Abstract: The invention relates to anti-CAIX antibodies comprising a heavy chain constant region comprising one or more amino acid substitutions compared to a wild-type IgG, wherein the one or more amino acid substitutions reduce the affinity of the antibody for the neonatal Fc receptor (FcRn), thereby reducing the serum half-life of the modified antibody compared to a wild-type antibody of class IgG. The one or more amino acid modification having the effect of reducing FcRn binding is selected from positions His310, His433, His435, His436, Ile253. Antibodies of the present invention are particularly suited for use in radioimmunotherapy.

Abstract: The invention relates to anti-PSMA antibodies comprising a heavy chain constant region comprising one or more amino acid substitutions compared to a wild-type IgG, wherein the one or more amino acid substitutions reduce the affinity of the antibody for the neonatal Fc receptor (FcRn), thereby reducing the serum half-life of the modified antibody compared to a wild-type antibody of class IgG. The one or more amino acid modification having the effect of reducing FcRn binding is selected from positions His310, His433, His435, His436, Ile253. Antibodies of the present invention are particularly suited for use in radioimmunotherapy.

Abstract: The present invention provides an isolated protein comprising an immunoglobulin variable region comprising at least two cysteine residues positioned within framework region (FR) 2 and/or at least two cysteine residues positioned within framework region (FR3), wherein if at least two of the cysteine residues in FR2 and/or FR3 are not conjugated to a compound then an intra-framework disulphide bond is capable of forming between the cysteine residues. Preferably the protein comprises an immunoglobulin heavy chain variable region (VH) and an immunoglobulin light chain variable region (VL), wherein at least one of the variable regions comprises the two cysteine residues. The present invention also provides conjugates of the protein and another compound.

Abstract: The present invention provides an isolated protein comprising an immunoglobulin variable region comprising at least two cysteine residues positioned within framework region 1 such that if at least two of the cysteine residues are not conjugated to another compound a disulphide bond forms between the cysteine residues. Preferably the protein comprises an immunoglobulin heavy chain variable region and an immunoglobulin light chain variable region, wherein at least one of the variable regions comprises the two cysteine residues. The present invention also provides a protein that binds to TAG72. The present invention also provides conjugates of the protein and another compound.