Cholesterol-dependent plasma membrane order (Lo) is critical for antigen-specific clonal expansion of CD4+ T cells

Abstract Early “T cell activation” events are initiated within the lipid microenvironment of the plasma membrane. Role of lipid membrane order (L o ) in spatiotemporal signaling through the antigen receptor in T cells is posited but remains unclear. We have examined the role of membrane order (L o )/disorder (L d ) in antigen specific CD4 + T cell activation and clonal expansion by first creating membrane disorder, and then reconstituting membrane order by inserting cholesterol into the disordered plasma membrane. Significant revival of antigen specific CD4 + T cell proliferative response was observed after reconstituting the disrupted membrane order with cholesterol. These reconstitution experiments illustrate Koch’s postulate by demonstrating that cholesterol-dependent membrane order (L o ) is critical for responses generated by CD4 + T cells and point to the importance of membrane order and lipid microenvironment in signaling through T cell membrane antigen receptors.