| First Author | van Den Engel NK | Year | 2000 |
| Journal | Blood | Volume | 95 |
| Issue | 4 | Pages | 1350-5 |
| PubMed ID | 10666210 | Mgi Jnum | J:110274 |
| Mgi Id | MGI:3639813 | Doi | 10.1182/blood.v95.4.1350.004k07_1350_1355 |
| Citation | van Den Engel NK, et al. (2000) Circulating forms of intercellular adhesion molecule (ICAM)-1 in mice lacking membranous ICAM-1. Blood 95(4):1350-5 |
| abstractText | Mice deficient in intercellular adhesion molecule-1 (ICAM-1), lacking membranous ICAM-1, show a normal development but abnormalities of inflammatory and immune functions. Although the membrane-bound form of ICAM-1 is not detectable in the mutant strain, circulating ICAM-1 (cICAM) is present in serum from ICAM-1-deficient mice in similar amounts as in serum from wild-type mice. These findings were confirmed in vitro by flow cytometric analysis of lipopolysaccharide-stimulated spleen cells, and cICAM-enzyme-linked immunosorbent assay analysis of supernatants of cultured spleen cells. To analyze for the source of cICAM-1, spleen cell RNA was isolated and ICAM-1 RNA was amplified by reverse transcriptase-polymerase chain reaction using primers binding in the 5' and 3' untranslated regions. Different fragments were cloned and sequenced. In wild-type RNA the common 5 domain form of ICAM-1 was identified. In RNA from ICAM-1 mutant mice only 3 smaller fragments were found. Sequencing these fragments identified 3 alternatively spliced isoforms of ICAM-1, lacking 2 or 3 extracellular domains. However, in all spliced fragments the transmembrane domain was included. Therefore, we postulate that circulating forms of ICAM-1 are generated by proteolytic cleavage of membranous ICAM-1. The data indicate that the expression of membranous ICAM-1 and the appearance of circulating forms in serum are independently regulated mechanisms. (Blood. 2000;95:1350-1355) |
