title: Cutting edge: mouse CD300f (CMRF-35-like molecule-1) recognizes outer membrane-exposed phosphatidylserine and can promote phagocytosis.
abstract: Reportedly, CD300f negatively regulates interactions between dendritic and T cells and acts as an anti-inflammatory molecule in a multiple sclerosis mouse model. We found that a CD300f/Fc chimeric protein specifically binds to apoptotic/dead splenocytes and to apoptotic cells from starved or irradiated lymphocytic cell lines, an observation extended to insect cells. CD300f also binds PMA/ionomycin-activated splenocytes and Ag-stimulated T cells, an interaction inhibited by Annexin V. By ELISA, cosedimentation, and surface plasmon resonance using phospholipid-containing liposomes, we show that CD300f preferentially binds phosphatidylserine and requires a metal ion. Exogenous expression of CD300f in cell lines results in enhanced phagocytosis of apoptotic cells. We conclude that expression of CD300f conveys additional capacity to recognize phosphatidylserine to myeloid cells. The result of this recognition may vary with the overall qualitative and quantitative receptor content, as well as signaling capacity of the expressing effector cell, but enhanced phagocytosis is one measurable outcome.
authors.affiliation: Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA.
authors.forename: Seung-Chul
authors.initials: SC
authors.lastname: Choi
authors.forename: Venkateswara R
authors.initials: VR
authors.lastname: Simhadri
authors.forename: Linjie
authors.initials: L
authors.lastname: Tian
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Gil-Krzewska
authors.forename: Konrad
authors.initials: K
authors.lastname: Krzewski
authors.forename: Francisco
authors.initials: F
authors.lastname: Borrego
authors.forename: John E
authors.initials: JE
authors.lastname: Coligan
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000276:immunology*; D017209:Apoptosis / Q000276:immunology; D002462:Cell Membrane / Q000276:immunology / Q000378:metabolism; D002469:Cell Separation; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D010587:Phagocytosis / Q000276:immunology*; D010718:Phosphatidylserines / Q000276:immunology*; D011971:Receptors, Immunologic / Q000276:immunology*; D015398:Signal Transduction / Q000276:immunology; D020349:Surface Plasmon Resonance; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D010718:Phosphatidylserines; D011971:Receptors, Immunologic