Figure 4 Figure 4. cDC1 are superior to other spleen antigen-presenting cells for MHC II presentation of PbA and non-PbA antigens (A) Gating strategy for FACS-sorting pDC (Lin- CD11clo B220+ Ly6C+), cDC1 (Lin- CD11c+ CD8α+), cDC2 (Lin- CD11c+ CD8α-) and a mix of macrophages moDC (Lin- CD11c- CD11b+ Ly6C+) from spleens of mice infected for 6 days with PbA pRBC. (B) I-Ab presentation of ETRAMP10.2 peptide by the indicated APC, measured with BEZ hybridomas. PbA pRBC-loaded MutuDC were used as controls. Representative of 2 experiments with 4 infected mice pooled per replicate. (C) Fold-change surface expression of I-Ab in cDC2 over cDC1 in day 6-infected mice (mean +/- SEM of 5 experiments). Difference is not significant based on unpaired t-test with Welch's correction. (D,E,F) I-Ab presentation of non-PbA antigens by cDC isolated from day 6 PbA-infected mice. (D) I-Ab-AS15 presentation after exogenous addition of AS15 peptide at the indicated concentrations, assessed with the BTg01Z hybridomas.Dotted line in D,E,F,H,I shows the basal response of the hybridomas in the absence of antigen. (D,E,F) I-Ab presentation of non-PbA antigens by cDC isolated from day 6 PbA-infected mice. (E) I-Ab-AS15 presentation by DC incubated with heat-killed T. gondii at the indicated ratio, assessed with the BTg01Z hybridomas. Dotted line in D,E,F,H,I shows the basal response of the hybridomas in the absence of antigen. (D,E,F) I-Ab presentation of non-PbA antigens by cDC isolated from day 6 PbA-infected mice. (F) I-Ab-IR17 presentation by DC incubated with OVA-expressing E. coli at the indicated ratio, assessed with the OTIIZ hybridomas. PbA pRBC-loaded MutuDC were used as controls. D,E,F: representative of 2 experiments with 4 infected mice pooled per replicate. Dotted line in D,E,F,H,I shows the basal response of the hybridomas in the absence of antigen. (G) In vivo pRBC uptake by cDC1 (XCR1+ CD172a-) and cDC2 (XCR1- CD172a+) analyzed at 6 days post-infection with PbA.GFP. Gates were positioned based on the auto-fluorescence of the cDC subset in day 6 PbA-infected mice. As GFP+ events are rare, 107 events were acquired for each mouse. Symbols show the mean percentage +/- SEM (N = 4 mice per group) of GFP+ cells in each DC subset. *, P = 0.0005 by unpaired t-test without assuming consistent SD. (H,I) I-Ab presentation by cDC isolated from naïve mice. (H) I-Ab-NL17 presentation by DC incubated with PbA pRBC at a ratio of 5:1, assessed with the BEZ hybridomas. H,I: representative of 2 independent experiments with 20 naïve mice pooled per experiment. Dotted line in D,E,F,H,I shows the basal response of the hybridomas in the absence of antigen. (H,I) I-Ab presentation by cDC isolated from naïve mice. (I) I-Ab-IR17 presentation by DC incubated with OVA-expressing E. coli at a ratio of 20:1, assessed with the OTIIZ hybridomas. H,I: representative of 2 independent experiments with 20 naïve mice pooled per experiment. Dotted line in D,E,F,H,I shows the basal response of the hybridomas in the absence of antigen. (J) Fold-change surface expression of I-Ab in cDC2 over cDC1 in naïve mice (mean +/- SEM of 4 experiments). Difference is not significant based on unpaired t-test with Welch's correction.