library_construction_protocol: DCs were enriched by magnisort negative selection and 4-8 million cells were stained with FACS antibodies, TruStain FcX Block (BioLegend, 101320) and the mouse cell surface protein antibody panel containing 155 oligo-conjugated antibodies (TotalSeq-A, BioLegend), 9 TotalSeq-A isotype controls and 4 different hashing antibodies. Each biological replicate was stained with a different hashing antibody, 20.000 cells were sorted per biological replicate and pooled together. For the steady state condition, 15.000 CCR7- cDC1s and 5.000 CCR7+ cDC1s were sorted. For the LNP conditions, 20.000 LNP+ cDC1s were sorted based on the Cy5 fluorochrome which was incorporated in the LNPs. For the pIC alone condition, 20.000 total cDC1s were sorted. Sorting was done on a FACS Symphony S6 (BD). cDC1s were gated on LD-, CD3e-, CD19-, CD64-, F4/80dim, CD11c+, MHCII+, XCR1+, CD172- and only the steady state condition was sorted based on CCR7. Sorted single-cell suspensions were resuspended at an estimated final concentration of 1000 cells/µl and loaded on a Chromium GemCode Single Cell Instrument (10x Genomics) to generate single-cell gel beads-in-emulsion (GEM). The scRNA-Seq libraries were prepared using the GemCode Single Cell 3' Gel Bead and Library kit, version NextGEM 3.1 (10x Genomics) according to the manufacturer's instructions with the addition of amplification primer (3 nM, 5'CCTTGGCACCCGAGAATT*C*C) during cDNA amplification to enrich the TotalSeq-A cell surface protein oligos. Size selection with SPRIselect Reagent Kit (Beckman Coulter) was used to separate amplified cDNA molecules for 3' gene expression and cell surface protein construction. TotalSeq-A protein library construction including sample index PCR using Illumina's Truseq Small RNA primer sets and SPRIselect size selection was performed according to the manufacturer's instructions. The cDNA content of pre-fragmentation and post-sample index PCR samples was analyzed using the 2100 BioAnalyzer (Agilent). Sequencing libraries were loaded on an Illumina NovaSeq 6000 flow cell at the VIB Nucleomics core with sequencing settings according to the recommendations of 10x Genomics, pooled in a 70:20:10 ratio for the combined 3' gene expression, cell surface protein (antibody-derived tags (ADT)) expression and HashTag-Oligo (HTO) data, respectively.