Cellular mechanisms for the formation of a soluble form derivative of T-cell receptor alpha chain by suppressor T cells.
Upon stimulation with anti-CD3, suppressor T-cell (Ts) hybridomas and homologous transfectants of T-cell receptor a (TCRalpha) cDNA in the T-cell hybridoma formed a 55-kDa TCRalpha chain derivative that bound both the monoclonal anti-TCRalpha chain and polyclonal antibodies against glycosylation inhibiting factor (GIF). The peptide is a subunit of antigen-specific suppressor T-cell factor (TsF), and is considered to be a posttranslationally-formed conjugate of TCRalpha chain with GIF peptide. The TCRalpha derivative is synthesized by the transfectant after stimulation with anti-CD3, and not derived from TCR present on the cell surface. Stimulation of the stable homologous transfectants with anti-CD3 induced translocation of the 13-kDa GIF peptide into endoplasmic reticulum (ER). When a helper Ts hybridoma or a stable transfectant of the same TCRalpha cDNA in a helper cell-derived TCRalpha- clone was stimulated with anti-CD3, translocation of GIF peptide was not detected, and these cells failed to secrete a TCRalpha derivative. However, further transfection of a chimeric cDNA encoding a procalcitonin-GIF fusion protein into the helper cell-derived stable transfectant of TCRalpha cDNA resulted in translocation of the GIF protein and formation of bioactive 55-kDa GIF. The results indicated that translocation of GIF peptide through ER is unique for Ts cells, and that this process is essential for the formation/secretion of the soluble form derivative of TCRalpha chain by T cells.
Ishii
Y
Y
La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA.
Nakano
T
T
Ishizaka
K
K
D000818:Animals; D000911:Antibodies, Monoclonal; D002460:Cell Line; D006031:Glycosylation; D006825:Hybridomas; D008222:Lymphokines / Q000096:biosynthesis / Q000378:metabolism; D046911:Macromolecular Substances; D051379:Mice; D029584:Prostatic Secretory Proteins; D011499:Protein Processing, Post-Translational; D011817:Rabbits; D017260:Receptor-CD3 Complex, Antigen, T-Cell / Q000276:immunology / Q000502:physiology*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D014162:Transfection
D000911:Antibodies, Monoclonal; D008222:Lymphokines; D046911:Macromolecular Substances; D029584:Prostatic Secretory Proteins; D017260:Receptor-CD3 Complex, Antigen, T-Cell; D016693:Receptors, Antigen, T-Cell, alpha-beta; D011993:Recombinant Fusion Proteins; C043076:beta-microseminoprotein; C013059:immunoglobulin-binding factors