Binding of alpha2-macroglobulin to collagen type I: modification of collagen matrix by alpha2-macroglobulin induces the enhancement of macrophage migration

Alpha2-macroglobulin (a2M) secreted by tissue macrophages and fibroblasts functions in the environment of extracellular matrix macromolecules. We supposed that it may interact with these molecules and change the properties of extracellular matrix. Modified variant of ELISA was used to prove the dire...

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Published inRussian journal of immunology : RJI : official journal of Russian Society of Immunology Vol. 7; no. 1; p. 34
Main Authors Larin, Sergei S, Gorlina, Natalia K, Kozlov, Ivan G, Cheredeev, Anatoly N, Zorin, Nikolai A, Zorina, Raisa M
Format Journal Article
LanguageEnglish
Published Russia (Federation) 01.04.2002
Subjects
alpha-Macroglobulins - immunology
alpha-Macroglobulins - metabolism
Cell Movement - immunology
Cells, Immobilized - immunology
Collagen Type I - immunology
Collagen Type I - metabolism
Extracellular Matrix - immunology
Extracellular Matrix - metabolism
Fibrinolysin - metabolism
Humans
Macrophage Activation - immunology
Macrophages - cytology
Macrophages - immunology
Macrophages - physiology
Protein Binding
Spleen - cytology
Spleen - immunology
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Summary:Alpha2-macroglobulin (a2M) secreted by tissue macrophages and fibroblasts functions in the environment of extracellular matrix macromolecules. We supposed that it may interact with these molecules and change the properties of extracellular matrix. Modified variant of ELISA was used to prove the direct binding of human a2M to collagen. Native and transformed by plasmin a2M, as well as plasmin, used as the control, were labeled by biotin. It has been found that the transformed, but not the native a2M form binds to type I collagen molecules: K(d)=(1.168 +/- 1.14) x 10(-11) M. The data obtained give a strong evidence of high power of the interaction between a2M and type I collagen: practically no reverse dissociation may be seen for such a binding. The modification of three-dimensional collagen matrix by binding to the transformed a2M resulted in the enhancement of migration of macrophages, carrying the receptors for a2M, but not splenocytes that lack for such receptors. Our results allow to suggest that a2M may be one of the components of extracellular matrix, and may change the properties of microenvironment for immunocompetent cells during the processes of inflammation, reparation and tumor invasion.
ISSN:1028-7221