Nano-structures on plasma membrane of immune cells: Isolation and characterization

Villanova University, USA Animal cells have nano-structures, also known as lipid rafts, on the plasma membrane. Saturated lipids, cholesterol and key signaling receptors as well as enzymes are present in these membrane structures. Lipid rafts play a prominent role in signaling from the cell membrane to the cell interior. Receptors that play a key role in immune response and cell-cell adhesion protein that participate in cellular interactions are present in these nano-structures. Their isolation and characterization will be essential to unraveling the mechanisms of biological response by cells. The insolubility of lipid raft nanostructures in non-ionic detergents has aided in their biochemical isolation from the plasma membrane of cells by density gradient centrifugation. More recently, isolation of lipid rafts was carried out using detergent-free methods. We have developed methods and approaches to investigate the lipid raft nano-structures by electron microscopy and a number of biochemical assays after their isolation by the detergent-based and detergentfree isolation. Characterization of isolated lipid rafts has indicated their heterogeneity in size and composition. Accumulation of immune stimulatory molecules in these natural, biological nano-structures may allow their use in the delivery of vaccines and therapeutics for human and animal health.