การประดิษฐ์ from such host cell may all be conventional techniques.
Typically, the culture method of the การประดิษฐ์นี้ is a serum-free culture method, usually by
culturing cells serum-free in suspension. Likewise, once produced, the โปรตีน ยึดเกาะ แอนติเจน of
the การประดิษฐ์ may be purified from the cell culture contents according to standard procedures of the
art, ที่รวมถึง ammonium sulfate precipitation, affinity columns, column chromatography, gel 10 electrophoresis and the like. Such techniques are within the skill of the art and do not limit this
การประดิษฐ์. For example, preparations of altered antibodies are described in WO 99/58679 and WO 96/16990.
Yet another method of expression of the โปรตีน ยึดเกาะ แอนติเจน may utilize expression in a
transgenic animal, such as described in U. S. Patent No. 4,873,316. This relates to an expression 15 system using the animals casein promoter which when transgenically incorporated into a mammal
permits the female to produce the desired recombinant protein in its milk.
ในลักษณะ ต่อไป of the การประดิษฐ์ there is provided a method of producing an antigen
binding protein (e.g. a ฮิวเมไนซ์ แอนติบอดี) of the การประดิษฐ์ which method ประกอบรวมด้วยs the step of
culturing a host cell transformed or ทรานสเฟคต์ with a vector encoding the light and/or heavy chain 20 of the antibody of the การประดิษฐ์ and recovering the โปรตีน ยึดเกาะ แอนติเจน thereby produced.
In accordance with the การประดิษฐ์นี้ there is provided a method of producing an anti-
LAG-3 โปรตีน ยึดเกาะ แอนติเจน (e.g. a ฮิวเมไนซ์ แอนติบอดี) of the การประดิษฐ์นี้ which binds to human LAG-3, which method ประกอบรวมด้วยs the steps of;
(a) providing a first vector encoding a heavy chain of the antibody;
25 (b) providing a second vector encoding a light chain of the antibody;
(c) transforming a mammalian host cell (e.g. CHO) with said first and second vectors;
(d) culturing the host cell of step (c) under conditions conducive to the secretion of the antibody from said host cell into said culture media;
(e) recovering the secreted antibody of step (d).
30 Once expressed by the desired method, the โปรตีน ยึดเกาะ แอนติเจน may then be examined
for in vitro activity by use of an appropriate assay, such as Biacore surface Plasmon resonance analysis, to assess binding of the โปรตีน ยึดเกาะ แอนติเจน to LAG-3. Additionally, other in vitro and in vivo assays may also be used to determine an โปรตีน ยึดเกาะ แอนติเจน's ability to cause การลดปริมาณ of cells expressing LAG-3, such as activated human T cell populations.
35 The skilled person will appreciate that, upon production of an โปรตีน ยึดเกาะ แอนติเจน such
as an antibody, in particular depending on the cell line used and particular amino acid sequence of the โปรตีน ยึดเกาะ แอนติเจน, post-translational modifications may occur. For example, this may
12
รวมถึง the cleavage of certain leader sequences, the addition of various sugar moieties in various glycosylation and phosphorylation patterns, deamidation, oxidation, disulfide bond scrambling, isomerisation, C-terminal lysine clipping, and N-terminal glutamine cyclisation. The การประดิษฐ์นี้
encompasses the use of โปรตีน ยึดเกาะ แอนติเจน which have been subjected to, or have undergone, 5 one or more post-translational modifications. Thus an "โปรตีน ยึดเกาะ แอนติเจน" or "antibody" of the
การประดิษฐ์ รวมถึง an "โปรตีน ยึดเกาะ แอนติเจน" or "antibody", respectively, as defined earlier which
has undergone a post-translational modification such as described herein.
Glycosylation of antibodies at conserved positions in their constant regions is known to have
a profound effect on antibody function, particularly เอฟเฟคเตอร์ functioning, see for example, Boyd et al. 10 (1996) Mol. Immunol. 32: 1311-1318. Glycosylation variants of the โปรตีน ยึดเกาะ แอนติเจน of the
การประดิษฐ์ โดยที่ one or more carbohydrate moiety is added, substituted, deleted or modified are
contemplated. Introduction of an asparagine-X-serine or asparagine-X-threonine motif creates a
potential site for enzymatic attachment of carbohydrate moieties and may therefore be used to
manipulate the glycosylation of an antibody. In Raju et al. (2001) Biochemistry 40: 8868-8876 the
15 terminal sialyation of a TNFR-IgG immunoadhesin was increased through a process of
regalactosylation and/or resialylation using beta-1, 4-galactosyltransferace and/or alpha, 2,3
sialyltransferase. Increasing the terminal sialylation is believed to increase the half-life of the
อิมมูโนโกลบูลิน. Antibodies, in common with most glycoproteins, are typically produced as a
mixture of glycoforms. This mixture is particularly apparent when antibodies are produced in
20 eukaryotic, particularly mammalian cells. A variety of methods have been developed to manufacture
defined glycoforms, see Zhang et al. (2004) Science 303: 371: Sears et al. (2001) Science 291:
2344; Wacker et al. (2002) Science 298: 1790; Davis et al. (2002) Chem. Rev. 102: 579; Hang et al. (2001) Acc. Chem. Res 34: 727. The antibodies (for example of the IgG isotype, e.g. IgG1) as herein described may ประกอบรวมด้วย a defined number (e.g. 7 or less, for example 5 or less, such as two
25 or a single) of glycoform(s).
Deamidation is an enzymatic reaction primarily converting asparagine (N) to iso-aspartic acid and aspartic acid (D) at approximately 3:1 ratio. To a much lesser degree, deamidation can occur with glutamine เรซิดิว in a similar manner. Deamidation in a CDR results in a change in charge of the molecule, but typically does not result in a change in antigen binding, nor does it impact on
30 PK/PD.
Oxidation can occur during production and storage (i.e. in the presence of oxidizing conditions) and results in a covalent modification of a protein, induced either directly by reactive oxygen species or indirectly by reaction with secondary by-products of oxidative stress. Oxidation happens primarily with methionine เรซิดิว, but occasionally can occur at tryptophan and free
35 cysteine เรซิดิว.
13
Disulfide bond scrambling can occur during production and basic storage conditions. Under certain circumstances, disulfide bonds can break or form incorrectly, resulting in unpaired cysteine เรซิดิว (-SH). These free (unpaired) sulfhydryls (-SH) can promote shuffling.
Isomerization typically occurs during production, purification, and storage (at acidic pH) and 5 usually occurs when aspartic acid is converted to isoaspartic acid through a chemical process.
N-terminal glutamine in the heavy chain and/or light chain is likely to form pyroglutamate
(pGlu). Most pGlu formation happens in the production bioreactor, but it can be formed non-
enzymatically, depending on pH and temperature of processing and storage conditions. pGlu formation is considered as one of the principal degradation pathways for recombinant mAbs.
10 C-terminal lysine clipping is an enzymatic reaction catalyzed by carboxypeptidases, and is
commonly observed in recombinant mAbs. Variants of this process รวมถึง removal of lysine from one or both heavy chains. Lysine clipping does not appear to impact bioactivity and has no effect on mAb เอฟเฟคเตอร์ function.
15 เอฟเฟคเตอร์ Function Enhancement
The interaction between the constant region of an โปรตีน ยึดเกาะ แอนติเจน and various Fc receptors (FcR) ที่รวมถึง FcyRI (CD64), FcyRII (CD32) and FcyRIII (CD16) is believed to mediate the เอฟเฟคเตอร์ functions, such as ADCC and CDC, of the โปรตีน ยึดเกาะ แอนติเจน.
The term "เอฟเฟคเตอร์ Function" as used herein is meant to refer to one or more of Antibody 20 dependant cell mediated cytotoxic activity (ADCC), Complement—dependant cytotoxic activity (CDC)
mediated responses, Fc-mediated phagocytosis or antibody dependant cellular phagocytosis (ADCP)
and antibody recycling via the FcRn receptor.
The ADCC or CDC properties of โปรตีน ยึดเกาะ แอนติเจน of the การประดิษฐ์นี้ may be enhanced in a number of ways.
25 Human IgG1 constant regions containing specific mutations or altered glycosylation on
เรซิดิว Asn297 have been shown to enhance binding to Fc receptors. In some cases these mutations have also been shown to enhance ADCC and CDC (Lazar et al. PNAS 2006, 103; 4005-
4010; Shields et al. J Biol Chem 2001, 276; 6591-6604; Nechansky et al. Mol Immunol, 2007, 44; 1815-1817).