CD16 on human gamma delta T lymphocytes: expression, function, and specificity for mouse IgG isotypes.
We examined the expression, the signal transduction capacity and mouse IgG-isotype specificity of CD16 on human gamma delta T cells. CD16 is expressed by the majority of gamma delta T cells in peripheral blood and by part of the gamma delta T cell clones. The amount of CD16 expressed on gamma delta T cell clones varied considerably with passaging of the cells, but was always significantly less than on freshly isolated gamma delta T cells. Like CD16 on CD3- CD16+ natural killer (NK) cells, CD16 on gamma delta T cells can act as an activation site triggering cytotoxic activity. CD16+ gamma delta T cell clones exerted antibody-dependent cellular cytotoxicity (ADCC) which could be blocked by anti-CD16 mAb. ADCC activity of gamma delta T cell clones was also inhibited by anti-CD3 mAb, suggesting a functional linkage between the CD16 and CD3 activation pathways. MAb directed against CD16 induced lysis of Fc gamma R+ target cells by CD16+ gamma delta T cell clones. The mouse IgG-isotype specificity of CD16 on gamma delta T cells was analyzed using isotype switch variants of a murine anti-glycophorin A mAb in EA rosette assays, and was found to be identical to that of CD16 on CD3- CD16+ NK cells, i.e., highest affinity for mIgG2a, intermediate affinity for mIgG2b, and undetectable binding of mIgG1-sensitized erythrocytes. CD16 was partly modulated from the cell surface of both gamma delta T cells and NK cells after rosette formation with mIgG2a-sensitized erythrocytes, indicating that the rosette formation was indeed mediated via the CD16 molecule.
Braakman
E
E
Department of Immunology, Daniel den Hoed Cancer Center, Rotterdam, The Netherlands.
van de Winkel
J G
JG
van Krimpen
B A
BA
Jansze
M
M
Bolhuis
R L
RL
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000943:Antigens, Differentiation / Q000032:analysis*; D003602:Cytotoxicity, Immunologic; D000939:Epitopes; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D007132:Immunoglobulin Isotypes / Q000276:immunology*; D051379:Mice; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000032:analysis* / Q000502:physiology; D011961:Receptors, Fc / Q000032:analysis*; D017452:Receptors, IgG; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D000939:Epitopes; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D016692:Receptors, Antigen, T-Cell, gamma-delta; D011961:Receptors, Fc; D017452:Receptors, IgG