Induction and Enhancement of Endocytosis in HeLa Cells by Use of Liposomes and Sendai Virus Envelopes

Phosphatidylserine liposomes were interacted with cultured HeLa cells to investigate the ingestion of the liposomes into the cells. It was shown by electron microscopy that great enhancement in entrappment of the liposomes into the cells was induced by adding reassembled Sendai virus envelopes. In the presence of the reassembled virus envelopes the ratio of liposome-endocytic cells was over the half of the examined cells in thin sections. To differentiate the entrapped vesicles from cell-originated intracytoplasmic vesicles, uninfective virus particle was introduced as a mark and it was shown that the uninfective virus particle was entrapped with the liposomes into the cells. These results may suggest that reconstituted Sendai virus envelopes could change HeLa cell membranes to endocytic ones.