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We recently reported that P2X7 receptor (P2X7R)-induced activation of caspase-1 inflammasomes is accompanied by release of MHC class II (MHC-II) protein into extracellular compartments during brief stimulation of murine macrophages with ATP. Here we demonstrate that MHC-II containing membranes released from macrophages or dendritic cells (DCs) in response(More)
Dendritic cells (DCs) internalize exogenous Ags and process them for cross-presentation by class I MHC (MHC-I) to CD8+ T cells. This processing can occur by transporter for Ag presentation (TAP)-dependent or TAP-independent mechanisms. We observed that CpG DNA enhanced cross-presentation of Ags by Flt-3L-cultured bone marrow-derived murine DCs by a type I(More)
Major histocompatibility complex class II (MHC-II) molecules are released by murine macrophages upon lipopolysaccharide (LPS) stimulation and ATP signaling through the P2X7 receptor. These studies show that infection of macrophages with Mycobacterium tuberculosis or M. bovis strain BCG enhances MHC-II release in synergy with ATP. Shed MHC-II was contained(More)
Peptides from the lumenal portion of invariant chain (Ii) spanning residues 80-106 (class II-associated Ii peptide [CLIP]) are found in association with several mouse and human major histocompatibility complex (MHC) class II allelic variants in wild-type and presentation-deficient mutant cells. The ready detection of these complexes suggests that such an(More)
Phagosomes contain class II MHC (MHC-II) and form peptide:MHC-II complexes, but the source of phagosomal MHC-II molecules is uncertain. Phagosomes may acquire nascent MHC-II or preexisting, recycling MHC-II that may be internalized from the plasma membrane. Brefeldin A (BFA) was used to deplete nascent MHC-II in murine macrophages to determine the relative(More)
Control of Mycobacterium tuberculosis infection requires CD4 T-cell responses and major histocompatibility complex class II (MHC-II) processing of M. tuberculosis antigens (Ags). We have previously demonstrated that macrophages process heat-killed (HK) M. tuberculosis more efficiently than live M. tuberculosis. These observations suggested that live M.(More)
Macrophages and dendritic cells are phagocytic antigen presenting cells that internalize bacteria and other particulate antigens into phagosomes. The phagosome must then balance microbicidal and proteolytic degradation functions with the generation of antigenic peptides for presentation by class I and class II MHC molecules to CD8 and CD4 T cells,(More)
Pathogen-associated molecular patterns (PAMPs) signal through Toll-like receptors (TLRs) to activate immune responses, but prolonged exposure to PAMPs from Mycobacterium tuberculosis (MTB) and other pathogens inhibits class II MHC (MHC-II) expression and Ag processing, which may allow MTB to evade CD4(+) T cell immunity. Alternate class I MHC (MHC-I)(More)
Mycobacterium tuberculosis (MTB) inhibits phagosomal maturation to promote its survival inside macrophages. Control of MTB infection requires CD4 T cell responses and major histocompatibility complex (MHC) class II (MHC-II) processing of MTB antigens (Ags). To investigate phagosomal processing of MTB Ags, phagosomes containing heat-killed (HK) or live MTB(More)
Processing of exogenous antigens and microbes involves contributions by multiple different endocytic and phagocytic compartments. During the processing of soluble antigens, different endocytic compartments have been demonstrated to use distinct antigen-processing mechanisms and to process distinct sets of antigenic epitopes. Processing of particulate and(More)