Plasma-desorption mass spectrometry as an express diagnostic test for bovine leukaemia

Plasma-desorption mass spectrometry with ionization of 252Californium fission fragments (252Cf-PD MS) was used to develop an express diagnostic test for bovine leukaemia. The test is based on the mass spectrometric parameters of artificial lipid membranes formed on the gold substrate from the lipid fraction of blood cells (mainly lymphocytes), by the self-assembly technique according to the biomimetic principle. Mass spectrometric analysis of artificial lipid membranes obtained from blood plasma of control and leukemic cattle gave a reliable diagnosis of leukaemia. The basis for the diagnosis were the ionization parameters of the fragmentation of lipid molecules from normal and leukemic cell membranes. In leukemic cell membranes, separate dense areas (rafts) 200 – 300 nm in diameter, saturated with cholesterol and phospholipids, are formed. The number of rafts per unit of cell membrane of leukemic cells significantly exceeded the permitted parameters of normal cell membranes. The increased number of rafts in artificial membranes formed in the membranes of leukemic cells was reliably reflected in mass spectra, due to the 180 – 250% increase in intensity of peaks of cholesterol fragment ions in comparison to control cells.