This project will study the production of the fatty acid modifying enzyme (FAME) by Staphylococcus aureus strains within abscesses. It will determine whether antibodies to FAME or lipase are protective for the host. The project will also determine whether lipase-negative mutants of S. aureus are less able to survive in abscesses. Studies will be done to determine whether diabetes, steroid administration, ether inhalation, or delayed hypersensitivity will alter the host's ability to synthesize the bactericidal lipids in abscesses. Attempts will be made to isolate the substance from Candida albicans that can increase the host's susceptibility to S. aureus. Efforts will be made to determine whether granulocytes or macrophages are involved in the synthesis of the bactericidal lipids and whether the conditions existing in inflammatory sites are required for such synthesis. Studies will also be conducted to see whether the resistance to reinfection with S. aureus can be transfered by lymphoid cells.