AIDS research laboratory. High-security doors and air locks isolate Dr Quentin Sattentau as he passes out of a high security (level 3) laboratory. He is a French AIDS researcher at the Immunology Centre of the CNRS (Marseille Luminy). Sattentau is researching CD4 receptors and 'anti- sense' treatment against AIDS. The AIDS virus infects T-cells of the human immune system, by recognising CD4 receptors on the cell membrane. The AIDS virus then inserts genetic material into T-cells, instructing the cells to produce virus proteins. Synthetic 'antisense' material, inserted into T-cells, may disable virus genetic material from being read and producing AIDS viral proteins.