Bias in synapse stability leads to suppression of naive CD8 T cell activation by memory CD8 T cells during secondary responses (IRC9P.709)

Abstract T cells can form either a stable synapse or a mobile junction termed kinapse when interacting with antigen presenting cells during an immune response. Stable synapses can lead to long dwell times with antigen presenting cells, whereas mobile kinapses likely favor transient interactions with antigen presenting cells. The underlying cell-intrinsic mechanisms determining the mode of interaction as well as their specific immunological consequences are not known. We have implemented methods borrowed from computer-vision and machine-learning disciplines to accurately quantify the positional stability of T cell junctions formed on model antigen presenting surfaces coated with ICAM-1 and anti-CD3. We have found that human memory CD8 T cells form stable synapses whereas naive CD8 T cells form kinapses or transient contacts. This bias in synapse stability is neither observed in human CD4 T cell subsets nor in murine CD8 T cell subsets under the conditions we have tested. Increased surface expression of LFA1 in human memory CD8 T cells contributes to their increased synapse stability. Using patterned surfaces to simulate competition for antigen presenting cells, we show that synapse stability exhibited by memory CD8 T cells causes suppression of naive cell activation by preventing access to antigen. Increased synapse stability of memory CD8 T cells is expected to promote the development of CTL escape variants during hyper-mutable viral infections and thus prove detrimental to the host.