Phenotypic profiles of APCs-MB, isolated within 2 hours from MOPC315 tumors (1-3 g) in BALB/c mice.

(A) APCs-MB (containing phagocytosed mouse IgG FITC-coated MBs giving a signal in the FL-1 channel) were double-stained with anti-CD11b–allophycocyanin and either biotinylated I-E^d-, CD11c-, or CD40-specific mAbs; or triple-stained with anti-CD11b–allophycocyanin, biotinylated anti-CD11c, and either PE-conjugated anti-CD11b, -CD80, or -CD86 mAbs. FITC⁺APCs-MB were gated, and stainings for indicated mAbs are shown as histograms (full lines) overlaid with corresponding isotype-matched control Abs (dashed lines). Events (1 × 10⁵) were acquired for each sample. (B) Tumor APCs-MB and conventionally purified DCs (APC-I) from spleen60 were triple-stained with PE–anti-CD11b, anti-CD11c–allophycocyanin, and biotinylated anti–class II mAbs. Gated CD11b ⁺ cells were analyzed for the expression of class II molecules (full lines) overlaid with isotype-matched control Abs (dashed lines). Approximately 1 × 10⁵ or 5 × 10⁴ events were acquired for the spleen or tumor APCs, respectively.