Chemistry: molecular biology and microbiology – Treatment of micro-organisms or enzymes with electrical or... – Modification of viruses
Reexamination Certificate
1996-03-25
2001-01-30
Ungar, Susan (Department: 1642)
Chemistry: molecular biology and microbiology
Treatment of micro-organisms or enzymes with electrical or...
Modification of viruses
C435S320100, C435S252300, C435S325000, C530S387100, C530S387300, C530S388100, C536S023100
Reexamination Certificate
active
06180377
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to humanised antibodies, having specificity for the epitope recognised by the murine monoclonal antibody L243, to processes for preparing said antibodies, to pharmaceutical compositions containing said antibodies, and to medical uses of said antibodies.
The term humanised antibody molecule is used to describe a molecule having an antigen binding site derived from an immunoglobulin from a non-human species, the remaining immunoglobulin-derived parts of the molecule being derived from a human immunoglobulin. The antigen binding site may comprise either complete variable regions fused onto human constant domains or only the complementarity determining regions (CDRs) grafted onto appropriate human framework regions in the variable domains.
BACKGROUND OF THE INVENTION
The proteins encoded in the Major Histocompatibility Complex region of the genome are involved in many aspects of immunological recognition. It is known that all mammals and probably all vertebrates possess basically equivalent MHC systems and that immune response genes are linked to the MHC.
In man the major histocompatibility complex is the HLA gene cluster on chromosome 6. The main regions are D, B, C, and A. The D region contains genes for Class II proteins which are involved in cooperation and interaction between cells of the immune system. Many diseases have been found to be associated with the D region of the HLA gene cluster. Studies to date have shown associations with an enormous variety of diseases including most autoimmune diseases (see for example European Patent No. 68790). European Patent No. 68790 suggests controlling diseases associated with a particular allele of certain regions of the MHC such as the HLA-D region in humans by selectively suppressing the immune response(s) controlled by a monoclonal antibody specific for an MHC-Class II antigen.
L243 is a murine IgG2A anti-HLA DR antibody which we believe to be of particular use in treatment of diseases such as autoimmune diseases since it shows particularly potent suppression of in vitro immune function and is monomorphic for all HLA-DR.
Since most available monoclonal antibodies are of rodent origin, they are naturally antigenic in humans and thus can give rise to an undesirable immune response termed the HAMA (Human Anti-Mouse Antibody) response. Therefore, the use of rodent monoclonal antibodies as therapeutic agents in humans is inherently limited by the fact that the human subject will mount an immunological response to the antibody and will either remove it entirely or at least reduce its effectiveness.
Proposals have been made for making non-human MAbs less antigenic in humans. Such techniques can be generically termed ‘humanisation’ techniques. These techniques generally involve the use of recombinant DNA technology to manipulate DNA sequences encoding the polypeptide chains of the antibody molecule. A simple form of humanisation involves the replacement of the constant regions of the murine antibody with those from a human antibody [Morrison et al (1984) Proc. Natl. Acad. Sci. USA 81 6851-55; Whittle et al (1987) Prot. Eng. 1 499-505]. The lowering of the level of the HAMA response to the chimeric antibodies leads to the expectation that further humanisation of the variable region outside of the antigen binding site may abolish the response to these regions and further reduce any adverse response.
A more complex form of humanisation of an antibody involves the redesign of the variable region domain so that the amino acids constituting the murine antibody binding site are integrated into the framework of a human antibody variable region. Humanisation has led to the reconstitution of full antigen binding activity in a number of cases [Co et al (1990) J. Immunol. 148 1149-1154; Co et al (1992) Proc. Natl. Acad. Sci. USA 88 2869-2873; Carter et al (1992) Proc. Natl. Acad. Sci. 89 4285-4289; Routledge et al (1991) Eur. J. Immunol. 21 2717-2725 and International Patent Specifications Nos. WO 91/09967; WO 91/09968 and WO 92/113831.
It can therefore be anticipated that the humanisation of L243 may lead to reduced immunogenicity in man and overcome the potential problem of the HAMA response previously associated with the use of murine antibodies in humans.
We have now prepared recombinant antibody molecules having specificity for the epitope recognised by the murine monoclonal antibody L243.
SUMMARY OF THE INVENTION
Thus according to a first aspect the invention provides a recombinant antibody molecule having specificity for antigenic determinants dependent on the DR&agr; chain.
The term recombinant antibody molecule is used to denote an antibody produced using recombinant DNA techniques. The antibody is preferably a humanised antibody, e.g. a chimeric or CDR-grafted antibody.
In a preferred embodiment of the first aspect the invention provides a recombinant antibody molecule have specificity for the epitope recognised by the murine monoclonal antibody L243.
In a preferred embodiment of the first aspect of the present invention there is provided a humanised antibody molecule having specificity for the epitope recognised by the murine monoclonal antibody L243 and having an antigen binding site wherein at least one of the complementarity determining regions (CDRs) of the variable domain is derived from the mouse monoclonal antibody L243 (MAb L243) and the remaining immunoglobulin-derived parts of the humanised antibody molecule are derived from a human immunoglobulin or an analogue thereof, said humanised antibody molecule being optionally conjugated to an effector or reporter molecule.
The humanised antibody molecule may comprise a chimeric humanised antibody or a CDR-grafted humanised antibody. When the humanised antibody molecule comprises a CDR-grafted humanised antibody, the heavy and/or light chain variable domains may comprise only one or two MAb L243 derived CDRs; though preferably all three heavy and light chain CDRs are derived from MAb L243.
As described above L243 is a monoclonal antibody previously described by Lampson & Levy [J. Immunol. (1980) 125 293]. The amino acid sequences of the light and heavy chain variable regions of the antibody are shown in
FIGS. 1 and 2
hereinafter. L243 has been deposited at the American Type Culture Collection, Rockville, Md. USA under Accession number ATCC HB55.
DETAILED DESCRIPTION OF THE INVENTION
The humanised antibody of the present invention may have attached to it an effector or reporter molecule. For instance a macrocycle for chelating a heavy metal atom, or a toxin such as ricin, may be attached to the humanised antibody by a covalent bridging structure. Alternatively, the procedure of recombinant DNA technology may be used to produce a humanised antibody molecule in which the Fc fragment, C
H
3 or C
H
2 domain of a complete antibody molecule has been replaced by or has attached thereto by peptide linkage a functional non-immunoglobulin protein such as an enzyme or toxin molecule.
The humanised antibody of the present invention may comprise a complete antibody molecule, having full length heavy and light chains; a fragment thereof, such as a Fab, Fab′, (Fab′)
2
, or Fv fragment; a single chain antibody fragment, e.g. a single chain Fv, a light chain or heavy chain monomer or dimer; multivalent monospecific antigen binding proteins comprising two, three, four or more antibodies or fragments thereof bound to each other by a connecting structure; or a fragment or analogue of any of these or any other molecule with the same specificity as MAb L243.
In a preferred embodiment the antibody comprises a complete antibody molecule, having full length heavy and light chains.
The remaining non-L243 immunoglobulin derived parts of the humanised antibody molecule may be derived from any suitable human immunoglobulin. For instance where the humanised antibody molecule is a CDR-grafted humanised antibody molecule, appropriate variable region framework sequences may be used having regard to class/type of the donor antibody from w
Athwal Diljeet Singh
Bodmer Mark William
Emtage John Spencer
Morgan Susan Adrienne
Celltech Therapeutics Limited
Ungar Susan
Woodcock Washburn Kurtz Mackiewicz & Norris LLP
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