Transgenic non-human animals producing modified heavy chain-only antibodies

An isolated human or chimeric heavy chain-only antibody (HCAb) having binding affinity to a target antigen in the absence of an antibody light chain, comprising a heavy chain variable (VH) domain comprising complementarity determining regions (CDRs) and framework regions (FRs), wherein said HCAb comprises a tryptophane (T) to arginine (R) substitution at the first amino acid position in the fourth FR region (FR4) of the native human VH amino acid sequence.

An isolated autonomous human antibody heavy chain variable (VH) domain comprising complementary determining regions (CDRs) and framework regions (FR), having binding affinity to a target antigen comprising a substitution of a different amino acid residue, that is capable of disrupting a surface-exposed hydrophobic patch comprising or associated with the native amino acid residue at that position, for the native amino acid residue at the first amino acid residue in the fourth framework (FR4) region.

A multi-valent binding protein containing multiple antigen binding domains that include at least one human VH domain comprising complementarity determining regions (CDRs) and framework regions (FRs), having binding affinity to a target antigen, wherein in said VH domain the native amino acid residue at the first position of the fourth framework region (FR4) of said multi-valent binding protein is substituted by a different amino acid residue that is capable of disrupting a surface-exposed hydrophobic patch comprising or associated with the native amino acid residue at that position.

A recombinant heavy chain-only immunoglobulin (Ig) locus comprising one or more human V gene segments, one or more human D gene segments, and one or more human J gene segments, which when recombined with each other in the genome of a non-human animal, and following affinity maturation, encode a heavy chain variable (VH) region comprising complementarity determining regions (CDRs) and framework (FR) regions, wherein at least one of said human J segments comprises a codon encoding a non-native amino acid residue at the first position of the fourth framework region (FR4) that is capable of disrupting a surface-exposed hydrophobic patch comprising or associated with the native amino acid residue at that position.

A transgenic non-human animal that does not express any functional immunoglobulin light chain genes and comprises a heterologous heavy chain-only Ig locus comprising one or more V gene segments, one or more D gene segments, and one or more J gene segments, which when recombined with each other and following affinity maturation encode a VH domain comprising complementarity determining regions (CDRs) and framework regions (FRs), in which the native amino acid residue at the first position of the fourth framework region (FR4) of said VH domain is substituted by a different amino acid residue that is capable of disrupting a surface-exposed hydrophobic patch comprising or associated with the native amino acid residue at that position, and one or more constant effector region gene segments, each of which encodes an antibody constant effector region including CH1 functionality, wherein the gene segments are arranged such that a V, a D and a J gene segment and a constant region gene segment recombine to produce a rearranged affinity matured heavy chain-only gene locus encoding a heavy chain-only antibody (HCAb).