Adsorption of typhus rickettsiae to ghosts of sheep erythrocytes

Rickettsia prowazeki will adsorb to ghosts derived from sheep erythrocytes by hypotonic lysis. Adsorption to ghosts, as to intact erythrocytes, is dependent on the metabolism of the rickettsiae. KCN and 0 C inhibit adsorption. Fluoride, while inhibiting hemolysis, has no effect on adsorption to ghosts or intact erythrocytes. The adsorption of rickettsiae to ghosts does not lead to lysis, in that fluorescent albumin can be retained by the ghost after adsorption. Both inside-out and right-side-out vesicles formed from the ghost are equally capable of adsorption, indicating that the receptor is stable during the process of vesiculation and is not localized to one aspect of the cell membrane. Adsorption to ghosts is slower and displays less affinity than to the intact erythrocyte. The ghost system will be useful in characterizing the membrane receptor for rickettsia and in establishing assays for adsorption to other cells.