INTERRELATIONS BETWEEN DIFFERENT TYPES OF CELLS .I. A COMPARATIVE STUDY OF BIOLOGICAL PROPERTIES OF A CATIONIC POLYPEPTIDE FROM LYSOSOMES OF POLYMORPHONUCLEAR LEUKOCYTES AND OTHER CATIONIC COMPOUNDS

Acid extracts or 20% ethanol-precipitated material from lysosomes of exudative polymorphonuclear leukocytes (PMN) of the rabbit and the rat have been fractionated by gel filtration through Sephadex G-25. Fractionation resulted in a separation into two main peaks. The first, representing large molecular weight components, is eluted with material passing readily through the column; the second, representing small molecular weight components, is retarded during gel filtration. Since the total yield of mastcell active material was much smaller in the rat, most of the work was carried out on extracts from rabbit PMN lysosomes. When the two fractions were tested on isolated rat mast cells, mast-cell rupturing activity was clearly associated with low molecular weight components. Further comparative studies with human and rabbit platelets and Ehrlich ascites tumor cells have demonstrated that the mast-cell lytic factor is not able of releasing cellular components from these types of cell; moreover, this agent does not induce chemotaxis of rabbit granulocytes in vitro and exhibits no antibacterial activity. Other cationic agents behave differently. The mast-cell lytic factor from PMN lysosomes thus shows a high degree of specificity and bears comparison with the well-known chemical histamine-liberators. © 1968 S. Karger AG, Basel.