RESUMO
BACKGROUND: Host-microbiota interactions shape T-cell differentiation and promote tumour immunity. Although IL-9-producing T cells have been described as potent antitumour effectors, their role in microbiota-mediated tumour control remains unclear. METHODS: We analysed the impact of the intestinal microbiota on the differentiation of colonic lamina propria IL-9-producing T cells in germ-free and dysbiotic mice. Systemic effects of the intestinal microbiota on IL-9-producing T cells and the antitumour role of IL-9 were analysed in a model of melanoma-challenged dysbiotic mice. RESULTS: We show that germ-free mice have lower frequency of colonic lamina propria IL-9-producing T cells when compared with conventional mice, and that intestinal microbiota reconstitution restores cell frequencies. Long-term antibiotic treatment promotes host dysbiosis, diminishes intestinal IL-4 and TGF-ß gene expression, decreases the frequency of colonic lamina propria IL-9-producing T cells, increases the susceptibility to tumour development and reduces the frequency of IL-9-producing T cells in the tumour microenvironment. Faecal transplant restores intestinal microbiota diversity, and the frequency of IL-9-producing T cells in the lungs of dysbiotic animals, restraining tumour burden. Finally, recombinant IL-9 injection enhances tumour control in dysbiotic mice. CONCLUSIONS: Host-microbiota interactions are required for adequate differentiation and antitumour function of IL-9-producing T cells.
Assuntos
Antibacterianos/efeitos adversos , Disbiose/imunologia , Vida Livre de Germes , Interleucina-9/metabolismo , Melanoma/microbiologia , Linfócitos T/imunologia , Animais , Diferenciação Celular , Linhagem Celular Tumoral , Disbiose/induzido quimicamente , Disbiose/terapia , Transplante de Microbiota Fecal , Microbioma Gastrointestinal , Interleucina-4/metabolismo , Masculino , Melanoma/imunologia , Camundongos , Mucosa/efeitos dos fármacos , Mucosa/imunologia , Transplante de Neoplasias , Linfócitos T/efeitos dos fármacos , Fator de Crescimento Transformador beta/metabolismo , Microambiente TumoralRESUMO
AIM: This study aimed to evaluate an attenuated Salmonella ihfA-null mutant strain as therapeutic agent to control tumor growth. MATERIALS & METHODS: After bacterial toxicity evaluation, C57BL/6JUnib mice were inoculated with B16F10 cells and treated with two Salmonella strains (LGBM 1.1 and LGBM 1.41). RESULTS: LGBM 1.1 can reduce tumor mass, but it exerts some toxic effects. Although LGBM 1.41 is less toxic than LGBM 1.1, it does not reduce tumor mass significantly. Indeed, animals treated with LGBM 1.41 present only slightly initial delay in tumor progression and increased survival rate as compared with the control. CONCLUSION: The null-mutants of ihfA gene of Salmonella Typhimurium could be a promising candidate for melanoma treatment.