Migration and formation of capillary blood vessels by endothelial cells.
blind well chamber –
A blind well chamber is based on the Boyden chamber design, and is used in much the same way. This instrument is comprised of a lower well, filter, and upper well. In some cases, a gasket is used to seal the lower and upper well. Blind well chambers are primarily used with adherent cell lines and are commonly available as single well and multi well chemotaxis chambers.
Boyden chamber –
A chemotaxis chamber based on an instrument devised by S. V. Boyden in the 1960’s. The term is sometimes used broadly to refer to any chemotaxis chamber, but is here used only for BY312 , the Neuro Probe single well chemotaxis chamber based on Boyden’s instrument.
cell activity –
Movement, invasion, angiogenesis, growth, proliferation, or differentiation of biological cells. Cell-activity assays referred to in this website are almost always intended to measure movement.
cell migration –
Multicellular organisms rely on cell migration for development, immune response, and wound healing among other things. These processes rely on cells to actively move in response to changes in chemical signals, a process known as chemotaxis.
cellulose nitrate filters –
Filters consisting of cellulose nitrate membrane with a sponge-like structure. Cellulose nitrate filters used for chemotaxis research are about 150 microns thick (10 to 15 times thicker than polycarbonate filters). During chemotaxis cells migrate into the filter to different depths, and the depths are measured.
checkerboard assay –
A method of differentiating chemoattraction from chemokinesis, using alternating concentrations of the chemokine in the upper and lower wells.
A substance exhibiting chemical properties that attract biological cells during chemotaxis.
A chemical substance that increases activity of a cell or organism. This activity may be toward the chemokine, away from it, or random.
Increased activity of a cell or organism due to a chemical substance.
chemokinetic controls –
Sites in a chemotaxis assay at which the chemotactic factor at the same concentration is placed in both the upper and the lower wells, so that chemoattractant is present, but there is no directional gradient in the concentration.
a chemokine that causes movement away from itself. This action is sometimes referred to as fugetaxis. Such chemokines may be used to inhibit chemoattraction.
Directional movement (migration) of biological cells or organisms in response to concentration gradients of chemicals, whereby the cells are attracted or repelled by substances exhibiting chemical properties.
chemotaxis chamber –
An instrument in which chemotaxis of cells across a membrane occurs in controlled conditions.
detection system –
A method and instruments used by a trained observer to tabulate the results of a cell-activity assay. For example fluorescent dyes, a fluorescence plate reader, and computer might form a detection system, as would staining equipment and a microscope.
differential count –
Meaning will vary with context.
In cell activity assays, the ratio of the number of cells counted at two different kinds of sites of an assay. For example in an assay that includes positive, negative, and experimental or unknown sites, the differential count of positive to negative controls might be 6:1, the differential count of experimental sites to negative controls might vary between 5.5:1 and 1:1 depending on the concentration of chemoattractant at the sites.
In cell settling assays, refers to percentages of various cell types in a mixed population.
experimental sites –
Sites in a chemotaxis assay at which the upper wells contain a cell suspension and the lower wells contain a chemical whose chemotactic properties are unknown. The assay is intended to measure the chemotactic effect of the chemical on the type of cells in upper wells.
human interleukin-8 (IL-8) – (also called neutrophil attractant protein-1 (NAP-1))
IL-8, an 8.0 kDa protein, promotes neutrophil chemotaxis and degranulation. It comes in two forms, containing either 72 or 77 amino acid residues. It is available as a lyophilized powder (recombinant-derived; source is E. coli) with a purity rating of greater than 98% by SDS-PAGE and N-terminal sequence analysis. Endoxin level is less than 0.1 ng per mg of IL-8. To use IL-8: IL-8 is available for research purposes only, and is not available for drug use. The lyophilized powder is soluble in water and most aqueous buffers.
Lyophilized IL-8 can be reconstituted in PBS to a concentration of 100 ng/ml. This solution can be diluted into other buffered solutions or stored at -20°C. The maximal chemotactic activity of human IL-8 on human neutrophils as assayed by a modified Boyden chamber was achieved at 20 ng/ml. Stability of IL-8: The lyophilized powder is stable at room temperature, but is best stored desiccated below 0°C. Reconstituted IL-8 should be stored in working aliquots at -20°C.
human macrophage chemoattractant protein-1 (MCP-1) – also called human macrophage/monocyte chemotactic and activating factor (MCAF)
MCP-1 is an 8.5 kDa protein containing 76 amino acid residues. It plays an important role in the inflammatory response of blood monocytes and tissue macrophages. MCP-1 (recombinant-derived; source is E coli) is lyophilized from PBS, and has a purity rating of greater than 99% by SDS-PAGE and P-HPLC analysis. To use MCP-1: The lyophilized powder MCP-1 is soluble in water and most aqueous buffers. Lyophilized MCP-1 can be reconstituted in PBS to a concentration of 0.1 mg/ml. This solution can be diluted into other buffered solutions or stored at -20° for future use. The maximal chemotactic activity of human MCP-1 on human blood monocytes was achieved at 20 ng/ml. MCP-1 is available for research purposes only; not for drug use. Stability of MCP-1: The lyophilized powder is stable at room temperature, but is best stored desiccated below 0°C.
human macrophage/monocyte chemotactic and activating factor –
Sites in a chemotaxis assay at which the upper wells contain the same cell suspension as is used at experimental sites, but the lower wells contain only cell-suspension media without any chemoattractant.
Filters of polycarbonate film with track-etched capillary pores. Polycarbonate filters used for chemotaxis research are usually less than eleven microns thick. During chemotaxis cells migrate in one side of the filter and out the other, where they are counted. (Compare with cellulose nitrate filters.) Track-etched filters may also be made from a polyester membrane.
positive controls –
Sites in a chemotaxis assay at which a chemoattractant with known properties is placed, at optimum concentration, in the lower wells to attract the cells of the assay. The same cell suspension as is used in the experimental sites is used in the upper wells of the positive controls. Cell activity at experimental sites can thus be compared to the activity produced by a known chemoattractant.