Uptake of proteins by red blood cells

Abstract

During hypotonic hemolysis red cells can take up 125I-myoglobin and 125I-immunoglobulin G. Cells which contain these proteins have distinctive cell morphology and are called gray ghosts. The association of protein with gray ghosts is fairly stable: these cells retain half of the proteins after 3 days. Passive diffusion of protein into the internal cell volume is the most plausible mechanism for uptake, and several lines of evidence indicate that the loaded proteins are freely diffusable within the red cells. Bacteriophage T4 is not taken up during hemolysis so uptake through large gaps in the red cell membrane with subsequent resealing seems unlikely. If an efficient procedure for fusing loaded gray ghosts to culture cells can be devised, it will be possible to introduce selected macromolecules into the cytoplasm of culture cells quite easily.