Ligand binding but undetected functional response of FcR after their capture by T cells via trogocytosis.
Intercellular transfer of cell surface proteins by trogocytosis is common and could affect T cell responses. Yet, the role of trogocytosis in T cell function is still elusive, and it is unknown whether a molecule, once captured by T cells, harbors the same biological properties as in donor APC. In this study, we showed that FcgammaR as well as the associated FcRgamma subunit could be detected at high levels on murine and human T cells after their intercellular transfer from FcgammaR-expressing APC. Capture of FcgammaR occurred during coculture of T cells with FcgammaR-expressing APC upon Ab- or Ag-mediated T cell stimulation. Once captured by T cells, FcgammaR were expressed in a conformation compatible with physiological function and conferred upon T cells the ability to bind immune complexes and to provision B cells with this source of Ag. However, we were unable to detect downstream signal or signaling-dependent function following the stimulation of FcgammaR captured by T cells, and biochemical studies suggested the improper integration of FcgammaR in the recipient T cell membrane. Thus, our study demonstrates that T cells capture FcgammaR that can efficiently exert ligand-binding activity, which, per se, could have functional consequences in T cell-B cell cooperation.
Hudrisier
Denis
D
Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France. denis.hudrisier@ipbs.fr
Clemenceau
Béatrice
B
Balor
Stéphanie
S
Daubeuf
Sandrine
S
Magdeleine
Eddy
E
Daëron
Marc
M
Bruhns
Pierre
P
Vié
Henri
H
D000818:Animals; D017951:Antigen Presentation / Q000276:immunology; D000936:Antigen-Antibody Complex / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D002118:Calcium / Q000276:immunology / Q000378:metabolism; D002450:Cell Communication / Q000276:immunology; D002460:Cell Line; D045744:Cell Line, Tumor; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D008024:Ligands; D051379:Mice; D008822:Mice, Transgenic; D009113:Muramidase / Q000276:immunology; D010047:Ovalbumin / Q000276:immunology; D010446:Peptide Fragments / Q000276:immunology; D017452:Receptors, IgG / Q000276:immunology* / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology; D014162:Transfection
D000936:Antigen-Antibody Complex; D015395:Histocompatibility Antigens Class I; D008024:Ligands; C110366:OVA-8; D010446:Peptide Fragments; D017452:Receptors, IgG; D010047:Ovalbumin; C421864:hen egg lysozyme; D009113:Muramidase; D002118:Calcium