Altered antibodies and their preparation

1. An antibody which is capable of binding to human CD4 antigen, in which the CDRs of the light chain of the antibody have the amino acid sequences:

CDR1: LASEDIYSDLA (SEQ ID NO:13)

CDR2: NTDTLQN (SEQ ID NO:14)

CDR3: QQYNNYPWT (SEQ ID NO:15)

in which the CDRs of the heavy chain of the antibody have the amino acid sequences:

CDR1: NYGMA (SEQ ID NO:16)

CDR2: TISHDGSDTYFRDSVKG (SEQ ID NO:17)

CDR3: QGTIAGIRH (SEQ ID NO:18), and

in which the framework of the variable domain of each chain and any constant domain present in said chain are derived from a mammalian non-rat species.

2. An antibody according to claim 1 , in which the mammalian non-rat species is human.

3. An antibody according to claim 2 , in which the variable domain framework region of the heavy chain consists essentially of the heavy chain variable domain framework region of the protein KOL.

4. An antibody according to claim 3 , in which the heavy chain variable domain has the amino acid sequence shown in the upper line in FIG. 10 (SEQ ID NO:39) or 12 (SEQ ID NO:40).

5. An antibody according to claim 2 , in which the variable domain framework region of the heavy chain consists essentially of the heavy chain variable domain framework region of the protein NEW.

6. An antibody according to claim 5 , in which the heavy chain variable domain has the amino acid sequence shown in the upper line of FIG. 6 (SEQ ID NO:41) or 7 (SEQ ID NO:42).

7. An antibody according to claims 2 , 3 , 4 , 5 or 6 , in which the variable domain framework of the light chain consists essentially of the variable domain framework of the protein REI.

8. An antibody according to claim 7 , in which the light chain has the amino acid sequence shown in the upper line of FIG. 3 (SEQ ID NO:43).

9. A pharmaceutical composition comprising a pharmaceutically acceptable carrier or diluent and, as active ingredient, an antibody as claimed in claim 1 .

10. An antibody which is capable of binding to human CD4 antigen, in which the CDRs of the light chain of the antibody have the amino acid sequences:

CDR1: LASEDIYSDLA (SEQ ID NO:13)

CDR2: NTDTLQN (SEQ ID NO:14)

CDR3: QQYNNYPWT (SEQ ID NO:15), and

in which the CDRs of the heavy chain of the antibody have the amino acid sequences:

CDR1: NYGMA (SEQ ID NO:16)

CDR2: TISHDGSDTYFRDSVKG (SEQ ID NO:17)

CDR3: QCTIAGIRH (SEQ ID NO:18), and

in which the framework of the variable domain of each chain and the constant region of said chain are derived from a human.

11. An antibody according to claim 1 , wherein the antibody has glycosylation characteristic of CHO cells.

12. A humanized antibody, or an antigen-binding fragment of said humanized antibody, wherein the humanized antibody comprises (1) a light chain variable domain comprising a framework and three complementarity determining regions (CDRs) followed by constant regions and (2) a heavy chain variable domain comprising a framework and three CDRs followed by constant regions, wherein:

the amino acid sequence of the CDRs consists of the amino acid sequence of the CDRs of an antibody of a first species, wherein the first species is a non-human mammal;

the amino acid sequence of the light chain framework, of the heavy chain framework, or of both the light and the heavy chain frameworks consists of the amino acid sequence of a selected human antibody variable region, wherein the light chain framework consists of four framework regions and the heavy chain framework consists of four framework regions;

wherein the humanized antibody differs from the antibody of a first species at least in that, for the humanized antibody:

i.) the sequence of all four framework regions of the light chain is identical to the sequence of all four framework regions of a single selected human antibody variable region; or

ii.) the sequence of all four framework regions of the heavy chain is identical to the sequence of all four framework regions of a single selected human antibody variable region; or

iii.) both i.) and ii); and

wherein:

iv.) the selected human antibody variable region of i.) is selected from the human light chain antibody variable regions with the most overall homology to the light chain variable region of the antibody of the first species; or

v.) the selected human antibody variable region of ii.) is selected from the human heavy chain antibody variable regions with the most overall homology to the heavy chain variable region of the antibody of the first species; or

vi.) both iv.) and v.); and

vii.); wherein the most overall homology is determined on the basis of the respective variable domains, considering the overall homology, without making a distinction between homology within the framework regions and CDRs, and wherein only CDR3 of either the selected human heavy chain and/or selected human light chain variable region has a different length as that of the corresponding CDRs of the first species antibody;

wherein the humanized antibody is capable of binding the same human antigen as the antibody of the first species, wherein said antigen is not a CD antigen;

wherein at least one of the constant regions is from a human immunoglobulin different from the antibody or antibodies from which the human frameworks are selected; and

wherein the antibody of the first species is not an antibody that binds a CD antigen.

13. A humanized antibody according to claim 12, or an antigen-binding fragment of said humanized antibody, wherein the non-human mammal is rat.

14. A humanized antibody according to claim 12, or an antigen-binding fragment of said humanized antibody, wherein the non-human mammal is mouse.

15. A humanized antibody according to claim 12, or an antigen-binding fragment of said humanized antibody, wherein the humanized antibody or fragment thereof is a (Fab′) 2 fragment.

16. A humanized antibody according to claim 12, or an antigen-binding fragment of said humanized antibody, wherein the humanized antibody or fragment thereof is a Fab fragment.

17. A humanized antibody according to claim 12, or an antigen-binding fragment of said humanized antibody, wherein the antibody has glycosylation characteristic of CHO cells.

18. A pharmaceutical composition comprising a humanized antibody according to claim 12, or an antigen-binding fragment of said humanized antibody, and a pharmaceutically acceptable carrier or diluent.