Patent Publication Number: US-2022220212-A1

Title: Compositions and methods to block and bind ccr2 to modulate cellular function

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional application No. 62/846,947, filed on May 13, 2019, the disclosure of which is incorporated herein by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     This invention was made with government support under EB023262 awarded by the National Institutes of Health. The government has certain rights in the invention. 
    
    
     BACKGROUND OF THE DISCLOSURE 
     Monocytes migrate to sites of inflammation under the influence of chemokines and cytokines. The CCR2 chemokine receptor mediates monocyte egress from the bone marrow under the influence of the chemokine CCL2, which is secreted by cells during inflammatory conditions including myocardial infarction, cancer, atherosclerosis, asthma, and rheumatoid arthritis. 1-3    
     At sites of inflammation, monocytes differentiate into functionally polarized macrophages in response to chemokines, cytokines, and other chemical factors. There are two main macrophage phenotypes: M1 and M2. 4  M1 macrophage activation generally occurs in the presence of lipopolysaccharide (LPS), 5  interferon gamma (IFN-γ), 6  and granulocyte-macrophage colony stimulating factor (GM-CSF). 7  M1 macrophages are considered pro-inflammatory and essential early responders at inflammatory disease onset. Macrophage colony-stimulating factor (M-CSF) 7  and specific interleukins (IL-4, IL-13, IL-10) 8-10  induce M2 macrophage activation, which is considered anti-inflammatory. While M2 macrophages are beneficial in the reparative phase of inflammation and contribute to wound healing after myocardial infarction, they can be detrimental in tumors as they promote tumor growth through increased angiogenesis and metastasis and suppression of anti-cancer immune responses. 11-13    
     In addition to driving monocyte migration, CCL2 signaling also contributes to M2 macrophage polarization. 14, 15  As the N-terminal domain (NTD) of the CCR2 receptor captures CCL2 to trigger downstream effects, 16, 17  the CCR2 NTD represents an ideal target to disrupt the CCR2/CCL2 axis for therapeutic benefit. 18  While several antibodies targeting the CCL2/CCR2 pathway have shown promise in clinical trials in myocardial infarction, atherosclerosis, and cancer, 19-23  none are clinically approved despite initial expectations. Thus, there remains a need to capitalize on antibody binding specificity while finding novel ways to improve efficacy. 
     SUMMARY OF THE DISCLOSURE 
     The present disclosure provides antibodies, compositions, and methods that inhibit chemokine ligand 2 (CCL2) from binding to the chemokine receptor type 2 (CCR2). The disclosure provides isolated antibodies including fragments and variants thereof. In an embodiment, the antibodies are single chain variable fragment (scFvs) antibodies directed against the N-terminal or extracellular loop (ECL) domains of CCR2. Binding of these scFvs to CCR2 inhibits the binding of CCL2 to CCR2, thus blocking downstream signaling events. The disclosure also provides compositions comprising the scFvs, and methods of using the scFvs or compositions for inhibiting binding of CCL2 to CCR2 for the treatment of a medical condition such as cancer. 
     In an aspect, the present antibodies, such as scFvs specifically bind to CCR2 relative to other chemokine receptors. The scFvs and compositions described in this disclosure can be used for treatment of conditions in which there is abnormal CCL2/CCR2 binding resulting in the recruitment of immune cells and their subsequent polarization to an immune suppressive phenotype, or in which a reduction in CCL2/CCR2 binding is desired. Conditions such as these often arise in diseases such as cancer. 
     Despite the important role of the tumor stroma in cancer progression, the vast majority of anticancer therapies target cancer cells and not the tumor microenvironment. This disclosure provides a therapeutic strategy that not only inhibits inflammatory monocyte migration to the tumor but also polarizes tumor associated macrophages (TAMs) towards the tumor-suppressive M1 phenotype and away from the immune-suppressive M2 phenotype by blocking the CCL2/CCR2 pathway. Antibodies and small molecules targeting the CCL2/CCR2 pathway have shown promise in clinical trials, but these are suboptimal and there remains a need for building upon antibody binding specificity and new ways to improve efficacy. 
     This disclosure also provides a method of treating a tumor in an individual in need of treatment comprising administering to the individual one or more scFvs or a composition comprising one or more scFvs that are specific for CCR2, such as, for example, human CCR2. Additionally, this disclosure includes methods and compositions for inhibiting metastasis and/or angiogenesis using the described antibodies. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       For a fuller understanding of the nature and objects of the disclosure, reference should be made to the following detailed description taken in conjunction with the accompanying figures. 
         FIG. 1 . Schematic of phage display screening against the CCR2 N-terminal peptide domain (A). The top five clones showing the highest affinity to the CCR2 N-terminus were sequenced (clones 13F (SEQ ID NO:53), 25B (SEQ ID NO:54), 26B (SEQ ID NO:55), 37B (SEQ ID NO:56), and 58C (SEQ ID NO:57)) (B). The top 2 clones showing highest affinity to the CCR2 ECL2 were sequenced (clones 4h (SEQ ID NO:6) and 11b (SEQ ID NO:7) (B). For each group of scFvs (NTD or ECL2) the framework regions (light and heavy chains, shaded) and complementarity determining regions (light and heavy chains; CDRL and CDRH, labeled and underlined) are aligned and compared. Linker sequences are identified by the dashed line. 
         FIG. 2 . Identification and characterization of 58C-scFv binding to CCR2. (A) Phage ELISA of clones generated through affinity selection using a scFv library. (B) Binding affinity of the top 5 phage clones as analyzed by ELISA (C) Binding of the recombinantly expressed 58C-scFv to the N-terminal domain of CCR2 as analyzed by ELISA (KD=59.8±13.9 nM) (D) SDS-PAGE of purified 58C-scFv (MW approx. 33 kDa) on a 12% gel: ladder (lane 1), 58C-scFv sample (lane 2). (E) 58C-scFv binding to RAW 264.7 (F) and MDA-MB-231 cells was concentration-dependent. (G) Mean fluorescent intensity (MFI) following incubation of HEK, MDA-MB-231, and Raw264.7 cells with the DyLight-650 labeled 58C-scFv. The MFI was determined at 2.5 μM for MDA-MB-231 and HEK, and RAW 264.7 cells. Data are represented as mean±sd, *p&lt;0.05, **p&lt;0.01, ***p&lt;0.001 with one-way ANOVA followed by Dunnett&#39;s post-test. 
         FIG. 3 . Effect of free, monomeric 58C-scFv on cellular migration. Transwell migration assay performed with MDA-MB-231 cells and RAW 264.7 cells incubated with increasing concentrations of 58C-scFv. Data are presented as mean±sd (n=3), *p&lt;0.05, **p&lt;0.01, ***p&lt;0.001 with one-way ANOVA followed by Dunnett&#39;s post-test. 
         FIG. 4 . Effect of free, monomeric 58C-scFv and multivalent 58C-scFv on cellular migration. (A) Schematic illustrating the effect of 58C-scFv and liposomal multivalent display of 58C-scFv on cellular migration. (B) TEM image of liposomes surface-decorated with 58C-scFv (high degree of valency), scale bar: 200 nm. Transwell migration assay performed with (C) RAW 264.7 murine macrophages (D) and MDA-MB-231 breast cancer cells. Experiments were performed in triplicate at 88.9 nM. Data are represented as mean±sd, *p&lt;0.05, **p&lt;0.01, ***p&lt;0.001 with one-way ANOVA followed by Dunnett&#39;s post-test. 
         FIG. 5 . Effect of free, monomeric 58C-scFv on macrophage polarization. iNOS and IL-6 were used as M1 markers and Arg-1 an Mgl2 were used as M2 markers. Raw 264.7 macrophages treated with (A) LPS, (B), 58C-scFv, (C), IL-4, and (D) 58C-scFv+Il4. In A-C the genes values were normalized to the untreated control, where D was normalized to the IL-4 only control. (E) Schematics of macrophage polarization. (F) Ratios of M1/M2 marker genes across different conditions normalized to untreated control. Data are represented as mean±sd, *p&lt;0.05, **p&lt;0.01, ***p&lt;0.001 with one-way ANOVA followed by Dunnett&#39;s post-test. 
         FIG. 6 . Effect of free, monomeric 58C-scFv and multivalent 58C-scFv on macrophage polarization. (A) Multivalent 58C-scFv induces a stronger M1 phenotype than monomeric, free 58C-scFv. (B,C,D,E) The ratios of the M1 markers (IL-6 and iNOS) and M2 markers (Arg-1 and Mgl2) were used to compare the different conditions (M1/M2 ratio). From left to right: 58C-scFv monomers; 58C-scFv displayed on liposomes with increasing ligand density: low ligand density, medium ligand density, and high ligand density. The dose was normalized to the 58C-scFv concentration. The M1/M2 ratio was normalized to the free, monomeric 58C-scFv. Liposome only control was not statistically significant from the untreated control (Supplemental  FIG. 5 ). Data are represented as mean±sd, *p&lt;0.05, **p&lt;0.01, ***p&lt;0.001 with one-way ANOVA followed by Dunnett&#39;s post-test. 
         FIG. 7 . Schematic of multivalent targeting against CCR2 receptors and the observed effects on cellular migration and macrophage polarization. Multivalent display of 58C-scFv enhanced inhibition of cellular migration and increased M1 polarization of macrophages compared to monomeric, free 58C-scFv. 
         FIG. 8 . Commercially available anti-mouse APC-conjugated CCR2-antibody (#FAB5538A, R&amp;D, Minneapolis, Minn.) was used to detect CCR2 expression in (A) RAW 264.7 murine macrophages (red line). Commercially available anti-human APC-conjugated CCR2-antibody (#357208, BioLegend, San Diego, Calif.) was used to detect CRR2 expression in (B) MDA-MB-231 cells (red line). Binding of the APC-labeled antibodies to the respective cells were analyzed by flow cytometry. 
         FIG. 9 . Effect of monomeric 58C-scFv and a commercially available CCR2-targeted antibody (Clone #475301, R&amp;D, Minneapolis, Minn.) on cellular migration of RAW 264.7 murine macrophages. Data are represented as mean±sd (n=3), *p&lt;0.05, **p&lt;0.01, ***p&lt;0.001 with one-way ANOVA followed by Dunnett&#39;s post-test. 
         FIG. 10 . Effect of free, monomeric 58C-scFv, multivalent 58C-scFv, and liposome only control on cellular migration. Transwell migration assay performed with RAW 264.7 murine macrophages (A) and MDA-MB-231 breast cancer cells (B). Conditions were normalized to the control (non-treated cells). Data are represented as mean±sd (n=3), *p&lt;0.05, **p&lt;0.01, ***p&lt;0.001 with one-way ANOVA followed by Dunnett&#39;s post-test. Liposome only control was not significantly different from the non-treated control cells (n.s.). 58C-scFv (free and on liposomes) was used at a concentration of 88.9 nM. 
         FIG. 11 . Effect of free, monomeric 58C-scFv and two different commercially available CCR2-targeted antibodies (Clone #475301, R&amp;D, Minneapolis, Minn. and NBP1-48337, Novus, Littleton, Colo.) on macrophage polarization. The same molar concentration was used for all three antibodies. The ratios of the M1 markers (IL-6 and iNOS) and M2 markers (Arg-1 and Mgl2) were used to compare the different conditions (M1/M2 ratio). Data are presented as mean±sd, **p&lt;0.01, ***p&lt;0.001 with one-way ANOVA followed by Dunnett&#39;s post-test. 
         FIG. 12 . Effect of free, monomeric 58C-scFv, multivalent 58C-scFv, and liposome only control on macrophage polarization. (A,B,C,D). The ratios of the M1 markers (IL-6 and iNOS) and M2 markers (Arg-1 and Mgl2) were used to compare the different conditions (M1/M2 ratio). From left to right: Control, liposome with no 58C-scFv, 58C-scFv monomers; 58C-scFv displayed on liposomes with increasing ligand density: low ligand density, medium ligand density, and high ligand density. The dose was normalized to the 58C-scFv concentration. The M1/M2 ratio was normalized to the free, monomeric 58C-scFv. Liposome only control was not statistically significant (n.s.) from the untreated control (non-treated cells). Data are presented as mean±sd, **p&lt;0.01, ***p&lt;0.001 with one-way ANOVA followed by Dunnett&#39;s post-test. 
         FIG. 13 . Binding of monomeric 58C-scFv (circles), low valency 58C-scFv attached to liposomes (triangles), and high valency 58C-scFv attached to liposomes (squares) to RAW 264.7 macrophage cells as determined by flow cytometry. The binding affinities for this experiment were K D =1.272 μM for the 58C-scFv monomer, K D =278 nM for the low valency 58C-scFv attached to liposomes, and K D =159 nM for the high valency 58C-scFv attached to liposomes. This is an 8-fold increase in binding affinity from the free to high valency and about a 1.75-fold increase from the low to high valency formulation. The liposomes were incubated with DyLight 650 NHS Ester labeled 58C-scFv at 4° C. overnight. Cells were detached with 5 mM EDTA and re-suspended in PBS to a concentration of 50,000 cells per 300 μL. The cells were incubated with various dilutions of DyLight 650 NHS Ester labeled 58C-scFv (free, low degree of valency, or high degree of valency) for 1 h at 4° C. Cells were washed three times with 5% BSA and analyzed in the APC channel of a MACSQuant Analyzer 10 flow cytometer (Miltenyi Biotec, Bergisch Gladbach, Germany). 
         FIG. 14 . Representation of simultaneous targeting of multiple CCR2 domains (epitopes) for enhancing M1 macrophage polarization. 
         FIG. 15 . NTD-scFv (A) binds with high affinity to the N-terminal domain (NTD) of the CCR2 receptor. (B) Protein sequence of the NTD-scFv (SEQ ID NO:61; same as the sequence in SEQ ID NO:57 without the last S at the C-terminus). The framework regions (light (V L  FR) and heavy chains (V H  FR)) and complementarity determining regions (light (V L  CDR) and heavy chains (V H  CDR)) are highlighted. 
         FIG. 16 . ECL2-scFv binding to the ECL2 domain of the CCR2 chemokine receptor. (A,B) Binding affinity of the ECL2-scFv to the ECL2 domain is K D =5.3 nM±1.7 nM, (C) ECL2-scFv binds both to RAW 264.7 cells and 4T1 breast cancer cells as analyzed by flow cytometry and expressed as mean fluorescence intensity (MFI). 
         FIG. 17 . Simultaneous targeting and blocking of the NTD and ECL2 of the CCR2 chemokine receptor enhances M1 macrophage polarization by up to ˜30-fold (A). Data are represented as mean±sd, n=3 with ****p&lt;0.0001 by one-way Anova followed by Tukey&#39;s post-test. (B) In all M1/M2 ratios tested (iNOS/Arg-1, iNOS/Mgl2, IL-6/Arg-1, IL-6 Mgl2), simultaneous targeting of the NTD and the ECL2 domain led to synergistic enhancement of M1 macrophage polarization as compared to blocking only the NTD or the ECL2 domain in RAW 264.7 macrophages. (C) Combination indices for the combined effects of NTD-scFv and ECL2-scFv in RAW 264.7. (D) Isobolograms indicate synergistic effects of M1 macrophage polarization when bone marrow-derived macrophages (BMDM) were treated with a combination of NTD-scFv and ECL2-scFv (represented as the dots that are all below the isobole). The results in BMDMs showed similar trends to RAW 264.7 cells. 
         FIG. 18 . Proposed scFv combinations to be tested for synergistic, antagonistic, and additive effects on M1 macrophage polarization and cellular migration. Schematics showing dual, triple, and quadruple combinations of scFvs targeting different domains and extracellular loops of CCR2. Proposed combinations for evaluating the effects on inducing M1 macrophage polarization and the effects on inhibiting cellular migration. 
         FIG. 19 . Tumor size of BALB/C mice treated with unpegylated NTD-scFv (n=5) at a dose of 1.25 mg/kg is significantly smaller than the tumor size of mice treated with PBS (n=4). Arrows indicate time of dosing. Data are represented as mean±sd, **p&lt;0.01 by two-tailed Student&#39;s t-test. 
         FIG. 20 . Biodistribution of PEG(5K)-NTD-scFv and NTD-scFv (labeled with DyLight 650) in tumored BALB/C mice. (A,B) PEGylation enhances deposition of fluorescently labeled PEG(5K)-NTD-scFv compared to unmodified fluorescently labeled NTD-scFv. (C) In vivo biodistribution of NTD-scFv and PEG(5K)-NTD-scFv expressed as % injected dose (ID). Data are presented as mean±sd (n=3). N.D.=not detectable. 
         FIG. 21 . Phamacokinetic profile of PEG(40K)-NTD-scFv compared to unpegylated NTD-scFv in female Balb/c mice. Data are presented as mean±sd, n=3. 
         FIG. 22 . Homo and hetero tandem scFvs obtain bivalent targeting ligands (A,B). To optimize binding affinity linker length will vary (C). Pegylation will be used to enhance circulatory half-life and tumor deposition. 
         FIG. 23 . Synthesis of 4arm-PEG10K-scFvs, 4arm-PEG20K-scFvs, and 4arm-PEG40K-scFvs. 
         FIG. 24 . Single cell suspension from the harvested tumors following dual epitope blocking were analyzed by flow cytometry. The cells were stained for (A) CD68+ TAMs, (B) MDSCs, (C) MHC class II macrophages (M1), and (D) CD206+ macrophages (M2). Data is shown for TAMs, MDSCs, and M2-Macrophages and increased M1-Macrophages in triple-negative breast cancer (TNBCs). 
         FIG. 25 . Dual-epitope scFv combo treatment outperforms small molecule CCR2 antagonist (SMA) and decreases immunosuppressive CD4 + FoxP3 +  Tregs, and increases cytotoxic CD8+ and CD4+ T cells. Single cell suspension from the harvested tumors were analyzed by flow cytometry. The cells were stained for (A) Foxp3+/CD4+ Tregs, (B) CD4+ T cells, and (C) CD8+ T cells. Treatment groups included: PBS, CCR2-small molecule antagonist (SMA), PEG(20K)-ECL2-scFv, PEG(20K)-NTD-scFv, and NTD &amp; ECL2 combo, *p&lt;0.05, **p&lt;0.01, and ***p&lt;0.001 by one-way ANOVA followed by Tukey&#39;s post-test, NS=not significant. 
         FIG. 26 . Tumor sizes in BALB/C mice treated with PBS, CCR2-small molecule antagonist (SMA) at 2 mg/kg, PEG(20K)-NTD-scFv, PEG(20K)-ECL2-scFv, and PEG(20K)-NTD-scFv &amp; PEG(20K)-ECL2-svFv combo at 1 mg/kg; (n=10) (A, B). Black arrows indicate time of dosing. Data are represented as mean±sd, *p&lt;0.05 and ***p&lt;0.001 by one-way ANOVA followed by Tukey&#39;s post-test. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     Although claimed subject matter is described in terms of certain embodiments/examples, other embodiments/examples, including embodiments/examples that do not provide all of the benefits and features set forth herein, are also within the scope of this disclosure. Various structural, logical, and process step changes may be made without departing from the scope of the disclosure. 
     Ranges of values are disclosed herein. The ranges set out a lower limit value and an upper limit value. Unless otherwise stated, the ranges include all values to the magnitude of the smallest value (either lower limit value or upper limit value) and ranges between the values of the stated range. 
     Throughout this application, the singular form encompasses the plural and vice versa. All sections of this application, including any supplementary sections or figures, are fully a part of this application. 
     The term “treatment” as used herein refers to alleviation of one or more symptoms or features associated with the presence of the particular condition or suspected condition being treated. Treatment does not necessarily mean complete cure or remission, nor does it preclude recurrence or relapses. Treatment can be effected over a short term, over a medium term, or can be a long-term treatment, such as, within the context of a maintenance therapy. Treatment can be continuous or intermittent. 
     The term “therapeutically effective amount” as used herein refers to an amount of an agent sufficient to achieve, in a single or multiple doses, the intended purpose of treatment. The exact amount desired or required will vary depending on the particular compound or composition used, its mode of administration, patient specifics and the like. Appropriate effective amount can be determined by one of ordinary skill in the art informed by the instant disclosure using only routine experimentation. 
     This disclosure provides single chain variable fragment (scFv) antibodies, vectors or cells comprising nucleic acids encoding scFvs, all nucleotide sequences encoding the scFvs described herein, compositions comprising any of the foregoing, methods of making any of the foregoing, and methods of using the scFvs or nucleic acid molecules in the treatment of conditions involving CCR2/CCL2 binding. This disclosure includes all amino acid sequences described herein and all contiguous segments thereof that are 3-25 amino acids in length, inclusive, and including all integers and ranges of integers there between. In embodiments, each CDR amino acid sequence of each antibody of this disclosure is included as a distinct sequence. 
     While specific sequences are listed in this disclosure, it will be appreciated that amino acid changes/substitutions may be made in the sequences without affecting the function/activity. such, sequences which are 85%, 90%, 95%, 96%, 97%, 98% and 99% identical to the sequences disclosed herein or to the nucleotide sequences encoding the amino acid sequences disclosed herein are considered to be part of the disclosure. 
     The ECL2 of CCR2 can be represented by the sequence 
     
       
         
           
               
               
            
               
                   
                 (SEQ ID NO: 60) 
               
               
                   
                 TKCQKEDSVYVCGPYFPRGWNNFHTIMR. 
               
            
           
         
       
     
     In an embodiment the scFv antibodies of the present disclosure comprise the following sequences: 
     Examples of scFv sequences against the N-terminal domain: 
     
       
         
           
               
            
               
                 13F-scFv: 
               
               
                 (SEQ ID NO: 1) 
               
               
                 MKKTAIAIAVALAGFATVAQADYKDDDDKLQAVLTQPSSLSASPGASASLT 
               
               
                   
               
               
                 CILRSDFSVVTQRVYWYQQKPGSPPRYLLRYNSDSDKRLGSGVPSRFSGSK 
               
               
                   
               
               
                 DVSANAASLLISGLQSDDEADYYCVIWHNSAVVFGGGTKLTVLGEGKSSGS 
               
               
                   
               
               
                 GSESKASEVQLLESGAEVKKPGESLKISCKGSGYSFTSYWIGWVRQMPGKG 
               
               
                   
               
               
                 LEWMGIIYPGDSDTRYSPSFQGQVTISADKSISTAYLQWSSLKASDTAMYY 
               
               
                   
               
               
                 CARRPQYYDILTGWHAGWFDPWGQGTLVTVSSVEASAAALDYKDDDDKLDH 
               
               
                   
               
               
                 HHHHH 
               
               
                   
               
               
                 25B-scFv: 
               
               
                 (SEQ ID NO: 2) 
               
               
                 MKKTAIAIAVALAGFATVAQADYKDDDDKLQSVLTQPPSVSGAPGQKVTIS 
               
               
                   
               
               
                 CSGSSSNIGNNYVSWYQQLPGTAPKLLIYGNNKRPSGIPDRFSGSKSGTSA 
               
               
                   
               
               
                 TLGITGLQTGDEADYYCATWDDSLSAVVFGGGTKLTVLGEGKSSGSGSESK 
               
               
                   
               
               
                 ASQVTLKESGAEVKKPGASVKVSCKASGYTFTNFYIHWVRRAPGQGLEWMG 
               
               
                   
               
               
                 IINPSDGRTTYAQKFQGRVTMTRDTSTSTLYMELTSLRSEDTAVYYCGRGG 
               
               
                   
               
               
                 HYSNYFGQPSTWGQGTLVTVSSVEASAAALDYKDDDDKLDHHHHHH 
               
               
                   
               
               
                 26B-scFv: 
               
               
                 (SEQ ID NO: 3) 
               
               
                 MKKTAIAIAVALAGFATVAQADYKDDDDKLQSVLTQPPSASGTPGQRVTIS 
               
               
                   
               
               
                 CSGSSSNIGSNYVYWYQQLPGTAPKLLIYRNNQRPSGVPDRFSGSKSGTSA 
               
               
                   
               
               
                 SLAISGLQSEDEADYYCAAWDDSLNGVVFGGGTELTVLGEGKSSGSGSESK 
               
               
                   
               
               
                 ASQVTLKESGAEVKKPGASVKVSCKASGYTFTNFYIHWVRRAPGQGLEWMG 
               
               
                   
               
               
                 IINPSDGRTTYAQKFQGRVTMTRDTSTSTLYMELTSLRSEDTAVYYCGRGG 
               
               
                   
               
               
                 HYSNYFGQPSTWGQGTLVTVSSVEASAAALDYKDDDDKLDHHHHHH 
               
               
                   
               
               
                 37B-scFv: 
               
               
                 (SEQ ID NO: 4) 
               
               
                 MKKTAIAIAVALAGFATVAQADYKDDDDKLEVQLVESGAEVKKPGASVKVS 
               
               
                   
               
               
                 CKASGYTFTSYYMHWVRQAPGQGLEWMGIINPSGGSTSYAQKFQGRVTMTR 
               
               
                   
               
               
                 DTSTSTVYMELSSLRSEDTAVYYCARDGNWFDPWGQGTLVTVSSGEGKSSG 
               
               
                   
               
               
                 SGSESKASEIVMTQSPGTLSLSPGERATLSCRASQSVSSSYLAWYQQKPGQ 
               
               
                   
               
               
                 APRLLIYGASSRATGIPDRFSGSGSGTDFTLTISRLEPEDFAVYYCQQYGS 
               
               
                   
               
               
                 SPPLTFGGGTKLDIKVEASAAALDYKDDDDKLDHHHHHH 
               
               
                   
               
               
                 58C-scFv: 
               
               
                 (SEQ ID NO: 5) 
               
               
                 MKKTAIAIAVALAGFATVAQADYKDDDDKLEIVLTQSPGTLSLSPGERATL 
               
               
                   
               
               
                 SCRASQSVSSSYLAWYQQKPGQAPRLLIYGASSRATGIPDRFSGSGSGTDF 
               
               
                   
               
               
                 TLTISRLEPEDFAVYYCQQYGSSLTFGGGTKVEIKEGKSSGSGSESKASEV 
               
               
                   
               
               
                 QLLESGAEVKKPGASVKVSCKTSGYTFTTYDIYWMRLATGQRLEWMGWVNP 
               
               
                   
               
               
                 DNGKTDYAQKFQGRVTISRDSSINTVFMELSNLRLEDTAIYFCARALTRWQ 
               
               
                   
               
               
                 QSPLGYWGQGTLVTVSSVEASAAALDYKDDDDKLDHHHHHH 
               
            
           
         
       
     
     Examples of scFv sequences against the 2 nd  extracellular loop (ECL2) of CCR2 
     
       
         
           
               
            
               
                 4h-scFv: 
               
               
                 (SEQ ID NO: 6) 
               
               
                 MKKTAIAIAVALAGFATVAQADYKDDDDKLQSVLTQPPSASGTPGQRVTIS 
               
               
                   
               
               
                 CSGSSSNIGSHTVNWYQQLPGTAPKLLIYRNNQRPSGVPDRFSGSKSGTSA 
               
               
                   
               
               
                 SLAISGLRSEDEADYYCAAWDDSLSGVVFGGGTKLTVLGEGKSSGSGSESK 
               
               
                   
               
               
                 ASQVTLKESGAEVKKPGASVKVSCKASGYTFTNFYIHWVRRAPGQGLEWMG 
               
               
                   
               
               
                 IINPSDGRTTYAQKFQGRVTMTRDTSTSTLYMELTSLRSEDTAVYYCGRGG 
               
               
                   
               
               
                 HYSNYFGQPSTWGQGTLVTVSSVEAS 
               
               
                   
               
               
                 11b-scFv: 
               
               
                 (SEQ ID NO: 7) 
               
               
                 MKKTAIAIAVALAGFATVAQADYKDDDDKLQPVLTQPSSASGTPGQRVTIS 
               
               
                   
               
               
                 CSGSSSNIGSNYVYWYQQLPGTAPKLLIYRNNQRPSGVPDRFSGSKSGTSA 
               
               
                   
               
               
                 SLAISGLQSEDEADYYCAAWDDTLIGPVFGGGTKLTVLGEGKSSGSGSESK 
               
               
                   
               
               
                 ASEVQLVESGGGLVKPGGSLTLSCAVSGFPFSDAWMNWVRQAPGKGLEWVG 
               
               
                   
               
               
                 RIRSKAGGGTTDSAAPVKDRFTFSGDDSKNTVYVEMNSLKIEDTAVYYCTG 
               
               
                   
               
               
                 EGYWGQGTLVTVSSVEAS 
               
            
           
         
       
     
     In embodiments, the scFvs may have sequences that lack the poly histidine sequence, signaling sequences, cleavage sequences, targeting sequences, or other non-CDR sequences. Examples of shortened versions of scFvs are listed below. 
     Examples of scFv sequences against the N-terminal domain: 
     
       
         
           
               
            
               
                 Shortened version of 13F-scFv: 
               
               
                 (SEQ ID NO: 53) 
               
               
                 LQAVLTQPSSLSASPGASASLTCILRSDFSVVTQRVYWYQQKPGSPPRYLL 
               
               
                   
               
               
                 RYNSDSDKRLGSGVPSRFSGSKDVSANAASLLISGLQSDDEADYYCVIWHN 
               
               
                   
               
               
                 SAVVFGGGTKLTVLGEGKSSGSGSESKASEVQLLESGAEVKKPGESLKISC 
               
               
                   
               
               
                 KGSGYSFTSYWIGWVRQMPGKGLEWMGIIYPGDSDTRYSPSFQGQVTISAD 
               
               
                   
               
               
                 KSISTAYLQWSSLKASDTAMYYCARRPQYYDILTGWHAGWFDPWGQGTLVT 
               
               
                   
               
               
                 VSS 
               
               
                   
               
               
                 Shortened version of 25B-scFv: 
               
               
                 (SEQ ID NO: 54) 
               
               
                 LQSVLTQPPSVSGAPGQKVTISCSGSSSNIGNNYVSWYQQLPGTAPKLLIY 
               
               
                   
               
               
                 GNNKRPSGIPDRFSGSKSGTSATLGITGLQTGDEADYYCATWDDSLSAVVF 
               
               
                   
               
               
                 GGGTKLTVLGEGKSSGSGSESKASQVTLKESGAEVKKPGASVKVSCKASGY 
               
               
                   
               
               
                 TFTNFYIHWVRRAPGQGLEWMGIINPSDGRTTYAQKFQGRVTMTRDTSTST 
               
               
                   
               
               
                 LYMELTSLRSEDTAVYYCGRGGHYSNYFGQPSTWGQGTLVTVSS 
               
               
                   
               
               
                 Shortened version of 26B-scFv: 
               
               
                 (SEQ ID NO: 55) 
               
               
                 LQSVLTQPPSASGTPGQRVTISCSGSSSNIGSNYVYWYQQLPGTAPKLLIY 
               
               
                   
               
               
                 RNNQRPSGVPDRFSGSKSGTSASLAISGLQSEDEADYYCAAWDDSLNGVVF 
               
               
                   
               
               
                 GGGTELTVLGEGKSSGSGSESKASQVTLKESGAEVKKPGASVKVSCKASGY 
               
               
                   
               
               
                 TFTNFYIHWVRRAPGQGLEWMGIINPSDGRTTYAQKFQGRVTMTRDTSTST 
               
               
                   
               
               
                 LYMELTSLRSEDTAVYYCGRGGHYSNYFGQPSTWGQGTLVTVSS 
               
               
                   
               
               
                 Shortened version of 37B-scFv: 
               
               
                 (SEQ ID NO: 56) 
               
               
                 LEVQLVESGAEVKKPGASVKVSCKASGYTFTSYYMHWVRQAPGQGLEWMGI 
               
               
                   
               
               
                 INPSGGSTSYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCARDGN 
               
               
                   
               
               
                 WFDPWGQGTLVTVSSGEGKSSGSGSESKASEIVMTQSPGTLSLSPGERATL 
               
               
                   
               
               
                 SCRASQSVSSSYLAWYQQKPGQAPRLLIYGASSRATGIPDRFSGSGSGTDF 
               
               
                   
               
               
                 TLTISRLEPEDFAVYYCQQYGSSPPLTFGGGTKLDIK 
               
               
                   
               
               
                 Shortened version of 58C-scFv: 
               
               
                 (SEQ ID NO: 57) 
               
               
                 LEIVLTQSPGTLSLSPGERATLSCRASQSVSSSYLAWYQQKPGQAPRLLIY 
               
               
                   
               
               
                 GASSRATGIPDRFSGSGSGTDFTLTISRLEPEDFAVYYCQQYGSSLTFGGG 
               
               
                   
               
               
                 TKVEIKEGKSSGSGSESKASEVQLLESGAEVKKPGASVKVSCKTSGYTFTT 
               
               
                   
               
               
                 YDIYWMRLATGQRLEWMGWVNPDNGKTDYAQKFQGRVTISRDSSINTVFME 
               
               
                   
               
               
                 LSNLRLEDTAIYFCARALTRWQQSPLGYWGQGTLVTVSS. 
               
            
           
         
       
     
     An antibody of this disclosure can be a monoclonal antibody comprising a heavy chain variable region (VH) and a light chain variable region (VL) comprising complementarity-determining regions (CDRs) 1-3 and having sequences set forth in  FIG. 1B . In  FIG. 1B  the sequences for the CDRs for the NTD scFvs and the ECL2 scFvs are the non-grayed regions underneath the appropriate heading label. The sequence for each labeled CDR region in the alignment is denoted by a line directly above the corresponding sequences. For example, the sequence for CDRL1 in 13F-scFv is ILRSDFSVVTQRVY (SEQ ID NO:8), and the sequence for CDRH1 in 58C-scFv is TYDIY (SEQ ID NO:9). 
     An antibody in this disclosure can be a scFv directed to the N-terminal domain (NTD) of CCR2 comprising a heavy chain variable region (VH) comprising 3 complementarity determining regions (CDRs) having sequences set forth in  FIG. 1 , and a light chain variable region comprising 3 CDRs having sequences set forth in  FIG. 1 . 
     An antibody in this disclosure can be a scFv directed to the ECL domains 1, 2, or 3 of CCR2 comprising a heavy chain variable region (VH) comprising 3 complementarity determining regions (CDRs) and a light chain variable region (VL) comprising 3 CDRs with the sequences for the scFv that binds the ECL2 domain described in SEQ ID NO:6 or 7 and also  FIG. 1 . 
     In an embodiment, this disclosure provides an antibody, such as an scFv, referred to herein as 13F comprising a variable light chain (VL) and a variable heavy chain (VH), wherein the VL comprises CDRL1, denoted by the sequence ILRSDFSVVTQRVY (SEQ ID NO:8); CDRL2, denoted by the sequence NSDSDKRLGS (SEQ ID NO:22); and CDRL3, denoted by the sequence VIWHNSAVV (SEQ ID NO:23); and the VH comprises CDRH1, denoted by the sequence SYWIG (SEQ ID NO:24); CDRH2, denoted by the sequence IIYPGDSDTRYSPSFQG (SEQ ID NO:25); and CDRH3, denoted by the sequence RPQYYDILTGWHAG (SEQ ID NO:26), wherein the antibody is specific for the N-terminal domain of CCR2. 
     In an embodiment, the antibody, such as a scFv, comprises the sequence of SEQ ID NO:1, or a sequence that is at least 80, 85, 90, 95, 98 or 99% identical to SEQ ID NO:1, and is specific for the N-terminal domain of CCR2. 
     In an embodiment, the antibody, such as a scFv, comprises the sequence of SEQ ID NO:53, or a sequence that is at least 80, 85, 90, 95, 98 or 99% identical to SEQ ID NO:53, and is specific for the N-terminal domain of CCR2. 
     In an embodiment, this disclosure provides an antibody, such as an scFv referred to herein as 25B, comprising a variable light chain (VL) and a variable heavy chain (VH), wherein the VL comprises CDRL1, denoted by the sequence SGSSSNIGNNYVS (SEQ ID NO:27); CDRL2, denoted by the sequence GNNKRPS (SEQ ID NO:28); CDRL3, denoted by the sequence ATWDDSLSAVV (SEQ ID NO:29); and the VH comprises CDRH1, denoted by the sequence NFYIH (SEQ ID NO:30); CDRH2, denoted by the sequence IINPSDGRTTYAQKFQG (SEQ ID NO:31); and CDRH3, denoted by the sequence GGHYSNYFGQ (SEQ ID NO:32), and wherein the antibody is specific for the N-terminal domain of CCR2. 
     In an embodiment, the antibody, such as a scFv, comprises the sequence of SEQ ID NO:2, or a sequence that is at least 80, 85, 90, 95, 98 or 99% identical to SEQ ID NO:2, and is specific for the N-terminal domain of CCR2. 
     In an embodiment, the antibody, such as a scFv, comprises the sequence of SEQ ID NO:54, or a sequence that is at least 80, 85, 90, 95, 98 or 99% identical to SEQ ID NO:54, and is specific for the N-terminal domain of CCR2. 
     In an embodiment, this disclosure provides an antibody, such as an scFv referred to herein as 26B, comprising a variable light chain (VL) and a variable heavy chain (VH), wherein the VL comprises CDRL1, denoted by the sequence SGSSSNIGSNYVY (SEQ ID NO:33); CDRL2, denoted by the sequence RNNQRPS (SEQ ID NO:34); CDRL3, denoted by the sequence AAWDDSLNGVV (SEQ ID NO:35); and VH comprises CDRH1, denoted by the sequence NFYIH-1 (SEQ ID NO:30); CDRH2, denoted by the sequence IINPSDGRTTYAQKFQG (SEQ ID NO:31); and CDRH3, denoted by the sequence GGHYSNYFGQ (SEQ ID NO:32) and wherein the antibody is specific for the N-terminal domain of CCR2. 
     In an embodiment, the antibody, such as a scFv, comprises the sequence of SEQ ID NO:3, or a sequence that is at least 80, 85, 90, 95, 98 or 99% identical to SEQ ID NO:3, and is specific for the N-terminal domain of CCR2. 
     In an embodiment, the antibody, such as a scFv, comprises the sequence of SEQ ID NO:55, or a sequence that is at least 80, 85, 90, 95, 98 or 99% identical to SEQ ID NO:55, and is specific for the N-terminal domain of CCR2. 
     In an embodiment, this disclosure provides an antibody, such as an scFv referred to herein as 37B, comprising a variable light chain (VL) and a variable heavy chain (VH), wherein the VL comprises CDRL1, denoted by the sequence KASGYTFTSYYMH (SEQ ID NO:36); CDRL2, denoted by the sequence NPSGGST (SEQ ID NO:37); CDRL3, denoted by the sequence ARDGNWFDP (SEQ ID NO:38); and wherein CDRH1, denoted by the sequence SSYLA (SEQ ID NO:39); CDRH2, denoted by the sequence IYGASSRATGIPDRFSG (SEQ ID NO:40); and CDRH3, denoted by the sequence QYGSS (SEQ ID NO:41) and wherein the antibody is specific for the N-terminal domain of CCR2. 
     In an embodiment, the antibody, such as a scFv, comprises the sequence of SEQ ID NO:4, or a sequence that is at least 80, 85, 90, 95, 98 or 99% identical to SEQ ID NO:4, and is specific for the N-terminal domain of CCR2. 
     In an embodiment, the antibody, such as a scFv, comprises the sequence of SEQ ID NO:56, or a sequence that is at least 80, 85, 90, 95, 98 or 99% identical to SEQ ID NO:56, and is specific for the N-terminal domain of CCR2. 
     In an embodiment, this disclosure provides an antibody, such as an scFv referred to herein as 58C, comprising a variable light chain (VL) and a variable heavy chain (VH), wherein the VL comprises CDRL1, denoted by the sequence RASQSVSSSYLA (SEQ ID NO:42); CDRL2, denoted by the sequence GASSRAT (SEQ ID NO:43); CDRL3, denoted by the sequence QQYGSSLT (SEQ ID NO:44); and wherein VH comprises CDRH1, denoted by the sequence TYDIY (SEQ ID NO:9); CDRH2, denoted by the sequence WVNPDNGKTDYAQKFQG (SEQ ID NO:45); and CDRH3, denoted by the sequence ALTRWQQS (SEQ ID NO:46) and wherein the antibody is specific for the N-terminal domain of CCR2. 
     In an embodiment, the antibody, such as a scFv, comprises the sequence of SEQ ID NO:5, or a sequence that is at least 80, 85, 90, 95, 98 or 99% identical to SEQ ID NO:5, and is specific for the N-terminal domain of CCR2. 
     In an embodiment, the antibody, such as a scFv, comprises the sequence of SEQ ID NO:57, or a sequence that is at least 80, 85, 90, 95, 98 or 99% identical to SEQ ID NO:57, and is specific for the N-terminal domain of CCR2. 
     In an embodiment, this disclosure provides an antibody, such as an scFv referred to herein as 4h, comprising a variable light chain (VL) and a variable heavy chain (VH), wherein the VL comprises CDRL1, denoted by the sequence SGSSSNIGSHTVN (SEQ ID NO:47); CDRL2, denoted by the sequence RNNQRPS (SEQ ID NO:34); CDRL3, denoted by the sequence AAWDDSLSGVV (SEQ ID NO:48); and wherein CDRH1, denoted by the sequence NFYIH (SEQ ID NO:30); CDRH2, denoted by the sequence IINPSDGRTTYAQKFQG (SEQ ID NO:31); and CDRH3, denoted by the sequence GGHYSNYFGQPST (SEQ ID NO:49), and wherein the antibody is specific for the extracellular loop 2 domain of CCR2. 
     In an embodiment, the antibody, such as a scFv, comprises the sequence of SEQ ID NO:6, or a sequence that is at least 80, 85, 90, 95, 98 or 99% identical to SEQ ID NO:6, and is specific for the extracellular loop 2 domain of CCR2. 
     In an embodiment, this disclosure provides an antibody, such as an scFv referred to herein as 11b, comprising a variable light chain (VL) and a variable heavy chain (VH), wherein the VL comprises CDRL1, denoted by the sequence SGSSSNIGSNYVY (SEQ ID NO:33); CDRL2, denoted by the sequence RNNQRPS (SEQ ID NO:34); CDRL3, denoted by the sequence AAWDDTLIGPV (SEQ ID NO:50); and wherein the VH comprises CDRH1, denoted by the sequence DAWMN (SEQ ID NO:51); CDRH2, denoted by the sequence RIRSKAGGGTTDSAAPVKD (SEQ ID NO:52); and CDRH3, denoted by the sequence EGY, and wherein the antibody is specific for the extracellular loop 2 domain of CCR2. 
     In an embodiment, the antibody, such as a scFv, comprises the sequence of SEQ ID NO:7, or a sequence that is at least 80, 85, 90, 95, 98 or 99% identical to SEQ ID NO:7, and is specific for the extracellular loop 2 domain of CCR2. 
     The terms “antibody” as used herein can encompass whole antibody molecules, full-length immunoglobulin molecules, such as naturally occurring full-length immunoglobulin molecules or full-length immunoglobulin molecules formed by immunoglobulin gene fragment recombinatorial processes, as well as antibody fragments including scFvs. Antibody fragments can be fragments comprising at least one antibody-antigen binding site. Antibody fragments can, for example, exhibit specific binding to CCR2 or fragments thereof. 
     The term “antibody” can include e.g. monoclonal, polyclonal, multispecific (for example bispecific), recombinant, human, chimeric and humanized antibodies. The term “antibody” can also encompass recombinantly expressed antigen binding proteins and antigen binding synthetic peptides. Further, the term “antibody” can encompass minibodies, and diabodies, all of which preferably exhibit specific binding to CCR2 or a fragment thereof, especially human CCR2. The term “antibody”, as used herein, can also encompass antibodies produced in vivo, as well as those produced in vitro, such as, for example, by a bacterial expression system or a mammalian hybridoma cell line. 
     An antibody of the present disclosure may be modified by, for example, acetylation, formylation, amidation, phosphorylation, or polyethylene glycolation (PEGylation), as well as glycosylation. The term “an antibody” as used herein is intended to cover all antibodies disclosed herein. For example, the term “an antibody” can refer to monoclonal, polyclonal, scFv, chimeric, human, or humanized antibodies, or antigen (i.e., CCR2) binding fragments thereof. 
     In an embodiment, anti-CCR2 scFvs are PEGylated to increase half-life and bioavailability. Various types of PEG molecules can be added to the scFvs, including but not limited to PEG(5K), PEG(10K), PEG(20K), and PEG(40K). The scFvs can be modified by the addition of a cysteine, lysine or serine amino acid to facilitate PEGylation. This modification can occur at, but is not limited to, the C-terminus of the scFv. 
     The antibodies of the disclosure may be whole immunoglobulin molecules such as polyclonal or monoclonal antibodies or may be antigen-binding fragments thereof, including but not limited to, Fab, F(ab′), F(ab′)2, Fv, dAb, Fd, CDR fragments, single-chain variable fragment antibodies (scFv), bivalent single-chain antibodies, single-chain phage antibodies, diabodies, nanobodies and the like. The fragments of the antibodies may be produced synthetically or by enzymatic or chemical cleavage of intact immunoglobulins or may be genetically engineered by recombinant DNA techniques. These techniques are well known in the art. 
     In one embodiment, this disclosure provides isolated antibodies. By the term “isolated” it is meant that the antibody or the fragment thereof, is separated and/or recovered from its natural environment. The isolation of the antibody from its natural environment can be such that the antibody can be used without interference from other active agents (such as other proteins) that normally are present in its natural environment. 
     “Fv” is the minimum antibody fragment that contains a complete antigen-recognition and -binding site and single-chain Fv also abbreviated as “sFv” or “scFv” are antibody fragments that comprise the VH and VL antibody domains connected into a single polypeptide chain. The term “diabodies” refers to small antibody fragments prepared by constructing sFv fragments with short linkers between the VH and VL domains such that inter-chain but not intra-chain pairing of the V domains is achieved, resulting in a bivalent fragment, i.e., fragment having two antigen-binding sites. A single domain antibody (sdAb) is an antibody fragment which has a single monomeric variable antibody domain. ScAbs can be made from heavy-chain antibodies found in camelids. An antibody fragment can be a single variable region or a peptide consisting of or comprising a single CDR. A single-chain antibody has a heavy chain variable domain and a light chain variable domain linearly linked to each other via a linker. A polynucleotide (such as DNA) encoding the single-chain antibody can be produced by binding a polynucleotide encoding the heavy chain variable domain, a polynucleotide encoding the linker (typically 10-20 nucleotides), and a polynucleotide encoding the light chain variable domain, with the heavy chain variable domain and the light chain variable domain being both derived from a human antibody. 
     As an example, this disclosure provides scFv antibodies, which can be isolated scFv antibodies, which specifically bind to CCR2, which can be human CCR2. As an example, scFvs designated 58C-scFv and 11b-scFv are provided. Specifically, 58C-scFv binds to the NTD of CCR2 whereas 11b-scFv binds to the ECL2 domain of CCR2. 
     The present disclosure also provides isolated nucleotide sequences encoding all or portions of the amino acid sequences disclosed herein. For example, the present disclosure provides an isolated nucleic acid molecule comprising the sequences of the CDRs, such as CDRL1, CDRL2, CDRL3, CDRH1, CDRH2, CDRH3 for the various scFvs disclosed herein. In an embodiment, the present disclosure also provides isolated nucleic acid molecules comprising or consisting of the sequence encoding one or more CDRs that recognize a NTD or ECL2 domain of CCR2. The disclosure also provides cells comprising an expression vector or other polynucleotide sequence encoding the antibodies provided herein (including scFvs). Nucleotide sequences encoding the scFvs can be expressed using any suitable expression vector, many of which are known in the art and/or are commercially available. A vector generally includes nucleic acid sequences, such as origin or replication that enables it to replicate in a host cell. A vector can also include selectable marker genes. 
     This disclosure provides compositions comprising anti-CCR2 scFvs loaded onto liposomes. Standard approaches for ligand attachment to aqueous liposome nanoparticles make use of maleimides, succinimidyl esters and carbodiimide-activated carboxylic acids. These can covalently react with amine and thiol groups of polypeptides. The use of maleimide-lipids has been explored extensively for antibody-conjugated liposomes. Conjugation yields may reach as high as 90% from an overnight reaction, but subsequent quenching of free maleimide groups and additional purification is required. Proteins may require a preparative step of thiolation and purification prior to conjugation. Antibody orientation is a major factor influencing the conjugated antibody target binding efficacy, but these approaches result in numerous antibody labeling sites and indiscriminate orientations. Biorthogonal synthetic strategies such as the click reaction have recently been applied to pre-formed liposomes, however these require the use exogenous catalysts and unconventional amino acids. 
     The liposomes in the present disclosure may be spherical or non-spherical. The size of the liposomes can be from 50 to 1000 nm or more. In one embodiment, the liposomes have a size (e.g., a longest dimension such as, for example, a diameter) of 50 to 1000 nm, including all integer nm values and ranges therebetween. For example, the size may be from 50 to 200 nm or from 20 to 1000 nm. If the liposomes are not spherical, the longest dimension can be from 50 to 1000 nm. These dimensions can be achieved while preserving the nanostructure width of the monolayer or the bilayer. The liposomes can carry cargo in the aqueous compartment. The cargo, or part thereof, can also, or alternatively, be incorporated in the monolayer or the bilayer. 
     In one embodiment, this disclosure provides liposomes comprising: a monolayer or a bilayer, wherein the monolayer or bilayer comprises anti-CCR2 scFv lipid conjugates, optionally phospholipids that are not conjugated to anti-CCR2 scFvs, and a polyhistidine-tagged presentation molecule, wherein the polyhistidine tag is linked to the scFv in the hydrophobic portion of the monolayer or the bilayer and one or more histidines of the polyhistidine tag are coordinated to nickel atoms attached to the lipids in the lipid monolayer or bilayer of the liposomes. 
     In an embodiment, anti-CCR2 scFvs are His-tagged and loaded on to liposomes containing lipids in the monolayer or bilayer that are bound with nickel as described in Example 1. Additionally scFvs can be conjugated to maleimide lipids for further downstream applications as described in Example 2 of this disclosure. 
     Reactivity of antibodies toward specific antigens, such as CCR2, can be measured by routine methods such as, for example, ELISA. Reactivity is an indication of the binding affinity. Binding affinity can also be measured by antigen/antibody dissociation rates or competition radioimmunoassays and the like. Specific binding of an antibody to an antigen means it binds the antigen with high affinity and does not specifically bind to unrelated antigens. 
     This disclosure provides compositions and methods for inhibiting cellular migration by blocking binding of CCL2 to CCR2. Monocytes and macrophages express CCR2 and migrate in response to CCL2 serving as a chemoattractant. In an example, the anti-CCR2 scFvs described in this disclosure specifically block macrophage migration toward a CCL2 chemotaxis gradient. In another example, the anti-CCR2 scFvs described in this disclosure block cancer cell migration, such as breast cancer cell migration. 
     This disclosure provides methods and compositions for inhibiting macrophage polarization. In an example, the scFvs described in this disclosure that target the N-terminal domain and ECL2 significantly promotes M1 macrophage polarization while inhibiting M2 macrophage polarization. This type of response is desirable in an anti-cancer setting as M1 macrophages suppress tumor growth whereas M2 macrophages promote tumor growth. 
     In an embodiment, this disclosure provides a method for inhibiting cellular migration or inhibiting macrophage polarization by blocking binding of CCL2 to CCR2 comprising contacting the cells with an effective amount of one or more anti-CCR2 scFvs. The antibody may be an antibody directed to the N-terminal domain of CCR2 or to ECL1, ECL2 or ECL3 or combinations thereof. Examples of scFvs directed against the N-terminal domain of CCR2 include 13F, 25B, 26B, 37B and 58C, and examples of scFvs directed against the ECL2 include 4h and 11b. In an embodiment, the method comprises contacting the cell with a scFv directed to the N-terminal domain of CCR2 and a scFv directed against the ECL2 of CCR2. Any of the scFvs specific for the N-terminal domain including 13F, 25B, 26B, 37B and 58C, and any of the scFvs specific for ECL2 of CCR2, including 4h and 11b may be used. In an embodiment, a combination of 58C and 4h is used. 
     When reference is made to any of the scFvs in this disclosure, then it includes the shortened version of the scFvs also. 
     In an aspect, the present disclosure also provides a pharmaceutical composition comprising a pharmaceutically acceptable carrier and one or more scFvs of the present disclosure. Examples of carriers include solutions, suspensions, emulsions, solid injectable compositions that are dissolved or suspended in a solvent before use, and the like. The injections may be prepared by dissolving, suspending or emulsifying one or more of the active ingredients in a diluent. Examples of diluents, include, but are not limited to distilled water for injection, physiological saline, vegetable oil, alcohol, dimethyl sulfoxide, and a combination thereof. Further, the injections may contain stabilizers, solubilizers, suspending agents, emulsifiers, soothing agents, buffers, preservatives, etc. The injections may be sterilized in the final formulation step or prepared by sterile procedure. The composition of the disclosure may also be formulated into a sterile solid preparation, for example, by freeze-drying, and can be used after sterilized or dissolved in sterile injectable water or other sterile diluent(s) immediately before use. Additional examples of pharmaceutically include, but are not limited to, sugars, such as lactose, glucose, and sucrose; starches, such as corn starch and potato starch; cellulose, including sodium carboxymethyl cellulose, ethyl cellulose, and cellulose acetate; powdered tragacanth; malt; gelatin; talc; excipients, such as cocoa butter and suppository waxes; oils, such as peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil, and soybean oil; glycols, such as propylene glycol; polyols, such as glycerin, sorbitol, mannitol, and polyethylene glycol; esters, such as ethyl oleate and ethyl laurate; agar; buffering agents, such as magnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen-free water; isotonic saline; Ringer&#39;s solution; ethyl alcohol; phosphate buffer solutions; and other non-toxic compatible substances employed in pharmaceutical formulations. Additional non-limiting examples of pharmaceutically acceptable carriers can be found in:  Remington: The Science and Practice of Pharmacy  (2005) 21 st Edition , Philadelphia, Pa. Lippincott Williams &amp; Wilkins. 
     The scFvs of the present disclosure, or a composition comprising one or more scFvs may be used to block CCR2 from binding CCL2. The activity may be altered in vitro or in vivo. As such, the present compositions may be administered to an individual who is exhibiting abnormal CCL2/CCR2 binding. Examples of conditions in which the present scFvs and compositions can be used is any condition in which CCL2/CCR2 binding is abnormal. Such conditions can include, but are not limited to, cancer and immune disorders. In an embodiment the method comprises administering to an individual in need of treatment (such as an individual who is exhibiting abnormal CCL2/CCR2 binding), one or more antibodies specific for the N-terminus of CCR2 and one or more antibodies specific for the ECL2. 
     In an aspect, the disclosure provides a method for treating an individual having or suspected of having cancer whose tumor sample has CCR2 expressing cells and/or CCL2 secreting cells. A sample from the individual&#39;s tumor (e.g., biopsy and/or blood sample) may be used to measure CCR2 and/or CCL2 levels. If the tumor is found to have elevated CCR2 and/or CCL2 levels, a suitable amount of the anti-CCR2 scFv therapy can be administered to the individual using a suitable route (e.g., intratumoral, intravenous, intradermal injection). The treatment may be carried out without first sampling CCR2 and/or CCL2 levels. In an embodiment, the individual may be administered one or more anti-CCR2 scFvs or a composition comprising one or more anti-CCR2 scFvs comprising or consisting of the sequences of SEQ ID NO:1-7. 
     The disclosure provides a method for treating tumors, such as tumors that comprise CCR2-expressing cells, for example tumor-associated macrophages (TAMs). Such tumors may be referred to herein as “CCR2-expressing tumors”. The term “treatment” refers to reduction in one or more symptoms or features associated with the presence of the particular condition being treated. Treatment does not necessarily mean complete remission, nor does it preclude recurrence or relapses. For example, the present disclosure provides a method for reducing the size of a tumor or arresting the growth of a tumor or reducing the rate of growth of a tumor (such as a tumor comprising CCR2-expressing cells and/or CCL2 secreting cells) or reducing any other symptom that is associated with an individual being afflicted with the tumor—all of which are considered as “treatment”—comprising administering to an individual in need of treatment, a therapeutically effective amount of a composition comprising antibodies, or fragments thereof as described herein. In one embodiment, the method of treatment is a method of passive immunization. 
     In an embodiment, this disclosure provides a method of reducing the growth of a tumor in an individual, such as a tumor comprising CCR2 expressing cells, comprising administering to the individual a therapeutically effective amount of one or more anti-CCR2 scFvs. The antibody may be an antibody directed to the N-terminal domain of CCR2 or to ECL1, ECL2 or ECL3 or combinations thereof. Examples of scFvs directed against the N-terminal domain of CCR2 include 13F, 25B, 26B, 37B and 58C, and examples of scFvs directed against the ECL2 include 4h and 11b. In an embodiment, the method comprises administering to the individual an scFv directed to the N-terminal domain of CCR2 and an antibody directed against the ECL2 of CCR2. Any of the scFvs specific for the N-terminal domain including 13F, 25B, 26B, 37B and 58C, and any of the scFvs specific for ECL2 of CCR2, including 4h and 11b may be used. In an embodiment the method comprises administering to an individual in need of treatment (such as an individual who has been diagnosed with a tumor), one or more antibodies specific against the N-terminus of CCR2 and one or more antibodies specific against the ECL2. In an embodiment the method comprises administering to an individual in need of treatment, one or more antibodies selected from 13F, 25B, 26B, 37B and 58C, and one or more antibodies selected from 4h and 11b. In an embodiment the method comprises administering to an individual in need of treatment, scFvs 58C and 4h. The administration of the antibodies may result in one or more of the following: inhibition of tumor growth, reduction of TAMs, reduction of MDSCs, reduction of M2-macrophages, reduction of Foxp3+/CD4+ Tregs, increase in M1-macrophages, increase in CD8+ T cells, and increase in CD4+ T cells. 
     Examples of tumors that can be treated by the present anti-CCR2 scFvs or compositions comprising anti-CCR2 scFvs include, but are not limited to, breast adenocarcinoma, glioma, glioblastoma, medulloblastoma, multiple myeloma, melanoma, meningioma, ovarian carcinoma, prostate carcinoma, leukemia, lymphoma, colon carcinoma, pancreatic cancer, hepatic cancer, kidney cancer, sarcoma and the like. The tumor may be metastatic. 
     In an embodiment, the present disclosure provides a method of reducing metastases of tumor such as a tumor comprising CCR2 expressing cells, the method comprising administering to the individual a therapeutically effective amount of one or more anti-CCR2 scFvs. The antibody may be an antibody directed to the N-terminal domain of CCR2 or to ECL1, ECL2 or ECL3 or combinations thereof. Examples of scFvs directed against the N-terminal domain of CCR2 include 13F, 25B, 26B, 37B and 58C, and examples of scFvs directed against the ECL2 include 4h and 11b. In an embodiment the method comprises administering to an individual in need of treatment, scFvs 58C and 4h. In an embodiment the method or inhibiting metastases comprises administering to an individual in need of treatment (such as an individual who has been diagnosed with a tumor), one or more antibodies specific against the N-terminus of CCR2 and one or more antibodies specific against the ECL2. In an embodiment the method or inhibiting metastases comprises administering to an individual in need of treatment (such as an individual who has been diagnosed with a tumor), one or more antibodies selected from 13F, 25B, 26B, 37B and 58C, and one or more antibodies selected from 4h and 11b. 
     In one aspect, the disclosure provides a method of passive immunization comprising administering to an individual in need of treatment, a therapeutically effective amount of one or more of the scFvs antibodies or a composition comprising one or more scFv antibodies and which antibodies have been isolated from the subject (human or non-human) they were raised in or obtained from a hybridoma supernatant, bacterial expression system, or may be engineered antibodies using sequences from the isolated antibodies. 
     The following examples are meant to illustrate, and are not intended to be limiting. 
     Example 1 
     This example describes that CCR2 inhibition and the strategy of multi-valent engagement of CCR2 modulates macrophage polarization. 
     Materials and Methods 
     Materials 
     All chemicals and solvents were purchased from Thermo Fisher Scientific (Waltham, Mass.), unless otherwise stated. 
     Phage library screening against CCR2 N-terminal domain 
     Biotinylated N-terminal CCR2 domain was captured on magnetic streptavidin coated beads and four rounds of affinity selections were performed as previously described. 24  The selection was performed at room temperature using a phage display library that was constructed from peripheral human blood lymphocytes and that expresses single-chain fragments of antibodies. To identify CCR2 N-terminal domain binders, single bacterial colonies were picked after the fourth round of selection for phage amplification followed by a phage enzyme-linked immunosorbent assay (ELISA). Clones that yielded a signal above background were sequenced and further analyzed with regard to binding affinity. 
     Protein Expression and Purification 
     The 58C-scFv cloned into the pET21a vector (Novagen, Burlington, Mass.) was expressed in BL-21 (DE3) cells (Lucigen, Middleton, Wis.). Bacterial cultures were grown overnight at 37° C. in 2×YT medium, ampicillin, and 1% glucose. A 1 L 2×YT culture was inoculated with 1% of the overnight culture and grown to an OD600 of ˜0.6. Protein expression was induced with 0.2 mM isopropyl β-D-1-thiogalactopyranoside (IPTG). After an overnight incubation at 24° C., the cells were harvested 18 h post-induction by centrifugation. The cell pellet was resuspended in lysis buffer containing 50 mM Tris, 100 mM KCl, and 2 M urea, pH 8.5. The cell suspension was centrifuged at 9,000×g for 5 minutes at 4° C. and the pellet collected and washed three times with lysis buffer. After the final wash, the pellet was re-suspended in solubilization buffer (50 mM Tris, 100 mM KCl, 5 M guanidine, and 10 mM β-mercaptoethanol, pH 8.5). The solution was incubated at 37° C. for 1 h and then centrifuged at 9,000×g for 10 min at 4° C. The supernatant was collected and diluted 1:10 into refolding buffer containing 50 mM Tris, 500 mM NaCl, 400 mM sucrose, 3 mM reduced glutathione, 0.3 mM oxidized glutathione, 0.5% Triton X-100, 10% glycerol, and 10 mM imidazole, pH 8.5. The solution was stirred at 200 rpm at 4° C. for 24 h, after which TALON cobalt beads (Clontech, Mountain View, Calif.) were equilibrated with refolding buffer and added to the solution. The beads were incubated with the solution and the protein was isolated by immobilized metal affinity chromatography (IMAC). 
     Enzyme-Linked Immunosorbent Assay (ELISA) 
     Nunc MaxiSorp 96-well plates were coated with NeutrAvidin at 5 μg/mL and incubated overnight at 4° C. The plate was thoroughly washed with 0.1% PBS-Tween (PBST), and 5 μg/mL biotinylated N-terminal domain CCR2 peptide (MEDNNMLPQFIHGILSTSHSLFTRSIQELDEGATTPYDYDDGEPC (SEQ ID NO:58); ABclonal, Woburn, Mass.) added and incubated for 1 h at room temperature. The wells were washed with 0.1% PBST and then blocked with casein blocking buffer for 1 h at room temperature. The wells were washed with 0.1% PBST followed by incubation of serially diluted scFv for 1 h at room temperature before being washed five times with 0.1% PBST. Washes were followed by the addition of 100 uL of the respective horse-radish peroxidase (HRP)-linked monoclonal antibody (mAb) for 1 h at room temperature with rocking. An anti-M13 mAb was used to detect phages (#27-9421-01, GE healthcare, Chicago, Ill.) and an anti-flag mAb was used to detect scFv (#A8592, Sigma Aldrich, St. Louis, Mo.). The wells were washed with 0.1% PBST followed by the addition of TMB-ELISA substrate. After 10 min incubation, 2 M H 2 SO 4  was added to stop the reaction. The absorbance was measured at 450 nm with a FilterMax F3 &amp; F5 multi-mode microplate reader (Molecular Devices, Sunnyvale, Calif.). A 1:1 binding ratio Hill model was used to fit the binding interaction data. 
     Cell Binding Analysis by Flow Cytometry 
     Cells were detached with 5 mM EDTA and re-suspended in PBS to a concentration of 50,000 cells per 300 μL. Cells were plated in a 48-well plate and incubated for 30 min at 4° C. After removing the PBS solution, the cells were incubated with various dilutions of DyLight 650 NHS Ester labeled 58C-scFv for 1 h at 4° C. Cells were washed three times with 5% BSA, detached with EDTA, and analyzed in the APC channel of a MACSQuant Analyzer 10 flow cytometer (Miltenyi Biotec, Bergisch Gladbach, Germany). 
     Transwell Migration Assay 
     Cells were serum starved for 24 h before being detached with 5 mM EDTA in PBS and re-suspended in transwell medium (DMEM without phenol red, 25 mM HEPES, and 0.1% BSA) at a concentration of 70×10 4  cells per 100 μL. Cells were incubated with various concentrations of scFv for 30 min at 4° C. and then added to the apical chamber of either a 5 μm (RAW 264.7) or 8 μm (MDA-MB-231) pore transwell plate (Milipore Sigma, Burlington, Mass.). The basolateral compartment contained 25 nM of CCL2 in serum-free medium to induce chemotaxis. Cells were incubated at 37° C. with 5% CO 2  for either 4 h (RAW 264.7) or 21 h (MDA-MB-231). After incubation, the cells in the apical chamber were removed and the wells were placed in a new feeder tray containing pre-warmed cell detachment solution. Wells were incubated with cell detachment buffer for 30 min at 37° C. with occasional rocking to detach migrated cells. Then, lysis buffer and dye solution were added to the detachment solution containing the migrated cells. The solution was incubated for 15 min and fluorescence measured on a SpectraMax microplate reader (Molecular Devices) with an excitation/emission of 480/520. 
     Macrophage Polarization 
     RAW 264.7 mouse macrophages were incubated with either LPS (100 ng/mL), IL-4 (20 ng/mL; PeproTech, Rocky Hill, N.J.), or 58C-scFv (1 μM) for 24 h. For the multivalency studies, RAW 264.7 mouse macrophages were first incubated with IL-4 (20 ng/mL) for 24 h to stimulate an M2 phenotype. Following the 24 h incubation, fresh media with 58C-scFv (89 nM) was added to the cells and incubated for an additional 24 h. Total RNA was isolated with QIAzol lysis reagent (Qiagen, Germany) and total cDNA was generated using the New England Biolabs first stand synthesis kit (Ipswich, Mass.). RNA expression was detected by reverse transcription (RT)-PCR performed with the SYBR Green PCR kit (Qiagen). For each sample, the ΔΔCt value was calculated. Experiments were performed in triplicate. The primers were: β-actin (forward: 5′-ccctgtatgcctctggtc-3′(SEQ ID NO:10), reverse: 5′-gtctttacggatgtcaacg-3′(SEQ ID NO:11)), iNOS (forward: 5′-tttgcttccatgctaatgcgaaag-3′(SEQ ID NO:12), reverse: 5′-gctctgttgaggtctaaaggctccg-3′(SEQ ID NO:13)), IL-6 (forward: 5′-tgggaaatcgtggaaatgag-3′(SEQ ID NO:14), reverse: 5′-ctgaaggactctggctttgtc-3′(SEQ ID NO:15)), ARG-1 (forward: 5′-cagaagaatggaagagtcag-3′(SEQ ID NO:16), reverse: 5′-cagatatgcagggagtcacc-3′(SEQ ID NO:17)), MGL2 (forward: 5′-agcgggaagagaaaaaccag-3′(SEQ ID NO:18), reverse: 5′-agatgaccaccagtagcaggag-3′(SEQ ID NO:19)). 
     Liposome Preparation 
     All lipids were purchased from Avanti Polar Lipids (Alabaster, Ala.). Lipids dissolved in chloroform were mixed, dried down to a thin film, and placed under high vacuum for 2 h. Lipid mixtures included DSPC:DGS-NTA(Ni):Chol (50:30:20), DSPC:DGS-NTA(Ni):Chol (70:10:20), and DSPC:DGS-NTA(Ni):Chol (75:5:20). The films were re-hydrated with 1 mL PBS at 60° C. and vortexed. The liposomes were sonicated at 60° C. for 10 min. The liposomes were extruded through a 100 nm polycarbonate membranes (Avanti Polar Lipids) at 60° C. Liposomes were incubated with a 660:1 molar ratio of DGS-NTA(Ni) lipid to His-tagged 58C-scFv to ensure maximum binding at 4° C. overnight. A sepharose CL-6B size exclusion column was used to remove free, unbound 58C-scFv. Fluorescently labeled 58C-scFv was used to determine the amount of scFv bound to liposomes. The low valency formulation had approximately 14 58C-scFvs per liposome, the medium valency formulation had approximately 28 58C-scFvs per liposome, and the high valency formulation had approximately 84 58C-scFvs per liposome (Table 1). This table provides the number of scFv molecules per liposome. Since a His-tag can bind to several NTA-lipids, we used a 660:1 molar ratio of NTA lipid to 58C-scFv to ensure maximal binding of the targeting ligand. The number of lipids per liposomes was calculated as previously described and was estimated to be ˜186,000 lipids per 150 nm liposome. The number of lipids per liposome was calculated using the following equation: 
     
       
         
           
             N 
             = 
             
               4 
               ⁢ 
               π 
               ⁢ 
               
                 
                   
                     
                       ( 
                       
                         d 
                         2 
                       
                       ) 
                     
                     2 
                   
                   + 
                   
                     
                       ( 
                       
                         
                           d 
                           2 
                         
                         - 
                         l 
                       
                       ) 
                     
                     2 
                   
                 
                 
                   A 
                   lipid 
                 
               
             
           
         
       
     
     Where N is the number of lipids, d is the diameter of the liposome, 1 is the thickness of the bilayer (˜5 nm) and A lipid  is the head group area of a phosphatidylcholine lipid (˜0.71 nm 2 ). This results in ˜14, 28, and 84 58C-scFv molecules per liposome for the low, medium, and high valency, respectively. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                 mol % 
                   
                 # of 
                 # of 
                   
               
               
                   
                 of NTA 
                 mol % 
                 scFv molecules 
                 liposomes 
                 scfv per 
               
               
                 Valency 
                 lipid 
                 of scFv 
                 per mol lipid 
                 per mol lipid 
                 liposome: 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 Low 
                 5 
                 0.0076 
                 4.58E+19 
                 3.23E+18 
                 14 
               
               
                 Med 
                 10 
                 0.015 
                 9.03E+19 
                 3.23E+18 
                 28 
               
               
                 High 
                 30 
                 0.045 
                 2.71E+20 
                 3.23E+18 
                 84 
               
               
                   
               
            
           
         
       
     
     Data Analysis and Statistics 
     Comparisons between groups were analyzed using one-way ANOVA with post-hoc Dunnett (*p&lt;0.05, **p&lt;0.01, ***p&lt;0.001). All statistical analyses were performed in Prism 7 (GraphPad Software, La Jolla, Calif.). All experiments were performed in triplicate. The error bars represent standard deviations (SD). 
     Results 
     Expression and Characterization of 58C-scFv Against the N-Terminal Domain of CCR2 
     A phage library expressing human scFvs with 2×10 9  diversity was panned against the flexible N-terminal domain of CCR2 ( FIG. 1A ). Binders with an absorbance above background were selected for further characterization. When sequenced, the top five binders all had unique complementarity determining regions (CDRs) ( FIG. 1B ). Phage clone 58C had the highest affinity by phage ELISA and was therefore chosen for subsequent studies ( FIGS. 2A &amp;B). The 58C-scFv protein bound to the CCR2 N-terminus with high affinity (K D =59.8 nM;  FIG. 2C ) and was recombinantly expressed with a yield of 1 mg/L and a molecular weight of approximately 33 kDa ( FIG. 2D ). 
     We next assessed if 58C-scFv also bound to cellular CCR2 using RAW 264.7 mouse macrophages and MDA-MB-231 human breast cancer cells, both of which express CCR2 ( FIGS. 8A and 8B ). 58C-scFv was fluorescently labeled and bound with concentration dependence to murine macrophages ( FIG. 2E ). Although a CCR2 peptide corresponding to the murine N-terminal domain was used for affinity selection, the human and mouse CCR2 N-terminal domains have 80% sequence similarity. Therefore, we were interested if the 58C-scFv cross-reacted and bound human CCR2. Indeed, 58C-scFv bound with concentration dependence to human MDA-MB-231 breast cancer cells ( FIG. 2F ). Human embryonic kidney (HEK) cells that are CCR2-negative served as a control. 58C-scFv demonstrated significantly higher binding to CCR2 expressing cells than CCR2-negative HEK cells ( FIG. 2G ). 
     The Effect of 58C-scFv on Macrophage and Breast Cancer Cell Migration 
     The effect of CCR2-targeting 58C-scFv on macrophage and breast cancer cell migration was tested. Monocytes, macrophages, and breast cancer cells express CCR2 and migrate along the CCR2/CCL2 chemotaxis gradient. RAW 267.4 and MDA-MB-231 cells were incubated with increasing concentrations of 58C-scFv, with CCL2 serving as the chemoattractant. 58C-scFv inhibited migration of breast cancer and macrophage cells by approximately 75% at the highest concentration tested ( FIG. 3 ), suggesting that this scFv is specific for the CCL2/CCR2 pathway and acts as a CCR2 antagonist. 58C-scFv demonstrated ˜40-60% higher inhibition of macrophage migration than a commercially available CCR2-targeted antibody ( FIG. 9 ). 
     CCR2 receptors cluster at the leading edge of cells when stimulated by CCL2. A multivalent targeting approach to CCR2 would prevent cellular migration better than the monomeric 58C-scFv ( FIG. 4A ). Liposomes were generated with varying molar ratios of DGS-NTA lipids to control the ligand density of 58C-scFv. The hydrodynamic diameter of the liposomes was between 146 nm and 155 nm as determined by DLS (Table 2) and TEM ( FIG. 4B ). Table 2 provides hydrodynamic diameter of the liposomal formulations containing increasing amounts of DGS-NTA(Ni) lipid for attachment of the His-tagged 58C-scFv by dynamic light scattering (DLS). 58C-scFv was incubated with liposomes containing 0.05 μM, 0.1 μM, or 0.3 μM of DGS-NTA(Ni) lipid, and the C-terminal hexa-histidine tag of the 58C-scFv was used for binding to the NTA(Ni) lipid. An excess of DGS-NTA (Ni) lipid was used to ensure maximum binding of 58C-scFv. The low valency formulation had approximately 14 58C-scFv per liposome, the medium valency formulation had approximately 28 58C-scFv per liposome, and the high valency formulation had approximately 84 58-scFv per liposome. Total protein was kept constant across conditions to assess how ligand density affected cellular migration. For the valency study, we normalized to the monomeric 58C-scFv, which already demonstrated a 1.75-fold and 1.87-fold enhancement over negative control for MDA-MB-231 and RAW 264.7 cells at a dose of 88.9 nM, respectively. Liposomes without 58C-scFv were not significantly different from the negative control ( FIGS. 10A and 10B ). Multivalent display of 58C-scFv at low, medium, and high valency further inhibited migration in RAW 264.7 and MDA-MB-231 cells ( FIGS. 4C &amp;D). At the highest valency, there was a significant 25% reduction in RAW 264.7 migration compared to free 58C-scFv. For MDA-MB-231 cells, multivalent display of 58C-scFv resulted in a significant 40% reduction in migration compared to free monomeric 58C-scFv. 
     
       
         
           
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                 Hydrodynamic 
                 Polydispersity 
               
               
                   
                 Diameter 
                 Index 
               
               
                 Liposome Formulation 
                 (mean ± sd) 
                 (mean ± sd) 
               
               
                   
               
             
            
               
                 DSPC:DGS-NTA(Ni):Chol 
                 146.1 ± 8.62 nm 
                 0.204 ± 0.016 
               
               
                 (75:5:20) 
               
               
                 DSPC:DGS-NTA(Ni):Chol 
                 147.0 ± 23.7 nm 
                 0.243 ± 0.032 
               
               
                 (70:10:20) 
               
               
                 DSPC:DGS-NTA(Ni):Chol 
                 155.2 ± 6.39 nm 
                 0.136 ± 0.016 
               
               
                 (50:30:20) 
               
               
                   
               
            
           
         
       
     
     The Effect of 58C-scFv on Macrophage Polarization 
     Cancer cell secretion of CCL2, a CCR2 agonist, into the tumor microenvironment can polarize macrophages to an M2 phenotype. The CCR2-targeting 58C-scFv was incubated with RAW 264.7 macrophages to test our hypothesis that CCR2 antagonism would polarize macrophages toward an M1 phenotype. Macrophages were polarized to M1 (iNOS and IL-6 expressing) by the addition of LPS, or to M2 (Arg-1 and Mgl-2 expressing) by the addition of IL-4. As expected, LPS induced M1 gene expression and downregulated Mgl2 gene expression compared to the untreated control ( FIG. 5A ). The 58C-scFv induced a quantitatively similar expression pattern to that of LPS, suggesting that 58C-scFv polarized macrophages to the M1 phenotype ( FIG. 5B ). IL-4 increased both Arg-1 and Mgl2 gene expression compared to the untreated control ( FIG. 5C ). Even in the presence of IL-4, the 58C-scFv still downregulated the M2 gene expression and upregulated M1 gene expression compared to the IL-4 only control ( FIG. 5D ). For cancer therapy, it is beneficial to have macrophages with M1 rather than M2 phenotypes because M2 macrophages have a tumor-promoting phenotype. To this end, we used four genes (two M1 and two M2 genes) to assay for the relative phenotype of macrophages upon different conditions ( FIG. 5E ). The ratios of M1 and M2 genes corroborated the phenotype of macrophages suggested from our single gene analysis ( FIG. 5F ). For LPS, three of the four M1/M2 ratios were significantly above control, suggesting the macrophages had an M1 phenotype. For IL-4, all four M1/M2 ratios were significantly below control, suggesting the macrophages had an M2 phenotype. The 58C-scFv had similar fold-changes as the LPS group with three of the four ratios being statistically significant. The M1/M2 ratio for monomeric 58C-scFv was significantly increased over the negative control by 1.0×10 4 -fold (iNOS/Arg-1), 5.1×10 4 -fold (iNOS/Mgl2), 3.4×10 5 -fold (IL-6/Arg-1), and 1.7×10 6 -fold (IL-6/Mgl2) ( FIG. 5F ). When 58C-scFv was co-incubated with the M2 promoting agent, IL-4, two of the ratios were significantly increased over control, with a clear trend for the third ratio (iNOS/Mgl2) having an M1 phenotype. Co-incubation of the IL-4 and 58C-scFv demonstrated 58C-scFv is able to polarize macrophages back to an M1 phenotype. 58C-scFv significantly increased the M1/M2 ratios in macrophages by 3- to 9-fold compared to two commercially available CCR2-targeted antibodies ( FIG. 11 ). 
     Impact of 58C-scFv Multivalency on Macrophage Polarization 
     We next investigated the effect of multivalency on macrophage polarization. Macrophages were first polarized to an M2 phenotype with IL-4 followed by incubation with different ligand densities of 58C-scFv ( FIG. 6A ). Monomeric 58C-scFv and all liposome-bound 58C-scFv shifted the macrophage phenotype from M2 to M1, as measured by the M1/M2 gene ratio ( FIG. 6B-E ). Four different ratios (iNOS/Arg-1, iNOS/Mgl2, IL-6/Arg-1, and IL-6/Mgl2) were compared across conditions. The M1/M2 ratios for the liposomes without 58C-scFv were not statistically different from the negative control ( FIG. 12A-D ). 
     Moreover, the three different ligand densities of 58C-scFv outperformed the monomeric 58C-scFv with a trend for increasing M1/M2 ratio from the lowest to the highest valency. Compared to monomeric 58C-scFv, the highest valency produced 2.2-fold, 2.1-fold, 1.6-fold, and 1.3-fold higher M1/M2 ratios for IL-6/Mgl2, IL-6/Arg-1, iNOS/Mgl2, and iNOS/Arg-1, respectively. Further, the IL-6/Mgl2, IL-6/Arg-1, and iNOS/Mgl2 ratios were significantly higher than the monomeric 58C-scFv at the highest valency ( FIG. 6 ,  FIG. 13 ). The medium valency was also significantly higher for the IL-6/ARG-1 ratio. The monomeric 58C-scFv strongly polarized macrophages to an M1 phenotype, but to a lesser degree than multivalent 58C-scFv. 
     Example 2 
     The present disclosure takes advantage of recent discoveries ( FIG. 14 ). Although the C-C chemokine receptor type 2 (CCR2) is composed of an N-terminal domain (NTD) and three extracellular loops (ECL)—herein referred to as ECL1, ECL2, and ECL3-conventional CCR2 targeting approaches mostly target the NTD, neglecting the other domains. This disclosure describes that targeting the NTD of the CCR2 receptor not only inhibits monocyte migration but also induces macrophage polarization towards the tumor-suppressive M1 phenotype. The NTD targeting single-chain variable fragment (NTD-scFv) increases M1 macrophage polarization 7-fold over commercially available antibodies and, furthermore, when the NTD and ECL2 are simultaneously targeted, there is a dramatic increase in M1 polarization by ˜20-30-fold. This disclosure provides that simultaneous targeting of multiple CCR2 domains (ECLs and NTD): (a) enhances M1 macrophage polarization and (b) better inhibits macrophage migration compared to targeting only one domain ( FIG. 14 ). 
     This disclosure provides recombinantly expressed scFvs that specifically target the CCR2 NTD and the ECL2 as shown in  FIGS. 15A, 15B and 16 . Both scFvs bind to their respective targets in the low nanomolar range. The NTD-scFv has a binding affinity of KD=59.8±13.9 nM ( FIG. 2 ) and the ECL2-scFv has a binding affinity of KD=5.3±1.7 nM ( FIG. 16 ). Both scFvs bind to cells expressing CCR2 such as RAW 264.7 macrophages and MDA-MB-231 and 4T1 breast cancer cells ( FIGS. 2E , F G &amp;  FIG. 16C ). Furthermore, both scFvs are cross-reactive and bind to human CCR2, which is important for future clinical translation. 
     Method to Screen for scFv Binders Specifically Targeting the CCR2 ECL of Interest. 
     This disclosure describes the phage display screening approach used to identify novel scFvs against the remaining ECLs of CCR2, including ECL 1 and ECL3 ( FIG. 1 ). Briefly, biotinylated peptides corresponding to ECL1 (AANEWVFGNIMCK-Biotin) (SEQ ID NO:20) and ECL3 (QESLGMSNCVID-KHLDQK-Biotin) (SEQ ID NO:21) of the murine CCR2 chemokine receptor will be captured on magnetic streptavidin-coated beads, and four affinity selection rounds will be performed. The biotinylated peptides will be custom synthesized by Abclonal (Woburn, Mass.). 
     The selection can be performed using a phage display library constructed from peripheral human blood lymphocytes expressing single-chain fragments of antibodies. First, the phage library was incubated with the biotinylated peptide corresponding to ECL1 or ECL3. The mixture is then incubated with magnetic streptavidin beads to bind the biotinylated peptides along with the bound phages. After several PBS washes, glycine (pH 2) is used to compete off the bound phages. After neutralizing with Tris buffer, TG1  E. coli  cells are infected with the phages and allowed to grow at 37° C. for 1 h. The mixture is plated onto carbenicillin-containing agar plates and grown overnight at 30° C. The TG1  E. coli  cells are scraped off the plate and grown in suspension culture for isolation of phages that are used for the 2 nd  round of selection. This is repeated for the 3 rd  and 4 th  round of selection. With each round, the stringency of the conditions is enhanced. To identify CCR2 ECL binders, single bacterial colonies will be picked after the fourth round of selection for phage amplification followed by a phage ELISA. Clones yielding a signal above background will be sequenced and further analyzed with regard to binding affinity. 
     Simultaneous Targeting of the NTD and ECL2 Domains of CCR2 Mediates Synergistic M1 Macrophage Polarization. 
     To assess the effects of the anti-CCR2 scFvs on macrophage polarization, RAW 264.7 and bone marrow-derived macrophages (BMDMs) were treated with NTD-scFv and ECL2-scFv. Inducible nitric oxide synthase (iNOS) and interleukin 6 (IL-6) were used as M1 markers. Arginase 1 (Arg1) and macrophage galactose N-acetyl-galactosamine-specific lectin 2 (Mgl2) were used as M2 markers. Preliminary data indicate that simultaneous targeting and blocking of the NTD and ECL2 using the recently developed anti-CCR2 scFvs synergistically increases macrophage polarization to the M1 phenotype by ˜6-9-fold (by iNOS/Arg1 and iNOS/Mgl2) and ˜20-30-fold as expressed by the M1/M2 marker ratio (IL-6/Arg1 and IL-6/Mgl2) ( FIG. 17 ). To determine whether these changes were additive, synergistic, or antagonistic, the combination indices (CI) were calculated for NTD-scFv and ECL2-scFv by treating cells with a combination of NTD-scFv and ECL2-scFv. CI was calculated by: CI=(C A,X /IC X,A )+(C B,X /IC X,B ), where C A,X  and C B,X  are the concentration of drug A (in this case NTD-scFv) and B (here, ECL2-scFv) used in combination to achieve x % drug effect. IC X,A  and IC X,B  are the concentrations for the single scFvs to achieve the same effect. CI&lt;1 indicates synergy, CI=1 indicates additivity, and CI&gt;1 indicates antagonism. As shown in  FIG. 17 , the computed CI values were all far below 1, indicating that, at the ratios tested, simultaneous NTD and ECL2 blockade led to synergistic M1 macrophage polarization. These studies were performed in RAW 264.7 cells ( FIG. 17A , B, C), but similar results were found for bone marrow-derived macrophages isolated from BALB/c mice ( FIG. 17D ). As shown by the isobolograms, the M1 polarization effects occurred at lower doses when NTD-scFv was used in combination with ECL2-scFv. As displayed in  FIGS. 17B  and D the dots (that represent NTD-scFv and ECL2-scFv combined) are all below the isobole. This indicates that the combined effects of NTD-scFv and ECL2-scFv were synergistic ( FIGS. 17B  and D). 
     NTD-scFv Inhibits Macrophage Migration. 
     Monocytes, macrophages, and breast cancer cells express CCR2 and migrate along the CCR2/CCL2 chemotaxis gradient. RAW 267.4 cells were incubated with increasing concentrations of NTD-scFv, with CCL2 serving as the chemoattractant in the basolateral chamber of transwells. NTD-scFv ( FIG. 3 ) inhibited ˜75% of RAW 264.7 macrophage migration. These data suggest that the NTD-scFv is specific for the CCL2/CCR2 pathway and act as a CCR2 antagonist. NTD-scFv demonstrated ˜40-60% higher inhibition of macrophage migration than a commercially available CCR2-targeted antibody. 
     NTD-scFv Also Inhibits Breast Cancer Cell Migration. 
     CCR2 has also been shown to be expressed on many different types of cancer cells, including breast cancer cells. More importantly, studies have shown that CCR2 mediates breast cancer migration and also contributes to tumor growth and metastatic spread. Thus, inhibiting CCR2/CCL2 mediated breast cancer migration can help to inhibit tumor growth. As shown in  FIG. 3 , NTD-scFv inhibited migration of MDA-MB-231 breast cancer cells by approximately 75% at the highest concentration tested. 
     Testing Dual, Triple, and Quadruple Combinations of Anti-CCR2-scFvs. 
     After assessing the effects of single scFvs blocking ECL1 and ECL3, we will test how different dual, triple, and quadruple combinations of scFvs affect M1 macrophage polarization and migration. The different scFv combinations are shown in  FIG. 18 . For the dual combinations, the list is not exhaustive and shows representative examples. 
     Tumor Treatment with Unmodified NTD-scFv. 
     To assess the therapeutic efficacy of the NTD-scFv, female BALB/c mice harboring 4T1 breast cancer cells in the mammary fat pad were treated with NTD-scFv when the tumor sizes reached 150 mm 3 . The NTD-scFv was administered via tail vein injection. Mice received five doses of NTD-scFv at two-day intervals at 1.25 mg/kg. PBS-treated mice served as controls. As shown in  FIG. 19 , tumors in female BALB/c mice treated with NTD-scFv were significantly smaller than mice treated with PBS. These results are highly encouraging because they were performed with the unmodified NTD-scFv, which is eliminated quickly after systemic administration and which shows low tumor deposition ( FIG. 20 ). 
     Site-Specific PEGylation to Enhance Tumor Deposition of Anti-CCR2 NTD-scFv. 
     Non-pegylated NTD-scFv shows low deposition in the tumor ( FIG. 20 ). PEGylation of proteins have been shown to enhance the circulatory half-life and tumor deposition. Further, PEGylating of proteins can be carried out to enhance their circulatory half-life and improve bioavailability. To enhance the tumor deposition of the NTD-scFv without masking its binding site to CCR2, the NTD-scFv was modified to contain a cysteine at the C-terminus for attachment to PEG(5K)-maleimide (Sigma Aldrich). The cysteine was introduced into the NTD-scFv via site-directed mutagenesis at the C-terminus, and the correct sequence confirmed through Sanger sequencing. The cysteine-modified NTD-scFv was added to a PEG(5K)-maleimide solution at a 1:5 molar ratio of NTD-scFv to PEG(5K)-maleimide to ensure complete PEGylation. Excess PEG was removed using a 10 kDa molecular weight cut-off column. When administered into BALB/c mice via tail vein injection, PEG(5K)-NTD-scFv showed significantly higher tumor deposition (4.0±0.2% of injected dose) compared to unPEGylated NTD-scFv ( FIG. 20A , C). While NTD-scFv does accumulate in the tumor as displayed in  FIG. 20B , the deposition is so minimal that it cannot be detected relative to the high signals found in the kidneys ( FIG. 20A , B). Both PEG(5K)-NTD-scFv and the unpegylated NTD-scFv showed high deposition in the kidneys which is indicative of fast renal clearance ( FIG. 20A , B). 
     PEG(40K) Significantly Enhances Circulatory Half-Life of the Anti-CCR2 NTD-scFv. 
     When attaching PEG(40K)-maleimide to the NTD-scFv a 7-fold greater elimination half-life was obtained (t 1/2  (β)=111h) compared to unmodified NTD-scFv, which has an elimination half-life of t 1/2  (β)=16h ( FIG. 21 ). The distribution half-life of PEG(40K)-NTD-scFv (t 1/2  (α)=0.12h) was 11-fold greater than that of NTD-scFv (t 1/2  (α)=0.01h). Since the PEG(40K) shows longer circulation compared to a PEG(5K), we expect that the PEG(40K)-NTD-scFv will result in enhanced tumor deposition compared to the PEG(5K)-NTD-scFv and unmodified NTD-scFv. 
     Tandem scFvs are created by linking two scFvs into a single polypeptide that is separated by a (GSGSGS)n (SEQ ID NO:59) linker ( FIG. 22A , B). Tandem scFvs are PEGylated using the procedure described above to enhance circulatory half-life and tumor deposition ( FIG. 20 ). Further, the linker length can be varied to optimize binding affinity to CCR2 ( FIG. 22C ). 
     Additionally, the scFvs can be conjugated to 4arm-PEG10K, 4arm-PEG20K, and 4-arm-PEG40K ( FIG. 23 ). The 4arm-PEG40K allows the synthesis of multivalent anti-CCR2 scFvs which can further lead to an increase in binding affinity and efficacy. 
     Example 3 
     This example demonstrates synergistic action of antibodies directed to N-terminal domain and ECL2 domain of CCR2. scFv 58C directed to the N-terminal domain and scFv 4h directed to the ECL2 of CCR2 were used. 
     At study completion, the tumors were harvested, digested, and single cell suspensions stained for immune cells. Dual-epitope blocking of CCR2 reduced TAMs, MDSCs, and M2-Macrophages and increased M1-Macrophages in triple-negative breast cancer (TNBCs). Co-dosing of the pegylated NTD- and ECL2-scFv (NTD &amp; ECL2 Combo) resulted in significant decreases in myeloid-derived suppressor cells (MDSCs) by ˜3-fold, CD68+ TAMs by ˜2.5-fold, M2-like macrophages by ˜2.6-fold, and an increase in MHC class II hi  M1-like macrophages by ˜1.4-fold compared to PBS-treated animals ( FIG. 24A-D ). The effects of the small molecule CCR2 antagonist (SMA, RS 504393) were not significant compared to control mice treated with PBS ( FIG. 24A-D ). 
     We observed that dual-epitope scFv combination treatment outperforms small molecule CCR2 antagonist (SMA) and decreased tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), and M2-macrophages and increased M1-macrophages. Single cell suspension from the harvested tumors were analyzed by flow cytometry. The cells were stained for (A) CD68+ TAMs, (B) MDSCs, (C) MHC class II macrophages (M1), and (D) CD206+ macrophages (M2). 
     Treatment groups included: PBS, CCR2 small molecule antagonist (SMA), PEG(20K)-ECL2-scFv, PEG(20K)-NTD-scFv, and NTD &amp; ECL2 combination (co-dosing of PEG(20K)-ECL2-scFv and PEG(20K)-NTD-scFv), with *p&lt;0.05, **p&lt;0.01, and ***p&lt;0.001 by one-way ANOVA followed by Tukey&#39;s post-test. 
     Further, we observed that dual-epitope targeting strategy restores anti-tumor immunity. Compared to the small molecule CCR2 antagonist and the other formulations tested, dual-epitope therapy showed the strongest reduction in immunosuppressive CD4 + FoxP3 +− Tregs (˜2.5-fold decrease,  FIG. 25A )). The dual-epitope combination therapy also significantly increased cytotoxic CD8+ T cells and CD4+ T cells in the tumor tissue ( FIG. 25B , C). While mice treated with the small molecule antagonist (SMA) and the individual scFvs against ECL2 and against NTD slightly decreased immunosuppressive Tregs and increasing cytotoxic CD8+ T cells and CD4+ T cells, no statistically significant reduction compared to PBS treated mice were found. This indicates that dual-epitope combination therapy is superior to conventional targeting approaches and can favorably restore anti-tumor immunity. 
     Further, we evaluated the effect of dual epitope blocking of CCCR2 on tumor growth. TNBCs were injected into the mammary fat pads of female BALB/c mice. Treatment of tumored mice started on days 7, 9, 12, 14, 16, and 18. To enhance the circulation half-life of the NTD-scFv and ECL2-scFv, we used site-directed mutagenesis to introduce a cysteine at the C-terminus of the scFvs for covalent attachment of a PEG-maleimide with molecular weight of 20 kDa. Animals (n=10 per group) were systemically (via tail vein injection) treated with (1) PBS, (2) CCR2-small molecule antagonist (SMA), (3) PEG(20K)-NTD-scFv, (4) PEG(20K)-ECL2-scFv, and (5) a NTD and ECL2 combo (co-dosing of PEG(20K)-NTD-scFv and PEG(20K)-ECL2-scFv). The NTD and ECL2 combination demonstrated highest reduction in tumor volume, followed by single PEG(20K)-NTD-scFv or PEG(20K)-ECL2-scFv treatment ( FIG. 26A , B). The small molecule CCR2 antagonist (SMA), RS 504393, had the weakest effect on tumor growth. 
     Although the present disclosure has been described using specific embodiments and examples, routine modifications will be apparent to those skilled in the art and such modifications are intended to be within the scope of the disclosure and the claims. 
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