WO2023003331A1

WO2023003331A1 - Sirp-alpha variants and use thereof

Info

Publication number: WO2023003331A1
Application number: PCT/KR2022/010551
Authority: WO
Inventors: Narae Lee; Young Bong Park; Jung-Hoon PYUN; Minji Choi; In Hwan Lim; Jun Hwan Kim
Original assignee: Yuhan Corporation
Priority date: 2021-07-19
Filing date: 2022-07-19
Publication date: 2023-01-26
Also published as: KR20230016152A

Abstract

A novel SIRPα (Signal regulatory protein alpha) variant, a fusion protein comprising the SIRPα variant, and uses of the variants and/or fusion proteins for immune enhancement and/or cancer treatment is provided.

Description

SIRP-ALPHA VARIANTS AND USE THEREOF

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority from Korean Patent Application No. 10-2021-0094468 filed on July 19, 2021, the full disclosure of which is incorporated herein as a part of the present disclosure.

The present disclosure provides a novel SIRPα (Signal regulatory protein alpha) variant, a fusion protein comprising the SIRPα variant, and uses of the variants and/or fusion proteins for immune enhancement and/or cancer treatment.

CD47 has increased its expression in various tumor cells, and is known as an innate immune checkpoint that inhibits the phagocytosis in macrophages through binding to SIRPα (Signal regulatory protein alpha) expressed in myeloid cells, such as macrophages. Currently, the development of various drugs targeting the CD47-SIRPα axis (CD47 target antibody, SIRPα-Fc fusion protein, SIRPα target antibody, etc.) has been advanced. These drugs block the binding between CD47-SIRPα and activate the phagocytosis in macrophages, thereby exhibiting anti-cancer effects.

Therefore, there is a need to develop a substance that more effectively inhibits the binding of CD47-SIRPα.

The present disclosure provides an SIRPα variant having a higher binding affinity for CD47 (e.g., human CD47) relative to a wild-type SIRPα, and uses thereof.

One embodiment provides a novel SIRPα variant. The SIRPα variant may be a fragment of a wild-type SIRPα, one in which at least one amino acid mutation is introduced into a wild-type SIRPα or a fragment of wild-type SIRPα, or a combination thereof. In one specific embodiment, the SIRPα variant may be at least one selected from SEQ ID NOs: 3 to 10.

Another embodiment provides a fusion protein comprising the SIRPα variant and an Fc region of immunoglobulin. The Fc region of immunoglobulin may comprise CH2 domain, CH3 domain, or both CH2 domain and CH3 domain of immunoglobulin, and additionally, it may or may not comprise the hinge region of immunoglobulin at N-terminus. The fusion protein may comprise an SIRPα variant and an Fc region of immunoglobulin in any order. That is, the fusion protein may comprise an SIRPα variant and an Fc region of immunoglobulin in order, or comprise an Fc region of immunoglobulin and an SIRPα variant in order, in N-terminal to C-terminal direction. In one embodiment, the fusion protein may comprise an SIRPα variant and an Fc region of an immunoglobulin in order in an N-terminal to C-terminal direction.

Another embodiment provides a polynucleotide encoding the SIRPα variant or the fusion protein.

Another embodiment provides a recombinant vector comprising the polynucleotide. The recombinant vector may be an expression vector for expressing the polynucleotide in a cell.

Another embodiment provides a recombinant cell comprising the polynucleotide or the recombinant vector.

Another embodiment provides a pharmaceutical composition for inhibiting the binding of CD47-SIRPα and/or enhancing immunity, comprising at least one selected from the group consisting of: (1) the SIRPα variant, (2) the fusion protein, (3) a polynucleotide encoding the SIRPα variant or the fusion protein, (4) a recombinant vector comprising the polynucleotide, and (5) a recombinant cell comprising the polynucleotide or the recombinant vector.

Another embodiment provides a method of inhibiting the binding of CD47-SIRPα and/or enhancing immunity, comprising administering to a subject in need thereof a pharmaceutically effective amount of at least one selected from the group consisting of: (1) the SIRPα variant, (2) the fusion protein, (3) a polynucleotide encoding the SIRPα variant or the fusion protein, (4) a recombinant vector comprising the polynucleotide, and (5) a recombinant cell comprising the polynucleotide or the recombinant vector.

Another embodiment provides a use of at least one selected from the group consisting of the following in inhibiting the binding of CD47-SIRPα and/or enhancing immunity: (1) the SIRPα variant, (2) the fusion protein, (3) a polynucleotide encoding the SIRPα variant or the fusion protein, (4) a recombinant vector comprising the polynucleotide, and (5) a recombinant cell comprising the polynucleotide or the recombinant vector.

Another embodiment provides a use of at least one selected from the group consisting of the following in the preparation of a pharmaceutical composition for inhibiting the binding of CD47-SIRPα and/or enhancing immunity: (1) the SIRPα variant, (2) the fusion protein, (3) a polynucleotide encoding the SIRPα variant or the fusion protein, (4) a recombinant vector comprising the polynucleotide, and (5) a recombinant cell comprising the polynucleotide or the recombinant vector.

The immune enhancement of the pharmaceutical composition for enhancing immunity may be due to an inhibition of the binding of CD47-SIRPα and/or an activation of the phagocytosis in macrophages.

Another embodiment provides a pharmaceutical composition for the prevention and/or treatment of an immune-related disease, comprising at least one selected from the group consisting of: (1) the SIRPα variant, (2) the fusion protein, (3) a polynucleotide encoding the SIRPα variant or the fusion protein, (4) a recombinant vector comprising the polynucleotide, and (5) a recombinant cell comprising the polynucleotide or the recombinant vector.

Another embodiment provides a method of preventing and/or treating a immune-related disease, comprising administering to a subject in need thereof a pharmaceutically effective amount of at least one selected from the group consisting of: (1) the SIRPα variant, (2) the fusion protein, (3) a polynucleotide encoding the SIRPα variant or the fusion protein, (4) a recombinant vector comprising the polynucleotide, and (5) a recombinant cell comprising the polynucleotide or the recombinant vector.

Another embodiment provides a use of at least one selected from the group consisting of the following in the prevention and/or treatment of immune-related diseases: (1) the SIRPα variant, (2) the fusion protein, (3) a polynucleotide encoding the SIRPα variant or the fusion protein, (4) a recombinant vector comprising the polynucleotide, and (5) a recombinant cell comprising the polynucleotide or the recombinant vector.

Another embodiment provides a use of at least one selected from the group consisting of the following in the preparation of a pharmaceutical composition for the prevention and/or treatment of immune-related diseases: (1) the SIRPα variant, (2) the fusion protein, (3) a polynucleotide encoding the SIRPα variant or the fusion protein, (4) a recombinant vector comprising the polynucleotide, and (5) a recombinant cell comprising the polynucleotide or the recombinant vector.

The prevention and/or treatment of the immune-related disease may be due to an inhibition of the binding of CD47-SIRPα and/or an activation of the phagocytosis in macrophages and/or an enhancement of the immune response.

In one embodiment, the immune-related disease may be cancer.

Another embodiment provides a pharmaceutical composition for the prevention and/or treatment of cancer comprising at least one selected from the group consisting of: (1) the SIRPα variant, (2) the fusion protein, (3) a polynucleotide encoding the SIRPα variant or the fusion protein, (4) a recombinant vector comprising the polynucleotide, and (5) a recombinant cell comprising the polynucleotide or the recombinant vector.

Another embodiment provides a method of preventing and/or treating cancer, comprising administering to a subject in need thereof a pharmaceutically effective amount of at least one selected from the group consisting of: (1) the SIRPα variant, (2) the fusion protein, (3) a polynucleotide encoding the SIRPα variant or the fusion protein, (4) a recombinant vector comprising the polynucleotide, and (5) a recombinant cell comprising the polynucleotide or the recombinant vector.

Another embodiment provides a use of at least one selected from the group consisting of the following in the prevention and/or treatment of cancer: (1) the SIRPα variant, (2) the fusion protein, (3) a polynucleotide encoding the SIRPα variant or the fusion protein, (4) a recombinant vector comprising the polynucleotide, and (5) a recombinant cell comprising the polynucleotide or the recombinant vector.

Another embodiment provides a use of at least one selected from the group consisting of the following in the preparation of a pharmaceutical composition for the prevention and/or treatment of cancer: (1) the SIRPα variant, (2) the fusion protein, (3) a polynucleotide encoding the SIRPα variant or the fusion protein, (4) a recombinant vector comprising the polynucleotide, and (5) a recombinant cell comprising the polynucleotide or the recombinant vector.

A novel SIRPα variant, a fusion protein comprising the SIRPα variant, and an immune enhancement and/or anti-cancer use of the variant and/or the fusion protein is provided. The SIRPα variant and/or the fusion protein has excellent binding affinity for CD47, thereby inhibiting the CD47-SIRPα axis, enhancing the phagocytosis in macrophages, enhancing the immune response, and/or having anti-cancer effects.

Definition of Terms

SIRPα (Signal regulatory protein alpha) is a regulatory membrane glycoprotein from SIRP family that is expressed mainly by myeloid cells (such as macrophages, etc.), bone marrow cells, stem cells, neurons, and the like, and is an innate immune checkpoint that interacts with the transmembrane protein CD47 and inhibits the macrophage phagocytosis. In the present disclosure, the SIRPα may be derived from mammals such as humans, and examples thereof may include human SIRPα (e.g., GenBank Accession No. AAH38510.1 (encoded by BC038510.2), NP_001035111.1 (encoded by NM_001040022.1), NP_001035112.1 (encoded by NM_001040023.2), NP_001317657.1 (encoded by NM_001330728.1), NP_542970.1 (encoded by NM_080792.3), and the like, but are not limited thereto.

As used herein, a polynucleotide (which may be used interchangeably with "gene" or “nucleic acid molecule”) or a polypeptide (which may be used interchangeably with "protein") "comprising a specific nucleic acid sequence or amino acid sequence" or "consisting of or being represented by a specific nucleic acid sequence or amino acid sequence" may mean that the polynucleotide or polypeptide essentially comprises the specific nucleic acid sequence or amino acid sequence, and may be interpreted as including "substantially equivalent sequences" in which a mutation(s) (deletion, substitution, modification, and/or addition) is made to the specific nucleic acid sequence or amino acid sequence within the range of maintaining the original function and/or the desired function of the polynucleotide or polypeptide, or may be interpreted as not excluding the mutation(s).

In one embodiment, a polynucleotide or polypeptide “comprising a specific nucleic acid sequence or amino acid sequence” or “consisting of or being represented by a specific nucleic acid sequence or amino acid sequence” may means that the polynucleotide or polypeptide (i) comprises said specific nucleic acid sequence or amino acid sequence, or (ii) consists of or consists essentially of a nucleic acid sequence or amino acid sequence having 70% or more, 75% or more, 80% or more, 85% or more, 90% or more, 91% or more, 92% or more, 93% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, 99% or more, 99.5% or more, or 99.9% or more identity with the specific nucleic acid sequence or amino acid sequence, and maintains its original function and/or a desired function. In the present disclosure, the original function and/or the desired function in the SIRPα variant may mean excellent binding affinity for CD47, inhibition of the binding between SIRPα and CD47, enhancement of the macrophage phagocytosis, and/or enhancement of the immune response. As used herein, the term “the inhibition of the binding between SIRPα and CD47” or “inhibiting the binding between SIRPα and CD47” may be meant to include “the inhibition of the CD47-SIRPα axis thereby”.

As used herein, the term "identity" (which may be used interchangeably with "homology") means the degree to which a given nucleic acid sequence or amino acid sequence is consistent, and may be expressed as a percentage (%). The homology to nucleic acid sequences can be determined, for example, by using the algorithm BLAST according to the literature (Karlin and Altschul, Pro. Natl. Acad. Sci. USA, 90, 5873, 1993) or FASTA by Pearson (see Methods Enzymol., 183, 63, 1990). Program called BLASTN or BLASTX has been developed based on such an algorithm BLAST (see: http://www.ncbi.nlm.nih.gov).

As used herein, a protein or polypeptide "comprising or consisting of or being represented by a specific amino acid sequence" may mean including both the case where it essentially comprises the amino acid sequence and the case where a meaningless mutation (e.g., substitution, deletion, and/or addition of amino acid residues) that does not affect the original activity and/or the desired activity (e.g., excellent binding affinity for CD47, inhibition of the binding between SIRPα and CD47, enhancement of the macrophage phagocytosis, and/or enhancement of the immune response, etc.) is introduced into the amino acid sequence.

The amino acid positions described herein are calculated from the N-terminus of the reference amino acid sequence, unless otherwise defined.

Hereinafter, the present disclosure will be described in more detail:

SIRPα variant

One embodiment of the present disclosure provides an SIRPα (signal regulatory protein alpha) variant. The variant may have superior binding affinity for CD47 as compared with SIRPα (e.g., wild-type SIRPα) which does not include the mutation(s) described below. In addition, the variant may have an effect of inhibiting the binding between SIRPα and CD47, enhancing the macrophage phagocytosis and/or enhancing the immune response, and may have an excellent anti-cancer effect.

More specifically, the SIRPα variant provided herein may consist essentially of at least a modified SIRPα V2 domain or a fragment thereof as SIRPα (Signal regulatory protein alpha) or a part thereof.

In one embodiment, the SIRPα may be represented by SEQ ID NO: 1, and the SIRPα V2 domain may be represented by SEQ ID NO: 2. The fragment of the SIRPα V2 domain refers to a portion that maintains the original function and/or the desired function of the SIRPα V2 domain, and may be one in which 1 to 10 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10) amino acids are deleted at the N-terminus, C-terminus, or both terminals. For example, it may be represented by SEQ ID NO: 3.

In one embodiment, the modified SIRPα V2 domain or a fragment thereof may be one in which, based on the wild-type SIRPα V2 domain (e.g., SEQ ID NO: 2), one or more amino acids selected from the following may be substituted with amino acids different from the original (wild-type):

the amino acid corresponding to the 31st position (30th position based on SEQ ID NO: 3), and

the amino acid corresponding to the 56th position (55th position based on SEQ ID NO: 3).

More specifically, the SIRPα variant,

comprises 118 or more consecutive amino acids containing an SIRPα V2 domain of SEQ ID NO: 2 in SIRPα, or 115 or more consecutive amino acids containing an SIRPα V2 domain fragment of SEQ ID NO: 3 or consists essentially of the above amino acid,

wherein the SIRPα V2 domain or SIRPα V2 domain fragment may be one in which (1) the amino acid corresponding to the 31st position of SEQ ID NO: 2 or the 30th position of SEQ ID NO: 3, (2) the amino acid corresponding to the 56th position of SEQ ID NO: 2 or the 55th position of SEQ ID NO: 3, or (3) both (1) and (2) is substituted with other amino acid.

The other amino acid may refer to an amino acid that is selected from the group consisting of alanine (A, Ala), asparagine (N, Asn), threonine (T, Thr), glutamic acid (E, Glu), serine (S, Ser), valine (V, Val), isoleucine (I, Ile), leucine (L, Leu), aspartic acid (D, Asp), cysteine (C, Cys), glutamine (Q, Gln), methionine (M, Met), phenylalanine (F, Phe), proline (P, Pro), tryptophan (W, Trp), tyrosine (Y, Tyr), arginine (R, Arg), histidine (H, His), lysine (K, Lys), and glycine (G, Gly), and is different from the original amino acid.

In one embodiment, the modified SIRPα V2 domain or a fragment thereof may be one in which:

(1) the amino acid corresponding to the 31st position of SEQ ID NO: 2 (wild-type SIRPα V2 domain) or the 30th position of SEQ ID NO: 3 (wild-type SIRPα V2 domain fragment) is tyrosine or lysine, or

(2) the amino acid corresponding to the 56th position of SEQ ID NO: 2 or the 55th position of SEQ ID NO: 3 is arginine or lysine, or

(3) (a) the amino acid corresponding to the 31st position of SEQ ID NO: 2 or the 30th position of SEQ ID NO: 3 is tyrosine or lysine, and (b) the amino acid corresponding to the 56th position of SEQ ID NO: 2 or the 55th position of SEQ ID NO: 3 is arginine or lysine.

The modified SIRPα V2 domain or a fragment thereof may further include deglycosylation mutations by substitution of amino acids at glycosylation sites with other amino acids, in addition to substitutions in the amino acid corresponding to the 31st position and/or the 56th position based on SEQ ID NO: 2 described above. In one embodiment, the deglycosylation mutation may be one in which the amino acid corresponding to the 80th position based on SEQ ID NO: 2 (79th position based on SEQ ID NO: 3) is substituted with an amino acid other than the original (wild type), and the other amino acid may be selected from all amino acids that allow deglycosylation, and for example, may be aspartic acid, but is not limited thereto.

In one embodiment, the SIRPα variant comprises 118 or more consecutive amino acids containing an SIRPα V2 domain of SEQ ID NO: 2 in SIRPα, or 115 or more consecutive amino acids containing an SIRPα V2 domain fragment of SEQ ID NO: 3,

wherein the SIRPα V2 domain or SIRPα V2 domain fragment may be one in which:

(1) the amino acid corresponding to the 31st position of SEQ ID NO: 2 or the 30th position of SEQ ID NO: 3,

(2) the amino acid corresponding to the 56th position of SEQ ID NO: 2 or the 55th position of SEQ ID NO: 3, or

(3) both (1) and (2)

is substituted with other amino acid.

More specifically, the SIRPα variant comprises,

118 or more consecutive amino acids containing an SIRPα V2 domain of SEQ ID NO: 2 in SIRPα, or 115 or more consecutive amino acids containing an SIRPα V2 domain fragment of SEQ ID NO: 3,

wherein the SIRPα V2 domain or SIRPα V2 domain fragment may be one in which:

(1) the amino acid corresponding to the 31st position of SEQ ID NO: 2 or the 30th position of SEQ ID NO: 3 is tyrosine or lysine (or is substituted with tyrosine or lysine),

(2) the amino acid corresponding to the 56th position of SEQ ID NO: 2 or the 55th position of SEQ ID NO: 3 is arginine or lysine (or is substituted with arginine or lysine), or

(3) both (1) and (2).

In another specific embodiment, the SIRPα variant comprises 118 or more consecutive amino acids containing an SIRPα V2 domain of SEQ ID NO: 2 in SIRPα, or 115 or more consecutive amino acids containing an SIRPα V2 domain fragment of SEQ ID NO: 3,

wherein the SIRPα V2 domain or SIRPα V2 domain fragment may be one in which:

(3) both (1) and (2)

is substituted with other amino acid, and

the amino acid corresponding to the 80th position of SEQ ID NO: 2 or the 79th position of SEQ ID NO: 3 is substituted with other amino acid.

For example, the SIRPα variant comprises 118 or more consecutive amino acids containing an SIRPα V2 domain of SEQ ID NO: 2 in SIRPα, or 115 or more consecutive amino acids containing an SIRPα V2 domain fragment of SEQ ID NO: 3,

wherein the SIRPα V2 domain or SIRPα V2 domain fragment may be one in which:

(3) both (1) and (2)

is substituted with other amino acid, and

the SIRPα variant further comprises a substitution of the amino acid corresponding to the 80th position of SEQ ID NO: 2 or the 79th position of SEQ ID NO: 3 with other amino acid.

More specifically, the SIRPα variant comprises 118 or more consecutive amino acids containing an SIRPα V2 domain of SEQ ID NO: 2 in SIRPα, or 115 or more consecutive amino acids containing an SIRPα V2 domain fragment of SEQ ID NO: 3,

wherein the SIRPα V2 domain or SIRPα V2 domain fragment may be one in which:

(3) both (1) and (2), and

the amino acid corresponding to the 80th position of SEQ ID NO: 2 or the 79th position of SEQ ID NO: 3 is substituted with other amino acid (e.g., aspartic acid).

wherein the SIRPα V2 domain or SIRPα V2 domain fragment may be one in which:

(3) both (1) and (2), and

the SIRPα variant further comprises a substitution of the amino acid corresponding to the 80th position of SEQ ID NO: 2 or the 79th position of SEQ ID NO: 3 with other amino acid (e.g., aspartic acid).

In one embodiment, the SIRPα variant may comprise an amino acid sequence selected from the group consisting of SEQ ID NO: 5 to SEQ ID NO: 12. For example, the SIRPα variant may consist essentially of an amino acid sequence selected from the group consisting of SEQ ID NO: 5 to SEQ ID NO: 12.

The amino acid sequences of SIRPα, SIRPα V2 domain, SIRPα V2 domain fragment, and SIRPα variant used herein are exemplified in Table 1 below:

Description	Amino acid sequence (N→C)	SEQ ID NO
Wild-type SIRPα	MEPAGPAPGRLGPLLCLLLAASCAWSGVAGEEELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISNITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKPSAPVVSGPAARATPQHTVSFTCESHGFSPRDITLKWFKNGNELSDFQTNVDPVGESVSYSIHSTAKVVLTREDVHSQVICEVAHVTLQGDPLRGTANLSETIRVPPTLEVTQQPVRAENQVNVTCQVRKFYPQRLQLTWLENGNVSRTETASTVTENKDGTYNWMSWLLVNVSAHRDDVKLTCQVEHDGQPAVSKSHDLKVSAHPKEQGSNTAAENTGSNERNIYIVVGVVCTLLVALLMAALYLVRIRQKKAQGSTSSTRLHEPEKNAREITQDTNDITYADLNLPKGKKPAPQAAEPNNHTEYASIQTSPQPASEDTLTYADLDMVHLNRTPKQPAPKPEPSFSEYASVQVPRK		1
Wild-type SIRPα V2 domain (1-118 a.a)	EEELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISNITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKPS	2
Wild-type SIRPα V2 domain fragment (2-116 a.a)	EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISNITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	3
SIRPα V2 domain fragment with H56R, N80D mutations	EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	5
SIRPα V2 domain fragment with H56K, N80D mutations	EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	6
SIRPα V2 domain fragment with I31K, N80D mutations	EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	7
SIRPα V2 domain fragment with I31Y, N80D mutations	EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	8
SIRPα V2 domain fragment with I31K, H56R, N80D mutations	EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	9
SIRPα V2 domain fragment with I31K, H56K, N80D mutations	EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	10
SIRPα V2 domain fragment with I31Y, H56R, N80D mutations	EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	11
SIRPα V2 domain fragment with I31Y, H56K, N80D mutations	EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	12

Fusion Protein

Another embodiment of the present disclosure provides a fusion protein comprising the aforementioned SIRPα variant and an Fc region of immunoglobulin. The fusion protein may have excellent binding affinity for CD47 as compared with a fusion protein containing SIRPα (e.g., wild-type SIRPα) which does not include the above-mentioned mutation(s), can have an effect of inhibiting the binding between SIRPα and CD47, enhancing the macrophage phagocytosis and/or enhancing the immune response, and may have excellent anti-cancer effect.

The SIRPα variant is as described above.

The immunoglobulin (Ig) may be a human immunoglobulin.

The immunoglobulin exists in major classes, namely IgA, IgD, IgE, IgG and IgM, of which IgG and IgA further have subclasses (isotypes) (e.g., IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2).

In the present disclosure, the immunoglobulin may be selected from the group consisting of IgA (e.g., IgA1 and IgA2), IgD, IgE, IgG (e.g., IgG1, IgG2, IgG3, and IgG4), and IgM, and more specifically, it may be an IgG (e.g., IgG1, IgG2, IgG3, or IgG4), but is not limited thereto.

The Fc region of the immunoglobulin may comprise CH2 domain, CH3 domain, or both CH2 domain and a CH3 domain of immunoglobulin described above. In addition, the Fc region of immunoglobulin may or may not comprise the hinge region of immunoglobulin described above. When a hinge region is comprised, the hinge region may be located at the N-terminal portion of the Fc region of immunoglobulin.

The fusion protein may comprise an SIRPα variant and an Fc region of immunoglobulin regardless of order. That is, the fusion protein may comprise an SIRPα variant and an Fc region of immunoglobulin in order, or comprise an Fc region of immunoglobulin and an SIRPα variant in order, in an N-terminal to C-terminal direction. In one embodiment, the fusion protein may comprise an SIRPα variant and an Fc region of immunoglobulin in order in an N-terminal to C-terminal direction, but is not limited thereto.

In one embodiment, the hinge region may be represented by SEQ ID NO: 13, but is not limited thereto.

In an embodiment, the Fc region (not comprising hinge) may be IgG Fc, for example, IgG1 Fc, and may be in a wild type (e.g., SEQ ID NO: 14) or a mutant (modified) type. In a specific embodiment, the mutant IgG1 Fc may be one wherein at least one amino acid residue of wild type IgG1 Fc, for example at least one (e.g., one, two, three, or four) selected from the group consisting of K392, K409, E356, and D399, is substituted with other amino acid. For example, the substitution may include a substitution of an anionic amino acid (aspartic acid or glutamic acid) with a cationic amino acid (lysine or arginine), and/or a substitution of a cationic amino acid with an anionic amino acid. For example, the substitution may include K392D and/or K409D, or E356K and/or D399K, but not be limited thereto.

In another specific embodiment, the mutant IgG1 Fc may be one modified from wild type IgG1 Fc so as to have at least one amino acid capable of forming at least one knob (protuberance) and/or at least one hole (cavity) (“knobs-into-holes” mutations), for giving advantage to pairing between two Fc regions and/or increasing stability. More specifically, among two Fc regions, one may be modified so as to have at least one amino acid capable of forming at least one knob (knob mutation), and the other may be modified so as to have at least one amino acid capable of forming at least one hole (hole mutation). The at least one amino acid capable of forming at least one knob (knob-forming amino acid) and the at least one amino acid capable of forming at least one hoe (hole-forming amino acid) may located at CH3 domain (for example, at least one amino acid of CH3 domain of one Fc region (a first Fc region) is substituted with a knob-forming amino acid, and at least one amino acid of CH3 domain of the other Fc region (a second Fc region) is substituted with a hole-forming amino acid). The knob-forming amino acid and the hole-forming amino acid exist at positions corresponding (interacting) to each other, thereby being capable of forming at least one knobs-into-holes amino acid pair between two Fc regions. The knob-forming amino acid may be an amino acid residue capable of forming a protruding structure by having relatively larger side chains than neighboring amino acid residues, and for example, the knob-forming amino acid may be one or more selected from the group consisting of Arg, Phe, Tyr, and Trp, but not be limited thereto. The hole-forming amino acid may be an amino acid residue capable of forming a dented structure by having relatively smaller side chains than neighboring amino acid residues, and for example, the hole-forming amino acid may be one or more selected from the group consisting of Ala, Ser, Thr, Gly and Val, but not be limited thereto.

For example, the Fc region (not including hinge) may be represented by SEQ ID NO: 14 (wild type IgG1 Fc), SEQ ID NO: 49 (K392D and K409D variant of IgG1 Fc), SEQ ID NO: 50 (E356K and D399K variant of IgG1 Fc), SEQ ID NO: 51 (T366W variant of IgG1 Fc; knob variant) and/or SEQ ID NO: 52 (T366S, L368A and Y407V variant of IgG1 Fc; hole variant), but not be limited thereto.

The amino acid sequences of the available hinges and Fc regions (not including hinge) are illustrated in Table 2 below:

	Amino acid sequence (N→C)	SEQ ID NO
Hinge	DKTHTCPPCP	13
IgG1 Fc (wild-type)	APELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	14
IgG1 Fc (K392D, K409D variant)	APELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYDTTPPVLDSDGSFFLYSDLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	49
IgG1 Fc (E356K, D399K variant)	APELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRKEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLKSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	50
IgG1 Fc (knob variant)	APELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLWCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	51
IgG1 Fc (hole variant)	APELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLSCAVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLVSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	52

In one embodiment, the fusion protein may comprise an amino acid sequence selected from SEQ ID NOs: 17 to 24, and 53 to 84.The amino acid sequences of the fusion proteins provided herein are exemplified in Table 3 below:

Amino acid sequence (N→C)	SEQ ID NO
EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	17
EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	18
EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	19
EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	20
EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	21
EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	22
EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	23
EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	24
EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYDTTPPVLDSDGSFFLYSDLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	53
EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYDTTPPVLDSDGSFFLYSDLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	54
EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYDTTPPVLDSDGSFFLYSDLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	55
EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYDTTPPVLDSDGSFFLYSDLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	56
EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYDTTPPVLDSDGSFFLYSDLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	57
EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYDTTPPVLDSDGSFFLYSDLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	58
EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYDTTPPVLDSDGSFFLYSDLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	59
EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYDTTPPVLDSDGSFFLYSDLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	60
EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRKEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLKSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	61
EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRKEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLKSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	62
EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRKEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLKSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	63
EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRKEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLKSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	64
EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRKEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLKSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	65
EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRKEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLKSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	66
EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRKEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLKSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	67
EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRKEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLKSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	68
EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLWCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	69
EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLWCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	70
EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLWCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	71
EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLWCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	72
EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLWCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	73
EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLWCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	74
EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLWCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	75
EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLWCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	76
EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLSCAVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLVSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	77
EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLSCAVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLVSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	78
EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLSCAVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLVSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	79
EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLSCAVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLVSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	80
EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLSCAVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLVSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	81
EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLSCAVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLVSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	82
EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLSCAVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLVSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	83
EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLSCAVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLVSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	84

In an embodiment, the fusion protein provided in the present disclosure may be a monomer (e.g., a single chain polypeptide). In another embodiment, the fusion protein is a multimer, wherein two or more fusion proteins are bound (multimerized) at Fc region (e.g., CH3 domain) and/or hinge region; for example, the fusion protein is a dimer (e.g., homodimer and/or heterodimer), wherein two fusion proteins are bound (dimerized) at Fc region (e.g., CH3 domain) and/or hinge region.

Polynucleotides, Recombinant Vectors, and Recombinant Cells

The SIRPα variant provided herein or a fusion protein comprising the same can be produced by recombinant or chemical synthesis.

One embodiment provides a polynucleotide encoding the SIRPα variant or the fusion protein.

Another embodiment provides a recombinant vector comprising the polynucleotide. The recombinant vector may be an expression vector for expressing the polynucleotide in a host cell.

Another embodiment provides a recombinant cell comprising the polynucleotide or the recombinant vector. The recombinant cell may be one in which the polynucleotide or the recombinant vector is introduced into a host cell.

Yet another embodiment provides a method for producing the SIRPα variant or fusion protein, comprising a step of expressing the polynucleotide in an appropriate host cell. The step of expression can be performed by culturing recombinant cells comprising the polynucleotide (e.g., contained in the recombinant vector) under conditions that allow expression of the polynucleotide. The production method may further comprise a step of isolating and/or purifying the SIRPα variant or fusion protein from the culture medium after the step of expressing or culturing.

The SIRPα variant or fusion protein may be as described above.

When the SIRPα variant or fusion protein provided herein is recombinantly produced, it may be a form to which a conventional signal peptide, cleavage site, tag, etc. are bound for purification. Thus, in a non-limiting example, the SIRPα variant or fusion protein provided herein is a form that further contains one or more selected from a signal peptide, cleavage site, tag (e.g., His tag, GST (glutathione) -s-transferase) tag, MBP (maltose binding protein) tag, etc.), or may be in a purified form from which they have been removed.

The term “vector” used herein refers to a means, typically a polynucleotide, of transporting and expressing a target gene (DNA or RNA) in a host cell. For example, the vector may comprise a plasmid vector, a cosmid vector, a bacteriophage vector, a virus vector, or the like. In one embodiment, the vector may be a virus vector selected from the group consisting of a lentivirus vector, an adenovirus vector, a retrovirus vector, an adeno-associated virus vector (AAV), murine leukemia virus vector, SFG vector, baculovirus vector, Epstein-Barr virus vector, papovavirus vector, vaccinia virus vector, herpes simplex virus vector, and the like, but is not limited thereto. In one embodiment, the recombinant vector may be prepared by manipulating a plasmid (e.g., pBR series, pUC series, pBluescriptII series, pGEM series, pGEX series, pTZ series, pCL, pcDNA series, pET series, etc.; more specifically, pSC101, pGV1106, pACYC177, ColE1, pKT230, pME290, pBR322, pUC8/9, pUC6, pBD9, pHC79, pIJ61, pLAFR1, pHV14, pDZ, pACYC177, pACYC184, pCL, pECCG117, pUC19, pBR322, pMW118, pCC1BAC, pcDNA3.1, pcDNA3.3, etc.), a phage (i.e., λgt4λB, λ-Charon, λΔz1, and M13, etc.), or a virus (e.g., SV40) often used in the art, but is not limited thereto.

In the recombinant vector, the nucleic acid molecule may be operably linked to a promoter. The term “operably linked” refers to a functional linkage between regulatory nucleotide sequences (for example, a promoter sequence) and other nucleotide sequences. The regulatory nucleotide sequences may be "operably linked" to regulate transcription and/or translation of other nucleotide sequences.

The recombinant vector may be constructed typically for cloning or expression. For example, a recombinant expression vector may be a vector known in the art for expressing foreign proteins in plants, animals or microorganisms. The recombinant vector may be constructed using various methods known in the art.

The recombinant vector may be constructed for use in prokaryotic or eukaryotic host cells. For example, when the vector used is an expression vector and a prokaryotic cell is used as the host cell, the expression vector generally comprises a strong promoter capable of initiating transcription (i.e., pL^λ promoter, CMV promoter, trp promoter, lac promoter, tac promoter, and T7 promoter, etc.), a ribosome binding site for initiating translation, and a transcription/translation termination sequence. When a eukaryotic cell is used as the host cell, the vector may contain an origin of replication, such as f1 origin of replication, SV40 origin of replication, pMB1 origin of replication, adeno origin of replication, AAV origin of replication, or BBV origin of replication, but is not limited thereto. A promoter in an expression vector for a eukaryotic host cell may be derived from a mammalian cell genome (e.g., a metallothionein promoter) or a mammalian virus (e.g., adenovirus late promoter, vaccinia virus 7.5K promoter, SV40 promoter, cytomegalovirus promoter, and tk promoter of HSV). A transcription termination sequence in an expression vector for a eukaryotic host cell is, in general, a polyadenylation sequence.

The recombinant cell may be obtained by introducing the recombinant vector into an appropriate host cell. The host cell, which is capable of stably and continuously cloning or expressing the recombinant vector, may be any host cell known in the art. A prokaryotic host cell may be a Bacillus genus bacterium, such as E. coli JM109, E. coli BL21, E. coli RR1, E. coli LE392, E. coli B, E. coli X 1776, E. coli W3110, Bacillus subtilis, and Bacillus thuringiensis, an intestinal bacterium, such as Salmonella typhimurium, Serratia marcescens, or various Pseudomonas species bacterium. A eukaryotic host cell may be a yeast (Saccharomyce cerevisiae), an insect cell, a plant cell, or an animal cell, such as Sp2/0, CHO (Chinese Hamster Ovary) cell (e.g., CHO K1, CHO DG44, CHO-S, CHO DXB11, CHO GS-KO, ExpiCHO), HEK293, Vero, PER.C6, W138, BHK, COS-7, HepG2, Huh7, 3T3, RIN, MDCK cell line, or the like, but are not limited thereto.

Transport (introduction) of the nucleic acid molecule or a recombinant vector comprising the same into a host cell may be performed using a transport method known in the art. For example, when a prokaryotic cell is used as the host cell, the transfer may be performed using a CaCl₂ method or an electroporation method, and when a eukaryotic cell is used as the host cell, the transfer may be performed by microinjection, calcium phosphate precipitation, electroporation, liposome-mediated transfection, or gene bombardment, but is not limited thereto.

A method of selecting a transformed host cell can be easily performed using a phenotype expressed by a selectable marker by a method known in the art. For example, when the selectable marker is a specific antibiotic resistance gene, a transformant can be easily selected by culturing the transformants in a medium containing the antibiotic.

Medical Uses

The SIRPα variant and/or fusion protein provided herein may have excellent binding affinity for CD47, can have an effect of inhibiting the binding between SIRPα and CD47, enhancing the macrophage phagocytosis and/or enhancing the immune response, and can have excellent anti-cancer effects.

The immune enhancement of the pharmaceutical composition for enhancing immunity may be due to an inhibition of the binding between CD47-SIRPα and/or an activation of the phagocytosis in macrophages.

Another embodiment provides a pharmaceutical composition for the prevention and/or treatment of immune-related diseases comprising at least one selected from the group consisting of: (1) the SIRPα variant, (2) the fusion protein, (3) a polynucleotide encoding the SIRPα variant or the fusion protein, (4) a recombinant vector comprising the polynucleotide, and (5) a recombinant cell comprising the polynucleotide or the recombinant vector.

Another embodiment provides a method of preventing and/or treating immune-related diseases, comprising administering to a subject in need thereof a pharmaceutically effective amount of at least one selected from the group consisting of: (1) the SIRPα variant, (2) the fusion protein, (3) a polynucleotide encoding the SIRPα variant or the fusion protein, (4) a recombinant vector comprising the polynucleotide, and (5) a recombinant cell comprising the polynucleotide or the recombinant vector.

The prevention and/or treatment of immune-related diseases may be due to an inhibition of the binding of CD47-SIRPα and/or an activation of the phagocytosis in macrophages and/or enhancing the immune response.

In one embodiment, the immune-related disease may be cancer.

Another embodiment provides a method for preventing and/or treating cancer, comprising administering to a subject in need thereof a pharmaceutically effective amount of at least one selected from the group consisting of: (1) the SIRPα variant, (2) the fusion protein, (3) a polynucleotide encoding the SIRPα variant or the fusion protein, (4) a recombinant vector comprising the polynucleotide, and (5) a recombinant cell comprising the polynucleotide or the recombinant vector.

The pharmaceutical composition provided herein may further comprise a pharmaceutically acceptable carrier, in addition to an active ingredient (an SIRPα variant and/or a fusion protein). The pharmaceutically acceptable carrier that is typically used in the formulation of drugs may be one or more selected from the group consisting of, but not limited to, lactose, dextrose, sucrose, sorbitol, mannitol, starch, gum acacia, calcium phosphate, alginate, gelatin, calcium silicate, microcrystalline cellulose, polyvinylpyrrolidone, cellulose, water, syrups, methyl cellulose, methylhydroxybenzoate, propylhydroxybenzoate, talc, magnesium stearate, mineral oil, and the like. The pharmaceutical composition may further comprise one or more selected from the group consisting of diluents, excipients, lubricants, wetting agents, sweeteners, aromatics, emulsifiers, suspensions, preservatives and the like, which are commonly used in preparing pharmaceutical compositions.

The effective amount of the pharmaceutical composition, or the active ingredient (an SIRPα variant and/or a fusion protein) may be administered orally or parenterally. Such a parenteral administration comprises intravenous injection, subcutaneous injection, intramuscular injection, intraperitoneal injection, endothelial administration, intranasal administration, intrapulmonary administration, intrarectal administration, or local administration to the lesion site, and the like. Because a protein or peptide is digested when administered orally, a composition for oral administration may be formulated so as to coat an active substance or to be protected against degradation in stomach. Also, the composition may be administered by any device which can transport active substances to target cells (e.g., a cancer cell).

An SIRPα variant and/or a fusion protein may be comprised in the pharmaceutical composition in a pharmaceutically effective amount or administered to a patient. The term “pharmaceutically effective amount”, as used herein, refers to an amount at which the active ingredient (an SIRPα variant and/or a fusion protein) can exert a desired effect (e.g., anti-cancer effect). The pharmaceutically effective amount may vary depending on various factors such as the patient's age, weight, sex, pathological condition, diet, the rate of excretion, sensitivity, the formulation method, the time and interval of administration, the route of administration, administration method, and the like. For example, the daily dose of the active ingredient may be in the range of 0.005 μg/kg to 1000 mg/kg, 0.005 μg/kg to 500 mg/kg, 0.005 μg/kg to 250 mg/kg, 0.005 μg/kg to 100 mg/kg, 0.005 μg/kg to 75 mg/kg, 0.005 μg/kg to 50 mg/kg, 0.01 μg/kg to 1000 mg/kg, 0.01 μg/kg to 500 mg/kg, 0.01 μg/kg to 250 mg/kg, 0.01 μg/kg to 100 mg/kg, 0.01 μg/kg to 75 mg/kg, 0.01 μg/kg to 50 mg/kg, 0.05 μg/kg to 1000 mg/kg, 0.05 μg/kg to 500 mg/kg, 0.05 μg/kg to 250 mg/kg, 0.05 μg/kg to 100 mg/kg, 0.05 μg/kg to 75 mg/kg, or 0.05 μg/kg to 50 mg/kg, but is not limited thereto. A daily dose may be formulated into a unit dose form or distributed into separate dose forms, or may be comprised within a multiple dose package.

The pharmaceutical composition may be formulated into a solution in an oily or aqueous medium, an injection, a suspension, a syrup, an emulsion, an extract, a powder, a granule, a tablet, or a capsule, and in the context of formulation, a dispersant or a stabilizer may be further employed.

The subject of the compositions and/or methods provided herein may be mammals, comprising primates such as humans, monkeys, etc., and rodents such as mice, rats, etc.

The cancer (including tumor) to be prevented and/or treated with the compositions and/or methods provided herein may be a solid cancer or a hematologic cancer, and may include, but not limited thereto, breast cancer, lung cancer, prostate cancer, ovarian cancer, brain cancer (e.g., meningioma, astrocytoma, glioblastoma or medulloblastoma), liver cancer, colorectal cancer, colon cancer, colorectal carninoma, rectal cancer, cervical cancer, endometrial cancer, uterine cancer, kidney cancer, nephroblastoma, skin cancer, oral squamous cell carcinoma, epidermal cancer, nasopharyngeal cancer, head and neck cancer, bone cancer, esophageal cancer, bladder cancer, lymphatic cancer (e.g., Hodgkin's lymphoma or non-Hodgkin's lymphoma), stomach cancer, pancreatic cancer, testicular cancer, thyroid cancer, follicular thyroid cancer, melanoma, myeloma, multiple myeloma, mesothelioma, osteosarcoma, myelodysplastic syndrome, tumors of mesenchymal origin, soft tissue sarcoma, liposarcoma, gastrointestinal stromal sarcoma, malignant peripheral nerve sheath tumor (MPNST), Ewing's sarcoma, leiomyosarcoma, mesenchymal chondrosarcoma, lymphosarcoma, fibrosarcoma, rhabdomyosarcoma, teratocarcinoma, neuroblastoma, medulloblastoma, glioma, benign skin tumor, leukemia, and the like. The lung cancer may be, for example, small cell lung carcinoma (SCLC) or non-small cell lung carcinoma (NSCLC). The leukemia can be, for example, acute myeloid leukemia (AML), chronic myeloid leukemia (CML), acute lymphocytic leukemia (ALL) or chronic lymphocytic leukemia (CLL). The cancer may be a primary cancer or a metastatic cancer.

As used herein, the treatment of cancer and/or tumor refers to all anti-cancer and/or anti-tumor effects that prevent, alleviate or ameliorate symptoms of cancer and/or tumor, such as inhibition of proliferation, death, and metastasis inhibition of cancer cells and/or tumor cells , or partially or completely kill cancer and/or tumors.

An SIRPα variant and/or a fusion protein comprising the same provided herein has excellent binding affinity for CD47, inhibits the binding between SIRPα and CD47 and/or has the phagocytosis enhancing activity of macrophages, and can exert excellent immune response enhancement and/or anti-cancer effects, and thus can be usefully applied in the pharmaceutical field, such as cancer immunotherapy.

FIG. 1 shows the results of SDS-PAGE analysis of fusion proteins comprising SIRPα variants;

FIG. 2 is a graph showing the results of measuring the binding affinity for human CD47 of fusion proteins comprising SIRPα variants by ELISA;

FIG. 3 is a graph showing the results of measuring ADCP (antibody-dependent cellular phagocytosis) activity of fusion proteins comprising SIRPα variants on human cancer cells; and

FIG. 4 is a graph showing the results of measuring ADCC (antibody-dependent cellular cytotoxicity) activity of fusion proteins comprising SIRPα variants against human cancer cells.

Hereinafter, the embodiments will be described by way of specific examples to aid in the understanding of the present disclosure. However, the following examples are for illustrative purposes only, and the scope of the present disclosure is not limited to these examples. The embodiments of the present disclosure are provided to more fully explain the invention to those with average knowledge in the art

Example 1. Preparation of SIRPα variants and fusion proteins comprising the same

1.1. Search for SIRPα variant sequences

Among the mutations in which each amino acid residue of the human SIRPα protein (encoded by GenBank Accession No. AAH38510.1; BC038510.2) is substituted with various amino acids, the mutations that were predicted to increase binding to CD47 without affecting the formation of CD47-SIRPα complex structure was selected, and based on this, SIRPα variants were derived (Table 4). Further, the amino acid sequences of the hinge and Fc (human IgG1 Fc) capable of fusion with the selected SIRPα variant are illustrated in Table 5, and the amino acid sequences of the SIRPα variants and the SIRPα-Fc fusion proteins (referred to as “SOM”) fused with an Fc containing a hinge is shown in Table 6, and the coding DNA sequences thereof are shown in Table 7:

Amino acid sequences of SIRPα variants

	Amino acid sequence (N→C)	SEQ ID NO	SEQ ID NO of nucleic acid sequence
Wild-type SIRPα	MEPAGPAPGRLGPLLCLLLAASCAWSGVAGEEELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISNITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKPSAPVVSGPAARATPQHTVSFTCESHGFSPRDITLKWFKNGNELSDFQTNVDPVGESVSYSIHSTAKVVLTREDVHSQVICEVAHVTLQGDPLRGTANLSETIRVPPTLEVTQQPVRAENQVNVTCQVRKFYPQRLQLTWLENGNVSRTETASTVTENKDGTYNWMSWLLVNVSAHRDDVKLTCQVEHDGQPAVSKSHDLKVSAHPKEQGSNTAAENTGSNERNIYIVVGVVCTLLVALLMAALYLVRIRQKKAQGSTSSTRLHEPEKNAREITQDTNDITYADLNLPKGKKPAPQAAEPNNHTEYASIQTSPQPASEDTLTYADLDMVHLNRTPKQPAPKPEPSFSEYASVQVPRK	1	25
Wild-type SIRPα V2 domain (1-118 a.a)	EEELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISNITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKPS	2	26
Wild-type SIRPα V2 domain fragment (2-116 a.a)	EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISNITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	3	27
Variant 1: N80D variant of SIRPα V2 domain fragment (2-116 a.a)	EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	4	28
Variant 2: H56R & N80D variant of SIRPα V2 domain fragment (2-116 a.a)	EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	5	29
Variant 3: H56K & N80D variant of SIRPα V2 domain fragment (2-116 a.a)	EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	6	30
Variant 4: I31K & N80D variant of SIRPα V2 domain fragment (2-116 a.a)	EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	7	31
Variant 5: I31Y & N80D variant of SIRPα V2 domain fragment (2-116 a.a)	EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	8	32
Variant 6: I31K, H56R & N80D variant of SIRPα V2 domain fragment (2-116 a.a)	EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	9	33
Variant 7: I31K, H56K & N80D variant of SIRPα V2 domain fragment (2-116 a.a)	EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	10	34
Variant 8: I31Y, H56R & N80D variant of SIRPα V2 domain fragment (2-116 a.a)	EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	11	35
Variant 9: I31Y, H56K & N80D variant of SIRPα V2 domain fragment (2-116 a.a)	EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAK	12	36

(In Table 4, H56R means an amino acid substitution mutation in which H, which is the 56th amino acid residue from the N-terminus based on the wild-type SIRPα V2 domain (1-118 a.a) (SEQ ID NO: 2) is substituted with R. The other amino acid substitution mutation is interpreted similarly)

Sequences of hinge and IgG1 Fc

	Amino acid sequence (N→C)	SEQ ID NO	SEQ ID NO of nucleic acid sequence
Hinge	DKTHTCPPCP	13	37
IgG1 Fc	APELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	14	38

Fusion proteins comprising SIRPα variant, hinge, and IgG1 Fc, in order (N→C) (hereinafter, “SOM”)

Fusion protein	SIRPα variant	Amino acid sequence (N→C)	SEQ ID NO
SOM1	-	EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISNITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	15
SOM2	Variant1	EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	16
SOM3	Variant	2	EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	17
SOM4	Variant	3	EELQVIQPDKSVSVAAGESAILHCTVTSLIPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	18
SOM5	Variant	4	EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	19
SOM6	Variant5	EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGHFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK		20
SOM7	Variant6	EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	21
SOM8	Variant7	EELQVIQPDKSVSVAAGESAILHCTVTSLKPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	22
SOM9	Variant8	EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGRFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	23
SOM10	Variant9	EELQVIQPDKSVSVAAGESAILHCTVTSLYPVGPIQWFRGAGPARELIYNQKEGKFPRVTTVSESTKRENMDFSISISDITPADAGTYYCVKFRKGSPDTEFKSGAGTELSVRAKDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK	24

DNA sequences coding the fusion proteins

Fusion protein	SEQ ID NO
SOM1	39
SOM2	40
SOM3	41
SOM4	42
SOM5	43
SOM6	44
SOM7	45
SOM8	46
SOM9	47
SOM10	48

1.2. Preparation of fusion proteins containing an SIRPα variant

1.2.1. Gene cloning for expression of fusion proteins containing an SIRPα variant

A nucleic acid sequence encoding the amino acid sequence of Table 6 (codon-optimized sequence for expression in ExpiCHO cells) was synthesized at Macrogen Co., Ltd., and the nucleic acid sequence was cloned using restriction enzymes ClaI and XhoI to prepare a pcDNA 3.3 expression vector (Invitrogen). This was introduced into ExpiCHO cells (ExpiCHO-S™ cells, Thermo Fisher, Cat# A29127) to express a fusion protein containing the SIRPα variant of Table 6.

1.2.2. Expression of fusion proteins containing an SIRPα variant in ExpiCHO cells

To express a fusion protein containing an SIRPα variant, the ExpiCHO transient expression system was used. ExpiCHO cells (ExpiCHO-S™ cells, Thermo Fisher, Cat# A29127) were maintained in an early log-phage state of 0.2x10⁶ ~ 0.3x10⁶ viable cells/mL while subculturing every 3 days. On the day prior to transfection, the cells were split at 3x10⁶ ~ 4x10⁶ cells/mL (viable cells/mL) and subcultured. It was measured whether the number of subcultured cells was 7x10⁶ ~ 10x10⁶ viable cells/mL and had a viability of 95% or more. After diluting at 6x10⁶ viable cells/mL in pre-warmed fresh ExpiCHO^TM expression medium (Gibco, Cat# A29100-01), the following 20 μg DNA was added to 1 mL of cold OptiPro SFM (Gibco, Cat# 12309-050) based on 35 mL production. After adding 80 μL of ExpiFectamine™ CHO Reagent (Gibco, Cat# A29129) to 0.92 mL of OptiPro SFM medium, DNA and diluted ExpiFectamine™ CHO Reagent were mixed, left at room temperature for 5 minutes, and then added to the cells. The cells were incubated with shaking at 125 rpm under the conditions of 37°C and 8% CO₂for 1 day. After incubating for 1 day, 150 μL of Enhancer and 4 mL of Feed were added to the culture medium, and then incubated at 125 rpm under the conditions of 32°C and 5% CO₂ for 4 days. After incubating for 4 days, 4 mL of Feed was further added to the culture medium and further incubated for 6 days. When the viability was 70%, the cultured ExpiCHO cells were harvested.

1.2.3. Purification of fusion proteins containing an SIRPα variant

To purify a fusion protein (dimerized at hinge region after expression in host cells, thereby existing in a homodimeric form) containing an SIRPα variant, the culture medium was centrifuged at 4°C at 4,800 rpm for 30 minutes. The culture supernatant was collected by filtrating with a 0.22 μm filter (Millipore). AKTA Go (Cytiva) was used as the purification system, 3 mL of Protein A resin (KANEKA, Cat# KPA02-B500) was filled, and then the column was equilibrated at a flow rate of 1 mL/min using DPBS buffer for 30 minutes. The harvested culture medium was loaded onto a Protein A affinity chromatography column at a flow rate of 0.5 mL/min. The column was washed with DPBS buffer at a flow rate of 1 mL/min for 1 hour, and then the proteins were eluted with 0.1 M glycine buffer (pH 3.3), respectively. The eluted fractions were analyzed. The parts in which the fusion protein containing the high-purity SIRPα variant exists was collected, and then dialyzed with the final formulation buffer (DPBS) at 4°C overnight. After completion of the dialysis, concentration was performed at 3000 rpm and 4°C using a 50,000 MW cut-off centrifugal filter. The concentration of the fusion protein containing the SIRPα variant was measured by UV quantitative analysis.

1.2.4. SEC-HPLC analysis of fusion proteins containing an SIRPα variant

After connecting the developing solvent to pump A of the HPLC system (Thermo, Ultimate 3000), the system was driven. After exchanging with the developing solvent, an SEC column (Sepax, SRT-C SEC 300, 7.8x300 mm 5 μm, 300 Å) was connected. The column was equilibrated by operating at a speed of 1 ml/min for 1 hour. After confirming that the baseline was stabilized in the chromatogram, the developing solvent was flowed. The purified protein to be analyzed was filtered with a 0.22 μm filter and then a 20 μg sample was injected. The results of protein purity analysis by SEC-HPLC are shown in Table 8:

SEC-HPLC analysis results for fusion proteins comprising an SIRPα variant

Fusion protein	Purity (%)
SOM1	87.5
SOM2	90.8
SOM3	93.5
SOM4	95.4
SOM5	95.1
SOM6	91.7
SOM7	97.6
SOM8	97.7
SOM9	93.3
SOM10	94.7

Example 2. Effect of SIRPα deglycosylation (N80D mutation)

2.1. Improvement of physical properties of proteins by SIRPα deglycosylation (SDS-PAGE analysis)

In order to confirm the purity of the fusion protein containing the purified SIRPα variant, SDS-PAGE was performed under reducing and non-reducing conditions. 3 μg of each of the fusion proteins containing the SIRPα variant purified in Example 1.2.3 were respectively mixed with a non-reducing sample buffer (60 mM Tris HCl, 25% Glycerol, 2% SDS, 0.1% bromophenol blue) and a reducing sample buffer (60 mM Tris HCl, 25% Glycerol, 2% SDS, 0.1% bromophenol blue, 14.4 mM β-mercaptoethanol), and heated at 70°C for 5 minutes. The denatured protein was loaded onto SDS-PAGE gels (GenScript, ExpressPlus™ PAGE Gels, Cat # M42010), and electrophoresed at 90 V for 140 minutes, and then stained with Comassie blue solution to visualize the protein band on the gel. The obtained results are shown in FIG. 1. As shown in FIG. 1, the SOM1 shows two bands, while the SOM2 to SOM10 show only one band. From this, it was confirmed that deglycosylation (N80D mutation) of SIRPα contributes to the improvement of the physical properties of proteins.

2.2. Improvement of physical properties of proteins by SIRPα deglycosylation (CE-SDS analysis)

The purity of the fusion protein containing the SIRPα variant was analyzed by CE-SDS using LabChip GXII (PerkinElmer). The fusion protein containing the SIRPα variant purified in Example 1.2.3 was prepared using the HT Protein Express Reagent Kit (PerkinElmer, Cat# CLS960008) according to the manufacturer's guide, and the obtained results were analyzed using LabChip GX Software. The analysis results are shown in Table 9.

CE-SDS analysis results for fusion proteins comprising an SIRPα variant

Fusion protein	Purity (%)
Fusion protein	Non-reducing	reducing
SOM1	38.0	60.5
SOM2	94.8	94.5
SOM3	96.6	95.7
SOM4	96.5	94.0
SOM5	96.4	88.4
SOM6	96.5	95.8
SOM7	97.9	95.6
SOM8	98.4	97.5
SOM9	95.3	93.7
SOM10	97.5	96.5

As shown in Table 9, it was confirmed that among the fusion proteins containing the SIRPα variant, the fusion proteins containing the deglycosylation (N80D mutation) of SIRPα (SOM2 to SOM10) have improved purity in both non-reducing and reducing conditions as compared with SOM1.

Example 3. Improvement of biological activities of proteins by SIRPα deglycosylation

3.1. Confirmation of improving binding affinity for human CD47 by a specific mutation of SIRPα

3.1.1. Binding affinity for human CD47 (ELISA assay)

ELISA analysis was performed to confirm the binding affinity of the fusion protein containing the SIRPα variant to human CD47 protein.

More specifically, human CD47 protein (Accession # NP_942088.1) was dispensed in 50 ng/100 μL/well in a 96-well plate (Nunc, Cat # 469949) and coated at 4°C for 16 hours. After washing 3 times with washing buffer (PBST), 200 μL/well of blocking buffer (PBST containing 3% BSA) was added and reacted at room temperature for 2 hours. After washing 3 times with a washing buffer, 100 μL/well of the fusion protein containing the SIRPα variant diluted according to the concentration was added, and reacted at room temperature for 2 hours. Then, after washing 3 times with a washing buffer, HRP-conjugated anti-human IgG1 antibody (Jackson IR, Cat# 109-035-098) was treated and reacted at room temperature for 1 hour. Finally, after washing 3 times with a washing buffer, 100 μL of TMB solution (Bio-rad, Cat# 172-1066) was added and developed for 5 minutes. The reaction was stopped by adding 100 μL of 2N H₂SO₄, and the absorbance was measured at 450 nm/595 nm.

The obtained results are shown in FIG. 2 and Table 10:

Binding affinity of fusion proteins comprising an SIRPα variant to human CD47

Fusion protein	EC₅₀ (nM)
SOM1	0.115
SOM2	0.148
SOM3	0.022
SOM4	0.032
SOM5	0.023
SOM6	0.022
SOM7	0.015
SOM8	0.018
SOM9	0.017
SOM10	0.018

As shown in Table 10, it was confirmed that 8 types of fusion proteins containing an SIRPα variant with specific SIRPα mutations (H56R, H56K, I31K, and/or I31Y), i.e., SOM3, SOM4, SOM5, SOM6, SOM7, SOM8, SOM9, and SOM10, have improved binding affinity for human CD47 as compared to SOM1 and SOM2.

3.1.2. Evaluation of binding affinity for human CD47 (SPR analysis)

The binding affinity of the fusion protein containing the SIRPα variant to human CD47 protein was evaluated using BIACORE T200 (Cytiva). The experimental conditions using surface plasmon resonance (SPR) are as follows. A CM5 chip (GE Healthcare, Cat# BR100530) on which a fusion protein containing each SIRPα variant was immobilized was used, and 20 mM NaOH and a running buffer as the regeneration buffer, and HBS-EP, pH 7.4 (GE Healthcare, Cat# BR100669) as the antibody-diluting, antigen-diluting buffer were used. Human CD47 protein (Novoprotein, Cat# C321) was serially diluted 2-fold from 100 nM, and analyzed at a total of 9 concentrations including 0 nM. In the association phase of human CD47 protein, the association time was set to 300 seconds and the flow rate was set to 30 μL/min, and in the dissociation phase, the dissociation time was set to 300 seconds and the flow rate was set to 30 μL/min. In the regeneration phase, the flow rate was set to 100 μL/min, and the flow time was set to 30 seconds. BIACORE Evaluation software was used for the analysis program, and fitted using a 1:1 binding model.

The obtained results are shown in Table 11.

K_D values for human CD47

	K_D (M)	k_a (1/Ms)	k_d (1/s)
SOM1	3.162 x 10^-8	2.303 x 10⁵	7.282 x 10^-3
SOM2	2.790 x 10^-8	2.526 x 10⁵	7.046 x 10^-3
SOM3	8.912 x 10^-9	2.892 x 10⁵	2.577 x 10^-3
SOM9	3.264 x 10^-9	1.599 x 10⁵	5.218 x 10^-4
SOM10	5.119 x 10^-9	1.718 x 10⁵	8.796 x 10^-4

As shown in Table 11, it was confirmed that in the 5 types of fusion proteins tested, the binding affinity (K_D) of SOM3, SOM9, and SOM10 to CD47 was significantly improved as compared with SOM1 and SOM2.

Example 4. Evaluation of ADCP activity against human CD47-expressing cancer cells by specific mutation of SIRPα

An experiment was performed to evaluate the antibody-dependent cellular phagocytosis (ADCP) of tumor cells by FcγRIIa-H signaling of a fusion protein containing an SIRPα variant. This experiment was performed using FcγRIIa-H ADCP Bioassay kit (Promega, Cat# G9996) and based on the protocol recommended by the manufacturer. As target cells, the MDA-MB-231 human breast cancer cell line (ATCC, Cat# HTB-26), were dispensed in a 96-well assay plate by 10,000 per well, and incubated in a CO₂ incubator for 16 hours, at 37°C. The culture medium of target cells was replaced with RPMI1640 medium containing 4% low IgG serum included in the kit, and then the target cells were treated with the fusion protein containing the SIRPα variant diluted 3-fold from 1000 nM into a total of 10 sections, and reacted for 15 minutes. The effector cells, FcγRIIa-H effector cells, were dispensed with the target cells (MDA-MB-231 cells prepared above) in a ratio of about 5:1, and incubated in a CO₂ incubator at 37°C for 6 hours, and then 75 μL of Bio-Glo™ reagent was dispensed into each well, and reacted at room temperature for 10 minutes. The response value (RLU, relative light unit) was measured with a microplate reader (Molecular Devices, SpectraMax L) capable of measuring luminescence, and the ADCP efficacy was evaluated.

The obtained results are shown in FIG. 3 and Table 12:

ADCP activity against human cancer cells of fusion proteins containing SIRPα variants

Fusion protein	EC₅₀ (nM)	Fold increase (compared to SOM1)
SOM1	3.46	1.00
SOM2	4.07	0.85
SOM3	2.28	1.52
SOM4	2.34	1.48
SOM5	2.73	1.27
SOM6	2.53	1.37
SOM7	1.85	1.87
SOM8	1.80	1.92
SOM9	2.28	1.52
SOM10	1.62	2.14

As shown in FIG. 3 and Table 12, it was confirmed that when comparing SOM1 and SOM2, SIRPα deglycosylation does not affect ADCP activity, and all of SOM3, SOM4, SOM5, SOM6, SOM7, SOM8, SOM9, and SOM10 are improved in the ADCP activity as compared with SOM2.

Example 5. Evaluation of ADCC activity against human CD47-expressing cancer cells by specific mutation of SIRPα

The above experiment was performed to evaluate antibody-dependent cellular cytotoxicity (ADCC) of tumor cells by FcγRIIIa signaling of a fusion protein containing an SIRPα variant. This experimernt was performed using Promega's FcγRIIIa ADCC Bioassay kit (Promega, Cat# G7018) and based on the method recommended by the manufacturer. As target cells, the MDA-MB-231 human breast cancer cell line, were dispensed in a 96-well plate with 10,000 cells per well, and incubated in a CO₂ incubator at 37°C for 16 hours. The culture medium of the 96-well plate was removed, and 25 μL of RPMI1640 medium containing 4% low IgG serum was dispensed. The fusion protein containing the SIRPα variant was serially diluted 5-fold from 300 nM to prepare a sample, and 25 μL of the diluted sample was dispensed into a 96-well plate and reacted in an incubator at 37°C for 15 minutes. ADCC (FcγRIIIa) effector cells were prepared at a concentration of 1x10⁶ cells/mL, and the 96-well plate was removed from the incubator, and 25 μL was dispensed per well. Finally, the fusion protein containing the SIRPα variant was serially diluted 5-fold from 100 nM and treated. The 96-well plate was again reacted in a CO₂incubator at 37°C for 6 hours. The 96-well plate was taken out at room temperature, treated with Bio-Glo reagent, and allowed to stand still for 10 minutes. The response value (RLU, relative light unit) was measured with a microplate reader (Molecular Devices, SpectraMax L) capable of measuring luminescence, and the ADCC efficacy was assessed.

The obtained results are shown in FIG. 4 and Table 13:

ADCC activity against human cancer cells of fusion proteins containing SIRPα variants

	EC₅₀ (nM)	Fold increase (compared to SOM1)
SOM1	0.16	1.00
SOM2	0.28	0.57
SOM3	0.05	3.20
SOM4	0.07	2.29
SOM5	0.03	5.33
SOM6	0.04	4.00
SOM7	0.02	8.00
SOM8	0.02	8.00
SOM9	0.02	8.00
SOM10	0.03	5.33

As shown in FIG. 4 and Table 13, it was confirmed that when comparing SOM1 and SOM2, SIRPα deglycosylation does not affect ADCC activity, and all of SOM3, SOM4, SOM5, SOM6, SOM7, SOM8, SOM9, and SOM10 are improved in the ADCC activity as compared with SOM2.It will be apparent to those of ordinary skill in the art that a specific part of the present disclosure is described in detail above, but such detailed description is only a preferred embodiment, and the scope of the present disclosure is not limited thereby. Therefore, the substantial scope of the present disclosure is to be determined by the appended claims and their equivalents.

Claims

An SIRPα (Signal regulatory protein alpha) variant comprising:

118 or more consecutive amino acids comprising an SIRPα V2 domain of SEQ ID NO: 2 in SIRPα, or 115 or more consecutive amino acids comprising an SIRPα V2 domain fragment of SEQ ID NO: 3,

wherein the SIRPα V2 domain or SIRPα V2 domain fragment is one in which:

(1) the amino acid corresponding to the 31st position of SEQ ID NO: 2 or the 30th position of SEQ ID NO: 3,

(2) the amino acid corresponding to the 56th position of SEQ ID NO: 2 or the 55th position of SEQ ID NO: 3, or

(3) both (1) and (2)

is substituted with other amino acid.
The SIRPα variant according to claim 1, wherein the SIRPα V2 domain or SIRPα V2 domain fragment is one in which:

(1) the amino acid corresponding to the 31st position of SEQ ID NO: 2 or the 30th position of SEQ ID NO: 3 is tyrosine or lysine,

(2) the amino acid corresponding to the 56th position of SEQ ID NO: 2 or the 55th position of SEQ ID NO: 3 is arginine or lysine, or

(3) (a) the amino acid corresponding to the 31st position of SEQ ID NO: 2 or the 30th position of SEQ ID NO: 3 is tyrosine or lysine, and (b) the amino acid corresponding to the 56th position of SEQ ID NO: 2 or the 55th position of SEQ ID NO: 3 is arginine or lysine.
The SIRPα variant according to claim 1, further comprising:

a substitution of the amino acid corresponding to the 80th position of SEQ ID NO: 2 or the 79th position of SEQ ID NO: 3 with other amino acid.
The SIRPα variant according to claim 2, further comprising:

a substitution of the amino acid corresponding to the 80th position of SEQ ID NO: 2 or the 79th position of SEQ ID NO: 3 with other amino acid.
The SIRPα variant according to claim 1, further comprising:

a substitution of the amino acid corresponding to the 80th position of SEQ ID NO: 2 or the 79th position of SEQ ID NO: 3 with aspartic acid.
The SIRPα variant according to claim 2, further comprising:

a substitution of the amino acid corresponding to the 80th position of SEQ ID NO: 2 or the 79th position of SEQ ID NO: 3 with aspartic acid.
The SIRPα variant according to claim 6, comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 5 to SEQ ID NO: 12.
A fusion protein comprising:

(i) the SIRPα variant according to any one of claims 1 to 7; and

(ii) an Fc region of immunoglobulin.
The fusion protein according to claim 8, wherein the Fc region of immunoglobulin comprises a hinge region.
The fusion protein according to claim 8, wherein the Fc region of immunoglobulin does not comprise a hinge region.
A polynucleotide encoding:

the SIRPα variant of any one according to claims 1 to 7, or

a fusion protein comprising the SIRPα variant and an Fc region of immunoglobulin.
A recombinant vector comprising the polynucleotide according to claim 11.
A recombinant cell comprising the polynucleotide according to claim 11 or a recombinant vector containing the same.
A pharmaceutical composition for the prevention or treatment of cancer, comprising at least one selected from the group consisting of:

the SIRPα variant of any one according to claims 1 to 7,

a fusion protein comprising the SIRPα variant and an Fc region of immunoglobulin,

a polynucleotide encoding the SIRPα variant or the fusion protein;

a recombinant vector comprising the polynucleotide, and

a recombinant cell comprising the polynucleotide or a recombinant vector containing the same.
The pharmaceutical composition for the prevention or treatment of cancer according to claim 14, wherein the prevention or treatment of the cancer is due to an inhibition of the binding of CD47-SIRPα, an activation of the phagocytosis in macrophages, or both.
The pharmaceutical composition for the prevention or treatment of cancer according to claim 14, wherein the cancer is selected from the group consisting of: breast cancer, lung cancer, prostate cancer, ovarian cancer, brain cancer, liver cancer, colorectal cancer, colon cancer, colorectal carninoma, rectal cancer, cervical cancer, endometrial cancer, uterine cancer, kidney cancer, nephroblastoma, skin cancer, oral squamous cell carcinoma, epidermal cancer, nasopharyngeal cancer, head and neck cancer, bone cancer, esophageal cancer, bladder cancer, lymphatic cancer, stomach cancer, pancreatic cancer, testicular cancer, thyroid cancer, follicular thyroid cancer, melanoma, myeloma, multiple myeloma, mesothelioma, osteosarcoma, myelodysplastic syndrome, tumor of mesenchymal origin, soft tissue sarcoma, liposarcoma, gastrointestinal stromal sarcoma, malignant peripheral nerve sheath tumor (MPNST), Ewing's sarcoma, leiomyosarcoma, mesenchymal chondrosarcoma, lymphosarcoma, fibrosarcoma, rhabdomyosarcoma, teratocarninoma, neuroblastoma, medulloblastoma, glioma, benign skin tumor, and leukemia.
A pharmaceutical composition for enhancing immunity, comprising at least one selected from the group consisting of:

the SIRPα variant of any one according to claims 1 to 7,

a fusion protein comprising the SIRPα variant and an Fc region of immunoglobulin,

a polynucleotide encoding the SIRPα variant or the fusion protein;

a recombinant vector comprising the polynucleotide, and

a recombinant cell comprising the polynucleotide or a recombinant vector containing the same.
The pharmaceutical composition for enhancing immunity according to claim 17, wherein enhancing immunity is due to an inhibition of the binding of CD47-SIRPα, an activation of the phagocytosis in macrophages, or both.