CD4+ T cell acquisition of the bystander pMHC I colocalizing in the same immunological synapse comprising pMHC II and costimulatory CD40, CD54, CD80, OX40L, and 41BBL.
We previously showed that CD4+ T cells acquired peptide/major histocompatibility complex (pMHC) I and costimulatory molecules by dendritic cell (DC) activation. However, the molecular mechanism for pMHC I acquisition is unclear. In this study, by using a panel of engineered DC2.4 cells or incubation of these cells with Con A-stimulated CD4+ T cells, we conducted capping and synapse formation assay and examined them by confocal fluorescence microscopy. We demonstrated that (i) CD54 and CD80 colocalized with pMHC I/II in the same lipid rafts, whereas CD40, OX40L, and 41BBL localized in the lipid rafts but separately from pMHC I/II, and (ii) MHC I/II colocalized with the costimulatory molecules in the same synapse formed between a DC and a CD4+ T cell, leading to expression of the acquired bystander pMHC I on CD4+ T cells via internalization/recycling pathway. These results provide some useful information in composition and dynamics of immunological synapses.
He
Tianpei
T
Research Unit, Saskatchewan Cancer Agency, Department of Oncology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 4H4.
Zong
Sam
S
Wu
Xiaochu
X
Wei
Yangdou
Y
Xiang
Jim
J
D000818:Animals; D024201:Bystander Effect / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D016207:Cytokines / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D051379:Mice; D013569:Synapses / Q000276:immunology*