Mesothelin binding molecule and application thereof

A mesothelin binding molecule, comprising an anti-mesothelin single domain antibody, wherein the complementarity determining region (CDR) of the single domain antibody comprises CDR1, CDR2 and CDR3, and CDR1 comprises the sequence shown in SEQ ID NO:

• 1, CDR2 comprises the sequence shown in SEQ ID NO:
• 2, and CDR3 comprises the sequence shown in SEQ ID NO:
• 3, wherein,
• SEQ ID NO:
• 1 is X1X2X3X4X5X6X7X8X9X10X11, wherein X1 is G, E, T or A, X2 is S, N, P, A, H, D, K, I or F, X3 is I, S, V, T, D, L, A, M or H, X4 is F, S, I, A, L or G, X5 is N, S, G, A, D, T, E, R or H, X6 is I, L, F, Y, E or N, X7 is N, A, G, D, K, Y, L or S, X8 is A, Y, V, D or N, X9 is E or null, X10 is F or null, X11 is A or null,
• SEQ ID NO:
• 2 is X1X2X3X4X5X6X7X8X9X10X11X12, wherein X1 is I, M, A, T or L, X2 is S, G, N, D, T or V, X3 is S, N, A, R, G or T, X4 is S, T, G, D or N, X5 is N, G, T or I, X6 is S, R, N, D, K, T or G, X7 is D, T, S, I or K, X8 is N, T, G, D or null, X9 is T, K, G or null, X10 is G, R or null, X11 is V, T or null, X12 is T or null,
• SEQ ID NO:
• 3 is X1X2X3X4X5X6X7X8X9X10X11X12X13X14X15X16X17X18X19X20X21X22X23, wherein X1 is N, H, A or Q, X2 is L, A, G or V, X3 is S, R, E, G, D or T, X4 is N, A, R, G, D, K, V, T, I, E or Q, X5 is Y, F, K, S, C, I, D, G, H or R, X6 is D, A, V, G, R, N, P, T, C, Q or S, X7 is R, Y, T, A, D, K, L, E, S or G, X8 is K, S, F, T, D, Q, E, G, P, R, Y or N, X9 is D, G, I, H, S, Y, Q, K, T, R or V, X10 is R, Y, H, N, T, D, P, V, K, C, L or S, X11 is Y, D, E, P, F, S, L, I or null, X12 is P, V, Q, A, Y, F, N, D, R or null, X13 is D, A, Y, V, Q, P or null, X14 is Y, L, P, A, E or null, X15 is C, S, M, P, T or null, X15 is C, S, M, P or null, X16 is V, D, S, Y or null, X17 is L, F, V, D or null, X18 is R, G, M, S or null, X19 is D, N, S or null, X20 is Y, L or null, X21 is Y or null, X22 is A or null, X23 is D or null.