He completed his Doctor of Medicine degree at Poitiers University in 1981 and then a four-year clinical hematology fellowship in Paris hospitals.
[3] From 1986 until the late 1990s, Triebel headed the cellular immunology group in the Department of Clinical Biology of the Institut Gustave Roussy.
[5] Triebel reported the first cloning of the LAG3 gene in 1990,[6] and two years later his team were able to show that the LAG-3 protein was a ligand for MHC Class II molecules like CD4.
[8] In 1998 Triebel et al. performed the first characterization of the human CD4/LAG-3 gene locus, in the process identifying the LAG-3 promoter regulatory elements.
[10] His team was the first to show that, as a soluble molecule, LAG-3 activates antigen-presenting cells through MHC class II signalling, resulting in antigen-specific T-cell responses.