Abstract: The present invention relates to amino acid sequences (also referred to herein as “single variable domain(s) of the invention”. “Nanobody™ of the invention” or “Nanobodies™ of the invention”, ilpolypeptide(s) of the invention”) that are directed against (as defined herein) members of the Notch signalling pathway such as the four mammalian members of the Notch Receptors (Notch-1, Notch-2, Notch-3, Notch-4, hereinafter also “Notch Receptors”) and the five mammalian members of the Notch Ligands (the Delta-like family with “DLL1”, “DLL3”, “DLL4” wherein “DLL” stands for Delta-like ligand; the Jagged family with “Jagged-1”, “Jagged-2”, hereinafter also “Notch Ligands”), as well as to constructs that comprise or essentially consist of one or more such single variable domain(s) (also referred to herein as “construct of the invention” and “constructs of the invention”, “Nanobody™ of the invention” or “Nanobodies™ of the invention”, respectively).

Abstract: The present invention relates to amino acid sequences that block the interaction between (a target on) an antigen presenting cell (APC) and (a target on) a T-cell. More particularly, the present invention relates to amino acid sequences that are directed against (as defined herein) a target on an APC (also referred to herein as “APC target”) or a target on a T-cell (also referred to herein as “T-cell target”).