Hybrid molecule comprising an antibody fc portion and at least one peptide binding to a self-reactive lymphocyte involved in autoimmune dermatitis, and uses thereof

Abstract

The invention relates to a hybrid molecule comprising at least one antibody Fc portion covalently bound to at least one peptide binding to a self-reactive lymphocyte responsible for autoimmune dermatitis, the uses of such a hybrid molecule, and a method for producing same.

Description

Title: Hybrid molecule comprising an antibody Fc fragment and at least one peptide binding to an autoreactive lymphocyte involved in autoimmune dermatitis, and its uses

[0001] The present invention relates to a hybrid molecule comprising at least one antibody Fc fragment covalently linked to at least one peptide binding to an autoreactive lymphocyte, involved in autoimmune dermatitis, the uses of such a hybrid molecule, as well as its production method. Autoreactive lymphocytes express receptors on their surface. Said autoreactive lymphocyte receptors are membrane receptors of a B lymphocyte (BCR) or a T lymphocyte (TCR). Background to the invention

[0002] Autoimmune dermatitis is a disease of the skin and mucous membranes, particularly linked to the production of autoantibodies by the body and / or pro-inflammatory cytokines secreted by T lymphocytes.

[0003] Autoimmune dermatitis is often classified based on the autoantibody involved. For example, the presence of class G autoantibodies against desmogleins (proteins of interkeratinocyte desmosomes) is highly specific for pemphigus. In contrast, the presence of autoantibodies against collagen XVII is more representative of bullous pemphigoid.

[0004] These autoantibodies are at the heart of autoimmune reactions specific to autoimmune dermatitis (eg Di Zenzo G, Thoma-Uszynski S, Calabresi V, Fontao L, Hofmann SC, Lacour JP, Sera F, Bruckner-Tuderman L, Zambruno G, Borradori L, Hertl M. Demonstration of epitopespreading phenomena in bullous pemphigoid: results of a prospective multicenter study. J Invest Dermatol. 2011 Nov;131(11):2271-80. doi: 10.1038 / jid.2011.180 Epub 2011 Jun 23. PMID: 21697892; pemphigus foliaceus Autoimmun. 2021 Jan;116:102561. doi: 10.1016 / j.jaut.2020.102561. Epub 2020 Nov 4. PMID: 33158670; PMCID: PMC7770069). These autoantibodies therefore represent a therapeutic target of choice.

[0005] The antigenic targets of the autoantibodies responsible for autoimmune dermatitis have been characterized and can be found in the IEDB database, Immune Epitope Database and analysis resource, http: / / www.iedb.org / home_v3.php. These autoantibodies are specifically directed against the polypeptide chain a-1 of collagen XVII, the polypeptide sequence of desmoglein-1, or the polypeptide sequence of desmoglein-3.

[0006] To date, there is no specific treatment for autoimmune dermatitis. Treatments generally consist of the administration of systemic corticosteroids, or even immunosuppressive drugs, which can cause serious side effects. Anti-CD20 antibodies can also be used, but these are not specific to the B cells that generate autoreactive antibodies and have no effect on autoreactive T cells.

[0007] An object of the present invention is thus to provide a more targeted treatment for autoimmune dermatitis. By targeting the B cells at the origin of autoreactive antibodies (autoantibodies) specific to autoimmune dermatitis, and / or the autoreactive T lymphocytes which are sources of pro-inflammatory cytokines, the present invention thus aims to provide a treatment adapted to each autoimmune dermatitis.

[0008] The present invention is based on the Inventors' research showing that it is possible to target autoreactive lymphocyte receptors that recognize self-peptides involved in the development of autoimmune dermatitis. More particularly, the present invention is based on the Inventors' research showing that it is possible to target B lymphocyte clones expressing autoreactive lymphocyte receptors involved in autoimmune dermatitis and / or autoreactive T lymphocytes (by binding a self-peptide involved in the development of autoimmune dermatitis to the TCR), and to eliminate them using a hybrid molecule comprising (i) at least one peptide binding to an autoreactive lymphocyte involved in autoimmune dermatitis and (ii) a human immunoglobulin Fc fragment.These hybrid molecules will specifically target B lymphocyte clones expressing autoantibodies responsible for autoimmune dermatitis and / or autoreactive T lymphocytes (using said peptide, which is recognized by B and / or T membrane receptors expressed by said B and / or T lymphocytes) which will then be eliminated, after fixation of the Fc fragment on the Fc receptors, by macrophages (via phagocytosis) and / or NK cells (via antibody-dependent cell-mediated cytotoxicity - ADCC), and / or by activation of the complement cascade.

[0009] By targeting B lymphocyte clones expressing autoantibodies responsible for autoimmune dermatitis and cells that differentiate into plasma cells that themselves secrete said autoantibodies and / or autoreactive T lymphocytes that are sources of pro-inflammatory cytokines, the hybrid molecules of the invention thus aim to eliminate these “pathogenic” autoantibodies and the source of inappropriate inflammation from the patients’ bodies. Statement of the invention

[0010] Hybrid molecule according to the invention

[0011] In a first aspect, the invention relates to a hybrid molecule comprising at least one antibody Fc fragment covalently linked to at least one peptide binding to an autoreactive lymphocyte involved in autoimmune dermatitis, at least one spacer being optionally present between said Fc fragment and said peptide. The scheme of such a construction is presented in Figure 1.

[0012] According to the invention, a “hybrid molecule” means a molecule having at least two components of a different nature, in this case the Fc fragment of the antibody and said peptide.

[0013] According to the invention, an antibody "Fc fragment" means the constant region of an immunoglobulin excluding the first immunoglobulin constant region domain (i.e. CH1-CL). Thus, the Fc fragment refers to a homodimer, each monomer comprising the last two constant domains of IgA, IgD, IgG (i.e. CH2 and CH3), or the last three constant domains of IgE and IgM (i.e. CH2, CH3 and CH4).

[0014] According to the invention, the expression "covalently bonded" means a covalent bond, that is to say a chemical bond in which two atoms share two electrons. Said covalent bond can be polar or non-polar.

[0015] According to the invention, a "spacer" is a linking agent that makes it possible to covalently link an antibody Fc fragment to said peptide binding to an autoreactive lymphocyte involved in autoimmune dermatitis, while distancing said Fc fragment from said peptide (thus reducing any possible steric hindrance). It may be any molecule, and in particular a peptide or a polypeptide. Preferably, the spacer does not modify the physicochemical properties of the hybrid molecule.

[0016] The presence of at least one spacer is advantageous: it facilitates the independent accessibility of the two partners of the hybrid molecule (the Fc fragment is more easily accessible to bind to the Fc receptors, just as said peptide is more easily accessible to bind to auto-reactive lymphocytes), and / or stabilizes the hybrid molecule, and / or increases the solubility of the hybrid molecule.

[0017] According to one embodiment, the hybrid molecule according to the invention may comprise one or more spacers. Preferably, the hybrid molecule comprises one or two spacers. According to one embodiment, when at least one spacer is present in said hybrid molecule of the invention, said Fc fragment is covalently linked to a spacer, said spacer itself being covalently linked to said peptide. According to another embodiment, when at least two spacers are present in said hybrid molecule of the invention, said Fc fragment is covalently linked to a first spacer, said first spacer itself being covalently linked to a second spacer and the second spacer itself is covalently linked to said peptide. The bond between the Fc fragment and the peptide may therefore be direct, or indirect in the presence of spacers.

[0018] According to one embodiment, the hybrid molecule according to the invention may comprise at least one peptide binding to an autoreactive lymphocyte involved in autoimmune dermatitis. This means that the Fc fragment may be linked to one or two peptides. Indeed, the Fc fragment comprises two monomers, and the Fc fragment may thus be covalently linked to a peptide on only one of the two monomers, or the Fc fragment may be covalently linked to a peptide on each monomer. Preferably, when two peptides are linked on the Fc fragment, the two peptides are identical.

[0019] According to one embodiment, said spacer is a polymer containing one or more repeating units containing the ether group. According to a particular embodiment, said spacer is polyethylene glycol of formula PEG-n, in which n represents an integer between 1 and 100, preferably between 1 and 10, and in particular 1, 2, 3, 4 or 8. According to the invention, said polyethylene glycol may be functionalized, for example with an amine group (PEG-n-amine such as PEG-NH2). According to the invention, “an integer between 1 and 100” represents all integer values ​​between 1 and 100, ie; 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 and 100.

[0020] The term "self-reactive lymphocyte receptor involved in autoimmune dermatitis" means a receptor on the surface of a T lymphocyte and / or a B lymphocyte that recognizes a self-peptide involved in the activation of cells leading to autoimmune dermatitis by inappropriate production of autoantibodies or pro-inflammatory cytokines. More particularly, said lymphocyte receptor is a B lymphocyte receptor (BCR) and / or a T lymphocyte receptor (TCR). The binding of the peptide to the BCR and / or the TCR is thus involved in the development of autoimmune dermatitis. For example, in the case of bullous pemphigoid the self-peptide involved may comprise all or part of collagen XVII, and the autoantibody involved is an autoantibody directed against collagen XVII.Typically, the binding of anti-collagen XVII autoantibodies disrupts the cohesion between the epidermis and the dermis, which causes the formation of a blister (“and consequently bullous pemphigoid”).

[0021] The term "autoreactive lymphocyte involved in autoimmune dermatitis" means a lymphocyte expressing on its surface a receptor that recognizes a self-peptide involved in the activation of cells leading to autoimmune dermatitis by inappropriate production of autoantibodies or pro-inflammatory cytokines. Preferably, it is a T lymphocyte and / or a B lymphocyte.

[0022] According to one embodiment, the expression "peptide binding to an autoreactive lymphocyte involved in autoimmune dermatitis" means a peptide comprising all or part of the polypeptide sequence of collagen XVII, all or part of the polypeptide sequence of desmoglein-1 (DSG1) and / or all or part of the polypeptide sequence of desmoglein-3 (DSG3). According to one embodiment, the expression "peptide binding to an autoreactive lymphocyte involved in autoimmune dermatitis" means a peptide comprising all or part of the polypeptide sequence of collagen XVII, all or part of the polypeptide sequence of desmoglein-1 (DSG1) or all or part of the polypeptide sequence of desmoglein-3 (DSG3). Preferably, it is a peptide comprising all or part of the polypeptide chain a-1 of collagen XVII, the polypeptide sequence of desmoglein-1 (DSG1) or the polypeptide sequence of desmoglein-3 (DSG3).

[0023] According to one embodiment, the peptide according to the invention comprises all or part of the polypeptide chain a-1 of collagen XVII. Preferably, said polypeptide chain a-1 of collagen XVII is represented by SEQ ID NO: 35.

[0024] According to another embodiment, the peptide according to the invention comprises all or part of the polypeptide sequence of desmoglein-1 (DSG1). Preferably, said polypeptide sequence of DSG1 is represented by SEQ ID NO: 36.

[0025] According to another embodiment, the peptide according to the invention comprises all or part of the polypeptide sequence of desmogiein-3 (DSG3). Preferably, said polypeptide sequence of DSG3 is represented by SEQ ID NO: 37.

[0026] According to one embodiment, a "peptide binding to an autoreactive lymphocyte involved in autoimmune dermatitis" means a peptide recognized by an autoantibody directed against collagen XVII, a peptide recognized by an autoantibody directed against DSG1 or a peptide recognized by an autoantibody directed against DSG3. Preferably, a "peptide binding to an autoreactive lymphocyte involved in autoimmune dermatitis" means a peptide recognized by an autoantibody directed against the α-1 chain of collagen XVII, a peptide recognized by an autoantibody directed against DSG1 or a peptide recognized by an autoantibody directed against DSG3. Such peptides can be obtained from fragments of collagen XVII (preferably the α-1 chain), DSG1, or DSG3, whether these fragments are natural, recombinant or synthetic. Such peptides can also be directly synthesized.The amino acids constituting the peptide may be of the L or D series, preferably of the L series. A peptide according to the invention binds to an autoantibody directed against type XVII collagen (preferably the a-1 chain), against DSG1 or against DSG3, and the binding between said peptide and the autoantibody may for example be verified using an ELISA test (see for example “Autoimmune bullous dermatoses: the autoantibodies involved”, Dr AS. Deleplancque Pr S. Dubucquoi, https: / / biologiepathologie.chu-lille.fr / fichiers / 377_Dermatoses%20bulleuses%20nov%202017.pdf).

[0027] According to one embodiment, in said hybrid molecule according to the invention, said peptide comprises all or part of the polypeptide sequence of desmoglein 1, of the polypeptide sequence of desmoglein 3, or of the a-1 chain of type XVII collagen. Even more particularly, said desmoglein 1, said desmoglein 3, or said a-1 chain of type XVII collagen is derived from mammalian origin and is preferably of human origin.

[0028] According to one embodiment, in said hybrid molecule according to the invention, the peptide has a size of at least 2 consecutive amino acids, 3 consecutive amino acids, 4 consecutive amino acids, preferably at least 5 consecutive amino acids. According to one embodiment, said peptide has a size of between 5 and 70 amino acids, in particular between 10 and 70. According to the invention, “between 5 and 70” means all the values: 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70.

[0029] According to one embodiment, in said hybrid molecule according to the invention, the peptide is linear.

[0030] According to one embodiment, in said hybrid molecule according to the invention, the peptide can be modified so as to improve its reactivity towards self-reactive lymphocytes. For example, the peptides can be cyclized, the peptides can be of the retro type (the L series amino acids are chained in a sequence inverse to that of the peptide to be reproduced), or of the retro-inverso type (the amino acids are of the D type instead of the natural L series and are chained in a sequence inverse to that of the peptide to be reproduced). According to an even more particular embodiment, in said hybrid molecule according to the invention, the terminal carboxyl function (COOH) of said peptide is replaced by a carboxamide function (CONH2).

[0031] According to another embodiment, in said hybrid molecule according to the invention, the peptide can be modified so as to facilitate its synthesis and / or improve its stability, for example by alkylation. According to an even more particular embodiment, in said hybrid molecule according to the invention, the terminal amine function (NH2) of said peptide is acetylated.

[0032] According to one embodiment, in said hybrid molecule according to the invention, the amine and carboxyl functions of the peptide can be in the form of the salt corresponding to the acid or to the base.

[0033] According to an even more particular embodiment, in said hybrid molecule according to the invention, said peptide is chosen from the group consisting of: SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, and SEQ ID NO: 30.

[0034] According to an even more particular embodiment, in said hybrid molecule according to the invention, said peptide is chosen from the group consisting of: SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 46, SEQ ID NO: 47 and SEQ ID NO: 48.

[0035] According to a still more particular embodiment, in said hybrid molecule according to the invention, said peptide is selected from the group consisting of: SEQ ID NO: 1 , SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: SEQ ID NO: 7 8, SEQ ID NO : 9, SEQ ID NO : 10, SEQ ID NO : 11 , SEQ ID NO : 12, SEQ ID NO : 13, SEQ ID NO : 14, SEQ ID NO : 15, SEQ ID NO : 16, SEQ ID NO : 17, SEQ ID NO : 18, SEQ ID NO : 19, SEQ ID NO : 20, SEQ ID NO : 21 , SEQ ID NO : 22, SEQ ID NO : 23, SEQ ID NO : 24, SEQ ID NO : 25, SEQ ID NO : 26, SEQ ID NO : 26 : 27, SEQ ID NO : 28, SEQ ID NO : 29, SEQ ID NO : 30, SEQ ID NO : 38, SEQ ID NO : 39, SEQ ID NO : 40, SEQ ID NO : 41 , SEQ ID NO : 42, SEQ ID NO : 43, SEQ ID NO : 44, SEQ ID NO : 45, SEQ ID NO : 46 : 47 and SEQ ID NO : 48.

[0036] According to an even more particular embodiment, in said hybrid molecule according to the invention, said peptide is chosen from the group consisting of: SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8 (Collagen XVII).

[0037] According to an even more particular embodiment, in said hybrid molecule according to the invention, said peptide is chosen from the group consisting of: SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, preferably SEQ ID NO: 38 or SEQ ID NO: 39.

[0038] According to an even more particular embodiment, in said hybrid molecule according to the invention, said peptide is chosen from the group consisting of: SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 38, SEQ ID NO: 39 and SEQ ID NO: 40 (Collagen XVII).

[0039] According to an even more particular embodiment, in said hybrid molecule according to the invention, said peptide is chosen from the group consisting of: SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21 (DSG1).

[0040] According to an even more particular embodiment, in said hybrid molecule according to the invention, said peptide is chosen from the group consisting of: SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43 and SEQ ID NO: 44 (DSG1).

[0041] According to an even more particular embodiment, in said hybrid molecule according to the invention, said peptide is chosen from the group consisting of: SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43 and SEQ ID NO: 44 (DSG1).

[0042] According to an even more particular embodiment, in said hybrid molecule according to the invention, said peptide is chosen from the group consisting of: SEQ ID NO: 10, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43 and SEQ ID NO: 44 (DSG1).

[0043] According to an even more particular embodiment, in said hybrid molecule according to the invention, said peptide is chosen from the group consisting of: SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29 and SEQ ID NO: 30 (DSG3).

[0044] According to an even more particular embodiment, in said hybrid molecule according to the invention, said peptide is chosen from the group consisting of: SEQ ID NO: 45, SEQ ID NO: 46, SEQ ID NO: 47 and SEQ ID NO: 48 (DSG3).

[0045] According to an even more particular embodiment, in said hybrid molecule according to the invention, said peptide is chosen from the group consisting of: SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 45, SEQ ID NO: 46, SEQ ID NO: 47 and SEQ ID NO: 48 (DSG3).

[0046] According to an even more particular embodiment, in said hybrid molecule according to the invention, said peptide is chosen from the group consisting of: SEQ ID NO: 26, SEQ ID NO: 45, SEQ ID NO: 46, SEQ ID NO: 47 and SEQ ID NO: 48 (DSG3).

[0047] According to one embodiment, in said hybrid molecule according to the invention, said Fc fragment is a human Fc fragment, in particular of IgG, more particularly of IgGI. The IgGI can correspond to any allotypic variant, for example G1 m3 or G1 m17. By way of example, the Fc fragment of IgGI is represented by SEQ ID NO: 31, SEQ ID NO: 32 (Fc+Qtag) or SEQ ID NO: 33 (Fc+Qtag bis).

[0048] According to one embodiment, in said hybrid molecule according to the invention, said Fc fragment is wild type or mutated. The mutation(s) may aim to increase the plasma half-life, decrease it, or modify the effector functions of the Fc fragment. According to an even more particular embodiment, said mutated Fc fragment comprises at least the following mutations: - L234A and L235A (LALA), or - L234A, L235A and P329G (LALAPG), or - G236A, S239D and I332E (GASDIE), or - G236A, S239D, A330L and I332E (GASDALIE), or - S239D, H268F, S324T and I332E (SDHFSTIE or SDH), the numbering being indicated in the sequence of a human IgG1 according to the EU index. Such mutations are notably described in the article Bruhns and Jonsson, Immunol Rev. 2015 Nov;268(1):25-51. Preferably, when the hybrid molecule is used in therapy, said mutated Fc fragment comprises at least the mutations GASDIE, GASDALIE, or SDH.

[0049] According to one embodiment, in said hybrid molecule according to the invention, said Fc fragment has a fucosylation level of between 0% and 100% of the glycosylated forms. According to the invention, “between 0% and 100%” represents all integer values ​​between 0 and 100, ie; 0, 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 , 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34, 35, 36, 37, 38, 39, 40, 41 , 42, 43, 44, 45, 46, 47, 48, 49, 50, 51 , 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 and 100%. Low fucosylation of the Fc fragment causes a strong ADCC response. Therefore, according to a mode of particular embodiment, said Fc fragment has a fucosylation level of between 0% and 60% of the glycosylated forms, in particular 50%, 40%, 30%, 20%, 10% or 0%. According to the invention, the fucosylation level is defined as the average proportion of fucose carried by the Fc fragment, relative to the maximum quantity of fucose that an Fc fragment can carry.

[0050] The Fc fragment and the peptide each have N- and C-terminal ends. The Fc fragment can therefore be linked via its N- or C-terminal end to the N- or C-terminal end of the peptide. According to a preferred embodiment, in said hybrid molecule according to the invention, said covalent bond is located between the C-terminal end of said Fc fragment and the N-terminal end of said peptide, or between the N-terminal end of said Fc fragment and the N-terminal end of said peptide. According to one embodiment, when a spacer is present, the spacer can be linked to the Fc fragment via its N- or C-terminal end. According to another embodiment, when two spacers are present, the first spacer can be linked to the Fc fragment via its N- or C-terminal end and the second spacer can be linked to the peptide via its N- or C-terminal end, in particular N-terminal.Alternatively, said covalent bond between said Fc fragment and said peptide (optionally in the presence of one or more spacers) can be created on all or part of the Fc fragment. According to the invention “all or part of the Fc fragment” means that different amino acids constituting the Fc fragment can be involved in a covalent bond with said peptide.

[0051] According to a preferred embodiment, when at least one spacer is present in said hybrid molecule of the invention, it makes it possible to link the Fc fragment to an azide or to an alkyne which will itself be involved in the covalent bond with said peptide. According to one embodiment, when at least one spacer is present in said hybrid molecule of the invention, it can also make it possible to link the peptide to an alkyne or to an azide which will itself be involved in the covalent bond with the Fc fragment. According to a preferred embodiment, the hybrid molecule according to the invention comprises at least two spacers: a first spacer which makes it possible to link the Fc fragment to an azide or to an alkyne and a second spacer which makes it possible to link the peptide to an azide (when the Fc fragment is linked to an alkyne) or to an alkyne (when the Fc fragment is linked to an azide).

[0052] According to one embodiment according to the invention, in said hybrid molecule according to the invention, said Fc fragment: - is coupled to at least one azide or an alkyne, such as a cyclooctyne, and in particular DBCO, or - is linked to at least one spacer which is itself coupled to an azide or to an alkyne, such as a cyclooctyne, and in particular DBCO, and said peptide is: - either coupled to an azide or an alkyne, such as a cyclooctyne, and in particular DBCO, - either linked to a spacer which is itself coupled to an azide or an alkyne, such as a cyclooctyne, and in particular DBCO, the covalent bond between said Fc fragment and said peptide, optionally in the presence of one or more spacers, being created between the azide and the alkyne.

[0053] According to one embodiment according to the invention, in said hybrid molecule according to the invention, - the Fc fragment is coupled to at least one azide and said peptide is coupled to an alkyne, such as a cyclooctyne, and in particular DBCO, or - the Fc fragment is coupled to at least one alkyne, such as a cyclooctyne, and in particular DBCO, and said peptide is coupled to an azide, the covalent bond between said Fc fragment and said peptide being created between the azide and the alkyne.

[0054] According to one embodiment according to the invention, in said hybrid molecule according to the invention: - the Fc fragment is coupled to at least one azide and said peptide is linked to a spacer, itself coupled to an alkyne, such as a cyclooctyne, and in particular DBCO or - the Fc fragment is coupled to at least one alkyne, such as a cyclooctyne, and in particular DBCO, and said peptide is linked to a spacer, itself coupled to an azide or - the Fc fragment is linked to at least one spacer, itself coupled to an azide, and said peptide is coupled to an alkyne, such as a cyclooctyne, and in particular DBCO or - the Fc fragment is linked to at least one spacer, itself coupled to an alkyne, such as a cyclooctyne, and in particular DBCO, and said peptide is coupled to an azide or - the Fc fragment is linked to at least one spacer, itself coupled to an azide, and said peptide is linked to a spacer, itself coupled to an alkyne, such as a cyclooctyne, and in particular DBCO or - the Fc fragment is linked to at least one spacer, itself coupled to an alkyne, such as a cyclooctyne, and in particular DBCO, and said peptide is linked to a spacer, itself coupled to an azide, the covalent bond between said Fc fragment and said peptide, in the presence of one or more spacers, being created between the azide and the alkyne.

[0055] According to the invention, the creation of the covalent bond between the azide and the alkyne corresponds to a step called "click chemistry", the N3 part of the azide reacting with an alkyne. Azide means salts of hydrazonic acid HN3, or organic azides in which one of the nitrogen atoms is covalently bonded to a carbon atom of an organic compound (for example methyl azide CH3N3). Preferably, the azide is represented by the formula N3. Alkyne means molecules having the general formula C n H2n-2, and which are characterized by the presence of at least one triple bond. Preferably the alkyne is a cyclooctyne, even more preferably dibenzocyclooctyne (DBCO).

[0056] The Fc fragment, said peptide and optionally said spacer(s), are coupled to the alkyne or azide by any conventionally used molecular coupling technique (such as conjugation). Any technique can also be used to covalently link the Fc fragment to the spacer and / or the peptide to the spacer.

[0057] More specifically, a conjugation technique means enzymatic conjugation or chemical conjugation. An enzymatic conjugation means, for example, conjugation using a transglutaminase that catalyzes the formation of covalent bonds between free amino groups and glutamine or lysine residues or using a transpeptidase such as sortase. For further information on enzymatic conjugation, see, for example, patent applications US20160361434 or US20170313787, or the publication Ohtsuka et al., Bioscience, Biotechnology, and Biochemistry Volume 64, 2000 - Issue 12, Comparison of Substrate Specificities of Transglutaminases Using Synthetic Peptides as Acyl Donors. The substrate of the transglutaminase is for example a peptide comprising a glutamyl residue (a Qtag), as represented by SEQ ID NO: 34 (LLQG).A chemical conjugation is understood, for example, to be a covalent bond between an isolated cysteine ​​or one participating in a disulfide bridge after reduction thereof and, for example, a maleimide. An example of such a conjugation is shown in Figure 4. In this example, the Fc fragment comprises a Qtag peptide and said Fc fragment is linked to a spacer (itself coupled to an azide), thanks to the action of transglutaminase which will create a covalent bond between the glutamyl residue of the Qtag and the NH2 group carried by the PEGn spacer.

[0058] According to the invention, the term "coupled" or "molecular coupling" means the establishment of a covalent bond, thus the Fc fragment and / or the peptide and / or the spacer is covalently bonded to an alkyne or an azide. The term "bonded" also means a covalent bond. Thus, by way of example, the expression "the Fc fragment is coupled to an azide and said peptide is bonded to a spacer, itself coupled to an alkyne, such as a cyclooctyne, and in particular DBCO" can also be read "the Fc fragment is covalently bonded to an azide and said peptide is covalently bonded to a spacer, said spacer itself being covalently bonded to an alkyne, such as a cyclooctyne, and in particular DBCO".

[0059] Use of the hybrid molecules according to the invention

[0060] In a second aspect, the present invention also relates to a hybrid molecule as defined above, for its use as a medicament.

[0061] More particularly, according to the invention, said hybrid molecules are intended to target and lyse in the body of patients, by ADCC and / or phagocytosis and / or complement activation, all cells expressing autoreactive lymphocyte receptors in the context of autoimmune dermatitis: namely B cells (lymphocytes) expressing on their surface the BCRs recognizing at least one of the peptides of the invention (autoantibodies responsible for autoimmune dermatitis, binding to at least one peptide according to the invention) and T lymphocytes expressing on their surface the TCRs recognizing at least one of the peptides according to the invention. Indeed, the hybrid molecule according to the invention binds to these cells thanks to the peptide: this is the epitope target of said autoreactive lymphocyte receptor. The hybrid molecule according to the invention binds also to cells allowing the destruction of B and / or T lymphocytes expressing on their surface the auto-reactive lymphocyte receptors involved in autoimmune dermatitis thanks to its Fc fragment, natural ligand of Fc receptors (for example Fc-gamma receptor (FcyR) if the Fc fragment is derived from an IgG), present in particular on the surface of macrophages but also of NK cells (“Natural Killers”).

[0062] According to a particular embodiment, the invention relates to a hybrid molecule, as defined above, for its use in the treatment of autoimmune dermatitis, in particular pemphigus or bullous pemphigoid. According to one embodiment, pemphigus is understood more particularly to mean pemphigus vulgaris or foliaceus.

[0063] According to a particular embodiment, the invention relates to a hybrid molecule as defined above and comprising a peptide chosen from the group consisting of: SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, for its use in the treatment of bullous pemphigoid.

[0064] According to a particular embodiment, the invention relates to a hybrid molecule as defined above and comprising a peptide chosen from the group consisting of: SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 38, SEQ ID NO: 39 and SEQ ID NO: 40, for its use in the treatment of bullous pemphigoid, preferably SEQ ID NO: 38 or SEQ ID NO: 40.

[0065] According to a particular embodiment, the invention relates to a hybrid molecule as defined above and comprising a peptide chosen from the group consisting of: SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21, for its use in the treatment of pemphigus, in particular pemphigus foliaceus.

[0066] According to a particular embodiment, the invention relates to a hybrid molecule as defined above and comprising a peptide chosen from the group consisting of: SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29 and SEQ ID NO: 30, for its use in the treatment of pemphigus, in particular pemphigus vulgaris.

[0067] According to a particular embodiment, the invention relates to a hybrid molecule as previously defined and comprising a peptide selected from the group consisting of: SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11 , SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO : 16, SEQ ID NO : 17, SEQ ID NO : 18, SEQ ID NO : 19, SEQ ID NO : 20, SEQ ID NO : 21 , SEQ ID NO : 22, SEQ ID NO : 23, SEQ ID NO : 24, SEQ ID NO : 25, SEQ ID NO : 26, SEQ ID NO : 27, SEQ ID NO : 27 28, SEQ ID NO : 29 and SEQ ID NO : 30, SEQ ID NO : 41 , SEQ ID NO : 42, SEQ ID NO : 43, SEQ ID NO : 44, SEQ ID NO : 45, SEQ ID NO : 46, SEQ ID NO : 47 and SEQ ID NO: 48, for its use in the treatment of pemphigus, in particular pemphigus vulgaris. According to a particular embodiment, the invention relates to a hybrid molecule as defined above and comprising a peptide chosen from the group consisting of: SEQ ID NO: 10, SEQ ID NO: 26, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 46, SEQ ID NO: 47 and SEQ ID NO: 48 for its use in the treatment of pemphigus vulgaris.

[0068] According to one embodiment, the invention also relates to a pharmaceutical composition comprising a hybrid molecule according to the invention, in combination with a pharmaceutically acceptable vehicle.

[0069] According to the invention, “a pharmaceutically acceptable vehicle” means any formulation making the composition suitable for administration to a patient, in any galenic form.

[0070] The present invention also relates to a method of treating autoimmune dermatitis, in particular pemphigus or bullous pemphigoid, comprising administering a therapeutically effective amount of a hybrid molecule according to the invention.

[0071] The invention also relates to the use of a hybrid molecule according to the invention for the preparation of a medicament intended for the treatment of autoimmune dermatitis, in particular pemphigus or bullous pemphigoid.

[0072] According to another embodiment, the hybrid molecule according to the invention can be coupled to at least one radioisotope or at least one fluorochrome, such as A488 or A647. Such molecules can advantageously be used as molecular tracer tools.

[0073] According to another embodiment, the invention thus relates to the in vitro or ex vivo use of a hybrid molecule comprising at least one antibody Fc fragment covalently linked to at least one peptide binding to an autoreactive lymphocyte involved in autoimmune dermatitis, at least one spacer being optionally present between said Fc fragment and said peptide, as a molecular tool. Such constructs can in particular be used to analyze the binding of the hybrid molecules to autoantibodies and to the Fc receptors of macrophages and NK cells, as well as to analyze the reactivity of macrophages and NK cells to the binding of the hybrids followed by the bridging of these by the autoantibodies.... The radioisotopes and / or fluorochromes are preferably coupled to the Fc fragment, even more particularly at the level of the Qtag (if present) or at the level of the lysines.

[0074] Process for producing hybrid molecules according to the invention

[0075] In another aspect, the invention also relates to a method for obtaining a hybrid molecule as defined above.

[0076] According to one embodiment, the invention thus relates to a method for producing a hybrid molecule as defined previously, comprising the following steps: - (i) obtaining an azide coupled to an Fc fragment or obtaining an alkyne coupled to an Fc fragment, - (ii) obtaining an alkyne coupled to a peptide or obtaining an azide coupled to a peptide, - (iii) realization of the covalent bond between the azide and the alkyne, - step (i) can be carried out before or after step (ii), or concurrently.

[0077] According to one embodiment, the invention thus relates to a method for producing a hybrid molecule as defined previously, comprising the following steps: - (i) coupling of at least one azide and one Fc fragment, optionally in the presence of at least one spacer, or coupling of at least one alkyne and at least one Fc fragment, optionally in the presence of a spacer, - (ii) coupling of an alkyne and a peptide, optionally in the presence of a spacer, or coupling of an azide and a peptide, optionally in the presence of a spacer, - (iii) realization of the covalent bond between the azide and the alkyne, - step (i) can be carried out before or after step (ii), or concurrently.

[0078] According to another embodiment, the invention thus relates to a method for producing a hybrid molecule as defined previously, comprising the following steps: - (i) coupling of at least one azide to each monomer of the Fc fragment, optionally in the presence of at least one spacer, or coupling of at least one alkyne to each monomer of the Fc fragment, optionally in the presence of a spacer, - (ii) coupling of an alkyne and a peptide, optionally in the presence of a spacer, or coupling of an azide and a peptide, optionally in the presence of a spacer, - (iii) creation of the covalent bond(s) between the azide and the alkyne, - step (i) can be carried out before or after step (ii), or concurrently.

[0079] According to one embodiment, the hybrid molecules according to the invention can also be obtained by bioproduction methods and encoded by a recombinant DNA encoding the peptide according to the invention and the Fc fragment, said peptide and said Fc fragment being optionally separated by a polypeptide linker. In such a case, the peptide of the hybrid molecule is unmodified (e.g. non-cyclized, non-retro, non-retro-inverso), and may be oriented N-terminally or C-terminally. The peptide can be C-terminal or N-terminal to the Fc fragment, the cDNA including its nucleotide coding sequence upstream or downstream of the Fc cDNA.

[0080] The sequences of the invention are shown in Table 1 below.

[0081] [Table 1] 00082] [Table 1]. Summary table of the sequences of the invention

[0083] Other characteristics, details and advantages of the invention will appear on reading the attached Figures and the examples which illustrate the invention and are not intended in any way to limit it. Brief description of the Figures Fig. 1

[0084] [Fig. 1] represents the diagram of an example of a hybrid molecule according to the invention.

[0085] A spacer (which is optional) is shown between the antibody Fc fragment and the peptide binding to an autoreactive lymphocyte involved in autoimmune dermatitis (referred to as the “peptide according to the invention”). Fig. 2

[0086] [Fig. 2] represents a B lymphocyte expressing on its surface BCR / transmembrane autoantibodies linked to a hybrid molecule according to the invention, said hybrid molecule itself being linked by the Fc fragment to an NK cell.

[0087] The NK cell will then be able to destroy the B lymphocyte by ADCC. More specifically, this Figure shows a B cell (or B lymphocyte) which expresses on its surface a BCR (the self- antibody) which interacts specifically with the peptide according to the invention carried by the hybrid molecule. The engagement of the Fc fragment carried by the same hybrid molecule to FcyRIIIa (CD16a) expressed on the surface of an NK cell will activate ADCC and induce the specific destruction of the B lymphocyte. (ADCC, Antibody-Dependent Cell Cytotoxicity; BCR, B-Cell Receptor; FcyR, Fc-gamma Receptor; NK cell, Natural Killer cell).

[0088] Nb: a similar representation could be achieved by replacing the B lymphocyte with a T lymphocyte, and the BCR with a TCR (T-Cell Receptor). Fig. 3

[0089] [Fig. 3] represents a B lymphocyte expressing on its surface transmembrane BCRs linked to a hybrid molecule according to the invention, said hybrid molecule itself being linked by the Fc fragment to a macrophage.

[0090] The macrophage will then be able to destroy the B lymphocyte by phagocytosis. More specifically, this Figure shows B cells (or B lymphocytes) which express on their surface a BCR (the autoantibody in membrane form) and which interact specifically with peptides according to the invention carried by the hybrid molecules. The engagement of the Fc fragments carried by these same hybrid molecules to different FcyRs expressed on the surface of a macrophage will activate ADCP, i.e. phagocytosis, and induce the specific destruction of B lymphocytes. (ADCP, Antibody-Dependent Cellular Phagocytosis; BCR, B-Cell Receptor; FcyR, Fc-gamma Receptor).

[0091] Nb: a similar representation could be achieved by replacing the B lymphocyte with a T lymphocyte, and the BCR with a TCR (T-Cell Receptor). Fig. 4

[0092] [Fig. 4] represents a method of manufacturing a hybrid molecule according to the invention, comprising the scheme of derivatization and conjugation of the Fc fragments. Fig. 5

[0093] [Fig. 5] represents the reactivity of 10 sera from patients with bullous pemphigoid (BP) on three peptides from the polypeptide sequence of collagen XVII. Sera from patients with bullous pemphigoid contain autoantibodies.

[0081] These peptides include peptide 1 EEVRKLKARVDELERIRRS (SEQ ID NO: 38) whose sequence is included in peptide SEQ ID NO: 3, peptide 2 RIRRSILPYGDSMDRIEK (SEQ ID NO: 39) whose sequence is included in peptide SEQ ID NO: 3, is partly included in peptide SEQ ID NO: 1, 4, 7 and includes peptide SEQ ID NO: 6; finally peptide 3 MDRIEKDRLQGMAP (SEQ ID NO: 40) whose sequence is included in peptides SEQ ID NO: 1, 3, 4 and 7 and partly included in peptide SEQ ID NO: 1.

[0082] The ordinate represents the OD measured at 492 nm and the abscissa represents the serum tested. Sera PB1 to PB10 represent sera collected from ten patients with bullous pemphigoid, sera PR1 and PR2 represent the sera of two patients with rheumatoid arthritis and sera SS1 and SS2 represent the sera of two healthy patients. Fig. 6

[0083] [Fig. 6] represents the fixation on human monocytes and macrophages of the hybrid molecules according to the invention

[0084] Flow cytometry analysis of the binding to the membrane of monocytes (Figure 6C) and macrophages (Figure 6F), of the 4 hybrid molecules FcGASDIE-DBCO-peptide 1(Nter), FcGASDIE-DBCO-peptide 1(Cter), FcGASDIE-DBCO-peptide 2(Nter) and FcGASDIE-DBCO-peptide 2(Cter) according to the invention, coupled to the fluorochrome Alexa Fluor (AF) 647.

[0085] FcGASDIE-DBCO-peptide 1(Nter) corresponds to an Fc fragment comprising the mutations G236A, S239D and I332E, which is linked to at least one PEGn spacer which is itself coupled to an azide covalently linked to a cyclooctyne DBCO coupled to a PEGn spacer which is itself linked to the N-terminal end of peptide 1 EEVRKLKARVDELERIRRS (SEQ ID NO: 38).

[0086] FcGASDIE-DBCO-peptide 1(Cter) corresponds to an Fc fragment comprising the mutations G236A, S239D and I332E, which is linked to at least one PEGn spacer which is itself coupled to an azide covalently linked to a cyclooctyne DBCO coupled to a PEGn spacer which is itself linked to the C-terminal end of peptide 1 EEVRKLKARVDELERIRRS (SEQ ID NO: 38).

[0087] FcGASDIE-DBCO-peptide 2(Nter) corresponds to an Fc fragment comprising the mutations G236A, S239D and I332E, which is linked to at least one PEGn spacer which is itself coupled to an azide covalently linked to a cyclooctyne DBCO coupled to a PEGn spacer which is itself linked to the N-terminal end of peptide 2 RIRRSILPYGDSMDRIEK (SEQ ID NO: 39).

[0088] FcGASDIE-DBCO-peptide 2(Cter) corresponds to an Fc fragment comprising the mutations G236A, S239D and I332E, which is linked to at least one PEGn spacer which is itself coupled to an azide covalently linked to a cyclooctyne DBCO coupled to a PEGn spacer which is itself linked to the C-terminal end of peptide 2 RIRRSILPYGDSMDRIEK (SEQ ID NO: 39).

[0089] In A, the Figure shows a flow cytometry diagram representing in the form of a point cloud ("density plot"), the unlabeled monocytes (NM). In B, the Figure shows a representative result of the labeling of monocytes by an anti-CD11 b antibody (AC BV421), the monocytes having also fixed the hybrid molecule FcGASDIE-DBCO-peptide 1(Nter) coupled to AF647. In C, the Figure shows in the form of histograms, the fixation profiles of the 4 hybrid molecules on the surface of the monocytes, as well as that of the isotype control coupled to TAF647 and that of the unlabeled monocytes (NM). In D, the Figure shows a flow cytometry diagram representing in the form of a point cloud ("density plot"), the unlabeled macrophages (NM).In E the Figure shows a representative result of the labeling of macrophages by an anti-CD1 1b antibody (e.g. the BV421 antibody), the macrophages having also fixed the hybrid molecule FcGASDIE-DBCO-peptide 1(Nter) coupled to AF647. In F, the Figure shows in form. histograms, the binding profiles of the 4 hybrid molecules on the surface of macrophages as well as that of the isotypic control coupled with AF647 and that of the unlabeled macrophages (NM). Fig. 7

[0090] [Fig. 7] represents the reactivity of 4 sera from patients with pemphigus vulgaris (PV) on 5 immunodominant peptides from desmoglein 1 (DSG-1). Sera from patients with pemphigus vulgaris contain autoantibodies.

[0091] The peptides derived from desmoglein 1 comprise peptide 1 YRISGVGIDQPPYGIFVINQKTGEIN (SEQ ID NO: 41), sequence included in that of SEQ ID NO: 36 and which comprises peptide SEQ ID NO: 12 and peptide SEQ ID NO: 13; peptide 2: RALNSMGQDLERPLELRVRVLDIN (SEQ ID NO: 42), sequence included in that of SEQ ID NO: 36 and which comprises peptide SEQ ID NO: 10 and peptide SEQ ID NO: 21; peptide 3: FKIIRQEPSDSPMFIINRNTGEIRT (SEQ ID NO: 43), sequence included in that of SEQ ID NO: 36 and which comprises the peptide SEQ ID NO: 11, 14 and 15; peptide 4: NERTNVGILKVVKPLDYE (SEQ ID NO: 44), sequence included in that of SEQ ID NO: 36 and which comprises the peptide SEQ ID NO: 9 peptide 5: ALNSMGQDLERPLELR (SEQ ID NO: 10) sequence included in that of SEQ ID NO: 36.

[0092] The ordinate represents the OD measured at 492 nm and the abscissa represents the tested serum. Sera PV1 to PV4 represent the sera collected from four patients with pemphigus vulgaris. Fig. 8

[0093] [Fig. 8] represents the reactivity of 4 sera from patients with pemphigus vulgaris (PV) on 5 immunodominant peptides from desmoglein 3 (DSG-3). Sera from patients with pemphigus vulgaris contain autoantibodies.

[0094]

[0095] The peptides derived from desmoglein 3 comprise: peptide 1 INVREGIAFRPASKTFTVQKGISSKK (SEQ ID NO: 45), corresponding to an assembly covering sequences INVREGIAFRPASKT SEQ ID NO: 27 and PASKTFTVQKGISSK SEQ ID NO: 28 and to the sequence included in that of SEQ ID NO: 37; peptide 2: REGEDNSKRNPIAKITSDYQ (SEQ ID NO: 46): sequence included in that of SEQ ID NO: 27 and in that of SEQ ID NO: 37; peptide 3: GTSYPTTSPGTRYGRPHSG (SEQ ID NO: 47): sequence included in that of SEQ ID NO: 24 and in that of SEQ ID NO: 37; peptide 4: KVVKALDYEQLQSVK (SEQ ID NO: 26), sequence included in that of SEQ ID NO: 37 and peptide 5: KFVKNMNRDSTFIVNK (SEQ ID NO: 48): including the peptide SEQ ID NO: 29): and sequence included in that of the peptide SEQ ID NO: 37.

[0096] The ordinate represents the OD measured at 492 nm and the abscissa represents the tested serum. Sera PV1 to PV4 represent sera collected from four patients with pemphigus vulgaris.

[0097] Examples

[0098] Example 1: Example of production of a hybrid molecule according to the invention

[0099] The hybrid molecule described here comprises the following construction: an Fc fragment covalently linked to at least one PEGn spacer, itself coupled to an azide, said azide being covalently linked to an alkyne, which is itself coupled to a PEGn spacer linked to a peptide according to the invention. Such a molecule can be read: Fc-PEGn-Ns-DBCO-PEGn-peptide. The two PEGns can be identical or different (for example the first PEGn is PEG3 and the second PEGn is PEG2). [000100] 1. Synthesis of an NH2-PEGn-N3 (i.e. a spacer coupled to an azide at one end and having a free amine function at another end). [000101] 2. Bringing the NFh-PEGn-Ns into contact with an Fc fragment having a Qtag, and a transglutaminase, preferably for 16 hours at 37°C. This so-called “derivatization” step is, for example, carried out with 20 times more moles of NFL-PEGn-Ns than moles of Fc fragment. The transglutaminase is used, for example at a level of 15U / pmol per Qtag present (on one or both monomers). Optionally, desalting can be carried out to remove the excess spacer not bound to the Fc fragment at the end of the step. An Fc-PEGn-Ns is thus obtained. If the Fc fragment has 2 Qtags (one carried on each monomer), then the Fc fragment can carry two PEGn-N3. [000102] 3. Synthesis of a Cys-PEGn-peptide (i.e. a spacer linked to a peptide at one end and having a free cysteine ​​at another end). An alkyne, for example a DBCO, is then coupled to the Cys-PEGn-peptide at the cysteine, and a DBCO-PEGn-peptide is thus obtained. [000103] 4. Realization of the “click”: coupling between N3 and DBCO. The DBCO-PEGn-peptide is placed in the presence of Fc-PEGn-Ns with, preferably, 11 times more moles of DBCO-PEGn-peptide than moles of Fc-PEGn-Ns. The click reaction takes place in particular at room temperature and is almost complete after 4 hours. [000104] 5. Obtaining the hybrid molecule: Fc-PEGn-Ns-DBCO-PEGn-peptide. This embodiment is illustrated in Figure 4. [000105] Similarly, an Fc-PEGn-DBCO and an Ns-PEGn-peptide can be obtained, then coupled to obtain Fc-PEGn-DBCO-Ns-PEGn-peptide. [000106] Similarly, an Fc-PEGn-DBCO and an Ns-peptide can be obtained, or an Fc-PEGn-Ns and a DBCO-peptide, then coupled to obtain respectively Fc-PEGn-DBCO-Ns-peptide or Fc-PEGn-Ns-DBCO-peptide. [0001071 Example 2: Reactivity of sera from patients suffering from autoimmune dermatitis with respect to the hybrid molecules according to the invention [000108] The sera used are sera from patients suffering from autoimmune dermatitis, more particularly pemphigus or bullous pemphigoid, which contain specific autoantibodies. [000109] ELISA microtiter plate wells were coated by passive adsorption using 100 pL of a solution containing either a peptide chosen from SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29 and SEQ ID NO: 30, or a combination of at least two covalently linked peptides, or a hybrid molecule according to the invention, the Fc fragment of which is wild-type (WT) or the Fc fragment comprises the GASDIE mutation. Such a hybrid molecule is for example “FcWT-PEG-SEQ ID NO: 1-30”,“FcLALAPG-PEG-SEQ ID NO: 1-30” or “FcGASDIE-PEG-SEQ ID NO: 1-30”. “FcWT-PEG-SEQ ID NO: 1-30” represents a wild-type Fc fragment that is linked to at least one PEGn spacer that is itself coupled to an azide covalently linked to a cyclooctyne DBCO coupled to a PEGn spacer that is itself linked to a peptide represented by any one of SEQ ID NO: 1 to SEQ ID NO: 30, “FcWT-LALAPG-SEQ ID NO: 1-30” represents an Fc fragment comprising the mutations L234A, L235A and P329G that is linked to at least one PEGn spacer that is itself coupled to an azide covalently linked to a cyclooctyne DBCO coupled to a PEGn spacer that is itself linked to a peptide represented by any one of SEQ ID NO: 1 to SEQ ID NO: 30, and “FcGASDIE-PEG-SEQ ID NO: : 1-30” represents an Fc fragment comprising the mutations G236A, S239D and I332E,which is linked to at least one PEGn spacer which is itself coupled to an azide covalently linked to a cyclooctyne DBCO coupled to a PEGn spacer which is itself linked to a peptide represented by any one of SEQ ID NO: 1 to SEQ ID NO: 30. In the constructs, n represents a number between 1 and 10 when a PEGn spacer is used, preferably 1, 2, 3, 4 or 8. The hybrid molecule may contain one or a combination of at least 2 covalently linked peptides., [000110] These solutions were each used at a concentration of 5 pg / mL in PBS (Phosphate Buffered Saline) buffer and incubated overnight at 4°C. The selected peptides and the hybrid molecules constructed with said peptides synthesized in random sequence (scramble) were used at the same concentration as negative controls. After washing in PBS Tween 0.05% the wells were then saturated with 5% milk for 1 h at room temperature. After washing, the sera were incubated in serial dilution in PBS buffer + 5% milk for 1 h at room temperature. After washing, the reactivity of the sera was detected using an anti-human IgG Fab detection antibody coupled to HRP diluted 1 / 2500 in PBS buffer 5% milk also incubated for 1 h at room temperature. After washing, the presence of autoantibodies recognized by the hybrid molecule is revealed by adding TMB and stopping the enzymatic reaction by adding H2SO4 and reading on a spectrophotometer at 450nm. [000111] The results are expressed in A DO (Delta-Optical Density), corresponding to the DO obtained with a hybrid peptide scramble or with the hybrid molecule constructed with said peptide. [000112] The results show a dose-dependent reactivity of the sera on the peptides with respect to the hybrid molecules. They show that included in the different hybrids, the peptides remain perfectly reactive to the sera comprising the autoantibodies. [0001131 Example 3: Kinetics of fixation of hybrid molecules on macrophages, at physiological temperature [000114] Human macrophages, differentiated in vitro in the presence of M-CSF (100 ng / mL) from CD14+ monocytes isolated from the peripheral blood of a healthy subject were incubated at 500,000 cells / well, in the presence of hybrid molecules at 5 pg / MI. The hybrid molecules are, for example, those described in [Example 2. [000115] The hybrid molecules are incubated for 2h, 8h, 16h, 24h and 48h at 37°C. The fixation of the hybrid molecules to the surface of the macrophages is demonstrated and quantified by cytofluorimetry (FACS Canto II) after incubation of the macrophages with an anti-Fc antibody coupled to FITC, used 1 / 1000. [000116] “NM” and “ANTI FC” respectively represent the well containing the macrophages incubated without antibody or with the anti-Fc antibody alone. “Wt”, “LALAPG” and “GASDIE” respectively represent the well containing the hybrid molecule with the wild-type Fc fragment or with the LALAPG mutation or with the GASDIE mutation. [000117] The results show that the hybrid molecules at the physiological temperature of 37°C, bind to the membrane of macrophages. These results also show that the binding of the hybrid comprising an Fc fragment comprising the GASDIE mutation is greater than that of the wild-type form. [0001181 Example 4: Phagocytosis induced by the Fc-WT hybrid or the Fc-GASDIE hybrid when B lymphocytes are armed via their FcyRIIb (CD32b) in the presence of sera [000119] Freshly purified human B lymphocytes from peripheral blood of healthy donors by CD19+ magnetic sorting were labeled with green PKH-67 (Paul Karl Horan / fluorescent lipid marker) and then incubated with sera from patients suffering from autoimmune dermatitis at a concentration of 5 pg / mL for 30 to 60 min at 37°C. Subsequently, the cells were washed and then placed in the presence of the hybrid according to the invention comprising a wild-type Fc fragment (Wt) or comprising the GASDIE mutations. The hybrid molecules are, for example, those described in [Example 2]. The cells were placed in the presence of the hybrids at 10 pg / mL for 30 to 60 min at 37°C. After washing, the cells were placed in contact with macrophages (marked PKH-26 red), at a rate of 1 B lymphocyte for 1 macrophage, for 2 hours at 37°C. The cells were then detached and analyzed by flow cytometry.Cells showing double fluorescence (PKH-67 green / PKH-26 red) correspond to macrophages that have phagocytosed lymphocytes. The different cell populations are expressed as a percentage of the total cell population: percentage of phagocytosis and percentage of B lymphocytes. [000120] The results obtained confirm that the phagocytosis activity is increased in the presence of the hybrids (increase in phagocytosis associated with a decrease in the B lymphocyte population). Indeed, a significant increase in the percentage of phagocytosis, always associated with a significant decrease in the B lymphocyte population, was observed when the B lymphocytes were covered with the hybrid. [000121] Example 5: Stability of the fixation of Fc-GASDIE A488 and Fc-GASDIE peptide hybrids, on NK cells after 30 min, 24 h and 48 h, at physiological temperature [000122] The NK cells were incubated for 30 min, 24 h or 48 h at 37°C in the presence of FcGASDIE-N3-DBCO-A488 (an Fc fragment comprising the mutations G236A, S239D and I332E which is linked to at least one PEGn spacer which is itself coupled to an azide covalently linked to a DBCO, the molecule being labeled with the fluorochrome A488) or FcGASDIE-N3-DBCO-PEG3-peptide-lysineA488 (an Fc fragment comprising the mutations G236A, S239D and I332E which is linked to at least one PEGn spacer which is itself coupled to an azide covalently linked to a DBCO which is coupled to a PEGn spacer linked to a peptide according to the invention (represented by any one of SEQ ID NO: 1 to SEQ ID NO: 30) the molecule being labeled with the fluorochrome A488 which is linked to the molecule via a lysine). The binding of these 2 fluorescent probes to NK cells was analyzed by cytofluorimetry.In the constructs, n represents a number between 1 and 10 when a PEGn spacer is used, preferably 1, 2, 3, 4 or 8. [000123] Results are presented at 30 minutes, 24 hours, and 48 hours. NM represents unlabeled NK cells without antibodies. [0001241 Example 6: Reactivity of 10 sera from patients with bullous pemphigoid (BP) to 3 immunodominant peptides from the polypeptide sequence of collagen XVII [000125] ELISA plate wells were coated with 100 μL of a solution containing the peptide EEVRKLKARVDELERIRRS (represented by SEQ ID NO: 38, sequence included in peptide SEQ ID NO: 3, also referred to as peptide 1) or the peptide RIRRSILPYGDSMDRIEK (represented by SEQ ID NO: 39, sequence included in peptide SEQ ID NO: 3, is partly included in peptide SEQ ID NO: 1, 4, 7 and included in peptide SEQ ID NO: 6, also referred to as peptide 2) or the peptide MDRIEKDRLQGMAP (represented by SEQ ID NO: 40, sequence included in peptides SEQ ID NO: 1, 3, 4 and 7 and partly included in peptide SEQ ID NO: 1, also referred to as peptide 3), at the concentration of 10 pg / mL in PBS (Phosphate Buffered Saline) 0.15M NaCI buffer, incubated overnight at 4°C. [000126] The wells were then saturated with 2% BSA (Bovine Serum Albumin) in PBS buffer 0.15M NaCl for 1 h at 4°C. After washing, the 10 sera from PB patients, 2 sera from patients with rheumatoid arthritis (named PR1 and PR2) and 2 sera from healthy subjects (named SS1 and SS2) were incubated diluted 1 / 100 in PBS buffer 2% BSA 2M NaCl for 1 h at 4°C. After washing, the reactivity of the sera was detected using a secondary goat anti-human IgG antibody coupled to peroxidase (HRP: Horse Radish Peroxidase) diluted 1 / 2500 in PBS buffer 2% BSA. The results are expressed as OD (Optical Density), read at 492 nm. The horizontal line represents the significance threshold. [000127] The results presented in Figure 5 show that 7 of the 10 sera from patients with PB exhibit significant reactivity of very variable intensity to peptide 2, three of them exhibiting very strong reactivity, whereas 5 of the 10 exhibit significant but weaker reactivities to peptide 1 and only 2 out of 10 exhibit very weak reactivity to peptide 3. There is significant heterogeneity of inter-individual reactivity and for a given patient heterogeneity of reactivity to the 3 peptides. As expected, the sera used as controls (PR1, PR2, SS1 and SS2) do not exhibit significant reactivities to the peptides tested, with the exception of weak reactivity of one of the patients with rheumatoid arthritis to peptide 3. [0001281 Example 7: Fixation on human monocytes and macrophages of the hybrid molecules according to the invention [000129] CD14+ monocytes isolated from the peripheral blood of a healthy subject and macrophages, differentiated in vitro in the presence of M-CSF (100ng / mL) from these same monocytes, were incubated at 100,000 cells / well for 1 h at 37°C, in the presence of the following hybrid molecules at 10pg / mL: FcGASDIE-DBCO-peptide 1(Nter) (an Fc fragment comprising mutations G236A, S239D and I332E, which is linked to at least one PEGn spacer which is itself coupled to an azide covalently linked to a cyclooctyne DBCO coupled to a PEGn spacer which is itself linked to the N-terminus of peptide 1 EEVRKLKARVDELERIRRS (SEQ ID NO: 38)), FcGASDIE- DBCO-peptide 1(Cter) (an Fc fragment comprising mutations G236A, S239D and I332E, which is linked to at least one PEGn spacer which is itself coupled to an azide covalently linked to a cyclooctyne DBCO coupled to a PEGn spacer which is itself linked to the C-terminus of peptide 1 EEVRKLKARVDELERIRRS (SEQ ID NO: 38)), FcGASDIE-DBCO-peptide 2(Nter) (an Fc fragment comprising mutations G236A, S239D and I332E, which is linked to at least one PEGn spacer which is itself coupled to an azide covalently linked to a cyclooctyne DBCO coupled to a PEGn spacer which is itself linked to the N-terminus of peptide 2 RIRRSILPYGDSMDRIEK (SEQ ID NO: 39)), FcGASDIE-DBCO-peptide 2(Cter) (an Fc fragment comprising mutations G236A, S239D and I332E, which is linked to at least one PEGn spacer which is itself coupled to an azide covalently linked to a cyclooctyne DBCO coupled to a PEGn spacer which is itself linked to the C-terminus of peptide 2 RIRRSILPYGDSMDRIEK (SEQ ID NO: 39)). [000130] These 4 hybrid molecules according to the invention, FcGASDIE-DBCO-peptide 1(Nter), FcGASDIE-DBCO-peptide 1(Cter), FcGASDIE-DBCO-peptide 2(Nter), FcGASDIE-DBCO-peptide 2(Cter), were labeled with an Alexa Fluor 647 fluorochrome (Kit "Lightning link"; Abeam). The fixation of the hybrid molecules labeled with the AF647 fluorochrome to the surface of monocytes and macrophages is demonstrated by cytofluorimetry (FACS Canto II). More than 10,000 events were analyzed per condition. The “NM” and “AF647 isotype control” conditions respectively represent wells containing monocytes or macrophages incubated without antibody or with a non-specific antibody corresponding to an isotype control coupled with the Alexa Fluor (AF) 647 fluorochrome. CD11 b-BV421 labeling makes it possible to highlight monocytes and macrophages. [000131] The results presented in Figure 6 and in Table 2 below show that at the physiological temperature of 37°C the four hybrid molecules according to the invention bind from the 1 ère hour to the membrane of monocytes and macrophages. More than 90% of monocytes and more than 55% of macrophages fix the hybrid molecules. For each hybrid molecule, the heterogeneity of labeling on the surface of macrophages is greater than that observed on the surface of monocytes. It is noted that the hybrid molecule FcGASDIE-DBCO-peptide 2(Cter) presents a more intense marking than that of the other 3 hybrid molecules (shift of the histogram towards high values). [000132] [Table 2]. Results of fixation at 37°C of the hybrid molecules on the surface of monocytes and macrophages. MFI: Mean Fluorescence Intensity; Ratio: ratio between the MFI obtained with each hybrid molecule and that obtained with the isotype control. [000133] Example 8: Reactivity of 4 sera from patients with pemphigus vulgaris (PV) towards 5 immunodominant peptides from DSG-1 [000134] ELISA plate wells were coated with 100 pL of a solution containing a peptide from desmoglein 1: - peptide 1: YRISGVGIDQPPYGIFVINQKTGEIN (SEQ ID NO: 41), or - peptide 2: RALNSMGQDLERPLELRVRVLDIN (SEQ ID NO: 42), or - peptide 3: FKIIRQEPSDSPMFIINRNTGEIRT (SEQ ID NO: 43), or - peptide 4: NERTNVGILKWKPLDYE (SEQ ID NO: 44), or - peptide 5: ALNSMGQDLERPLELR (SEQ ID NO: 10), or a control peptide from collagen XVII: - peptide 1: EEVRKLKARVDELERIRRS (SEQ ID NO: 38, also referred to as peptide PB1 in Figure 7), or - peptide 2: RIRRSILPYGDSMDRIEK (SEQ ID NO: 39, also referred to as peptide PB2 in Figure 7). [000135] The peptides are incubated at a concentration of 10 pg / mL in PBS (Phosphate Buffered Saline) 0.15M NaCI buffer, overnight at 4°C. [000136] The wells were then saturated with 2% BSA (Bovine Serum Albumin) in PBS buffer 0.15M NaCl for 1 h at 4°C. After washing, the 4 sera from Pg patients were incubated diluted 1 / 100 in PBS buffer 2% BSA 2M NaCl for 1 h at 4°C. After washing, the reactivity of the sera was detected using a secondary goat anti-human IgG antibody coupled to peroxidase (HRP: Horse Radish Peroxidase) diluted 1 / 2500 in PBS buffer 2% BSA. The results are expressed as OD (Optical Density), read at 492 nm. The horizontal line represents the significance threshold. [000137] The results presented in Figure 7 show that only the PV3 serum shows a weak reactivity towards peptide 1 and peptide 2, that only the PV1 serum shows a clear reactivity towards peptide 3, that only the PV5 serum recognizes peptide 4, very strongly, and peptide 5, significantly. As expected, none of the 4 sera significantly recognizes the 2 peptides PB1 and PB2, targets of the autoantibodies associated with bullous pemphigoid. [000138] Example 9: Reactivity of 4 sera from patients with pemphigus vulgaris (PV) to 5 immunodominant peptides from DSG-3 [000139] ELISA plate wells were coated with 100 pL of a solution containing a peptide derived from desmoglein 3: - peptide 1: INVREGIAFRPASKTFTVQKGISSKK (SEQ ID NO: 45); - peptide 2: REGEDNSKRNPIAKITSDYQ (SEQ ID NO: 46); - peptide 3: GTSYPTTSPGTRYGRPHSG (SEQ ID NO: 47); - peptide 4: KVVKALDYEQLQSVK (SEQ ID NO: 26), and - peptide 5: KFVKNMNRDSTFIVNK (SEQ ID NO: 48), or a control peptide from collagen XVII: - peptide 1 EEVRKLKARVDELERIRRS (SEQ ID NO: 38, also referred to as peptide PB1 in Figure 8), or - peptide 2 RIRRSILPYGDSMDRIEK (SEQ ID NO: 39, also referred to as peptide PB2 in Figure 8). [000140] The peptides are incubated at a concentration of 10 pg / mL in PBS (Phosphate Buffered Saline) 0.15M NaCI buffer, overnight at 4°C. [000141] The wells were then saturated with 2% BSA (Bovine Serum Albumin) in PBS buffer 0.15M NaCl for 1 h at 4°C. After washing, the 4 sera from Pg patients were incubated diluted 1 / 100 in PBS buffer 2% BSA 2M NaCl for 1 h at 4°C. After washing, the reactivity of the sera was detected using a secondary goat anti-human IgG antibody coupled to peroxidase (HRP: Horse Radish Peroxidase) diluted 1 / 2500 in PBS buffer 2% BSA. The results are expressed as OD (Optical Density), read at 492 nm. The horizontal line represents the significance threshold. [000142] The results presented in Figure 8 show that only sera PV3 and PV4 show a weak reactivity towards peptide 1 and peptide 2, that only sera PV2, PV3 and PV4 show a clear reactivity towards peptide 3, that none of the sera recognizes peptide 4, and finally that only serum PV4 clearly recognizes peptide 5. As expected, none of the 4 sera significantly recognizes the 2 peptides PB1 and PB2, targets of the autoantibodies associated with bullous pemphigoid.

Claims

Claims

1. A hybrid molecule comprising at least one antibody Fc fragment covalently linked to at least one peptide binding to an autoreactive lymphocyte involved in autoimmune dermatitis, at least one spacer being optionally present between said Fc fragment and said peptide.

2. Hybrid molecule according to the preceding claim, in which said peptide comprises all or part of the sequence of desmoglein 1, desmoglein 3, and / or type XVII collagen, in particular the a-1 chain of type XVII collagen.

3. Hybrid molecule according to the preceding claim, in which the sequence of desmoglein 1, desmoglein 3, or collagen type XVII is of human origin.

4. Hybrid molecule according to any one of the preceding claims, wherein said spacer is a polymer containing one or more repeating units containing the ether group, said spacer preferably being polyethylene glycol of formula PEGn, in which n represents an integer between 1 and 100, preferably between 1 and 10 and in particular 1, 2, 3, 4 or 8. [Revendication 5] Molécule hybride selon l’une quelconque des revendications précédentes, dans laquelle ledit peptide est choisi dans le groupe constitué par : SEQ ID NO : 1 , SEQ ID NO : 2, SEQ ID NO : 3, SEQ ID NO : 4, SEQ ID NO : 5, SEQ ID NO : 6, SEQ ID NO : 7, SEQ ID NO : 8, SEQ ID NO : 9, SEQ ID NO : 10, SEQ ID NO : 11 , SEQ ID NO : 12, SEQ ID NO : 13, SEQ ID NO : 14, SEQ ID NO : 15, SEQ ID NO : 16, SEQ ID NO : 17, SEQ ID NO : 18, SEQ ID NO : 19, SEQ ID NO : 20, SEQ ID NO : 21 , SEQ ID NO : 22, SEQ ID NO : 23, SEQ ID NO : 24, SEQ ID NO : 25, SEQ ID NO : 26, SEQ ID NO : 27, SEQ ID NO : 28, SEQ ID NO : 29, SEQ ID NO : 30, SEQ ID NO : 38, SEQ ID NO : 39, SEQ ID NO : 40, SEQ ID NO : 41 , SEQ ID NO : 42, SEQ ID NO : 43, SEQ ID NO : 44, SEQ ID NO : 45, SEQ ID NO : 46, SEQ ID NO : 47 et SEQ ID NO :

48.

6. A hybrid molecule according to any one of the preceding claims, wherein said Fc fragment is a human Fc fragment, in particular of IgG, more particularly of IgGI.

7. A hybrid molecule according to any one of the preceding claims, wherein said Fc fragment is wild type or mutated, said mutated Fc fragment preferably comprising at least the following mutations: - L234A and L235A, or - L234A, L235A and P329G, or - G236A, S239D and I332E, or - G236A, S239D, A330L and I332E, or - S239D, H268F, S324T and I332E, the numbering being indicated in the sequence of a human IgG 1 according to the EU index.

8. A hybrid molecule according to any preceding claim, wherein: - the Fc fragment is coupled to at least one azide and said peptide is coupled to an alkyne, such as a cyclooctyne, and in particular DBCO, or - the Fc fragment is coupled to at least one alkyne, such as a cyclooctyne, and in particular DBCO, and said peptide is coupled to an azide, or - the Fc fragment is coupled to at least one azide and said peptide is linked to a spacer itself coupled to an alkyne, such as a cyclooctyne, and in particular DBCO or - the Fc fragment is coupled to at least one alkyne, such as a cyclooctyne, and in particular DBCO, and said peptide is linked to a spacer itself coupled to an azide or - the Fc fragment is linked to at least one spacer, itself coupled to an azide, and said peptide is coupled to an alkyne, such as a cyclooctyne, and in particular DBCO or - the Fc fragment is linked to at least one spacer, itself coupled to an alkyne, such as a cyclooctyne, and in particular DBCO, and said peptide is coupled to an azide or - the Fc fragment is linked to at least one spacer, itself coupled to an azide, and said peptide is linked to a spacer, itself coupled to an alkyne, such as a cyclooctyne, and in particular DBCO or - the Fc fragment is linked to at least one spacer, itself coupled to an alkyne, such as a cyclooctyne, and in particular DBCO, and said peptide is linked to a spacer, itself coupled to an azide, the covalent bond between said Fc fragment and said peptide, optionally in the presence of one or more spacers, being created between the azide and the alkyne.

9. Hybrid molecule according to any one of the preceding claims, for its use as a medicament, in particular for its use in the treatment of autoimmune dermatitis, in particular pemphigus vulgaris or bullous pemphigoid.

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