Multi-epitopic construct
11332515 · 2022-05-17
Assignee
Inventors
Cpc classification
A61K2039/64
HUMAN NECESSITIES
A61K2039/58
HUMAN NECESSITIES
A61K39/118
HUMAN NECESSITIES
A61P9/10
HUMAN NECESSITIES
C07K14/70596
CHEMISTRY; METALLURGY
A61K39/0008
HUMAN NECESSITIES
International classification
C07K14/705
CHEMISTRY; METALLURGY
A61K39/00
HUMAN NECESSITIES
Abstract
The invention relates to multiple epitope constructs, immunogenic and vaccine compositions comprising recombinant molecules presenting inserted multiple and different epitopes from a variety of antigens. The antigenic determinants being associated with different pathways leading to atherosclerosis. In particular, the invention relates to such compositions for eliciting an immune response against antigens and pathogens involved in the development of atherosclerosis the invention includes inter alia methods of treating and/or preventing the disease and recombinant protein products.
Claims
1. A recombinant construct comprising: (i) a scaffold portion; (ii) a first species of epitope capable of eliciting an anti-arteriosclerotic vascular disease response via a first pathway wherein the first species of epitope is a C5a receptor (C5aR) protein selected from the group consisting of SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, and SEQ ID NO:9; (iii) a second species of epitope capable of eliciting an anti-arteriosclerotic vascular disease response via a second pathway that is independent from the first pathway and is independently selected from the group consisting of an apolipoprotein (Apo) epitope and a heat-shock protein (HSP) epitope selected from the group consisting of peptide 1 (AA) 153-160: AELKKQSK (SEQ ID NO:10), peptide 1 (AA) 153-163: AELKKQSKPVT (SEQ ID NO:11), peptide 1 (AA) 303-312: PGFGDNRKNQ (SEQ ID NO:12), peptide 2: AA 277-286 PGFGDNRKNQ (SEQ ID NO:13), and peptide (AA) 516-528: KGIIDPTKWRTA (SEQ ID NO:14); and iv) a third species of epitope capable of eliciting an anti-arteriosclerotic vascular disease response via a third pathway that is independent from the first pathway and is independently selected from the group consisting of a protease-activated receptor-1 (PAR-1) epitope or a Mycobacterium bovis HSP epitope.
2. The construct according to claim 1 comprising a plurality of first and/or second species of epitopes.
3. The construct according to claim 1, wherein the scaffold portion is a dendroaspin scaffold protein as depicted in SEQ ID NO:1; optionally, wherein the first and/or second species of epitope is incorporated into any one or more of the following positions: (a) loop I and/or loop II; (b) loop I and/or loop III; (c) loop II and/or loop III; (d) loop I, loop II and loop III; (e) an N terminus or C terminus of the dendroaspin scaffold.
4. The construct according to claim 1, wherein the epitopes portion of the construct comprises AH.sup.hH.sup.mR and wherein A is ApoB100.sup.688-707 (ApoB100 peptide, amino acids 688-707 (numbered including signal peptide)), H.sup.h is SEQ ID NO: 12, H.sup.m is SEQ ID NO: 15 and R is SEQ ID NO: 9.
5. An antigenic composition comprising the construct according to claim 1, optionally wherein the composition comprises an antigenic hydrophobic complex comprising: (i) an isolated microsome optionally wherein it is an inverted microsome or (ii) an MHC protein or (iii) an inverted micelle or (iv) a synthetic product.
6. A pharmaceutical composition comprising the recombinant construct according to claim 1, formulated as an injectable or oral product, optionally wherein the pharmaceutical composition further includes a suitable adjuvant, excipient, diluent and/or carrier.
7. A pharmaceutical composition comprising the recombinant construct according to claim 1.
8. A vaccine comprising the construct according to claim 1.
9. A method of eliciting an anti-atherosclerosis response in a mammal comprising administering to an individual the recombinant construct of claim 1.
10. A method of treating, or reducing atherosclerosis in an individual comprising administering to said individual the recombinant construct of claim 1.
11. A method of treating an individual with early stage atherosclerosis or an individual identified as at risk of developing atherosclerosis comprising administering to said individual the recombinant construct of claim 1.
12. A method of eliciting an immune response against epitopes associated with at least two independent pathways associated with atherosclerosis formation, the method comprising: 1. incubating eukaryotic cells with the recombinant construct of claim 1; 2. preparing microsomes from said incubated eukaryotic cells; 3. incorporating said microsomes of (2) with one or more pharmaceutically acceptable constituents to produce an orally or injectable administrable preparation; and 4. administering said preparation to a mammal or human.
13. The recombinant construct according to claim 1 comprising: a first species of epitope capable of eliciting an anti-arteriosclerotic vascular disease response via a first pathway is a C5a receptor (C5aR) protein selected from the group consisting of SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, and SEQ ID NO:9; and a second species of epitope capable of eliciting an anti-arteriosclerotic vascular disease response via a second pathway that is independent from the first pathway and is an apolipoprotein (Apo) epitope; and another second species of epitope capable of eliciting an anti-arteriosclerotic vascular disease response via a second pathway that is independent from the first pathway and is a heat-shock protein (HSP) epitope selected from the group consisting of HSP 60 and a HSP 65, and wherein the HSP 60 is selected from the group consisting of peptide 1 (AA) 153-160: AELKKQSK (SEQ ID NO:10), peptide 1 (AA) 153-163: AELKKQSKPVT (SEQ ID NO:11), peptide 1 (AA) 303-312: PGFGDNRKNQ (SEQ ID NO:12), peptide 2: AA 277-286 PGFGDNRKNQ (SEQ ID NO:13), and peptide (AA) 516-528: KGIIDPTKWRTA (SEQ ID NO:14); and a third species of epitope capable of eliciting an anti-arteriosclerotic vascular disease response via a third pathway that is independent from the first pathway and is independently selected from the group consisting of a PAR-1 epitope or a Mycobacterium bovis HSP epitope.
14. The construct according to claim 1, wherein the epitopes portion of the construct comprises RPHC wherein R is SEQ ID NO: 9, P is SEQ ID NO: 19, H is SEQ ID NO: 12 and C is a combination of amino acid 66-73 (SEQ ID NO: 16) from major outer membrane protein (MOMP) and amino acid 283-291 (SEQ ID NO: 17) from outer membrane protein 5 of Chlamydia pneumoniae.
15. The construct according to claim 1, wherein the PAR-1 epitope comprises an amino acid selected from the group consisting of EWEPKPVNQVYT (SEQ ID NO:18) and SFLLRNPNDKYEPF (SEQ ID NO:19).
16. The construct according to claim 1, wherein the Mycobacterium bovis HSP epitope is mycobacterium (AA) 253-268: EGEALSTLVVNKIRGT (SEQ ID NO:15).
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:
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DETAILED DESCRIPTION
(50) Data indicates that the C5a/C5aR pathway towards atherosclerosis is independent from that of PAR-1/HSP/Cpn pathway based on studies of immunized Apob.sup.tm2SgyLdlr.sup.tm1Her/J mice. The present invention provides products and vaccines for targeting both pathways simultaneously using combined epitopes within a dendroaspin scaffold.
(51) Our previous study demonstrated that construct AHHC [ApoB100.sup.688-707+hHSP60.sup.303-312+hHSP60.sup.153-163+Cpn derived peptide (C)] significantly reduced atherosclerotic lesion (Lu et al Atherosclerosis 2012, 225: 56-68). The present invention provides modulations and derivatives of this construct with a sequential epitope-substitution named RHHC in which A was replaced by an “R” (C5aR.sup.1-31) and RPHC with a further “H” (hHSP60.sup.303-312) conversion into “P” (protease-activated receptor-1.sup.42-55) in mice. An alternative embodiment is the construct AH.sup.hH.sup.mR wherein the antigenic epitopes are from ApoB (AA688-707), designated as A, human HSP60 (AA303-312) (SEQ ID NO: 12) designated as H.sup.h, mycobacterium (AA253-268) (SEQ ID NO:15) designated as H.sup.m and complement component 5a receptor (AA1-31) (SEQ ID NO:9) designated as R. Immunization of B6;129S-Ldelr.sup.tm1HerApob.sup.tm2Sgy/J mice with these elicited production of high levels of antibodies against each epitope (apart from hHSP60.sup.153-163 and P which induced a low antibody response). Histological analyses demonstrated that the mice immunized with either RPHC or RHHC showed significant reductions in the size of atherosclerostic lesions compared to those with AHHC (69.5±1.1% versus 55.7±3.4%, P=0.006 or 65.6±1.3% versus 55.7±3.4%, P=0.045). Reduction of plaque size in the aortic sinus and descending aorta correlated with alterations in cellular immune responses when compared with controls. We conclude that these new recombinant constructs may provide new antigenic and structural features which are favourable for significant reduction in atherosclerotic lesion formation. This present invention offers a novel strategy for developing anti-atherosclerotic agents.
(52) Based on the effects of the peptides derived from C5aR and PAR-1 on reducing the atherosclerotic lesion, we hypothesized that the effect of a multi-epitopic construct on reducing atherosclerotic lesion may be modulated towards favorable plaque phenotype and increased lesion reduction with inclusion of C5aR and PAR-1 in vaccination. In the present study we investigated the effect of C5aR and PAR-1 including constructs through a sequential substitution: AHHC.fwdarw.RHHC (R denotes an epitope derived from C5aR) in RHHC.fwdarw.RPHC (P denotes an epitope derived from PAR-1) on reducing atherosclerotic lesion. The induced immune response is associated with an anti-atherogenic effect, detected as a significant reduction in the size of the atheromatous lesion area both in aorta sinus and descending aortas with a rate in the following order: RPHC≥RHHC>AHHC.
(53) Native dendroaspin is a 59 amino acid peptide and the dendroaspin scaffold lends itself to modification. When dendroaspin (including the RGD motif) is modified to incorporate further functional amino acid sequences e.g. active portions or motifs of agonists, antagonists or inhibitors of factors in the clotting cascade, the resulting molecules are particularly useful as anticoagulants and do not suffer from the drawbacks associated with existing anticoagulants (see International application WO 01/57210). Such hybrid polypeptides may comprise a first amino acid sequence including the RGD motif and conferring dendroaspin activity and a further amino acid sequence conferring activity other than that of dendroaspin activity. In this way the hybrid dendroaspin-based molecules molecules may be rendered multifunctional.
(54) C5a is a protein fragment released from complement component C5. This 74 amino acid peptide in humans is generated by the cleavage of C5a convertase on the C5 α-chain during the classical, alternative, and lectin pathways of complement activation.
(55) The C5a receptor also known as component 5a receptor (C5AR1) or CD88 (cluster of differentiation 88) is a G protein-coupled receptor for Ca. Human C5aR is an integral membrane glycoprotein consisting of 350 amino acids forming a single poly-peptide chain. The C5aR is not released as a soluble receptor and does not circulate. C5aR is expressed on differentiated myeloid cells, such as U937 and HL-60. C5aR is expressed on liver parenchymal cells, lung vascular smooth muscle, lung and umbilical vascular endothelial cells, bronchial and alveolar epithelial cells, HepG2 cells, a hepatoma cell line, mesangial cells, as well as astrocytes and microglial cells, on cultured human fetal astrocytes and astrocyte cell line.
(56) Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.
(57) Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
(58) The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.
(59) Expression and Purification of Recombinant Glutathione S-Transferase Constructs
(60) Glutathione S-transferase-dendroaspin (GST-tagged-den here referred to as a control,
(61) Animal Experiments
(62) B6;129S-Ldelr.sup.tm1HerApob.sup.tm2Sgy/J mice were used, each group of mice consisting of 5-6-week-old males. Dendroaspin as a control antigen, since dendroaspin was used as a scaffold and previous data showed no effect of dendroaspin on lesion reduction when used for subcutaneous immunization in mice.
(63) The immunizing antigens used were constructs AHHC, RHHC and RPHC, respectively. The repetitive immunization multiple sites strategy (RIMMS) was adopted [1] and mice were sacrificed at the end of week 12 (a high-fat diet was started at the end of week 2 and continued for 10 weeks). The control groups followed the diet program after immunization with GST-tagged Den and Alum (adjuvant).
(64) Tissue Preparation and Antibody Response Measurements
(65) Twelve weeks after the first immunization, aorta tissues were harvested and mounted in optimal cutting temperature compound (OCT) and in paraffin, for immunohistochemical (IHC) analyses and lesion measurement, respectively. Atherosclerotic lesions in aortic roots were examined by an Olympus UULH Optical microscope (Olympus Optical Co. Ltd, Tokyo, Japan) and analyzed with Image-Pro Plus™ software, version 7.0 (Media Cybernetics, Inc., Bethesda, Md., USA). Longitudinally opened descending aortas were evaluated for the extent of atherosclerosis after Oil Red O (ORO) staining. The peptide-specific antibody levels in the plasma samples were measured by ELISA following the manufacturer's instructions. One third of spleens were embedded in OCT and the remaining part was homogenized by pressing through 70 μm cell strainer and frozen for further analysis.
(66) IHC and Morphometric Analyses, Quantitative Measurements of Atherosclerosis, and IHC Analysis of Forkhead Box Protein 3 (Foxp3) Expression in CD4.sup.+ Splenocytes.
(67) OCT-embedded samples were used for detection of CD68, CD11c, Interleukin (IL)-10 and tumour necrosis factor (TNF)-α, Foxp3, vascular cell adhesion molecule (VCAM)1, alpha smooth muscle cell (alpha-SMC), matrix metalloproteinase 9 (MMP9) by IHC analyses. Sections of paraffin-embedded tissues were stained with hematoxylin and eosin (HE) and elastin/van Gieson (Sigma) for histological examination by the Olympus U-ULH Optical microscope.
(68) Flow Cytometric Analysis of Foxp3, IL-2, IL-4 and IL-17A Expression in CD4.sup.+ T-Cells in Splenocytes and Differentiation of PBMC into Macrophage (CD206).
(69) Spleen cells were processed for staining (30 min at 4° C.) using allophycocyanin-anti-mouse Foxp3, IL-2, IL4 and IL-17 antibodies (BioLegend, Cambridge, UK). For cell differentiation assay, mouse (C57BL/6) PBMCs were stimulated with different antigens or pre-incubated with antiserum of antigen (in order to see any antagonism of antiserum). Antigen-induced differentiation of monocytes into macrophages was measured by flow cytometry which was compared to cell populations from non-induced cells or control antigen (GST-Den)-induced cells.
(70) Measurement of Cytokines
(71) IL-10 and TNF-α levels in the lesions were quantified by IHC analyses (rat anti-mouse TNF-α and IL-10 purchased from BioLegend, CA, USA). Plasma levels of the cytokines, IL-10, transforming growth factor beta (TGF-β), TNF-α and interferon gamma (IFN-γ) were measured by ELISA following the manufacturer's instructions (R&D systems, Abingdon, UK). Levels of concanavalin A (ConA)-induced IL-10, TGF-β, TNF-α, and IFN-γ in splenocyte cultures were also measured.
(72) Antigen-Specific Regulatory T Cell Function Assays
(73) To assess antigen-specific regulatory T cell function, CD4.sup.+CD25.sup.+ Treg cells were isolated by using regulatory T cell isolation kit of Miltenyi Biotec (Bergisch Gladbach, Germany) from spleen CD4.sup.+ T cells of B6;129S-Ldelr.sup.tm1HerApob.sup.tm2Sgy/J mice immunized subcutaneously with constructs, respectively. CD4.sup.+CD25.sup.− T effector cells were isolated from spleen CD4.sup.+ T cells (unbound to beads binding CD4.sup.+CD25.sup.+ cells, 99.5% of CD4.sup.+ cells) of same construct-immunized mice respectively. CD4.sup.+CD25.sup.− cells (2×10.sup.5) were co-cultured with CD4.sup.+CD25.sup.+ cells (2×10.sup.5), and stimulated with 1 μM related construct or with GST-Den control. After 2 days of culture, the proliferation of T effector cells was measured for the shift in fluorescence intensity of a population of cells by flow cytometry expressed as mean fluorescence intensity (MFI).
(74) Statistical Analyses
(75) Data are reported as mean±standard error of the mean (±SEM), unless otherwise indicated. Figures were plotted using graph-pad Prism 5.01 and Sigma plot 9.0. For atherosclerotic lesion size, data were compared and intergroup differences were analyzed using one-way ANOVA for multiple comparisons and post hoc Bonferroni test. Other data were analyzed using Student's t-test (2-tailed analyses). Non-parametric distributions were analyzed using the Mann-Whitney U test for pair wise comparisons and the Kruskal-Wallis test for multiple comparisons. Differences between groups were considered significant at P values below 0.05.
Example 1
(76) Peptide-specific immunoglobulin G in the sera of immunized mice was assessed. Antibody levels were measured by ELISA test in the sera of mice immunized with either dendroaspin (GST-tagged) or constructs within dendroaspin scaffold (GST-tagged) at weeks 2 and week 12 respectively after first immunization. In AHHC-immunized mice, ApoB peptide-, hHSP60.sup.303-312- and Cpn-peptide-specific antibodies were observed when these peptides were used as ELISA antigens (
(77) Interestingly, a peptide-induced specific immunoglobulin (Ig)G1 response was observed in serum of peptide-immunized mice against all peptide antigen epitopes at high dilutions except for those against hHSP60.sup.153-163 and PAR-1 peptides when compared with GST-Den control (
Example 2
(78) The reduction of atherosclerotic lesion size in the aortic sinus was assessed. Following immunization with AHHC, RHHC, RPHC, and after a 10-week high-fat diet, the aortic sinuses of the mice were evaluated for the extent of atherosclerosis. The calculated plaque sizes from the immunized animals were compared with those of the controls.
(79) Representative photomicrograph of sections with lesions from experimental groups are shown in
(80) The impact of treatment with these recombinant constructs on the collagen content in these lesions was also examined. The reduction of atherosclerosis in mice treated with these constructs was associated with an increase in collagen content: approximately 3-fold for either AHHC-immunized mice or RHHC-immunized mice versus control mice (18.6±1.2% or 19.4±0.9% versus control 5.9±0.3%; P<0.001), respectively (
(81) Longitudinally opened descending aortas were stained en face with oil red 0 (ORO) and positively stained plaques areas were measured. Representative en face stained descending aortas from experimental groups are shown in
Example 3
(82) The amount of inflammatory cells and CD4.sup.+ T cells expressing Foxp3 in local (lesions of aortas) and remote organs: splenocytes and lymphocytes was assessed. The percentage of anti-CD68-stained area in the lesions showed 14.9±1.6%, 13.6±1.3% and 10.3±0.8% in mice immunized with AHHC, RHHC and RPHC, respectively compared to 43.7±3.2% in control mice immunized with GST-Den (P<0.001). Lesser anti-CD68-stained area was observed in RPHC-immunized mice compared with that in AHHC-immunized mice (P=0.034) (
Example 4
(83) The expression of anti-inflammatory cytokines and proinflammatory cytokines in lesion sites and levels of cytokines in plasma and in the supernatants of stimulated splenocytes was assessed. IL-10 expression in the aortic lesions of mice immunized with AHHC, RHHC and RPHC, detected by IHC analyses is shown in
(84) Plasma levels of atheroprotective cytokines IL-10 were significantly increased in mice immunized with these three constructs compared with controls (
(85) Supernatants of splenocytes from mice immunized with these constructs individually showed significantly increased secretion of IL-10 (
(86) The proportion of IL-4 (Th2-related), IL-17A (Th17 related) and IL-2 (Th1-related) expressing CD4.sup.+ spleen cells from mice immunized with these three constructs was significantly lower (P<0.001 for IL-4.sup.+ and P≤0.001 for IL-17A.sup.+, respectively), showing 2.74±0.11% (AHHC), 2.85±0.12% (RHHC), and 2.87±0.02% (RPHC) for IL-4.sup.+ when compared to 8.44±0.21% (control) (
Example 5
(87) Antigen-induced specific Treg cell function was investigated. To assess whether functional Treg cells were induced by immunization, antigen-specific Treg cells (CD4.sup.+CD25.sup.+ T cells) were co-cultured with CD4.sup.+ effector T-cells (CD4.sup.+CD25.sup.− T cells). Proliferation of effector T-cells from control mice immunized with GST-Den in response to stimulation with GST-Den at 1 μM did not show suppression in the presence of Treg cells from GST-Den-immunized mice (
Example 6
(88) An evaluation of expression of smooth muscle alpha actins, VCAM1, MMP9 and specific antigens ApoB and HSP60 in the lesions was undertaken. To assess whether immunization with the constructs of the present invention influences vascular SMC behavior and vascular remodeling, the SMC content of lesions and expression of VCAM1 and MMP9 at lesion sites was analysed by IHC analyses. Anti-SMC stained area was significantly smaller in the plaques of mice immunized with AHHC and RPHC, showing 5.2±0.7% and 4.9±0.8%, respectively, but it was not reduced significantly in mice immunized with RHHC when compared with that in controls immunized with GST-Den (
Example 7
(89) Evaluation of monocyte differentiation into macrophages in PBMC from C57BL/6 background naive mice in response to treatment with recombinant constructs and the effect of construct-specific immune sera on the differentiation was investigated. In vitro, monocytes can differentiate into macrophage (or subsets) upon stimulation with macrophage-colony stimulating factor (M-CSF) or atherogenic antigens. To assess whether AHHC converted into RHHC with a single domain substitution could maintain the same effect on stimulation of monocyte (from naive mice C57BL/6 with same background), PBMCs were stimulated with either RHHC or AHHC. After 3 days, the expression of cell surface marker CD206 (mannose receptor, a macrophage marker) was assessed. Both RHHC- and AHHC-induced monocyte differentiation into macrophages (based on the cell number changes) when compared with non-stimulated cells (
Example 8
(90) Evaluation of the contents of Toll-like receptor 4(TLR4) and myeloid differentiation factor 88 (MyD88) which are involved in the TLR4 signal pathway related to atherosclerosis at the lesion sites was investigated. The impact of the treatment with these recombinant constructs on TLR4 and MyD88 contents in lesions was examined. The reduction of atherosclerosis in mice treated with these constructs was associated with a decrease in both TLR4 and MyD88 contents. Anti-TLR4 stained area was significantly smaller in the plaques of mice immunized with AHHC, RHHC and RPHC, showing 4.6±1.0%, 3.4±0.5% and 4.2±0.6%, respectively, compared with that in controls immunized with dendroaspin (8.1±1.1%) (
Example 9
(91) Experiments were conducted to compare two HSP60 peptides derived from human and mycobacterium, respectively, for their ability to reduce atherosclerotic lesions through immunization in Apob.sup.tm2SgyLdlr.sup.tm1Her/J Mice. Mice were immunized with two Keyhole limpet hemocyanin (KLH)-conjugated peptides derived from mycobacterial heat shock protein (HSP) 60 (AA253-268) (SEQ ID NO:15) designated as mHSP60.sup.253-268, human HSP60 (AA516-528) (SEQ ID NO:14) designated as hHSP60.sup.516-528, respectively. Mice were immunized with these two peptides and two weeks after the first immunization, mice were placed on a high-fat diet. Results indicated that the two peptides showed similar functions apart from that mHSP60 peptide has lower titres for IgG and IgG1 and little for IgG2c, than those of hHSP60 peptide. Similar functions include: induced specific immune responses; lesion reduction; increased Treg expression; increased concentration of atheroprotective cytokines: IL-10 and TGF-β and decreased concentration of pro-inflammatory cytokines: TNF-α and INF-γ; inhibition of CD4.sup.+CD25.sup.− T-cell proliferation by Treg cells and down-regulation of TLR4/MyD88 pathway (data not shown). In conclusion, after immunization of B6; 129S-Ldlrtm1HerApobtm2Sgy/J mice with mHSP60 and hHSP60 peptides, in spite of a low sequence homology (31%) between two peptides and lower immune responses obtained from mHSP60 peptide, both peptides have similar effects on significantly reduced early atherosclerotic lesions. This data confirms that such immunization with the constructs of the present invention offers attractive opportunities for the design and development of peptide-based vaccines against atherosclerosis.
Example 10
(92) The transcriptional regulator FOXP3 (forkhead box P3) governs mouse CD4.sup.+CD25.sup.+ Treg function (Fontenot et al., Nat Immunol. 2003;4:330-336; Hori S, Nomura T, Sakaguchi S. Science. 2003; 299:1057-1061) and it has been shown that transfer of natural CD4.sup.+CD25.sup.+ Tregs significantly reduces plaque progression in the ApoE-KO mouse model (Ait-Oufella et al., Nat Med. 2006;12:178-180; Mor et al Arterioscler Thromb Vasc Biol. 2007; 27: 893-900). Accordingly it is known that naturally occurring Tregs are capable of influencing the size and composition of atherosclerotic lesions, several reports support the theory that antigen-specific responses may be operable in the evolving atheromatous plaque. We hypothesized that atherogenic antigen-induced Treg may have a specific function on lesion reduction. We conducted experiments to assess the effect of adoptively transferred Treg cells isolated from the blood of antigen-immunized mice on atherosclerotic lesion formation in B6;129S-Ldelr.sup.tm1HerApob.sup.tm2Sgy/J mice by testing humeral immune response, the effect on atherosclerotic lesion size and local and systemic cellular responses.
(93) The first method, to look at the immune response and adoptive transfer in KO mice, involved incorporating construct AH.sup.hH.sup.mR into a dendroaspin scaffold to generate a recombinant construct. The antigenic epitopes from ApoB (AA688-707) was designated as A, human HSP60 (AA303-312) (SEQ ID NO: 12) designated as H.sup.h, mycobacterium (AA253-268) (SEQ ID NO:15) designated as H.sup.m and complement component 5a receptor (AA1-31) (SEQ ID NO:9) designated as R. Mice were immunized with AH.sup.hH.sup.mR by RIMM (repetitive, multiple site immunization strategy) protocol. Treg cells were purified from the blood of immunized mice with AH.sup.hH.sup.mR (Treg.sup.S) and with dendroaspin (Treg.sup.C) respectively). Adoptive transfer was achieved though retro-orbital plexus of the mice.
(94) The second method, to evaluate the effect of Treg cells on atherosclerotic lesion formation, involved adoptive transfer of Treg cells from the blood of AGD-den (Control)- and AHhHmR—immunized mice, respectively. Recipients were from the same strain non-immunized naive mice and were fed with a high-fat diet (HFD) for 10 weeks then sacrificed. Histological and immunohistochemical assessment of lesion development, analysis of cytokine level, assessment of Treg activity and foam cell formation were evaluated.
(95) Data (not shown) indicated that Treg.sup.s isolated from the blood of atherogenic anti-immunized mice, after adoptively being transferred into the vein of a non-immunized mice when compared to Treg from the blood of non-atherogenic antigen-immunized mice showed lesser lesion formation. Transfer of natural CD4.sup.+CD25.sup.+ Tregs significantly reduced plaque progression in the ApoE-KO mouse model. In addition to lesser lesion formation they also showed increased collagen content in lesion sites, increased Treg expression in lesion sites, higher concentration of atheroprotective cytokines (IL-10 and TGF-β) and lower concentration of pro-inflammatory cytokines (TNF-α and INF-γ) in plasma. Down-regulation of expression of αSMC and PECAM at the lesion sites was also observed.
(96) These results show that the constructs of the present invention offer attractive opportunities in the cell-based therapy for the treatment of atherosclerosis.