Telomere Transfer Dynamics in T-APC Synapses

Planar bilayers were constructed as above described and incubated with primary human CD3⁺ CD4⁺ CD27⁺ CD28⁺ T cells. After 20 min activation on bilayers, CD3⁺ CD4⁺ CD27⁺ CD28⁺ T cells were removed with cold PBS. The released synaptic TCRs were retained on the bilayer, as described^{19 (link)}. Next, telomere-live-labelled APCs (obtained by introducing and TelC probe by glass beads as above described) were loaded with antigen pool and transferred on the TCR coated planar bilayers. The % of APCs releasing telomeres on bilayers was quantified 24h later. In control experiments, APCs were not loaded with antigen pool; or they were transferred onto bilayers constructed with ICAM-1 molecules alone without UCTH1. The vesicular nature of the released telomeres was further tested by pre-incubating TelC labelled APCs with antibodies to the vesicle marker CD63 (clone H5c6; Biolegend Cat. 353015) at 1:50 dilution prior to transfer on bilayer.