title: Laser ablation-inductively coupled plasma mass spectrometry: an emerging technology for detecting rare cells in tissue sections.
abstract: Administering immunoregulatory cells to patients as medicinal agents is a potentially revolutionary approach to the treatment of immunologically mediated diseases. Presently, there are no satisfactory, clinically applicable methods of tracking human cells in patients with adequate spatial resolution and target cell specificity over a sufficient period of time. Laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) represents a potential solution to the problem of detecting very rare cells in tissues. In this article, this exquisitely sensitive technique is applied to the tracking of gold-labeled human regulatory macrophages (Mregs) in immunodeficient mice. Optimal conditions for labeling Mregs with 50-nm gold particles were investigated by exposing Mregs in culture to variable concentrations of label: Mregs incubated with 3.5 × 10(9) particles/ml for 1 h incorporated an average of 3.39 × 10(8) Au atoms/cell without loss of cell viability. Analysis of single, gold-labeled Mregs by LA-ICP-MS registered an average of 1.9 × 10(5) counts/cell. Under these conditions, 100% labeling efficiency was achieved, and label was retained by Mregs for ≥36 h. Gold-labeled Mregs adhered to glass surfaces; after 24 h of culture, it was possible to colabel these cells with human-specific (154)Sm-tagged anti-HLA-DR or (174)Yb-tagged anti-CD45 mAbs. Following injection into immunodeficient mice, signals from gold-labeled human Mregs could be detected in mouse lung, liver, and spleen for at least 7 d by solution-based inductively coupled plasma mass spectrometry and LA-ICP-MS. These promising results indicate that LA-ICP-MS tissue imaging has great potential as an analytical technique in immunology.
authors: Centre for Analytical Science, Department of Chemistry, Loughborough University, Loughborough, Leicestershire LE11 3TU, United Kingdom;
authors: Amy J
authors: AJ
authors: Managh
authors: Electro Scientific Industries, Huntingdon, Cambridgeshire PE29 6XS, United Kingdom;
authors: Robert W
authors: RW
authors: Hutchinson
authors: Division of Experimental Surgery, Department of Surgery, University Hospital Regensburg, Regensburg 93053, Germany;
authors: Paloma
authors: P
authors: Riquelme
authors: Division of Experimental Surgery, Department of Surgery, University Hospital Regensburg, Regensburg 93053, Germany;
authors: Christiane
authors: C
authors: Broichhausen
authors: Department of Obstetrics and Gynaecology, University Hospital Regensburg, Regensburg 93053, Germany;
authors: Anja K
authors: AK
authors: Wege
authors: Institute for Immunology, University of Regensburg, Regensburg 93053, Germany; and.
authors: Uwe
authors: U
authors: Ritter
authors: Department of Transfusion Medicine, University Hospital Regensburg, Regensburg 93053, Germany.
authors: Norbert
authors: N
authors: Ahrens
authors: Division of Experimental Surgery, Department of Surgery, University Hospital Regensburg, Regensburg 93053, Germany;
authors: Gudrun E
authors: GE
authors: Koehl
authors: Division of Experimental Surgery, Department of Surgery, University Hospital Regensburg, Regensburg 93053, Germany;
authors: Lisa
authors: L
authors: Walter
authors: Division of Experimental Surgery, Department of Surgery, University Hospital Regensburg, Regensburg 93053, Germany;
authors: Christian
authors: C
authors: Florian
authors: Division of Experimental Surgery, Department of Surgery, University Hospital Regensburg, Regensburg 93053, Germany;
authors: Hans J
authors: HJ
authors: Schlitt
authors: Centre for Analytical Science, Department of Chemistry, Loughborough University, Loughborough, Leicestershire LE11 3TU, United Kingdom;
authors: Helen J
authors: HJ
authors: Reid
authors: Division of Experimental Surgery, Department of Surgery, University Hospital Regensburg, Regensburg 93053, Germany;
authors: Edward K
authors: EK
authors: Geissler
authors: Centre for Analytical Science, Department of Chemistry, Loughborough University, Loughborough, Leicestershire LE11 3TU, United Kingdom;
authors: Barry L
authors: BL
authors: Sharp
authors: Division of Experimental Surgery, Department of Surgery, University Hospital Regensburg, Regensburg 93053, Germany; james.hutchinson@ukr.de.
authors: James A
authors: JA
authors: Hutchinson
mesh_terms: D000818:Animals; D058846:Antibodies, Monoclonal, Murine-Derived; D006046:Gold / Q000494:pharmacology*; D064593:Heterografts; D006801:Humans; D007834:Lasers; D017493:Leukocyte Common Antigens / Q000737:chemistry / Q000276:immunology*; D008168:Lung / Q000166:cytology / Q000276:immunology; D013058:Mass Spectrometry / Q000295:instrumentation*; D051379:Mice; D016688:Mice, Inbred NOD; D009000:Monocytes / Q000166:cytology / Q000276:immunology / Q000637:transplantation
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D006046:Gold; D017493:Leukocyte Common Antigens; C516769:PTPRC protein, human