Abstract: The present invention relates to a method for monitoring Cathepsin S inhibitor activity in tissue samples of animals comprising: a) providing a tissue sample of an animal to whom a Cathepsin S inhibitor has been administered or providing a tissue sample of an animal that was contacted in vitro with a Cathepsin S inhibitor, wherein the tissue samples comprise white blood cells, b) measuring li p10 peptide level in white blood cells of the tissue sample of step a) by flow cytometry and c) correlating li p10 peptide level in white blood cells to Cathepsin S inhibitor dose, wherein a Cathepsin S inhibitor leads to increased level of li p10 peptide in the white blood cells.

Abstract: The present invention relates to a method of producing a modified protein having an increased stability and/or improved folding efficiency as compared to the unmodified protein, the method comprising (i) modifying a nucleic acid molecule encoding a protein comprising at least one immunoglobulin constant domain-like region by (a-i) replacing the nucleotides encoding at least one amino acid, preferably an uncharged amino acid, in the loop separating the C strand from the D strand with nucleotides encoding a charged amino acid selected from the group consisting of Arg, Lys, His, Glu and Asp and/or replacing the nucleotides encoding at least one amino acid, preferably an uncharged amino acid, in the helix connecting the E strand with the F strand with nucleotides encoding a charged amino acid selected from the group consisting of Arg, Lys, His, Glu and Asp; (a-ii) replacing the nucleotides encoding at least one amino acid not having a side chain that can form a hydrogen bond in the loop separating the C strand fr