NK cells: A discrete leukocyte subset of still undefined origin mediating biologically relevant functions upon specific stimulation

Adaptive features of natural killer (NK) cells have been reported in various species with different underlying mechanisms. It is unclear, however, which NK cell populations are capable of mounting antigen-specific recall responses and how such functions are regulated at the molecular level. Here, we identify and characterize a discrete population of CD49a+CD16− NK cells in the human liver that displays increased epigenetic potential to elicit memory responses and has the functional properties to exert antigen-specific immunity in the skin as an effector site. Integrated chromatin-based epigenetic and transcriptomic profiling revealed unique characteristics of hepatic CD49a+CD16− NK cells when compared with conventional CD49a−CD16+ NK cells, thereby defining active genomic regions and molecules underpinning distinct NK cell reactivity. In contrast to conventional NK cells, our results suggest that adaptive CD49a+CD16− NK cells are able to bypass the KIR receptor-ligand system upon antigen-specific stimulation. Furthermore, these cells were highly migratory toward chemokine gradients expressed in epicutaneous patch test lesions as an effector site of adaptive immune responses in the skin. These results define pathways operative in human antigen-specific adaptive NK cells and provide a roadmap for harnessing this NK cell subset for specific therapeutic or prophylactic vaccine strategies.

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Investigation of thin sections of biological standards by EDX, EELS, and Auger electron spectroscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010013451x ◽

1990 ◽

Vol 48 (2) ◽

pp. 184-185

Author(s):

S. Lehner ◽

H.E. Bauer ◽

R. Wurster ◽

H. Seiler

Keyword(s):

Processing System ◽

Beam Current ◽

Beam Diameter ◽

Thin Sections ◽

Biologically Relevant ◽

Energy Filtering ◽

Low Viscosity ◽

Carbon Foils ◽

Electron Microscopical ◽

Exchange Membrane

In order to compare different microanalytical techniques commercially available cation exchange membrane SC-1 (Stantech Inc, Palo Alto), was loaded with biologically relevant elements as Na, Mg, K, and Ca, respectively, each to its highest possible concentration, given by the number concentration of exchangeable binding sites (4 % wt. for Ca). Washing in distilled water, dehydration through a graded series of ethanol, infiltration and embedding in Spurr’s low viscosity epoxy resin was followed by thin sectioning. The thin sections (thickness of about 50 nm) were prepared on carbon foils and mounted on electron microscopical finder grids.The samples were analyzed with electron microprobe JXA 50A with transmitted electron device, EDX system TN 5400, and on line operating image processing system SEM-IPS, energy filtering electron microscope CEM 902 with EELS/ESI and Auger spectrometer 545 Perkin Elmer.With EDX, a beam current of some 10-10 A and a beam diameter of about 10 nm, a minimum-detectable mass of 10-20 g Ca seems within reach.

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Quantification of cell-surface expressed antigenic sites with 5-nm gold markers: Getting close to biologically relevant data

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100157231 ◽

1989 ◽

Vol 47 ◽

pp. 1050-1051

Author(s):

Etienne de Harven ◽

Hilary Christensen ◽

Richard Leung ◽

Cameron Ackerley

Keyword(s):

Cell Surface ◽

Human Peripheral Blood ◽

Contour Length ◽

Thin Sections ◽

Gold Particles ◽

Biologically Relevant ◽

Transmission Electron ◽

Entire Cell ◽

Electron Imaging ◽

Cell Contour

The T-derived subset of human peripheral blood normal lymphocytes has been selected as a model system to study the usefulness of 5 nm gold markers for quantification of single epitopes expressed on cell surfaces. The chosen epitopes are parts of the CD3 and CD5 molecules and can be specifically identified by hybridoma produced monoclonal antibodies (MoAbs; LEU-4 and LEU-1; Becton-Dick- inson, Mountain view, CA) . An indirect immunolabeling procedure, with goat anti-murine IgG adsorbed on the surface of 5 nm colloidal gold particles (GAM-G5, Janssen Pharmaceutica, Beerse, Belgium) has been used. Backscattered Electron Imaging (BEI) in a field emission scanning electronmicroscope (SEM) and transmission electron microscopy of thin sections of lymphocytes labeled before plastic embedding, were both used to identify and quantitate gold labeled cell surface sites, Estimating that the thickness of “silver” sections is approximately 60 nm and counting the number of gold particles on the entire cell perimeter, we calculated that, for LEU-4, the number of markers per um2 of cell surface is in the 140-160 range (Fig.l). Cell contour length measurements indicated that the surface of one lymphocyte is approximately 130-160 um2 that of a smooth sphere of identical diameter, reflecting the role of microvilli in expanding the surface area. The total number of gold labeled sites on the surface of one lymphocyte averages, therefore between 20,000 and 24,000 per cell.

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