title: Immunosuppressive activity of recombinant ILT3.
abstract: Tolerogenic antigen presenting cells (APC) are characterized by high expression of the inhibitory receptors ILT3 and ILT4. We have engineered ILT3 and ILT4 cytoplasmic deletion mutants (ILT3delta and ILT4delta), which were transfected in the dendritic-like cell line KG1, to investigate ILT3 and ILT4's capacity to signal extracellularly. KG1.ILT3delta, similar to untruncated ILT3, inhibits T cell responses such as proliferation and cell-mediated cytotoxicity. In contrast, KG1.ILT4delta lost the suppressive activity of untruncated ILT4. This indicates that the inhibitory function of ILT4 relies entirely on the cytoplasmic region containing ITIM motifs. We further demonstrated that recombinant soluble ILT3 inhibits T helper and cytotoxic function while inducing the differentiation of CD8(+) Ts cells. Hence, Ts modulate APC function inducing inhibitory receptors, which in turn elicit the generation of Ts.
authors.affiliation: Department of Pathology, Columbia University, 630 West 168th Street, P and S 14-401, New York, NY 10032, USA.
authors.forename: George
authors.initials: G
authors.lastname: Vlad
authors.forename: Zhuoru
authors.initials: Z
authors.lastname: Liu
authors.forename: Qing-Yin
authors.initials: QY
authors.lastname: Zhang
authors.forename: Raffaello
authors.initials: R
authors.lastname: Cortesini
authors.forename: Nicole
authors.initials: N
authors.lastname: Suciu-Foca
mesh_terms: D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007166:Immunosuppressive Agents / Q000276:immunology / Q000494:pharmacology*; D007371:Interferon-gamma / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D007959:Lymphocyte Culture Test, Mixed; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D009154:Mutation / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics / Q000276:immunology*; D011971:Receptors, Immunologic / Q000235:genetics / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000276:immunology / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000187:drug effects / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism; D014162:Transfection
chemical_list: D016207:Cytokines; D007166:Immunosuppressive Agents; C491341:LILRB2 protein, human; C107907:LILRB4 protein, human; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; D011993:Recombinant Fusion Proteins; D007371:Interferon-gamma