Production of humanized antibodies in transgenic animals
This invention relates to humanized antibodies and antibody preparations produced from transgenic non-human animals. The non-human animals are genetically engineered to contain one or more humanized immunoglobulin loci which are capable of undergoing gene rearrangement and gene conversion in the transgenic non-human animals to produce diversified humanized immunoglobulins. The present invention further relates to novel sequences, recombination vectors and transgenic vectors useful for making these transgenic animals. The humanized antibodies of the present invention have minimal immunogenicity to humans and are appropriate for use in the therapeutic treatment of human subjects.
1. A transgenic vector comprising a humanized Immunoglobulin (Ig) locus, wherein
(a) said humanized Ig locus comprises multiple Ig gene segments, including multiple variable (V) gene segments, multiple J gene segments, and one or more constant region gene segments,
(b) at least one of said gene segments is a functional V gene segment encoding a human V region amino acid sequence,
(c) said V gene segments are separated only by non-coding, non-human sequences derived from a non-human animal that generates antibody diversity primarily through gene conversion and/or hypermutation,
(d) at least one of said functional V gene segments encoding a human V region amino acid sequence is placed downstream of the other V gene segments, and
(e) said Ig gene segments are juxtaposed in an unrearranged, partially rearranged or fully rearranged configuration, and
wherein, as a result of structural features (a)–(e), said humanized Ig locus is capable of undergoing gene conversion and producing a repertoire of humanized immunoglobulins with V region amino acid sequences encoded by segments of more than one V region gene, in said non-human animal.
2. The transgenic vector of claim 1 , wherein said non-human animal is rabbit, pig, chicken, sheep or cow.
3. The transgenic vector of claim 1 , wherein said humanized Ig locus is a heavy chain locus and comprises at least two human V gene segments, at least one D gene segment, at least two J gene segments and one or more constant region segments.
4. The transgenic vector of claim 1 , wherein said humanized Ig locus is a light chain locus and comprises at least two V gene segments, at least two J gene segments, and one or more constant region gene segments.
5. The transgenic vector of claim 3 , wherein the non-human animal is a rabbit, and at least one of said non-coding sequences comprises the sequence of SEQ ID NO: 10.
6. The transgenic vector of claim 3 , wherein said constant region gene segment is a human heavy chain constant region gene segment.
7. The transgenic vector of claim 6 , wherein said human heavy chain constant region gene segment is a Cγ.
8. The transgenic vector of claim 6 , comprising about 10–100 V gene segments and at least two human V gene segment, wherein said human V gene segment is placed downstream to said 10–100 V gene segments.
9. The transgenic vector of claim 8 , wherein said V gene segments are selected from V gene segments at the 3′ V-region of said non-human animal and human V gene segments.
10. The transgenic vector of claim 4 , wherein said constant region gene segment is a human light chain constant region gene segment.
11. The transgenic vector of claim 10 , wherein said human light chain constant region gene segment is Cλ or Cκ.
12. The transgenic vector of claim 10 , comprising about 10–100 V gene segments and at least two human V gene segment, wherein said human V gene segment is placed downstream to said 10–100 V gene segments.
13. The transgenic vector of claim 12 , wherein said V gene segments are selected from V gene segments at the 3′ V-region of said non-human animal and human V gene segments.
14. The transgenic vector of claim 10 , wherein said human V gene segment is placed immediately 5′ to a J gene segment in a rearranged configuration.
15. A method of making a transgenic vector comprising a humanized Immunoglobulin (Ig) locus capable of producing a functional repertoire of humanized antibodies in a non-human animal generating antibody diversity primarily through gene conversion and/or hypermutation, comprising:
(i) obtaining a DNA fragment comprising an Ig locus or a portion therefor from said non-human animal, which comprises at least two V gene segments, at least one J gene segment and at least one constant region gene segment, and non-coding sequences; and
(ii) integrating by homologous recombination at least one functional human V gene segment encoding a human V region amino acid sequence, into said DNA fragment of step (i) to produce a humanized Ig locus,
wherein the V gene segments present are separated only by non-coding, non-human sequences derived from said non-human animal that generates antibody diversity primarily through gene conversion and/or hypermutation, and at least one of the functional V gene segments encoding a human V region amino acid sequence is placed downstream of the other V gene segments, and
wherein said Ig gene segments are juxtaposed in an unrearranged, partially rearranged or fully rearranged configuration, as to permit gene rearrangement and gene conversion of said humanized Ig locus and the production of a functional repertoire of humanized antibodies with V region amino acid sequences encoded by more than one V region gene segment, in said non-human animal.
16. The method of claim 15 , wherein the integration of said human Ig gene segment by homologous recombination, replaces an Ig gene segment in said Ig locus or said portion thereof from said non-human animal.
17. The method of claim 16 , wherein the homologous recombination is achieved in a bacterial cell, a yeast cell, or a non-human animal cell.
18. The method of claim 16 , wherein the human Ig gene segment is provided on a recombination vector, and is linked to a 5′ nucleotide sequence and a 3′ nucleotide sequence which are homologous to the 5′ and 3′ flanking sequences of said Ig gene segment from the non-human animal.