Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
  • G01N33/575—Immunoassay; Biospecific binding assay; Materials therefor for cancer
  • G01N33/57525—Immunoassay; Biospecific binding assay; Materials therefor for cancer of the liver or pancreas
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
  • G01N33/575—Immunoassay; Biospecific binding assay; Materials therefor for cancer
  • G01N33/5758—Immunoassay; Biospecific binding assay; Materials therefor for cancer involving compounds serving as markers for tumours, cancers or neoplasias, e.g. cellular determinants, receptors, heat shock/stress proteins, A-protein, oligosaccharides or metabolites
  • G01N33/57585—Immunoassay; Biospecific binding assay; Materials therefor for cancer involving compounds serving as markers for tumours, cancers or neoplasias, e.g. cellular determinants, receptors, heat shock/stress proteins, A-protein, oligosaccharides or metabolites involving compounds identifiable in body fluids
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K16/00—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies
  • C07K16/18—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from animals or humans
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
  • G01N33/577—Immunoassay; Biospecific binding assay; Materials therefor involving monoclonal antibodies binding reaction mechanisms characterised by the use of monoclonal antibodies
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/68—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids
  • G01N33/6893—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids related to diseases not provided for elsewhere
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/20—Immunoglobulins specific features characterized by taxonomic origin
  • C07K2317/24—Immunoglobulins specific features characterized by taxonomic origin containing regions, domains or residues from different species, e.g. chimeric, humanized or veneered
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/30—Immunoglobulins specific features characterized by aspects of specificity or valency
  • C07K2317/33—Crossreactivity, e.g. for species or epitope, or lack of said crossreactivity
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/30—Immunoglobulins specific features characterized by aspects of specificity or valency
  • C07K2317/34—Identification of a linear epitope shorter than 20 amino acid residues or of a conformational epitope defined by amino acid residues
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/50—Immunoglobulins specific features characterized by immunoglobulin fragments
  • C07K2317/56—Immunoglobulins specific features characterized by immunoglobulin fragments variable (Fv) region, i.e. VH and/or VL
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/50—Immunoglobulins specific features characterized by immunoglobulin fragments
  • C07K2317/56—Immunoglobulins specific features characterized by immunoglobulin fragments variable (Fv) region, i.e. VH and/or VL
  • C07K2317/565—Complementarity determining region [CDR]
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2333/00—Assays involving biological materials from specific organisms or of a specific nature
  • G01N2333/435—Assays involving biological materials from specific organisms or of a specific nature from animals; from humans
  • G01N2333/78—Connective tissue peptides, e.g. collagen, elastin, laminin, fibronectin, vitronectin, cold insoluble globulin [CIG]

Definitions

• the present invention relates to immunoassays, in particular immunoassays for detecting and/or monitoring cancer in a patient, and to monoclonal antibodies and immunoassay kits for use in carrying out said immunoassays.
• Background Cancer is a major global health problem and is estimated to cause more than 600.000 cancer deaths in 2021 in the United States alone[1]. Despite continuous research and progress, the cancer burden persists.
• One immediate need for cancer patients is better non-invasive diagnostic and prognostic biomarkers. Contrary to traditional tissue-based approaches, blood-based biomarkers do not require tissue biopsies and are less invasive, resulting in less discomfort and fewer complications[2],[3].
• the tumor microenvironment is intricately involved in cancer development and was recently recognized alongside the traditional hallmarks of cancer[4].
• the tumor microenvironment comprises the cancer cells and the surrounding stroma. Within the stroma are various cells of the immune system and fibroblasts. Fibroblasts contribute to production of collagens that are key components of the large non-cellular component of most tissues, the extracellular matrix (ECM).
• ECM extracellular matrix
• the ECM can accumulate around a tumor, forming a surrounding layer of matrix that encapsulates the growth, and can inhibit the ability of immune cells or drugs to challenge the cancer[5].
• ECM components are constantly produced and degraded in a delicate balance. In cancer, however, this balance in turnover is skewed[6],[7].
• Collagens of which 28 have been identified to date, are the major constituents of the ECM along with laminins, proteoglycans, and glycoproteins.
• the collagens span the ECM from the basement membrane (BM), at the basal side of epithelial and endothelial cells and into the interstitial matrix (IM).
• BM basement membrane
• IM interstitial matrix
• FACITs fibril-associated collagens with interrupted triple helices
• Collagen XXII (COL22) is a minor collagen and a member of the FACIT family of collagens. COL22 is known to be expressed at sites of tissue junctions in muscle, cartilage, heart, skin and associated with maintaining vascular stability[9],[10]. COL22 also has prognostic value in squamous cell carcinoma of the head and neck (HNSCC) where COL22A1 mRNA expression was significantly increased in cases with lymph node metastasis. Moreover, mRNA expression levels were significantly associated with earlier disease recurrence and upregulation of COL22A1 mRNA was associated with a decrease in disease free survival[11].
• HNSCC head and neck
• COL22 was identified in a human ex-vivo and in vitro model as an early response gene to transforming growth factor beta using both skin- and lung-derived cells (including adenocarcinomic human alveolar basal epithelial cells, A549 cells). This induction of COL22A1 was significantly increased on both mRNA and protein levels[12]. It has been observed for several FACITs that they are more pronounced during development and/or tissue repair, among these are type XVI, XX and XXII collagens [13],[14],[15]. The role of COL22 in cancer was investigated by the inventors, as several parallels have been suggested to exist between cancer and development, as well as tissue repair [16],[17].
• the applicant has now developed an enzyme-linked immunosorbent assay (ELISA) to quantify the presence of a biomarker (referred to herein as “PRO-C22”) of type XXII collagen, in blood.
• ELISA enzyme-linked immunosorbent assay
• the assay was optimized and validated, and used to determine the levels of circulating type XXII collagen in the serum of cancer patients and healthy controls. It was found that the assay was robust, with specificity for type XXII collagen and with sensitivity to detect levels in both healthy controls and patients with disease (cancer).
• the data shows that PRO-C22 levels were significantly elevated in the serum of cancer patients compared to healthy controls.
• the present invention provides a method of immunoassay, the method comprising: (i) contacting a sample from a patient with a monoclonal antibody that specifically binds to a C-terminus amino acid sequence AARPGNVKGP (SEQ ID No. 1) (which C-terminus amino acid sequence is referred to herein as “PRO-C22” and/or the “target sequence”, peptides consisting of or comprising said C-terminus amino acid sequence also being referred to herein as “PRO- C22” and/or the “target peptide”); and (ii) detecting and determining the amount of binding between said monoclonal antibody and peptides in the sample.
• AARPGNVKGP SEQ ID No. 1
• the method is preferably a method of immunoassay for detecting and/or monitoring a disease in a patient.
• the method preferably further comprises: (iii) correlating said amount of binding of said monoclonal antibody as determined in step (ii) with values associated with normal healthy subjects, and/or with values associated with known disease severity, and/or with values obtained from said patient at a previous time point, and/or with a predetermined cut-off value.
• the disease is cancer.
• the cancer may for example be bladder cancer, breast cancer, colorectal cancer, head and neck cancer, kidney cancer, lung cancer, melanoma, ovarian cancer, pancreatic cancer, prostate cancer, or stomach cancer.
• the cancer is pancreatic cancer.
• the method can be used to provide a prognosis of overall survival.
• the method may further comprise providing a prognosis of overall survival, wherein an amount of binding of said monoclonal antibody as determined in step (ii)above the median (50 th percentile) value associated with known pancreatic cancer patients is associated with poor overall survival. An amount of binding below the median (50 th percentile) is associated with improved overall survival.
• the monoclonal antibody does not specifically bind to an elongated version of the target sequence which is AARPGNVKGPX (SEQ ID No. 2) where X is any amino acid (i.e.
• the ratio of the affinity of said antibody for the PRO-C22 target sequence to the affinity of said antibody for the elongated version of the target sequence is at least 10 to 1, and more preferably is at least 20 to 1 or at least 30 to 1.
• the monoclonal antibody does not specifically bind to a truncated version of the target sequence which is AARPGNVKG (SEQ ID No. 4)(i.e. a version of the PRO-C22 target sequence truncated by removal of the final proline residue).
• the ratio of the affinity of said antibody for the PRO-C22 target sequence to the affinity of said antibody for the truncated version of the target sequence is at least 10 to 1, and more preferably is at least 20 to 1 or at least 30 to 1.
• the monoclonal antibody is a monoclonal antibody that is raised against a synthetic peptide having the C- terminus amino acid sequence AARPGNVKGP (SEQ ID No. 1).
• the method may further comprise the step of administering a suitable treatment to the patient.
• a suitable treatment for that cancer can be administered such as chemotherapy, radiotherapy, hormone therapy, immunotherapy, stem cell transplant, surgery, targeted therapy or a combination thereof.
• the sample is preferably a biofluid.
• the biofluid may be, but is not limited to, blood, serum, plasma, urine or a supernatant from cell or tissue cultures.
• the biofluid is blood, serum or plasma.
• the immunoassay may be, but is not limited to, a competition assay or a sandwich assay.
• the immunoassay may, for example, be a radioimmunoassay or an enzyme-linked immunosorbent assay (ELISA).
• ELISA enzyme-linked immunosorbent assay
• ELISA enzyme-linked immunosorbent assay
• the term “ELISA” refers to an immunoassay in which the target peptide present in a sample (if any) is detected using antibodies linked to an enzyme, such as horseradish peroxidase or alkaline phosphatase. The activity of the enzyme is then assessed by incubation with a substrate generating a measurable product. The presence and/or amount of target peptide in a sample can thereby be detected and/or quantified.
• ELISA is a technique known to those skilled in the art.
• the term “competitive ELISA” refers to a competitive enzyme-linked immunosorbent assay.
• the target peptide present in a sample competes with known amount of target of peptide (which for example is bound to a fixed substrate or is labelled) for to binding an antibody, and is a technique known to the person skilled in the art.
• the term “sandwich immunoassay” refers to the use of at least two antibodies for the detection of an antigen in a sample, and is a technique known to the person skilled in the art.
• the term “amount of binding” refers to the quantification of binding between the monoclonal antibody and peptides in the patient sample. Said quantification may for example be determined by comparing the measured values of binding in the patient sample against a calibration curve produced using measured values of binding in standard samples containing known concentrations of a peptide to which the antibody specifically binds, in order to thereby determine the quantity of peptide to which the antibody specifically binds in the patient sample.
• an ELISA method is used in which spectrophotometric analysis is used to measure the amount of binding both in the patient samples and when producing the calibration curve.
• any suitable analytical method can be used.
• predetermined cut-off value means an amount of binding that is determined statistically to be indicative of a high likelihood of a disease or a particular severity thereof in a patient, in that a measured value of the target peptide in a patient sample that is at or above the statistical cut-off value corresponds to at least a 70% probability, preferably at least an 75% probability, more preferably at least an 80% probability, more preferably at least an 85% probability, more preferably at least a 90% probability, and most preferably at least a 95% probability of the presence of said disease or said particular severity thereof.
• values associated with normal healthy subjects means standardised quantities of binding determined by the method described supra for samples from subjects considered to be healthy, i.e.
• C-terminus refers to a C-terminal peptide sequence at the extremity of a polypeptide, i.e. at the C-terminal end of the polypeptide, and is not to be construed as meaning in the general direction thereof.
• peptide and “polypeptide” are used synonymously.
• the term “monoclonal antibody” refers to both whole antibodies and to fragments thereof that retain the binding specificity of the whole antibody, such as for example a Fab fragment, F(ab’)2 fragment, single chain Fv fragment, or other such fragments known to those skilled in the art.
• whole antibodies typically have a "Y-shaped" structure of two identical pairs of polypeptide chains, each pair made up of one "light” and one "heavy” chain.
• the N- terminal regions of each light chain and heavy chain contain the variable region, while the C-terminal portions of each of the heavy and light chains make up the constant region.
• the variable region comprises three complementarity determining regions (CDRs), which are primarily responsible for antigen recognition.
• the constant region allows the antibody to recruit cells and molecules of the immune system.
• Antibody fragments retaining binding specificity comprise at least the CDRs and sufficient parts of the rest of the variable region to retain said binding specificity.
• a monoclonal antibody comprising any constant region known in the art can be used.
• Human constant light chains are classified as kappa and lambda light chains.
• Heavy constant chains are classified as mu, delta, gamma, alpha, or epsilon, and define the antibody's isotype as IgM, IgD, IgG, IgA, and IgE, respectively.
• the IgG isotype has several subclasses, including, but not limited to IgG1, IgG2, IgG3, and IgG4.
• the monoclonal antibody may preferably be of the IgG isotype, including any one of IgG1, IgG2, IgG3 or IgG4.
• the CDR of an antibody can be determined using methods known in the art such as that described by Kabat et al[18].
• Antibodies can be generated from B cell clones as described in the examples.
• the isotype of the antibody can be determined by ELISA specific for human IgM, IgG or IgA isotype, or human IgG1, IgG2, IgG3 or IgG4 subclasses.
• the amino acid sequence of the antibodies generated can be determined using standard techniques. For example, RNA can be isolated from the cells, and used to generate cDNA by reverse transcription.
• the cDNA is then subjected to PCR using primers which amplify the heavy and light chains of the antibody.
• primers which amplify the heavy and light chains of the antibody For example primers specific for the leader sequence for all VH (variable heavy chain) sequences can be used together with primers that bind to a sequence located in the constant region of the isotype which has been previously determined.
• the light chain can be amplified using primers which bind to the 3’ end of the Kappa or Lamda chain together with primers which anneal to the V kappa or V lambda leader sequence.
• the full length heavy and light chains can be generated and sequenced.
• the present invention provides a monoclonal antibody that specifically binds to a C-terminus amino acid sequence AARPGNVKGP (SEQ ID No. 1).
• the monoclonal antibody is suitable for use in an immunoassay according to the first aspect of the invention, and preferred and other optional embodiments of the monoclonal antibody according to the second aspect of the invention will be apparent from the discussion supra of the monoclonal antibodies for use the in the first aspect of the invention and preferred and other optional embodiments thereof.
• Monoclonal antibodies that specifically bind to the C-terminus amino acid sequence AARPGNVKGP can be generated via any suitable techniques known in the art. For example, the monoclonal antibody may be raised against a synthetic peptide having the amino acid sequence AARPGNVKGP (SEQ ID No.
• AARPGNVKGP SEQ ID No. 1
• an immunogenic carrier protein such as keyhole limpet hemocyanin
• isolating and cloning a single antibody producing cell and assaying the resulting monoclonal antibodies to ensure that they have the desired specificity.
• An exemplary protocol for producing a monoclonal antibody that that specifically bind to the C-terminus amino acid sequence AARPGNVKGP (SEQ ID No. 1) is described infra.
• the monoclonal antibody or fragment thereof may preferably comprise one or more complementarity-determining regions (CDRs) selected from: CDR-L1: KASQDIYSSLS (SEQ ID No. 5) CDR-L2: RANRLIN (SEQ ID No. 6) and CDR-L3: LQYDDFPYM (SEQ ID No. 7) CDR-H1: TYGVH (SEQ ID No. 8) CDR-H2: AIWRGGSTDYNPAFMS (SEQ ID No. 9) and CDR-H3: RSTLFYFDY (SEQ ID No. 10)
• CDR-L1 KASQDIYSSLS
• CDR-L2 RANRLIN
• CDR-L3 LQYDDFPYM
• CDR-H1 TYGVH
• CDR-H2 AIWRGGSTDYNPAFMS
• CDR-H3 RSTLFYFDY
• the antibody or fragment thereof comprises at least 2, 3, 4, 5 or 6 of the above listed CDR
• the monoclonal antibody or fragment thereof has a light chain variable region comprising the CDR sequences CDR-L1: KASQDIYSSLS (SEQ ID No. 5) CDR-L2: RANRLIN (SEQ ID No. 6) and CDR-L3: LQYDDFPYM (SEQ ID No.
• the monoclonal antibody or fragment thereof has a light chain that comprises framework sequences between the CDRs, wherein said framework sequences are substantially identical or substantially similar to the framework sequences between the CDRs in the light chain sequence below (in which the CDRs are shown in bold and underlined, and the framework sequences are shown in italics) KASQDIYSSLSWFQQKPGKSPKTLIYRANRLINGVPSRFSGSGSGQDYSLTISSLEYEDVGI YYCLQYDDFPYM (SEQ ID No. 11)
• the monoclonal antibody or fragment thereof has a heavy chain variable region comprising the CDR sequences CDR-H1: TYGVH (SEQ ID No.
• CDR-H2 AIWRGGSTDYNPAFMS (SEQ ID No. 9) and CDR-H3: RSTLFYFDY (SEQ ID No. 10)
• the monoclonal antibody or fragment thereof has a heavy chain that comprises framework sequences between the CDRs, wherein said framework sequences are substantially identical or substantially similar to the framework sequences between the CDRs in the heavy chain sequence below (in which the CDRs are shown in bold and underlined, and the framework sequences are shown in italics)
• TYGVHWIRQSPGKGLEWLGAIWRGGSTDYNPAFMSRLSITKDISKSQVFFKMNSLQADDTAI YYCAKRSTLFYFDY (SEQ ID No.
• the framework amino acid sequences between the CDRs of an antibody are substantially identical or substantially similar to the framework amino acid sequences between the CDRs of another antibody if they have at least 70%, 80%, 90% or at least 95% similarity or identity.
• the similar or identical amino acids may be contiguous or non- contiguous.
• the framework sequences may contain one or more amino acid substitutions, insertions and/or deletions. Amino acid substitutions may be conservative, by which it is meant the substituted amino acid has similar chemical properties to the original amino acid. A skilled person would understand which amino acids share similar chemical properties.
• the following groups of amino acids share similar chemical properties such as size, charge and polarity: Group 1 Ala, Ser, Thr, Pro, Gly; Group 2 Asp, Asn, Glu, Gln; Group 3 His, Arg, Lys; Group 4 Met, Leu, Ile, Val, Cys; Group 5 Phe Thy Trp.
• a program such as the CLUSTAL program to can be used to compare amino acid sequences. This program compares amino acid sequences and finds the optimal alignment by inserting spaces in either sequence as appropriate. It is possible to calculate amino acid identity or similarity (identity plus conservation of amino acid type) for an optimal alignment.
• a program like BLASTx will align the longest stretch of similar sequences and assign a value to the fit.
• the monoclonal antibody or fragment thereof may comprise the light chain variable region sequence: DIKMTQSPSSMHASLGERVTITCKASQDIYSSLSWFQQKPGKSPKTLIYRANRLINGVPSRF SGSGSGQDYSLTISSLEYEDVGIYYCLQYDDFPYMFGGGTKLEIK (SEQ ID No.
• the application relates to an immunoassay kit comprising a monoclonal antibody according to the second aspect, and at least one of; - a streptavidin coated well plate; - a biotinylated peptide Biotin-L- AARPGNVKGP (SEQ ID No. 15), wherein L is an optional linker; - a secondary antibody for use in a sandwich immunoassay; - a calibrator protein comprising the C-terminus amino acid sequence AARPGNVKGP (SEQ ID No.
• Figure 1 shows specificity of PRO-C22 ELISA.
• Biotin- AARPGNVKGP SEQ ID No. 15
• monoclonal antibody interaction by the assay specific standard peptides respectively 30
• GPSPGPPGQCDPSQCAYFASLAARPGNVKGP SEQ ID No. 16
• AARPGNVKGP SEQ ID No. 1
• PRO-C22 levels are presented individually with bars marking the mean as scatter plots. Samples measuring below the LLOQ were given the LLOQ value determined in the validation of PRO-C22. **** indicates a p-value below 0.0001. *** below 0.001. ** below 0.01.
• Figure 4 shows that high PRO-C22 (above the median: 50th percentile) is significantly associated with poor overall survival in pancreas cancer. Examples The presently disclosed embodiments are described in the following Examples, which are set forth to aid in the understanding of the disclosure, and should not be construed to limit in any way the scope of the disclosure as defined in the claims which follow thereafter.
• Hybridoma cells were produced by fusing spleen cells with SP2/0 myeloma cells as previously described (Gefter, Margulies and Scharff, 1977). The resultant hybridoma cells were then cultured in 96-well microtiter plates and subcloning was done while limiting dilution of cells. The selected monoclonal cells were seeded in 24-well plates and then expanded in T25, then T75 and finally in T150 flasks before collection of supernatants.
• SOP standard operating procedure
• RACE rapid amplification of cDNA ends
• Amplified antibody fragments were cloned into a standard cloning vector separately. Colony PCR was performed to screen for clones with inserts of correct sizes. No less than five colonies with inserts of correct sizes were sequenced for each fragment. The sequences of different clones were aligned and the consensus sequence of these clones was provided.
• CDR-H1 TYGVH (SEQ ID No. 8)
• CDR-H2 AIWRGGSTDYNPAFMS (SEQ ID No. 9)
• CDR-H3 RSTLFYFDY (SEQ ID No. 10)
• Light chain Amino acid sequence (234 aa) (mouse Kappa isotype) DIKMTQSPSSMHASLGERVTITCKASQDIYSSLSWFQQKPGKSPKTLIYRANRLINGVPSRF SGSGQDYSLTISSLEYEDVGIYYCLQYDDFPYMFGGGTKLEIKRADAAPTVSIFPPSSEQ LTSGGASVVCFLNNFYPKDINVKWKIDGSERQNGVLNSWTDQDSKDSTYSMSSTLTLTKDEYE RHNSYTCEATHKTSTSPIVKSFNRNEC (SEQ ID No.
• PRO-C22 ELISA Protocol The final PRO-C22 protocol was performed as follows: a 96-well streptavidin-coated ELISA plate was coated with 100 ⁇ L/well of 20 ng/mL biotinylated AARPGNVKGP (Biotin-AARPGNVKGP (SEQ ID No.
• TMB 3,3′,5,5′-Tetramethylbenzidine
• the reaction was stopped by adding 100 ⁇ L/well of 1% H 2 SO 4 .
• Absorbance was measured at 450 nm with 650 nm as reference.
• a standard curve was generated using 20 ⁇ L/well of 125 ng/mL GPPGPPGQCDPSQCAYFASLAARPGNVKGP (SEQ ID No. 16) standard peptide, serially diluted two-fold.
• a four-parametric logistic regression model was used to fit a curve.
• Each plate included two kit controls of peptide-in-assay-buffer, and three quality control samples comprising one human serum sample, one pig serum sample and one synovial fluid sample.
• Technical validation of the PRO-C22 ELISA The specificity of the antibody was evaluated by signal inhibition. Using two-fold dilutions of two versions of the selection peptide, a ten amino acid (AA) version (AARPGNVKGP (SEQ ID No. 1)) and a 30 AA version (GPPGPPGQCDPSQCAYFASLAARPGNVKGP (SEQ ID No. 16)) and comparing those to a truncated (AARPGNVKG (SEQ ID No. 4)), elongated (AARPGNVKGPA (SEQ ID No.
• the intra- assay variation was calculated as the mean coefficient of variance (CV%) within plates.
• the inter-assay variation was based on the mean CV% between plates.
• the upper limit of quantification (ULOQ) was determined as the highest accepted standard point based on the recovery percentage (RE%) and CV% of this.
• the criteria of acceptance was CV% ⁇ 20 % and %RE within 80-120%.
• the lower limit of quantification (LLOQ) was determined as the concentration at which CV% goes above 20% for most samples based on four human serum samples with low analyte concentrations that were measured in sextuplicates over five independent runs. Linearity or parallelism was tested by serially diluting four healthy human serum samples two-fold and calculating the CV% through three independent runs.
• the RE% was calculated relative to the 1:2 diluted values.
• the acceptance criteria of the CV% was ⁇ 20 % and the RE% within 80-120%.
• Accuracy was evaluated by spiking 30AA standard peptide into three human serum samples and calculating the RE%.
• Acceptance criteria of the mean RE% was 80-120%.
• the accuracy was further evaluated by mixing three sets of serum samples in different amounts (e.g., 25% serum A + 75% serum B, 50% serum A + 50% serum B, etc.) and calculating the RE% to the individual reference serum sample values.
• RE% of each spiking ratio should be within 80-120%.
• biotin, lipids and hemoglobin Effect of commonly interfering substances biotin, lipids and hemoglobin was tested using three serum samples and by different concentrations (biotin low: 5ng/mL, high: 100ng/mL; lipids low: 1.5mg/mL, high: 5mg/mL; hemoglobin: ten concentrations ranging from 0.5mg/mL to 5.0mg/mL, varying by 0.5mg/mL). Interference was evaluated by RE% and accepted within 80-120%. Analyte stability was assessed by incubating aliquots of three serum samples for 2, 4, 24 or 48 hrs at both 4°C and 20°C. The RE% was calculated relative to control serum samples, thawed upon analysis, and RE% was accepted within 80-120%.
• Stability was further evaluated through repeated freeze-thaw cycles of serum samples: up to five rounds of freeze-thaw cycles. Freeze-thaw stability was calculated based on the RE% relative to samples that underwent a single thawing prior to analysis, accepted if RE% was within 80-120%.
• the technical stability of the assay was evaluated by three runs of the assay using kit reagents incubated at 20°C for 24 hrs and calculating the RE% of ten samples measured using reagents from frozen storage, acceptance criteria of RE% within 80-120%.
• Patient samples The first cohort included 223 cancer samples and 33 healthy samples.
• the second cohort included 20 healthy donors and 39 patients with pancreas ductal adenocarcinoma (PDAC). All patients were from the Danish BIOPAC study “BIOmarkers in patients with Pancreatic Cancer” (NCT03311776). Patients were recruited from six Danish hospitals from December 2008 until September 2017. PC patients had histologically confirmed tumors. The PC patients were treated with various types of chemotherapy according to national guidelines (www.gicancer.dk). The study was carried out in accordance with the recommendations of the Danish Regional Committee on Health Research Ethics. The BIOPAC protocol was approved by the Danish Regional Committee on Health Research Ethics (VEK ref. KA-20060113) and the Data Protection Agency (j.nr. 2006-41-6848). Blood samples were obtained at the time of diagnosis or before operation.
• PDAC pancreas ductal adenocarcinoma
• BIOPAC cohort Statistics Comparison of PRO-C22 levels were made using a Kruskal-Wallis test followed by Dunn’s multiple comparison test comparing each solid cancer type to the healthy control group. This was followed by testing diagnostic accuracy of PRO-C22 by area under the receiver operating characteristic (AUROC) curve.
• the BIOPAC cohort was used to evaluate associations with overall survival (OS) using the median as cut point to define a group with high PRO-C22 levels.
• Kaplan Meier curve analysis and univariate Cox regression analysis were used to evaluate associations between PRO-C22 and OS. Asterisks indicate the following significance levels: ** p ⁇ 0.01; *** p ⁇ 0.001; **** p ⁇ 0.0001.
• Results PRO-C22 ELISA development Through the ELISA development process, optimizing steps were made to find an appropriate assay buffer, incubation time and temperature as well as concentrations of antibody and peptides to give the best competitive setting for the assay.
• the competitive immunoassay PRO-C22 used a horseradish peroxidase labeled mAb (HRP-mAb) to quantify the amount of COL22 in serum samples.
• the assay included a standard peptide (GPPGPPGQCDPSQCAYFASLAARPGNVKGP (SEQ ID No. 16)) that by competing away the interaction between HRP-mAb and a biotinylated version of the peptide (Biotin-AARPGNVKGP (SEQ ID No.
• the low lipid concentration of 1.5mg/mL in three serum samples had a mean RE% of 104.6% and the high concentration of 5mg/mL a mean RE% of 102.3%.
• the interference cut-off of hemoglobin was determined using concentrations varying by 0.5mg/mL of hemoglobin ranging from 0.50mg/mL to 5.0mg/mL. At 3.0mg/mL the mean RE% of three serum samples was 126.6% and exceeded the acceptable range of RE% (80-120%). Hence the cut- off was determined to be at a concentration of 2.5 mg/mL based on the mean RE% of 112.5%. Stability was evaluated regarding both analyte and kit reagent stability.
• the mean RE% of three serum samples that underwent five freeze-thaw cycles was 103.1%. Serum samples incubated up to 48hrs at 4°C had a RE% of 107.2% and 106.1% for samples incubated up to 48hrs at 20°C.
• the kit reagents buffer, biotinylated-peptide and HRP-mAb were evaluated after 24hrs of incubation at 20°C.
• the stability of the reagents was evaluated by measuring the same ten samples used for intra- and inter- variation and calculating the RE%. The ten samples, measured in three individual runs, showed a mean RE% of 94.4%.
• a summary of the technical validation is depicted in Table 3. Table 3. Summary of the technical validation of PRO-C22.
• PRO-C22 was validated to be elevated in patients with pancreas cancer in the second (BIOPAC) cohort ( Figure 3).
• high PRO-C22 (above the median: 50th percentile) was significantly associated with poor OS in pancreas cancer with a Hazard Ratio of 3.987 (95%CI: 1.724-8.806) compared to patients with low levels.
• the levels of circulating type XXII collagen could be assessed in the serum of cancer patients and healthy controls with levels of PRO-C22 being significantly higher in all cancers tested compared to healthy controls.
• the levels of PRO-C22 may be used to distinguish between cancer patients and healthy controls.
• the levels of PRO-C22 may also be used to provide a prognosis for overall survival in pancreatic cancer.
• the word ‘or’ is used in the sense of an operator that returns a true value when either or both of the stated conditions is met, as opposed to the operator ‘exclusive or’ which requires that only one of the conditions is met.
• the word ‘comprising’ is used to mean ‘including or consisting of’. All prior teachings acknowledged above are hereby incorporated by reference.

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