BACTERIAL HEMOLYSINS AND LEUKOTOXINS AFFECT TARGET-CELLS BY FORMING LARGE EXOGENOUS PORES INTO THEIR PLASMA-MEMBRANE - ESCHERICHIA-COLI HEMOLYSIN-A AS A CASE EXAMPLE

Many bacteria include among their virulence factors exoproteins which exert leukocidal and cytolytic functions and have the ability to form pores in model membranes. We show that, at least in the case of the RT X hemolysin produced by Escherichia coli (HlyA), formation of pores in planar lipid membranes is parallelled by opening of strikingly simila r channels in the plasma membrane of exposed macrophages. Formation of such lesions in leukocytes can give rise to a variety of effects lead ing altogether to a diminished immune response towards the invasive ba cteria.