Presentation of exogenous antigens by macrophages: analysis of major histocompatibility complex class I and II presentation and regulation by cytokines

Abstract

There is an antigen presenting cell (APC) in the lymphoid organs capable of presenting exogenous antigen (Ag) with major histocompatibility complex (MHC) class I molecules. This study was initiated to isolate clones of these APC to definitively establish their phenotype and to further study their properties. Murine bone marrow macrophages (BM M psi) were immortalized by overexpression myc and raf oncogenes. Five BM M psi cell lines were generated that are phagocytic and expressed at their surface M psi differentiation Ag. All five cell lines processed and presented exogenous ovalbumin (OVA) with MHC class I molecules. They all presented OVA-linked to a phagocytic substrate 10(2)-10(4)-fold more efficiently than soluble Ag. Clonal isolates of two of the M psi cell lines had an identical phenotype and functional properties as the uncloned lines. These results definitively establish that M psi are APC with the capacity of presenting exogenous Ag with MHC class I molecules. Interferon (IFN)-gamma interleukin-4, granulocyte-macrophage colony stimulating factor and lipopolysaccharide either alone or in combination induced little or no augmentation and in some cases decreased presentation of exogenous OVA with MHC class I. In contrast, all of M psi activating factors increased MHC class I expression. Moreover, IFN-gamma increased the presentation of cytosolic OVA, demonstrating differences between the presentation of cytosolic Ag versus exogenous Ag with MHC class I. Finally, some lines constitutively processed and presented exogenous OVA with MHC class II while others only presented after stimulation with IFN-gamma. These results demonstrate that the pathways involved in the presentation of exogenous Ag with MHC class I and class II are independently regulated and that a cloned cell is capable of presenting exogenous Ag through both pathways.

A Trivalent Virus-Like Particle Vaccine Elicits Protective Immune Responses against Seasonal Influenza Strains in Mice and Ferrets

“…In general, VLPs have the potential to activate both endogenous and exogenous antigen pathways leading to the presentation of viral peptides by MHC class I and class II molecules [36]. In this study, we showed that anti-HA specific CD8+ T cells were elicited by a seasonal influenza VLP vaccine indicating that a multi-epitope vaccine is more likely than an inactivated, split vaccine to generate a broad-based immune response.…”

“…These viral proteins can be processed and presented on MHC class I molecules, therefore promoting presentation to T-cells by professional antigen presenting cells. In addition, cell-free VLPs bound with antibodies could be taken up by phagocytic cells via Fc receptors, thus increasing MHC class II presentation [36]. Antigens expressed in their native three-dimensional conformational form can elicit more effective antibody responses compared to proteins in their non-native forms [37].…”

Dependence of pathogen molecule-induced Toll-like receptor activation and cell function on Neu1 sialidase

“…Cell lines BMC-2 and BMA macrophage cells [12] and DC2.4 dendritic cells [13] supplemented with 5% fetal calf serum (FCS). Stable HEK-TLR cells were obtained by calcium phosphate transfection of a pCDNA3 expession vector for a specific chimeric TLR with an in frame C-terminal YFP and selection in 0.4μg/ml G418.…”

“…Here, we show that TLR ligands zymosan A (TLR-2), poly I:C (TLR-3) and LPS (TLR-4) induced sialidase activity on the cell surface of live BMC-2 macrophage [12] and DC2.4 dendritic [13] cells in culture after 2 min. This activity was revealed by a fluorescence (λem 450 nm) surrounding the cells treated with the fluorogenic sialidase substrate, 4MU-NeuAc (2′-(4-methylumbelliferyl)-α-N-acetylneuraminic acid) and caused by the emission of 4-methylumbelliferone (Fig.…”

Gene Deletions in Mycobacterium bovis BCG Stimulate Increased CD8+T Cell Responses

“…More specifically, the A3.1A7 macrophage cell line has been shown to present the immunodominant epitope of chicken ovalbumin, SIINFEKL, in association with the H-2K b MHC class I molecule (15). As previously demonstrated, when this antigenpresenting cell (APC) line is pulsed with SIINFEKL and then incubated with the T cell hybridoma RF33.70, IL-2 is produced by the RF33.70 T cell hybridoma at levels proportional to the number of H-2K b :SIINFEKL complexes expressed on the surface of the pulsed APCs (16).…”