THE INTERACTION OF AMPHOTERICIN-B WITH CELL-MEMBRANE OF RAT THYMOCYTES

Amphothericin B (AB) at micromolar concentrations increases cell membr ane permeability and induced swelling of rat thymus lymphocytes. Potas sium efflux is a precondition for AB to induce swelling of the cells. The rate constants for potassium loss and volume changes were proporti onal to the 1.24th and the 2nd power of the antibiotic concentration r espectively. The reflection coefficients for nonelectrolytes with diff erent hydrodynamic radii were determined, and the equivalent radius of the amphotericin pore in the thymocyte cell membrane was estimated to be 4.1 +/- 0.3 angstrom at polyene concentrations varying between 2.5 mumol/l and 80 mumol/l. It is suggested that channel formation by AB in cell membranes is actually able to modulate immune responses.