THE PRESENT INVENTION RELATES TO METHODS FOR PREVENTING OR TREATING HUMAN IMMUNODEFICIENCY VIRUS (HIV) INFECTION, INFLAMMATORY CONDITIONS, AND GRAFT-VERSUS-HOST-DISEASE (GVHD) IN A SUBJECT. THERAPEUTIC COMPOSITIONS OF THE PRESENT INVENTION COMPRISE LEUKOCIDIN E (LUKE) AND/OR D PROTEINS OR POLYPEPTIDES. THE INVENTION FURTHER RELATES TO METHODS OF TREATING STAPHYLOCOCCUS AUREUS INFECTION BY ADMINISTERING A COMPOSITION COMPRISING A CCR5 ANTAGONIST OR ANY MOLECULE THAT BLOCKS LUKE/D INTERACTION WITH CCR5⁺ CELLS IN AN AMOUNT EFFECTIVE TO TREAT THE S. AUREUS INFECTION IN THE SUBJECT. FIGURE 1A
