Ergosterol-conferred sensitivity to amphotericin B in cultured L1210 mouse leukemia cells

The sensitivity of cellular membranes to disruption by amphotericin B (AMP-B) depends on the sterol content of such membranes. L1210 murine leukemia cells, grown in medium containing ergosterol and then briefly treated with AMP-B, were more sensitive to the antibiotic than control populations. Cell lysis and damage were assessed by estimation of cell number, trypan blue uptake and cell viability by cloning in soft nutrient-agar. Cells grown in ergosterol required less than half the AMP-B needed for equivalent damage to controls, and were reduced in number and viability by over 99.9 per cent at an AMP-B concentration which barely affected the reproductive capacity of control cell populations.