Antibodies for targeting cd28 and uses thereof

An isolated polypeptide or polypeptide complex comprising a peptide that impairs binding of a CD28 binding domain to CD28 expressed on an effector cell, wherein the peptide comprises an amino acid sequence according to:

• X1-X2-W-C-X3-X4-X5-X6-X7-X8-X9-C-X10-X11, wherein
• X1 is selected from A, R, N, D, Q, E, G, H, I, L, K, F, P, S, T, W, Y, and V;
• X2 is selected from D, P, and Y;
• X3 is selected from P and Q;
• X4 is selected from R, L, and I;
• X5 is selected from D, H, Y, and I;
• X6 is selected from L, S, and R;
• X7 is selected from W and G;
• X8 is selected from V, A, D, H, L, and N;
• X9 is selected from H, L, E, and D;
• X10 is selected from F, Y, and L;
• and
• X11 is selected from A, N, H, and T.

An isolated polypeptide or polypeptide complex comprising a CD28 binding domain that is linked to a peptide that impairs binding of the CD28 binding domain to CD28, wherein the peptide comprises an amino acid sequence according to:

• Z1-C-Z2-Z3-Z4-Z5-Z6-Z7-Z8-Z9-Z10-Z11-C-Z12, wherein:
• Z1 is selected from Y, H, and A;
• Z2 is selected from D, E, A, Q, S, V, M, H, L, F, T, W, and N;
• Z3 is selected from G, E, S, and A;
• Z4 is selected from H, L, W, and A;
• Z5 is selected from L, S, A, T, I, V, M, R, E, D, F, H, K, Q, N, Y, W, and G;
• Z6 is selected from P, A, E, Q, S, L, W, G, V, D, K, I, M, R, T, F, H, N, and Y;
• Z7 is selected from E, Q, I, M, V, A, L, R, W, P, D, T, K, S, G, H, and N;
• Z8 is selected from Y, H, F, W, N, Q, and A;
• Z9 is selected from M, I, L, R, V, K, F, Q, Y, W, and A;
• Z10 is selected from A, Q, S, W, E, L, G, D, T, M, N, V, H, R, Y, K, P, F, and I;
• Z11 is selected from K, Q, N, H, E, P, and A;
• and
• Z12 is selected from L, M, I, F, V, Y, Q, D, T, and A.

An isolated polypeptide or polypeptide complex comprising a CD28 binding domain that is linked to a peptide that impairs binding of the CD28 binding domain to CD28, wherein the peptide comprises an amino acid sequence according to:

• U1-C-U2-U3-U4-U5-U6-U7-U8-U9-U10-U11-C-U12, wherein:
• U1 is selected from T, S, L, M, W, Q, P, R, G, N, I, Y, D, E, V, H, and A;
• U2 is selected from A, S, T, K, E, R, G, N, W, and D;
• U3 is selected from A, E, P, D, G, W, Q, V, and F;
• U4 is selected from G, V, F, D, E, R, and A;
• U5 is selected from A, F, V, S, L, P, and M;
• U6 is selected from T, S, H, M, A, N, P, G, Q, D, Y, V, L, I, E, K, F, and R;
• U7 is selected from Y, W, F, L, N, T, Q, I, and A;
• U8 is selected from P, S, T, A, E, K, Q, N, V, G, H, L, D, Y, I, M, and R;
• U9 is selected from W, L, and A;
• U10 is selected from P, S, R, L, E, and A;
• U11 is selected from L, A, T, M, V, W, Y, E, Q, I, F, S, P, K, R, D, H, N, and G;
• and
• U12 is selected from L, F, V, M, I, Y, E, W, and A.

An isolated polypeptide or polypeptide complex comprising a CD28 binding domain that is linked to a peptide that impair binding of the CD28 binding domain to CD28, wherein the peptide comprises an amino acid sequence according to X1-X2-X3-C-X4-X5-X6-X7-X8-X9-X10-C-X11-X12, wherein:

• X1 is selected from M, I, L, and V;
• X2 is selected from D, H, N, A, F, S, T, Y, and V;
• X3 is selected from W, L, and F;
• X4 is selected from P, A, and L;
• X5 is selected from R, T, I, M, S, K, L, V, W, F, A, P, and D;
• X6 is selected from E, D, Y, H, S, F, A, N, T, I, P, and V;
• X7 is selected from L, M, R, S, Q, and H;
• X8 is selected from W and Q;
• X9 is selected from H, N, D, A, S, Y, T, F, V, L, and I;
• X10 is selected from E, V, L, D, Y, R, Q, H, F, K, A, M, and N;
• X11 is selected from F, Y, L, W, and V;
• and
• X12 is selected from N, A, F, S, Y, H, D, T, and L.