Anti-CTLA - 4 blockade was conceived by Allison and Krummel along with CTLA - 4 's inhibitory role in T cell activation .
Anti-CTLA - 4 blockade is the invention that gave rise to ipilimumab .
Anti-CTLA - 4 blockade , the invention that gave rise to ipilimumab , was conceived by Allison and Krummel along with CTLA - 4 's inhibitory role in T cell activation .