Figure 1.

Phenotypic analysis of B16, granulocyte–macrophage colony-stimulating factor gene-modified dendritic cells (DC.GM) and their fusion hybrid. (a) B16, DCs, DC.GM and purified B16/DC.GM fused cells were analysed by flow cytometry for expression of major histocompatibility complex (MHC) class I (D^b, K^b) and class II (IA^b) antigens, co-stimulatory molecule (B7.1), DC marker CD11c (N418) and B16 tumour marker (M562), as detailed in the Materials and methods. (b) DC.GM were fused with B16 at a fusion ratio of 10:1 by polyethylene glycol (PEG). A bulk B16/DC.GM fusion preparation was cultured overnight and the non-adherent cells (unfused DCs and dead cells) were removed. The retained adherent cells were harvested and double stained with M562 monoclonal antibody (mAb), or with M562 plus mAbs against IA^b, or D^b or B7.1. Numbers in the quadrants of dual-parameter histograms represent the percentage of cells contained within that quadrant. FITC, fluorescein isothiocyanate; PE, phycoerythrin.