Functional analysis of alpha 1 beta 1 integrin in human natural killer cells.
Upon activation with interleukin (IL)-2 human natural killer (NK) cells acquire on their surface the alpha 1 beta 1 and alpha 2 beta 1 integrins and down-regulate the expression of alpha 6 beta 1. By employing alpha 1 beta 1-specific monoclonal antibody (mAb) HP-2B6, characterized in our laboratory, we examined the functional role of the alpha 1 beta 1 integrin in NK cells. Treatment with HP-2B6 mAb partially interfered with attachment of cultured NK cells to type I collagen, and combined with an anti-alpha 2 beta 1 (TEA 1/41) mAb, it completely abrogated cell adhesion to this extracelular matrix protein. In contrast, NK cell attachment to laminin was completely blocked by the anti-beta 1 LIA 1/2 mAb, but was unaffected by alpha 1 and alpha 2-specific mAb; as alpha 3 beta 1 and alpha 6 beta 1 were undetectable, the data indicate that the alpha 1 beta 1 integrin binding sites for type I collagen and laminin are different. Incubation with anti-alpha 1 HP-2B6 or its F(ab')2 fragments specifically induced a rapid homotypic aggregation of NK cells that was dependent on active metabolism, an intact cytoskeleton and the presence of divalent cations (Ca2+ and Mg2+); homotypic cell adhesion was selectively blocked by anti-CD18, CD11a or CD54 mAb. In addition, stimulation of cultured NK cells with the anti-alpha 1 HP-2B6 enhanced TNF-alpha production and induced tyrosine phosphorylation of a 110-kDa protein. Pretreatment with specific inhibitors of protein tyrosine kinase (PTK) activity (tyrphostin 25 and herbimycin A) completely abrogated the functional effects induced by the anti-alpha 1 HP-2B6 mAb. Our data show that ligation of the alpha 1 beta 1 integrin positively modulates IL-2-activated NK cell function via a PTK-dependent pathway.
Pérez-Villar
J J
JJ
Servicio de Immunología, Hospital de la Princesa, Madrid, Spain.
Melero
I
I
Gismondi
A
A
Santoni
A
A
López-Botet
M
M
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002478:Cells, Cultured; D006801:Humans; D039222:Integrin alpha1beta1; D016023:Integrins / Q000502:physiology*; D018799:Intercellular Adhesion Molecule-1 / Q000502:physiology; D007694:Killer Cells, Natural / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D017452:Receptors, IgG / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D000911:Antibodies, Monoclonal; D039222:Integrin alpha1beta1; D016023:Integrins; D017452:Receptors, IgG; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1