Supplementary Figure S1: Uptake of Alexa488-labelled IC by WT or FcγRIIb KO BM is similar.

BM-DCs were incubated for one hour with medium (filled histogram) or 1 µg/ml IC (unfilled histogram) and analyzed by flow cytometry. The percentage of Alexa488-positive cells was assessed (IC-Alexa488).

Supplementary Table I: Comparison of Steady State Gene expression levels in DCs of different genotypes

Top 10 genes differentially expressed between unstimulated WT and FcR γ-chain KO BM- DCs (a) and WT and FcγRIIb KO BM-DCs (b) assessed by error weighted ANOVA using Benjamin Hochberg FDR correction and Student-Newman-Keuls post-hoc test.

Ia: Genes expressed at a higher level in FcR γ-chain KO compared to WT. Top 10 of 194 genes. Gene name Alias Fold higher in FcR γ-chain KO NeoR Neomycine Resistent cassette >20 Gbp1 Guanulate binding protein 1 7.50 Cd209a DC SIGN 4.55 Slco2b1 Solute carrier family 22, member 9 4.26 Cd209c SIGNR2 2.95 Tspan8 Tetraspanin 8 2.82 Fcrls IgSR 2.80 Myo5a Myosin 5 a 2.77 LOC268730 Predicted sequence (withdrawn from refseq) 2.70 LOC383125 Predicted sequence 2.70

Genes expressed at a lower level in FcR γ-chain KO compared to WT. Top 10 of 194 genes. Gene name Alias Fold higher in WT Fcer1g FcR γ-chain >10 AI480556 serine arginine-rich pre-mRNA splicing factor SR-A1 4.36 Saa3 Serum Amyloid A3 4.16 Anpep alanyl (membrane) amino peptidase 3.97 Gpr84 G-protein coupled receptor 84 3.38 Foxp4 Forkhead box P4 3.18 A530032J19Rik Unknown sequence 3.18 Tgfb1 Transforming growth factor β 3.07 Ap2a1 Adaptor protein complex AP-2, α 1 subunit 2.93 Fmnl1 Lymphocyte specific formin related protein 2.74

Ib: Genes expressed at a higher level in FcγRIIb KO compared to WT Top 10 of 64 genes. Gene name Alias Fold higher in FcγRIIb KO Wdfy1 WD repeat and FYVE domain containing 1 3.41 Anpep alanyl (membrane) amino peptidase 2.14 Bcat2 branched chain aminotransferase 2,mitochondrial 1.96 Thy1 CD90 1.93 Nt5dc2 5'-nucleotidase domain containing 2 1.70 Dgat2 diacylglycerol O-acyltransferase 2 1.69 Tmem104 trans membrane protein 104 1.67 Aldoa fructose-bisphosphate aldolase A 1.55 Fcnb Ficolin B 1.54 Slc7a8 Solute carrier family 7, member 8 1.54

Genes expressed at a lower level in FcγRIIb KO compared to WT. Top 10 of 64 genes. Gene name Alias Fold higher in WT Enah enabled homolog 3.16 Slco2b1 solute carrier organic anion transporter family member 2b1 2.45 Tm6sf1 trans membrane 6 superfamily member 1 1.91 Usp47 ubiquitin specific peptidase 47 1.74 0610010K06Rik hypothetical protein LOC71678 1.48 Hmgcs1 3-hydroxy-3-methylglutaryl-Coenzyme A synthase 1 1.48 6330403M23Rik RIKEN cDNA 6330403M23 gene 1.41 A930005I04Rik RIKEN cDNA A930005I04 gene 1.41 Flnb Filamin β 1.38 Camk1d calcium/calmodulin-dependent protein kinase 1.38