T Cells Can Use Either T Cell Receptor or Cd28 Receptors to Absorb and Internalize Cell Surface Molecules Derived from Antigen-Presenting Cells

Abstract

At the site of contact between T cells and antigen-presenting cells (APCs), T cell receptor (TCR)–peptide–major histocompatibility complex (MHC) interaction is intensified by interactions between other molecules, notably by CD28 and lymphocyte function-associated antigen 1 (LFA-1) on T cells interacting with B7 (B7-1 and B7-2), and intracellular adhesion molecule 1 (ICAM-1), respectively, on APCs. Here, we show that during T cell–APC interaction, T cells rapidly absorb various molecules from APCs onto the cell membrane and then internalize these molecules. This process is dictated by at least two receptors on T cells, namely CD28 and TCR molecules. The biological significance of T cell uptake of molecules from APCs is unclear. One possibility is that this process may allow activated T cells to move freely from one APC to another and eventually gain entry into the circulation.

Intercellular Trogocytosis Plays an Important Role in Modulation of Immune Responses

“…Of late new reports of intercellular membrane transfer started pouring in. It was demonstrated that T cells can acquire not only the MHC class I and class II proteins (18,19), but also the costimulatory proteins (20)(21)(22), the membrane fragments (23,24) from APCs and the proteins from endothelial cells (25). Till recently, the protein transfer by trogocytosis is believed to be unidirectional in murine system (1).…”

“…Proteins are associated with cell surface by hydrophobic interactions, and the disruption of this hydrophobic interaction is necessary to initiate the intercellular transfer of proteins (9). Absorption, exosome uptake, internalization, and membrane nanotube formation are the probable mechanisms of intercellular membrane transfer ( Figure 1) (16,18,20,(40)(41)(42).…”

T cell activation correlates with an increasedproportion of antigen among the materials acquiredfrom target cells

“…The identity of the molecules acquired differs according to the target cell type [14][15][16], and mainly concerns plasma membrane molecules [4, 10,14]. Transfer via trogocytosis has clearly been shown to occur for MHC [16][17][18][19][20][21][22] and co-stimulatory molecules [16,18,19,[23][24][25], virus receptors [26], adhesion molecules [18][19][20] and lipids [4,10,15,16,26,27]. Trogocytosis has been recorded with every lymphocyte type, and its proposed role(s) differ depending on the cell type.…”

“…Therefore, depending on antigen concentration, there is a correlation between IS formation and what CTL function(s) get triggered. Regarding trogocytosis, the limited amounts of information available on its dependence upon antigen concentration were obtained in multiple separate systems, thus precluding their direct correlation with functional events [4, 18,19]. The aim of our study was, therefore, to analyse how trogocytosis is affected by antigen concentration in relation to various CTL functions and in particular with respect to fratricide.…”

Cell-Cell Communication Via Extracellular Membrane Vesicles and Its Role in the Immune Response

“…Here, membrane-bound receptors and their cognate ligands may play essential roles (Gomez-Rodriguez et al, 2007;Huang et al, 1999;Hwang and Ki, 2011;Hwang et al, 2000;Peterson, 2003;Vestweber, 2007). The set of receptors and ligands making contact with each other in cells determine the phenotypic changes in those cells during or after the contact.…”