Intracellular Calcium and Calcineurin Regulate Neutrophil Motility on Vitronectin Through a Receptor Identified by Antibodies to Integrins αv and β3

• Published in: Blood 1996-03, Vol.87 (5), p.2038-2048
• Main Authors: Hendey, Bill, Lawson, Moira, Marcantonio, Eugene E., Maxfield, Frederick R.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Immunobiology; Myeloid cells: ontogeny, maturation, markers, receptors; Polynuclears
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V87.5.2038.2038

Buffering of intracellular calcium ([Ca2+]i) or inhibition of the calcium/calmodulin-dependent phosphatase, calcineurin, results in neutrophils being unable to detach from vitronectin with a consequent loss of motility. Treatment of [Ca2+]i-buffered or calcineurin-inhibited neutrophils with monoclonal antibodies (MoAbs) to β3 or αvβ3 integrins allowed neutrophils to detach and restored motility. Quantitative immunofluorescence and flow cytometry showed that MoAbs specific for β3, αv, or αvβ3 integrins bind to neutrophils. Immunolocalization studies using antibodies to the highly conserved cytoplasmic domains of αv and β3 also identified the receptor on neutrophils. Whereas antibodies to αv, αvβ3, and β3 recognized the receptor in intact cells, only the 03 MoAb immunoprecipitated the receptor from a neutrophil cell lysate. The α subunit co-immunoprecipitated by the 03 antibody reacted with an antibody to αv by Western blot. Peptide maps of V8 protease digests showed a strong similarity in α and β chains precipitated by antibodies to β3 from neutrophils and endothelial cells. These results indicate that [Ca2+]i and calcineurin regulate neutrophil motility on vitronectin through an αvβ3-like receptor. Although we cannot rule out the possibility that neutrophils have an isoform of αv, such an isoform would have to be similar enough to react with αv- and αvβ3-specific MoAbs in intact cells.