Enhanced lentiviral vector production in 293FT cells expressing Siglec-9.

Siglecs, sialic acid-recognizing Ig-superfamily lectins, regulate various aspects of immune responses, and have also been shown to induce the endocytosis of binding materials such as anti-Siglec antibodies or sialic acid-harboring bacteria. In this study, we demonstrated that the expression of Siglec-9 enhanced the transfection efficiency of several cell lines such as macrophage RAW264 and non-hematopoietic 293FT cells. We applied this finding to the production of a lentiviral vector in which cells were transfected simultaneously with multiple vectors, and achieved a twice increase in viral production levels. Furthermore, 293FT cells expressing lectin-defective Siglec-9 produced three- to seven-fold higher titer of viral vector compared with parental 293FT cells. These results suggest that Siglec-9 enhanced lentiviral vector production in a lectin-independent manner.