Characterization of the Ghost Fusion Method: a Method for Introducing Exogenous Substances into Cultured Cells

Abstract

When erythrocytes were fused to cultured cells with HVJ, hemoglobin in erythrocytes was transferred to the cells. The hemoglobin became uniformly distributed in cells within 5 min, but components of the erythrocyte membranes did not become completely incorporated into recipient-cell membranes for about 2 h. Division of recipient cells was normal but did not start until one day after fusion. Human and guinea-pig erythrocytes had the highest fusion capacities of various animal erythrocytes tested. When these erythrocytes and iodinated bovine serum albumin (BSA) were dialyzed against hypotonic solution, BSA was trapped in erythrocyte ghosts within 30 min, at about 50 % of initial concentration in the dialysis bag. Of BSA trapped in ghosts, 80 % was found in the cytoplasmic fraction and 20 % associated with the membrane fraction. BSA was quite stable in these ghosts. Other proteins with various isoelectric points were also introduced into ghosts, and these proteins were transferred to recipient cells by virus-induced cell fusion of these ghosts. About 80 % of recipient cells in either monolayers or suspensions fused with the ghosts. Use of iodinated BSA showed that 0.25 % of the initial amount of BSA in the dialysis bag was introduced into recipient cells.