Around 14 January 1983, Barré-Sinoussi and colleagues begin culturing lymphocytes from a biopsied lymph node of an AIDS-risk patient at the Institut Pasteur.
Around 14 January 1983, Françoise Barré-Sinoussi and her colleagues at the Institut Pasteur began the decisive experiment: culturing lymphocytes taken from a biopsied swollen lymph node of a patient considered at risk for the newly emerging acquired immunodeficiency syndrome (AIDS).
This step put into action the strategy devised days earlier with clinician Willy Rosenbaum and virologist Françoise Brun-Vézinet. The choice to culture lymph node tissue, rather than relying solely on blood samples, proved to be an inspired methodological decision, as it allowed the team to observe viral replication dynamics in a tissue type where the unknown pathogen was actively present and detectable.
This experiment represents the opening act of the discovery process that would, within days, yield the first biochemical evidence of a novel retrovirus. It is historically significant as the concrete laboratory beginning of what became the identification of HIV, the virus responsible for AIDS. The urgency of this work reflected the alarming spread of a disease with no known cause and no treatment, and the meticulous, resource-limited conditions under which Barré-Sinoussi and her collaborators operated at the time. Her expertise in detecting reverse transcriptase activity — a hallmark enzyme of retroviruses — made her uniquely positioned to lead this critical phase of the investigation.