A biotin-streptavidin-biotin bridge dramatically enhances cell fusion

Abstract

Although the generation of hybrid cells by cell fusion plays a significant role in biotechnology and biomedicine, the low cell-fusion rates and the limitation of large-scale cell fusion for clinical applications of the two widely used approaches, polyethylene-glycol (PEG)-mediated cell fusion and electrofusion, hinder the application of this critical technology in certain key areas, including cancer immunotherapy. In the present study, a simple procedure that can not only significantly increase the heterologous cell fusion but is also capable of producing fused cells on a large scale is reported. A biotin-streptavidin-biotin (BSB) bridge was created by coating one to-be-fused cell with biotin and the other with biotin-streptavidin. The BSB bridge enhances cell-fusion rates induced with PEG fusion or electrofusion by 10-30% depending on the cell types when compared with cell fusions without the bridge. The procedure described increases heterologous cell pairing and eliminates the alignment step required for the majority of electrofusions. Notably, it can be used to make large-scale cell fusions for clinical applications.

Keywords: biotin; cell fusion; electroporation; polyethylene-glycol; streptavidin.

Figure 1

Biotin-SA-biotin bridge enhances cell fusions between tumor cells. (A) B16F0 cells were stained with green fluorescent dye, PKH67, or red fluorescent dye, PKH26, and mixed together. Cell fusions were then induced by (C) PEG, (E) electroporation or (G) viral envelope. By contrast, B16F0 tumor cells were first coated with biotin. Half of the cells were stained with PKH67 and the other half were stained with PKH26 and then treated with an excess amount of SA. (B) The green cells with biotin were mixed with red cells with biotin-SA and cell fusions were induced by (D) PEG or (F) electroporation. SA, streptavidin; PEG, polyethylene-glycol.

Figure 2

Fluorescence-activated cell sorting analysis of biotin-SA-biotin bridge-mediated cell fusion. B16F0 cells were either stained with green fluorescent dye, PKH67, or red fluorescent dye, PKH26, and mixed together. Cell fusions were then induced by (A) PEG, (C) electroporation or (E) viral envelope. By contrast, B16F0 tumor cells were first coated with biotin. Half of the cells were stained with PKH67 and the other half were stained with PKH26 and then treated with an excess amount of SA. The green cells with biotin were mixed with red cells with biotin-SA and cell fusions were induced by (B) PEG or (D) electroporation. SA, streptavidin; PEG, polyethylene-glycol.

Figure 3

BSB bridge increases cell-fusion rate between DCs and tumor cells. DC/tumor fusions were induced by (A and C) PEG or (B and D) electroporation, (A and B) without or (C and D) with a BSB bridge. BSB, biotin-streptavidin-biotin; DC, dendritic cell; PEG, polyethylene-glycol.