The effect of T4 and HAP1 bacteriophages on B16 mouse melanoma migration on fibronectin. The insert: an 8-μm 0.3-cm2 membrane was covered with fibronectin. B16 melanoma cells were applied at 5 × 105 cells per insert in DMEM. The final concentrations of the bacteriophage preparations were 1.5–2.5 × 109 pfu/ml and 10 U/ml of residual LPS. The LPS control was also 10 U/ml (which equals 0.25 ng/ml). The concentration of the attracting agent FBS in the lower section of the migration chamber was 7.3–7.5%. Migration was carried out for 2 h at 37°C in CO2. The cells were stained and counted under light microscopy on the whole membrane. The mean number of cells per membrane (bars) and SD (lines) are presented.