Supplemental materials vetizou et al One Sentence Summary: Bacteroides involved in anti-CTLA4 Ab-mediated cancer Abbreviations list: ACS: antibiotic treatment with ampicillin, colistin and streptomycin, Bc: Burkholderia cepacia, Bf Bacteroides fragilis, BM-DC: Bone marrow-derived dendritic cells, CTLA4: Cytotoxic T-Lymphocyte Antigen-4, DC: Dendritic cells, EMA: European Medicine Agency, FDA: Food and drug administration, FItC: fluorescein isothiocyanate, FMT: fecal microbial transplantation, GF: Germ-free, GM-CSF: Granulocyte-macrophage colony-stimulating factor, HV: Healthy volunteers, IBD: Inflammatory bowel diseases, ICB Immune checkpoint blocker, ICOS: Inducible T-cell costimulatory, IEC: intestinal epithelial cells, IEL: intraepithelial lymphocytes, IL-12: Interleukin-12, LP: Lamina propria, mAb Monoclonal antibody, MHC II: class II molecules, mLN: Mesenteric lymph node, MM Metastatic melanoma, MOI: Multiplicity of infection, NOD2: Nucleotide-binding oligomerization domain-containing protein 2, PCA: Principle component analysis, PD1 Programmed cell death protein 1, PS: Polysaccharide, PBMC: peripheral blood mononuclear cells, SPF: Specific pathogen free, Tcl: Type 1 cytotoxic T-cells, Th1: T helper type 1, TLR: Toll like receptor, Trl: Type 1 regulatory T-cells, Tregs: Regulatory T cells, WT: Wild type Key words: CTLA4, ipilimumab, cancer, immunity, Bacteroides fragilis, Bacteroides thetaiotaomicron, Burkholderia cepacia, microbiome, IL-12 Acknowledgments: We are grateful to the staff of the animal facility of Gustave roussy and Institut Pasteur. We thank P Gonin, B. Ryffel, T. Angelique, N. Chanthapathet, H. Li and S. Zuberogoitia for technical help. The data presented in this manuscript are tabulated in the main paper and in the supplementary materials. DNA sequence reads from this study have been submitted to the NCBI under the Bioproject ID PRJNA299112. LZ, MV and PL have filed patent applications n EP 14190167 that relates to specific topic: Methods and products for modulating microbiota composition for improving the efficacy of a cancer treatment with an immune checkpoint blocker. MV and JMP were supported by La Ligue contre le cancer and ARC respectively. Lz received a special prize from the Swiss bridge Foundation and ISREC. GK and Lz were supported by the ligue Nationale contre le cancer (Equipes labellisees), Agence Nationale pour la Recherche (ANR AUTOPH, ANR Emergence), European Commission (ArtForce), European Research Council Advanced Investigator Grant(to GK), Fondation pour la Recherche Medicale(FRM), Institut National du Cancer (INCa), Fondation de france, Canceropole Ile-de-France, Fondation Bettencourt- Schueller, Swiss Bridge Foundation, the LabEx Immuno-Oncology, the SIRIC Stratified Oncology Cell DNA Repair and Tumor Immune Elimination (SOCRATE); the SIRIC Cancer Research and Personalized Medicine(CARPEM), and the Paris Alliance of Cancer Research Institutes(PACRI. SM was supported by nih (ro1 CA161879 PI: SM). MC was supported by the Fondation la Recherche Medical the Fondation ARC pour la recherche sur le cancer and Institut Nationale du’’Ž‡‡ƒŽƒ‡‹ƒŽ•±‹œ‘‡ƒŽǤ One Sentence Summary: Bacteroides involved in anti-CTLA4 Ab-mediated cancer immunosurveillance. „„‡‹ƒ‹‘• Ž‹•ǣǣ ƒ‹„‹‘‹… ‡ƒ‡ ™‹Š ƒ’‹…‹ŽŽ‹ǡ …‘Ž‹•‹ ƒ† •‡’‘›…‹ǡ …ǣ Š‘Ž†‡‹ƒ…‡’ƒ…‹ƒǡ ˆǣƒ…‡‘‹†‡•ˆƒ‰‹Ž‹•ǡ Ǧǣ ‘‡ ƒ‘™Ǧ†‡‹‡† †‡†‹‹… …‡ŽŽ•ǡ Ͷǣ ›‘‘š‹… Ǧ›’Š‘…›‡ ‹‰‡ǦͶǡ ǣ ‡†‹‹… …‡ŽŽ•ǡ ǣ ‘’‡ƒ ‡†‹…‹‡ ‰‡…›ǡ ǣ ‘‘† ƒ† †‰ ƒ†‹‹•ƒ‹‘ǡ ǣ ˆŽ‘‡•…‡‹ ‹•‘Š‹‘…›ƒƒ‡ǡ ǣ ˆ‡…ƒŽ ‹…‘„‹ƒŽ ƒ•’Žƒƒ‹‘ǡ ǣ ‡Ǧˆ‡‡ǡ Ǧ ǣ ƒŽ‘…›‡Ǧƒ…‘’Šƒ‰‡ …‘Ž‘›Ǧ•‹Žƒ‹‰ ˆƒ…‘ǡǣ‡ƒŽŠ›‘Ž‡‡•ǡ ǣˆŽƒƒ‘›„‘™‡Ž†‹•‡ƒ•‡•ǡǣ ‡…Š‡…’‘‹„Ž‘…‡ǡǣ†…‹„Ž‡Ǧ…‡ŽŽ…‘•‹Žƒ‘›ǡ ǣ‹‡•‹ƒŽ‡’‹Š‡Ž‹ƒŽ …‡ŽŽ•ǡ ǣ ‹ƒ‡’‹Š‡Ž‹ƒŽ Ž›’Š‘…›‡•ǡ Ǧͳʹǣ ‡Ž‡‹Ǧͳʹǡ ǣ ƒ‹ƒ ’‘’‹ƒǡ „ǣ ‘‘…Ž‘ƒŽ ƒ‹„‘†›ǡ  ǣ …Žƒ••  ‘Ž‡…Ž‡•ǡ ǣ ‡•‡‡‹… Ž›’Š ‘†‡ǡ ǣ ‡ƒ•ƒ‹… ‡Žƒ‘ƒǡ ǣ Ž‹’Ž‹…‹› ‘ˆ ‹ˆ‡…‹‘ǡ ʹǣ …Ž‡‘‹†‡Ǧ„‹†‹‰ ‘Ž‹‰‘‡‹œƒ‹‘ †‘ƒ‹Ǧ…‘ƒ‹‹‰ ’‘‡‹ ʹǡ ǣ ‹…‹’Ž‡ …‘’‘‡ ƒƒŽ›•‹•ǡ ͳǣ ‘‰ƒ‡† …‡ŽŽ †‡ƒŠ ’‘‡‹ ͳǡ ǣ ‘Ž›•ƒ……Šƒ‹†‡ǡ ǣ ’‡‹’Š‡ƒŽ „Ž‘‘† ‘‘…Ž‡ƒ…‡ŽŽ•ǡ ǣ’‡…‹ˆ‹…’ƒŠ‘‰‡ˆ‡‡ǡ…ͳǣ›’‡ͳ…›‘‘š‹…Ǧ…‡ŽŽ•ǡŠͳǣŠ‡Ž’‡ ›’‡ ͳ ǡ ǣ ‘ŽŽŽ‹‡ ‡…‡’‘ǡ ͳǣ ›’‡ ͳ ‡‰Žƒ‘› Ǧ…‡ŽŽ•ǡ ‡‰•ǣ‡‰Žƒ‘›  …‡ŽŽ•ǡ ǣ‹Ž†›’‡Ǥ Key words: CTLA4, ipilimumab, cancer, immunity, Bacteroides fragilis, Bacteroides thetaiotaomicron, Burkholderia cepacia, microbiome, IL-12. …‘™Ž‡†‰‡•ǣ‡ ƒ‡ ‰ƒ‡ˆŽ ‘ Š‡ •ƒˆˆ ‘ˆ Š‡ ƒ‹ƒŽ ˆƒ…‹Ž‹› ‘ˆ •ƒ‡ ‘••› ƒ†•‹ƒ•‡Ǥ‡ŠƒǤ ‘‹ǡǤ›ˆˆ‡ŽǡǤ‰‡Ž‹‡ǡǤŠƒŠƒ’ƒŠ‡ǡǤ‹ƒ† Ǥ„‡‘‰‘‹‹ƒ ˆ‘ ‡…Š‹…ƒŽŠ‡Ž’ǤŠ‡†ƒƒ’‡•‡‡†‹ Š‹•ƒ•…‹’ƒ‡ ƒ„Žƒ‡†‹ Š‡ƒ‹’ƒ’‡ƒ†‹ Š‡•’’Ž‡‡ƒ›ƒ‡‹ƒŽ•Ǥ•‡‡…‡‡ƒ†• ˆ‘ Š‹••†› Šƒ‡ „‡‡ •„‹‡† ‘ Š‡  †‡ Š‡ ‹‘’‘Œ‡…   ʹͻͻͳͳʹǤǡ  ƒ†  Šƒ‡ ˆ‹Ž‡† ’ƒ‡ ƒ’’Ž‹…ƒ‹‘• ιͳͶͳͻͲͳ͸͹Šƒ ‡Žƒ‡• ‘ •’‡…‹ˆ‹… ‘’‹…ǣ‡Š‘†•ƒ† ’‘†…• ˆ‘ ‘†Žƒ‹‰ ‹…‘„‹‘ƒ …‘’‘•‹‹‘ ˆ‘ ‹’‘‹‰ Š‡ ‡ˆˆ‹…ƒ…› ‘ˆ ƒ …ƒ…‡ ‡ƒ‡™‹Šƒ‹‡…Š‡…’‘‹ „Ž‘…‡Ǥƒ† ™‡‡ •’’‘‡† „› ƒ ‹‰‡ …‘‡Ž‡ …ƒ…‡ ƒ†  ‡•’‡…‹‡Ž›Ǥ  ‡…‡‹‡† ƒ •’‡…‹ƒŽ ’‹œ‡ ˆ‘ Š‡ ™‹••‹†‰‡ ‘†ƒ‹‘ƒ†Ǥ ƒ†™‡‡•’’‘‡†„›Š‡‹‰‡ƒ‹‘ƒŽ‡…‘‡Ž‡ƒ…‡ ȋ‹’‡• Žƒ„‡ŽŽ‹•±‡•Ȍǡ ‰‡…‡ ƒ‹‘ƒŽ‡ ’‘ Žƒ ‡…Š‡…Š‡ ȋ ǡ  ‡‰‡…‡Ȍǡ ‘’‡ƒ ‘‹••‹‘ ȋ ‘…‡Ȍǡ ‘’‡ƒ ‡•‡ƒ…Š ‘…‹Ž †ƒ…‡† ‡•‹‰ƒ‘ ƒȋ‘ Ȍǡ ‘†ƒ‹‘’‘Žƒ‡…Š‡…Š‡±†‹…ƒŽ‡ȋ Ȍǡ•‹ƒ‹‘ƒŽ †ƒ…‡ȋƒȌǡ ‘†ƒ‹‘†‡ ƒ…‡ǡƒ…±‘’ØŽ‡Ž‡Ǧ†‡Ǧ ƒ…‡ǡ ‘†ƒ‹‘‡‡…‘Ǧ …Š‡ŽŽ‡ǡ ™‹•• ‹†‰‡ ‘†ƒ‹‘ǡ Š‡ ƒ„š ‘Ǧ…‘Ž‘‰›ǡ Š‡  ƒ‹ˆ‹‡† …‘Ž‘‰› ‡ŽŽ‡’ƒ‹ ƒ† ‘ ‡ Ž‹‹ƒ‹‘ ȋȌǢ Š‡ ƒ…‡ ‡•‡ƒ…Šƒ†‡•‘ƒŽ‹œ‡†‡†‹…‹‡ȋȌǡƒ†Š‡ƒ‹•ŽŽ‹ƒ…‡‘ˆƒ…‡‡•‡ƒ…Š •‹‡•ȋȌǤ™ƒ••’’‘‡†„›ȋͲͳͳ͸ͳͺ͹ͻǣȌǤ™ƒ••’’‘‡†„› Š‡ ‘†ƒ‹‘ ’‘ Žƒ ‡…Š‡…Š‡ ±†‹…ƒŽ‡ǡ Š‡ ‘†ƒ‹‘  ’‘ Žƒ ‡…Š‡…Š‡ • Ž‡ …ƒ…‡ ƒ† •‹ ƒ‹‘ƒŽ‡ †