title: Processing and presentation of an antigen of Mycobacterium avium require access to an acidified compartment with active proteases.
abstract: We have generated a murine T-cell hybridoma, 1C9, which recognizes an antigen expressed by a virulent clinical isolate of Mycobacterium avium. Both peritoneal exudate macrophages and bone marrow-derived macrophages infected in vitro with M. avium process and present the antigen to the T-cell hybridoma. Gel filtration chromatography of a sonicate of M. avium followed by T-cell Western blotting (immunoblotting) demonstrated that the antigen recognized by hybridoma 1C9 is approximately 50 kDa. In addition, treatment of macrophages with the lysosomotropic agent chloroquine or with inhibitors of acid proteases inhibits processing and presentation of the antigen. These results indicate that the antigen must encounter an acidic compartment with active proteases for processing and presentation to occur. Our results are discussed in the context of our current understanding of how mycobacterial antigens are processed and presented by infected macrophages to T cells.
authors.affiliation: Center for Immunology and Department of Pathology, Washington University Medical Center, St. Louis, Missouri 63110, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Holsti
authors.forename: P M
authors.initials: PM
authors.lastname: Allen
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D000942:Antigens, Bacterial / Q000276:immunology*; D010450:Endopeptidases / Q000502:physiology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006825:Hybridomas / Q000276:immunology; D007376:Interleukin-2 / Q000096:biosynthesis; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D009162:Mycobacterium avium / Q000276:immunology*; D011480:Protease Inhibitors / Q000494:pharmacology
chemical_list: D000942:Antigens, Bacterial; D000949:Histocompatibility Antigens Class II; D007376:Interleukin-2; D011480:Protease Inhibitors; D010450:Endopeptidases