ISSN:
0730-2312
Keywords:
integrin
;
CD11b/CD18
;
Mac-1
;
Leu-CAM
;
neutrophil
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Full-length (membrane bound) and truncated (secreted) forms of the beta 2 integrin heterodimer, CD11b/CD18 (Mac-1), were expressed in a human kidney cell line (293) that normally does not express leukocyte adhesion molecules (Leu-CAMs). The biosynthesis of recombinant Mac-1 in 293 cells differed from that reported for leukocytes in that heterodimer formation was not required for CD11b to be exported to the cell surface. A stable cell line was constructed that constitutively secreted the recombinant, truncated Mac-1 heterodimer into growth conditioned cell culture medium. A novel monoclonal antibody that enabled an immunoaffinity method for the selective purification of recombinant Mac-1 heterodimers was identified. Sufficient protein was purified to allow the first measurement of the 50% inhibitory concentration (IC50) for CD11b/CD18 and for the direct comparison of the inhibitory activity of recombinant soluble Mac-1 with that of various CD18 and CD11b specific monoclonal antibodies. Purified recombinant soluble Mac-1 inhibited the binding of neutrophils, activated by opsonized zymosan or fMet-Leu-Phe peptide, to human umbilical vein endothelial cells. Similarly, the recombinant integrin was effective in inhibiting the binding of unactivated neutrophils to tumor necrosis factor (TNF-alpha) activated endothelial cells. The availability of an abundant source of purified, biologically active Mac-1 will enable direct physical and chemical investigations into the relationship between the structure and function of this leukocyte adhesion molecule.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcb.240520210
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