Alveolar macrophages: antigen presentation activity in vivo.

Previous studies on the antigen-presenting activity of alveolar macrophages (AM) have been restricted to the use of in vitro assay systems, and have generally shown suppression of T cell activation by these macrophages. The present study exploits the rapid adaptability of AM to changes in oxygen tension, which facilitates their transfer to other tissues in a functional state. Employing this rationale, antigen-pulsed AM were shown to trigger T cell-dependent immune responses following subcutaneous or intraperitoneal inoculation, while suppressing similar responses in tissue culture.