REAGENT or RESOURCE	SOURCE	IDENTIFIER
Antibodies
anti-human/anti-mouse CX43	Abcam	Cat #ab11370; AB_297976
anti-human XBP1s	Cell Signaling	Cat #12782S; AB_2687943
anti-human/anti-mouse/anti-canine Vinculin	Sigma	Cat #V9131; AB_477629
anti-canine CX43	Thermo Fisher Scientific	Cat #13-8300; AB_2533038
Anti-human CHOP	Cell Signaling	Cat # 2895S; AB_2089254
Anti-mouse CD8 (clone YTS 169.4)	BioXcell	Cat # 53-0341-82; RRID:AB_2866440
Anti-mouse CD4 (clone GK1.5)	BioXcell	Cat # 560230; RRID:AB_1645200
rat IgG2a anti-trinitrophenol (clone 2A3)	BioXcell	Cat # ab185230; RRID:AB_2715497
Fixable Viability Stain 510	BD Biosciences	Cat # 564406; RRID:AB_2869572
Goat anti-canine IgG (H+L) FITC	Invitrogen	Cat # A18764; RRID:AB_2535541
Anti-Human PAN HLA	InVivoMab	Cat #BE0079; RRID:AB_1107730
Anti-Human HLA-A∗02:01 PE	Biolegend	Cat # 343306; RRID:AB_1877227
Anti-human CD3 V450	BD Biosciences	Cat # 560366; RRID:AB_1645569
Anti-human CD8 PerCP	Biolegend	Cat # 344708; RRID:AB_1967149
Anti-human CD4 FITC	BD Biosciences	Cat # 555346; RRID:AB_395751
Anti-human IFNγ APC	BD Biosciences	Cat # 551385; RRID:AB_398505
Anti-human CD107a PE-Cy7	Biolegend	Cat # 328618; RRID:AB_11147955
Bacterial and virus strains
S. typhimurium SL3261AT	This paper	N/A
Vivofit® (Thyphoid vaccine live oral Ty21a)	This paper	N/A
Biological samples
PBMC isolation from Buffycoat (approved by the Ethics Committee of Humanitas Clinical and Research Center License No. Humanitas01/2016)	Humanitas Clinical and Research Center	N/A
Chemicals, peptides, and recombinant proteins
Heptanol	Sigma-Aldrich	Cat # 51778
MG132	Sigma-Aldrich	Cat # 474790
4μ8c	Sigma-Aldrich	Cat # 412512
Brefeldin A	Biolegend	Cat # 420601
Thapsigargin	Sigma-Aldrich	Cat # T9033
Freund’s Incomplete Adjuvant (IFA)	Sigma-Aldrich	Cat # F5506
Aldara 5% Cream (Imiquimod)	Meda AB	N/A
ODN1826	Invivogen	Cat # vac-1826-1
Epoxomycin	Sigma-Aldrich	Cat # E3652
CMV peptide	JPT Peptide Technologies	Cat# PM-PP65-1
Mart126-35	Iba Lifesciences	Cat# 6-7007-901
IL2 (Proleukin)	Clinigen Healthcare B.V.	N/A
RIPA	Cell Signaling	Cat # 9806S
Phosphatase Inhibitor	Sigma-Aldrich	Cat # P5726
Protease Inhibiotors	Roche	Cat # 05892988001
Gentamicin Sulfate	Euroclone	Cat# ECM0012B
Concanavalin A	Sigma-Aldrich	Cat# C2010
Critical commercial assays
CellTiter-Glo Luminescent Cell Viability Assay	Promega	Cat # G7572
DuoSet ELISA human IFNg	R&D Systems	Cat # DY285B
DuoSet ELISA mouse IL-2	R&D Systems	Cat # DY402; RRID:AB_2797392
Canine IFNγ ELISA	R&D Systems	Cat # CAIF00
PE Annexin V Apoptosis Detection Kit I	BD PharMingen	Cat # 559763; RRID:AB_2869265
SPE C18 devices	Macherey-Nagel	Cat# MANA730003.250
T Cell TransAct	Miltenyi Biotec	Cat #130-111-160
Delfia-BATDA	Perkin Elmer	Cat # AD0116
fluorometric proteasome 20S assay kit	Sigma-Aldrich	Cat # MAK172-1KT
XbpI human gene knockout kit	Origene	Cat# KN401959
XbpI mouse gene knockout kit	Origene	Cat# KN519483
G’NOME DNA isolation kit	MPBiomedicals	Cat # 112010600
Direct-zol RNA MiniPrep Plus Kit	Zymo Research	Cat# R2072
Deposited data
Original data, Peptidomic Datasets, R-scripts	This paper	Zenodo Repository https://zenodo.org/record/4738409#.YJJEIqHONaQ
Experimental models: cell lines
B16F10	Saccheri et al., 2010	N/A
B16F10-XBP1KO	This paper	N/A
B16F10-OVA	Saccheri et al., 2010	N/A
B16F10-OVA-CX43KO	Saccheri et al., 2010	N/A
B3Z-Hybridoma	Rotta et al., 2003	N/A
DC1	Rotta et al., 2003	N/A
624-38	Sabatino et al., 2008	N/A
624-38 XBP1KO	This paper	N/A
624-28	Sabatino et al., 2008	N/A
HT29	This paper	N/A
SkMel24	Saccheri et al., 2010	N/A
A375	This paper	ATCC-CRL-1619; RRID:CVCL_0132
MeWo	This paper	ATCC-HTB-65; RRID:CVCL_0445
C32	This paper	ATCC-CRL-1585; RRID:CVCL_1097
hMel2	This paper	N/A
hMel3	This paper	N/A
T2	This paper	N/A
THP1	This paper	N/A
Mela23, Mela41	This paper	N/A
Experimental models: organisms/strains
Mouse: C57BL/6J	Charles River	Cat # 027
Mouse: C57BL/6-Tg(TcraTcrb)1100Mjb/Crl (OTI)	Charles River	Cat # 642
Mouse: NOD.Cg-Prkdcscid Il2rgtm1Wjl /SzJ (NSG)	Jackson Laboratories	Cat # 005557
Oligonucleotides
Primers, see Table S3	This paper	N/A
Software and algorithms
MaxQuant (version 1.5.5.1)	MaxQuant	https://www.maxquant.org/
Perseus (version 1.5.0.31)	Perseus	https://maxquant.net/perseus/
Image Lab	Biorad	http://www.bio-rad.com/en-us/product/image-lab-software?ID=KRE6P5E8Z
FlowJo v10.5.3	TreeStar	https://www.flowjo.com/solutions/flowjo; RRID:SCR_008520
Prism	GraphPad	https://www.graphpad.com:443/
Other
Count Bright Absolute Counting Beads	Invitrogen	Cat # C36950