Triggering through CD16 or phorbol esters enhances adhesion of NK cells to laminin via very late antigen 6.
Very late antigens VLA-1, VLA-2, VLA-3, and VLA-6, belonging to the beta 1 subfamily of integrins, have been identified as receptors for different binding domains of laminin (LM). We have detected VLA-6, but not VLA-1 and VLA-2 on a subset (50-70%) of fresh peripheral blood CD3-, CD16+, CD56+ human natural killer (NK) cells by immunofluorimetric and biochemical analysis. Binding assays performed on LM-coated plates showed that 10-15% of NK cells spontaneously adhere to LM, and this adhesion is mediated by VLA-6. Activation of NK cells through CD16 triggering or by phorbol ester results in a rapid increase of adhesion to LM, which is still mediated by VLA-6. The enhanced adhesiveness is not associated with changes in beta 1 LM receptor expression, while it correlates with changes in the phosphorylation status of alpha 6 subunit. The expression of VLA-6 on NK cells and the modulation of its avidity by activating stimuli may be relevant for NK cell migration and tissue location during inflammation or immune response.
Gismondi
A
A
Department of Experimental Medicine, University of Rome, Italy.
Mainiero
F
F
Morrone
S
S
Palmieri
G
G
Piccoli
M
M
Frati
L
L
Santoni
A
A
D000818:Animals; D002448:Cell Adhesion; D006801:Humans; D066298:In Vitro Techniques; D007694:Killer Cells, Natural / Q000502:physiology*; D007797:Laminin / Q000378:metabolism*; D008213:Lymphocyte Activation; D051379:Mice; D010766:Phosphorylation; D017452:Receptors, IgG / Q000502:physiology*; D017474:Receptors, Laminin / Q000032:analysis; D016029:Receptors, Very Late Antigen / Q000032:analysis / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D007797:Laminin; D017452:Receptors, IgG; D017474:Receptors, Laminin; D016029:Receptors, Very Late Antigen; D013755:Tetradecanoylphorbol Acetate