Nystatin- and amphotericin B-induced structural alterations of the erythrocyte membrane: importance of reduced ionic strength.

The effect of the polyene antibiotics nystatin and amphotericin B on the membrane structure of human erythrocytes has been investigated by freeze-fracture electron microscopy. Nystatin induces the same particlefree elevations on the erythrocyte membrane as already observed after treatment with amphotericin B. This structural alteration appears only in presence of an isotonic medium with reduced ionic strength. The dependence on the ionic strength supports the interpretation of these structures to be lipid domains.