16. Hoffmann PR, Kench JA, Vondracek A, Kruk E, Daleke DL, et al. (2005) Interaction between phosphatidylserine and the phosphatidylserine receptor inhibits immune responses in vivo. J Immunol 174: 1393–1404. 17. Daleke DL (2003) Regulation of transbilayer plasma membrane phospholipid asymmetry. J Lipid Res 44: 233–242. 18. Devaux PF, Lopez-Montero I, Bryde S (2006) Proteins involved in lipid translocation in eukaryotic cells. Chem Phys Lipids 141: 119–132. 19. Serinkan BF, Gambelli F, Potapovich AI, Babu H, Di Giuseppe M, et al. (2005) Apoptotic cells quench reactive oxygen and nitrogen species and modulate TNF- alpha/TGF-beta1 balance in activated macrophages: involvement of phospha- tidylserine-dependent and -independent pathways. Cell Death Differ 12: 1141–1144. 20. Lauber K, Bohn E, Krober SM, Xiao YJ, Blumenthal SG, et al. (2003) Apoptotic cells induce migration of phagocytes via caspase-3-mediated release of a lipid attraction signal. Cell 113: 717–730. 21. Hanayama R, Tanaka M, Miwa K, Shinohara A, Iwamatsu A, et al. (2002) Identification of a factor that links apoptotic cells to phagocytes. Nature 417: 182–187. 22. Arur S, Uche UE, Rezaul K, Fong M, Scranton V, et al. (2003) Annexin I is an endogenous ligand that mediates apoptotic cell engulfment. Dev Cell 4: 587–598. 23. Obeid M, Tesniere A, Ghiringhelli F, Fimia GM, Apetoh L, et al. (2007) Calreticulin exposure dictates the immunogenicity of cancer cell death. Nat Med 13: 54–61. 24. Martin SJ, Reutelingsperger CP, McGahon AJ, Rader JA, van Schie RC, et al. (1995) Early redistribution of plasma membrane phosphatidylserine is a general feature of apoptosis regardless of the initiating stimulus: inhibition by overexpression of Bcl-2 and Abl. J Exp Med 182: 1545–1556. 25. Park D, Tosello-Trampont AC, Elliott MR, Lu M, Haney LB, et al. (2007) BAI1 is an engulfment receptor for apoptotic cells upstream of the ELMO/Dock180/ Rac module. Nature 450: 430–434. 26. Miyanishi M, Tada K, Koike M, Uchiyama Y, Kitamura T, et al. (2007) Identification of Tim4 as a phosphatidylserine receptor. Nature 450: 435–439. 27. Hanayama R, Tanaka M, Miyasaka K, Aozasa K, Koike M, et al. (2004) Autoimmune disease and impaired uptake of apoptotic cells in MFG-E8- deficient mice. Science 304: 1147–1150. 28. Scott CD, Povitsky A, Dateo C, Gokcen T, Willis PA, et al. (2003) Iron catalyst chemistry in modeling a high-pressure carbon monoxide nanotube reactor. J Nanosci Nanotechnol 3: 63–73. 29. Gorelik O, Nikolaev P, Arepalli S (2000) Purification procedures for single-wall carbon nanotubes. 30. Arepalli S, Nikolaev P, Gorelika O, Hadjievb VG, Holmesa W, et al. (2004) Protocol for the characterization of single-wall carbon nanotube material quality. Carbon 42(8–9): 1783–1791. 31. Vallhov H, Qin J, Johansson SM, Ahlborg N, Muhammed MA, et al. (2006) The importance of an endotoxin-free environment during the production of nanoparticles used in medical applications. Nano Lett 6: 1682–1686. 32. Liu J, Rinzler AG, Dai H, Hafner JH, Bradley RK, et al. (1998) Fullerene pipes. Science 280: 1253–1256. 33. Birch ME (2003) MONITORING OF DIESEL PARTICULATE EXHAUST IN THE WORKPLACE. NIOSH. pp 229–254. 34. Folch J, Lees M, Sloane Stanley GH (1957) A simple method for the isolation and purification of total lipides from animal tissues. J Biol Chem 226: 497–509. 35. Bo¨ttcher CSF, Van Gent CM, Fries C (1961) A rapid and sensitive sub-micro phosphorus determination. Anal Chim Acta 24: 203–204. 36. Rao GV, Tinkle S, Weissman DN, Antonini JM, Kashon ML, et al. (2003) Efficacy of a technique for exposing the mouse lung to particles aspirated from the pharynx. J Toxicol Environ Health A 66: 1441–1452. 37. Bettinger I, Thanos S, Paulus W (2002) Microglia promote glioma migration. Acta Neuropathol 103: 351–355. 38. Buentke E, Heffler LC, Wallin RP, Lofman C, Ljunggren HG, et al. (2001) The allergenic yeast Malassezia furfur induces maturation of human dendritic cells. Clin Exp Allergy 31: 1583–1593. 39. Romani N, Gruner S, Brang D, Kampgen E, Lenz A, et al. (1994) Proliferating dendritic cell progenitors in human blood. J Exp Med 180: 83–93. 40. Ogretmen B, Pettus BJ, Rossi MJ, Wood R, Usta J, et al. (2002) Biochemical mechanisms of the generation of endogenous long chain ceramide in response to exogenous short chain ceramide in the A549 human lung adenocarcinoma cell line. Role for endogenous ceramide in mediating the action of exogenous ceramide. J Biol Chem 277: 12960–12969. 41. Wang S, Liang Z, Wang B, Zhang C (2006) Statistical characterization of single- wall carbon nanotube length distribution. Nanotechnology 17: 634–639. 42. White B, Banerjee S, O’Brien S, Turro JN, Herman PI (2007) Zeta-Potential Measurements of Surfactant-Wrapped Individual Single-Walled Carbon Nanotubes. J Phys Chem 37: 13684–13690. 43. Mohanty B, Verma AK, Claesson P, Bohidar HB (2007) Physical and anti- microbial characteristics of carbon nanoparticles prepared from lamp soot. Nanotechnology 18: 9pp. 44. van Engeland M, Nieland LJ, Ramaekers FC, Schutte B, Reutelingsperger CP (1998) Annexin V-affinity assay: a review on an apoptosis detection system based on phosphatidylserine exposure. Cytometry 31: 1–9. 45. Vermes I, Haanen C, Steffens-Nakken H, Reutelingsperger C (1995) A novel assay for apoptosis. Flow cytometric detection of phosphatidylserine expression Targeting Phagocytes by PS-CNT on early apoptotic cells using fluorescein labelled Annexin V. J Immunol Methods 184: 39–51. 46. Porter AE, Gass M, Muller K, Skepper JN, Midgley PA, et al. (2007) Direct imaging of single-walled carbon nanotubes in cells. Nature Nanotechnology 2: 713–717. 47. Vadiveloo PK (1999) Macrophages–proliferation, activation, and cell cycle proteins. J Leukoc Biol 66: 579–582. 48. Underhill DM (2003) Macrophage recognition of zymosan particles. J Endotoxin Res 9: 176–180. 49. Kagan VE, Tyurin VA, Jiang J, Tyurina YY, Ritov VB, et al. (2005) Cytochrome c acts as a cardiolipin oxygenase required for release of proapoptotic factors. Nature Chemical Biology 1: 223–232. 50. Yang H, Wang SC, Mercier P, Akins DL (2006) Diameter-selective dispersion of single-walled carbon nanotubes using a water-soluble, biocompatible polymer. Chem Commun (Camb). pp 1425–1427. 51. Gotovac S, Yang CM, Hattori Y, Takahashi K, Kanoh H, et al. (2007) Adsorption of polyaromatic hydrocarbons on single wall carbon nanotubes of different functionalities and diameters. J Colloid Interface Sci 314: 18–24. 52. Parnaik R, Raff MC, Scholes J (2000) Differences between the clearance of apoptotic cells by professional and non-professional phagocytes. Curr Biol 10: 857–860. 53. Kisin E, Murray AR, Johnson V, Gorelik O, Arepalli S, et al. (2005) Pulmonary toxicity of carbon nanotubes. The Toxicologist 84: A1041. 54. Houben EN, Nguyen L, Pieters J (2006) Interaction of pathogenic mycobacteria with the host immune system. Curr Opin Microbiol 9: 76–85. 55. Celli J (2006) Surviving inside a macrophage: the many ways of Brucella. Res Microbiol 157: 93–98. 56. Lecaroz C, Gamazo C, Blanco-Prieto MJ (2006) Nanocarriers with gentamicin to treat intracellular pathogens. J Nanosci Nanotechnol 6: 3296–3302. 57. Twigg HL 3rd (2004) Macrophages in innate and acquired immunity. Semin Respir Crit Care Med 25: 21–31. 58. Serhan CN, Savill J (2005) Resolution of inflammation: the beginning programs the end. Nat Immunol 6: 1191–1197. 59. Schuurhuis DH, Fu N, Ossendorp F, Melief CJ (2006) Ins and outs of dendritic cells. Int Arch Allergy Immunol 140: 53–72. 60. Grayson MH (2006) Lung dendritic cells and the inflammatory response. Ann Allergy Asthma Immunol 96: 643–651; quiz 652–643, 678. 61. Service RF (2004) Nanotoxicology. Nanotechnology grows up. Science 304: 1732–1734. 62. Fadeel B, Kagan VE, Krug H, Shvedova AA, Svartengren M, et al. (2007) There’s plenty of room at the forum: potential risks and safety assessment of engineered nanomaterials with focus on carbon particles and nanotubes. Nanotoxicology 1: 73–84. 63. Borm PJ, Kreyling W (2004) Toxicological hazards of inhaled nanoparticles– potential implications for drug delivery. J Nanosci Nanotechnol 4: 521–531. 64. Chellat F, Merhi Y, Moreau A, Yahia L (2005) Therapeutic potential of nanoparticulate systems for macrophage targeting. Biomaterials 26: 7260–7275. 65. Dumortier H, Lacotte S, Pastorin G, Marega R, Wu W, et al. (2006) Functionalized carbon nanotubes are non-cytotoxic and preserve the function- ality of primary immune cells. Nano Lett 6: 1522–1528. 66. Champion JA, Mitragotri S (2006) Role of target geometry in phagocytosis. Proc Natl Acad Sci U S A 103: 4930–4934. 67. Cherukuri P, Bachilo SM, Litovsky SH, Weisman RB (2004) Near-infrared fluorescence microscopy of single-walled carbon nanotubes in phagocytic cells. J Am Chem Soc 126: 15638–15639. 68. Wang H, Wang J, Deng X, Sun H, Shi Z, et al. (2004) Biodistribution of carbon single-wall carbon nanotubes in mice. J Nanosci Nanotechnol 4: 1019–1024. 69. Jia G, Wang H, Yan L, Wang X, Pei R, et al. (2005) Cytotoxicity of carbon nanomaterials: single-wall nanotube, multi-wall nanotube, and fullerene. Environ Sci Technol 39: 1378–1383. 70. Leu D, Manthey B, Kreuter J, Speiser P, DeLuca PP (1984) Distribution and elimination of coated polymethyl [2-14C]methacrylate nanoparticles after intravenous injection in rats. J Pharm Sci 73: 1433–1437. 71. Vauthier C, Dubernet C, Fattal E, Pinto-Alphandary H, Couvreur P (2003) Poly(alkylcyanoacrylates) as biodegradable materials for biomedical applications. Adv Drug Deliv Rev 55: 519–548. 72. Lynch I, Dawson KA, Linse S (2006) Detecting cryptic epitopes created by nanoparticles. Sci STKE 2006: pe14. 73. Voll RE, Herrmann M, Roth EA, Stach C, Kalden JR, et al. (1997) Immunosuppressive effects of apoptotic cells. Nature 390: 350–351. 74. Jiang J, Serinkan BF, Tyurina YY, Borisenko GG, Mi Z, et al. (2003) Peroxidation and externalization of phosphatidylserine associated with release of cytochrome c from mitochondria. Free Radic Biol Med 35: 814–825. 75. Molloy A, Laochumroonvorapong P, Kaplan G (1994) Apoptosis, but not necrosis, of infected monocytes is coupled with killing of intracellular bacillus Calmette-Guerin. J Exp Med 180: 1499–1509. 76. Longhi C, Conte MP, Ranaldi S, Penta M, Valenti P, et al. (2005) Apoptotic death of Listeria monocytogenes-infected human macrophages induced by lactoferricin B, a bovine lactoferrin-derived peptide. Int J Immunopathol Pharmacol 18: 317–325. 77. Larroche C, Mouthon L (2004) Pathogenesis of hemophagocytic syndrome (HPS). Autoimmun Rev 3: 69–75. 78. Szekanecz Z, Koch AE (2007) Macrophages and their products in rheumatoid arthritis. Curr Opin Rheumatol 19: 289–295. PLoS ONE | www.plosone.org 16 February 2009 | Volume 4 | Issue 2 | e4398