A method of preparing a therapeutically active antibody-peptide fusion protein, the method comprising, preparing a codon optimized nucleotide sequence of the antibody-peptide fusion protein, wherein the codon optimized nucleotide sequence is optimized for expression in a Chinese Hamster Ovary host cell, wherein the antibody-protein fusion protein comprises a targeting moiety and immunomodulating moiety, wherein the targeting moiety and the immunomodulating moiety are linked by an amino acid spacer selected from SEQ ID NO: 3 or SEQ ID NO: 11, wherein the immunomodulating moiety is TGF-βRII comprising the amino acid sequence of SEQ ID NO: 4; wherein the targeting moiety is selected from the group consisting of an Anti-EGFR1 antibody, consisting of heavy chain SEQ ID NO: 5 and light chain SEQ ID NO: 6, an Anti-HER2/Neu antibody consisting of heavy chain SEQ ID NO: 1 and light chain SEQ ID NO: 2; and anti-CTLA4 antibody consisting of heavy chain of SEQ ID NO: 7 and a light chain of SEQ ID NO: 8,-wherein SEQ ID NO: 4 is attached via the amino acid spacer to the C-terminus of SEQ ID NO: 1 or SEQ ID NO: 2 of Anti-HER2/Neu; C-terminus of SEQ ID NO: 5 or SEQ ID NO: 6 of Anti-EGFRl; or C-terminus of SEQ ID NO: 7 or SEQ ID NO: 8 of Anti-CTLA-4; cloning the optimized sequence of said antibody-peptide fusion protein in a Chinese Hamster Ovary host cell capable of transient or continued expression; growing the CHO host cell in a feed batch mode in a fermentation medium under suitable conditions for growing and allowing the CHO host cell to express a cloned protein, wherein the fermentation medium comprises a divalent transitional metallic salt;, wherein the divalent transitional metallic salt includes a zinc ion, wherein the divalent transitional metallic salt is zinc sulphate hepta hydrate salt and purifying the expressed antibody-peptide fusion protein and optionally checking the bi-specific binding capabilities of the antibody-peptide fusion protein to its targets. preparing a codon optimized nucleotide sequence of the antibody-peptide fusion protein, wherein the codon optimized nucleotide sequence is optimized for expression in a Chinese Hamster Ovary host cell, wherein the antibody-protein fusion protein comprises a targeting moiety and immunomodulating moiety, wherein the targeting moiety and the immunomodulating moiety are linked by an amino acid spacer selected from SEQ ID NO: 3 or SEQ ID NO: 11, wherein the immunomodulating moiety is TGF-βRII comprising the amino acid sequence of SEQ ID NO: 4; wherein the targeting moiety is selected from the group consisting of an Anti-EGFR1 antibody, consisting of heavy chain SEQ ID NO: 5 and light chain SEQ ID NO: 6, an Anti-HER2/Neu antibody consisting of heavy chain SEQ ID NO: 1 and light chain SEQ ID NO: 2; and anti-CTLA4 antibody consisting of heavy chain of SEQ ID NO: 7 and a light chain of SEQ ID NO: 8,-wherein SEQ ID NO: 4 is attached via the amino acid spacer to the C-terminus of SEQ ID NO: 1 or SEQ ID NO: 2 of Anti-HER2/Neu; C-terminus of SEQ ID NO: 5 or SEQ ID NO: 6 of Anti-EGFRl; or C-terminus of SEQ ID NO: 7 or SEQ ID NO: 8 of Anti-CTLA-4; cloning the optimized sequence of said antibody-peptide fusion protein in a Chinese Hamster Ovary host cell capable of transient or continued expression; growing the CHO host cell in a feed batch mode in a fermentation medium under suitable conditions for growing and allowing the CHO host cell to express a cloned protein, wherein the fermentation medium comprises a divalent transitional metallic salt;, wherein the divalent transitional metallic salt includes a zinc ion, wherein the divalent transitional metallic salt is zinc sulphate hepta hydrate salt and purifying the expressed antibody-peptide fusion protein and optionally checking the bi-specific binding capabilities of the antibody-peptide fusion protein to its targets.