title: Scavenger receptor-A negatively regulates antitumor immunity.
abstract: The scavenger receptor-A (SR-A), originally recognized by its ability to internalize modified lipoproteins, has largely been studied in relation to atherosclerosis as well as innate immunity against pathogen infection. SR-A was recently shown to be a receptor on antigen-presenting cell for heat shock protein (HSP) and was implicated in the cross-presentation of HSP-chaperoned antigens. Here, we show that SR-A is not required for antitumor immunity generated by HSP-based (e.g., grp170) vaccine approaches in vivo. The lack of SR-A significantly enhances HSP- or lipopolysaccharide-mediated vaccine activities against poorly immunogenic tumors, indicating that SR-A is able to attenuate immunostimulatory effects of adjuvants or "danger" molecules. The improved antitumor response in SR-A knockout mice is correlated with an increased antigen-specific T-cell response. Moreover, SR-A-deficient dendritic cells are more responsive to inflammatory stimuli and display a more effective antigen-presenting capability compared with wild-type cells. This is the first report illustrating that SR-A negatively regulates antigen-specific antitumor immunity, which has important clinical implications in vaccine design for cancer immunotherapy.
authors.affiliation: Department of Cellular Stress Biology, Roswell Park Cancer Institute, Buffalo, New York 14263, USA. xiang-yang.wang@roswellpark.org
authors.forename: Xiang-Yang
authors.initials: XY
authors.lastname: Wang
authors.forename: John
authors.initials: J
authors.lastname: Facciponte
authors.forename: Xing
authors.initials: X
authors.lastname: Chen
authors.forename: John R
authors.initials: JR
authors.lastname: Subjeck
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Repasky
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D019496:Cancer Vaccines / Q000276:immunology*; D045744:Cell Line, Tumor; D003713:Dendritic Cells / Q000276:immunology; D006023:Glycoproteins / Q000276:immunology*; D018840:HSP70 Heat-Shock Proteins / Q000276:immunology*; D008546:Melanoma, Experimental / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D051117:Scavenger Receptors, Class A / Q000172:deficiency / Q000235:genetics / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
chemical_list: D019496:Cancer Vaccines; D006023:Glycoproteins; D018840:HSP70 Heat-Shock Proteins; D051117:Scavenger Receptors, Class A; C098410:glucose-regulated protein 170