy against cancer were developed including vaccines combined with antibodies against T reg or anti-myeloid-derived suppressor cells and, more recently, immune checkpoint inhibitors such as antibodies against cytotoxic T lymphocyte-antigen 4 (CTLA-4), programmed death receptor (PD-1) or programmed death-ligand (PDL-1). However, differently from experimental tumors induced by massive doses of chemicals, most tumors originated spontaneously in mice exhibit undetectable immunogenicity. This feature could be shared with most common human cancers and should be taken into account in order to improve immunotherapy strategies. The objective of this work was to study the immunosuppressive mechanisms through the growth of the murine spontaneous LMM3 mammary adenocarcinoma displaying undetectable immunogenicity. We also used the MC-C strongly immunogenic methylcholanthrene-induced fibrosarcoma, as a control. Cytokines production was evaluated by ELISA and cell populations by flow cytometry. LMM3 tumor cells showed a higher expression of PDL-1 compared to MC-C (p