Masked chimeric antigen receptor specific to tyrosine-protein kinase like 7 (PTK7) and immune cells expressing such

A masked chimeric antigen receptor (CAR) specific to tyrosine-protein kinase-like 7 (PTK7), the masked CAR comprising:

• (i) an extracellular antigen binding domain, which comprises a single chain variable fragment (scFv) that binds PTK7 and a mask peptide linked to the N-terminus of the scFv via a protease cleavage site;
• and
• (ii) one or more intracellular signaling domains,
• wherein the mask peptide comprises the amino acid sequence selected from the group consisting of:
• (a)
• (SEQ ID NO:
• 1)
• EVAPGKRWFYNHVKQVPHLV,
• (b)
• (SEQ ID NO:
• 2)
• HEEVHMRPNKLSLTWAYTGPQLR,
• and
• (c) X1CX2X3X4X5X6X7X8X9X10X11X12X13, in which X1 is V, W, or absent;
• X2 is T, H, or Y;
• X3 is M, F, Y, I, or H;
• X4 is P, G, or V;
• X5 is P, N, S, Y, K, L, V, or A;
• X6 is S, T, W, A, H, R, or Q;
• X7 is P, T, V, H, I, M, A, F, or W;
• X8 is R, M, A, H, V, Y, or absent;
• X9 is S, Q, Y, T, P, A, M, or I;
• X10 is K, R, I, C, S, Q, H, or absent;
• X11 is V, T, R, L, F, W, or A;
• X12 is I, F, L, W, or H;
• and X13 is C, I, or M.