CD40 ligand: the essential link in B/T cell collaboration and immune activation

This Pillars of Immunology article is a commentary on 2 pivotal articles that shaped the CD40-CD40L field - "Defective expression of T-cell CD40 ligand causes X-linked immunodeficiency with hyper-IgM," written by U. Korthäuer, D. Graf, H.W. Mages, F. Brière, M. Padayachee, S. Malcolm, A.G. Ugazio, L.D. Notarangelo, R.J. Levinsky, and R.A. Kroczek, and published in Nature, in 1993. https://www.nature.com/articles/361539a0; and "CD40 ligand mutations in X-linked immunodeficiency with hyper-IgM" written by J.P. DiSanto, J.Y. Bonnefoy, J.F. Gauchatt, A. Fischer, and G. de Saint Basile, and published in Nature, in 1993. https://www.nature.com/articles/361541a0.