Diesel-enriched particulate matter functionally activates human dendritic cells.
Epidemiologic studies have associated exposure to airborne particulate matter (PM) with exacerbations of asthma. It is unknown how different sources of PM affect innate immunity. We sought to determine how car- and diesel exhaust-derived PM affects dendritic cell (DC) activation. DC development was modeled using CD34+ hematopoietic progenitors. Airborne PM was collected from exhaust plenums of Fort McHenry Tunnel providing car-enriched particles (CEP) and diesel-enriched particles (DEP). DC were stimulated for 48 hours with CEP, DEP, CD40-ligand, or lipopolysaccharide. DC activation was assessed by flow cytometry, enzyme-linked immunosorbent assay, and standard culture techniques. DEP increased uptake of fluorescein isothiocyanate-dextran (a model antigen) by DC. Diesel particles enhanced cell-surface expression of co-stimulatory molecules (e.g., CD40 [P < 0.01] and MHC class II [P < 0.01]). By contrast, CEP poorly affected antigen uptake and expression of cell surface molecules, and did not greatly affect cytokine secretion by DC. However, DEP increased production of TNF, IL-6, and IFN-gamma (P < 0.01), IL-12 (P < 0.05), and vascular endothelial growth factor (P < 0.001). In co-stimulation assays of PM-exposed DC and alloreactive CD4+ T cells, both CEP and DEP directed a Th2-like pattern of cytokine production (e.g., enhanced IL-13 and IL-18 and suppressed IFN-gamma production). CD4+ T cells were not functionally activated on exposure to either DEP or CEP. Car- and diesel-enriched particles exert a differential effect on DC activation. Our data support the hypothesis that DEP (and to a lesser extent CEP) regulate important functional aspects of human DC, supporting an adjuvant role for this material.
Porter
Michael
M
Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Karp
Matthew
M
Killedar
Smruti
S
Bauer
Stephen M
SM
Guo
Jia
J
Williams
D'Ann
D
Breysse
Patrick
P
Georas
Steve N
SN
Williams
Marc A
MA
D015703:Antigens, CD / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000166:cytology / Q000187:drug effects* / Q000276:immunology* / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D004705:Endocytosis / Q000187:drug effects; D005434:Flow Cytometry; D006684:HLA-DR Antigens / Q000378:metabolism; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism; D018836:Inflammation Mediators / Q000378:metabolism; D037181:Lectins, C-Type / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D052638:Particulate Matter / Q000494:pharmacology*; D011956:Receptors, Cell Surface / Q000378:metabolism; D019707:Receptors, Chemokine / Q000378:metabolism; D013997:Time Factors; D051195:Toll-Like Receptor 2 / Q000235:genetics; D051197:Toll-Like Receptor 4 / Q000235:genetics; D001335:Vehicle Emissions; D000097802:CD83 Antigen
D015703:Antigens, CD; D016207:Cytokines; D006684:HLA-DR Antigens; D007136:Immunoglobulins; D018836:Inflammation Mediators; D037181:Lectins, C-Type; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins; D008562:Membrane Glycoproteins; D052638:Particulate Matter; D011956:Receptors, Cell Surface; D019707:Receptors, Chemokine; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D001335:Vehicle Emissions; D000097802:CD83 Antigen