{
  "patent_number": "US 4376110",
  "country": "US",
  "title": "How Two Special Antibodies Find Substances in Body Fluids",
  "original_title": "Immunometric assays using monoclonal antibodies",
  "summary": "This patent describes a \"sandwich\" method using two highly specific, man-made antibodies to detect and measure tiny amounts of specific substances, like disease markers, in a fluid sample.",
  "what_it_does": "This patent describes a \"sandwich\" method to find or measure tiny amounts of a specific substance, called an \"antigenic substance,\" in a fluid. First, a sample of the fluid is mixed with a measured amount of a special, man-made \"first monoclonal antibody\" that has a label, like a radioactive tag (Claim 1(a), Claim 8). This first antibody attaches to the target substance. Then, this mixture is exposed to a \"second monoclonal antibody\" that is stuck to a solid surface (Claim 1(b)). This second antibody also attaches to the target substance, creating a \"sandwich\" where the target substance is held between the two antibodies. The solid surface is then separated and washed (Claim 1(c), Claim 5), and the amount of labeled first antibody stuck to it is measured (Claim 1(d)). By comparing this measurement to known samples, the presence or amount of the target substance can be determined (Claim 1(e)). For example, this could be used to detect hepatitis B proteins in a blood sample.",
  "what_it_does_not_cover": [
    "Does not cover assays that use polyclonal antibodies, which are mixtures of different antibodies.",
    "Does not cover single-antibody detection methods or competitive binding assays.",
    "Does not cover methods where both antibodies are soluble or both are bound to a solid surface.",
    "Does not cover antibodies with an affinity lower than 10^8 liters/mole for the target substance."
  ],
  "filed": "1980-08-04",
  "granted": "1983-03-08",
  "expires": null,
  "status": "active",
  "holder": "Hybritech Inc",
  "holder_url": "https://patentbrief.org/company/hybritech-inc",
  "inventors": [
    {
      "name": "Gary S. David",
      "url": "https://patentbrief.org/inventor/gary-s-david"
    },
    {
      "name": "Howard E. Greene",
      "url": "https://patentbrief.org/inventor/howard-e-greene"
    }
  ],
  "times_cited": 1572,
  "tags": [
    "biotech",
    "pharmaceutical",
    "diagnostics",
    "medical_devices"
  ],
  "abstract": "\"Two-site\" or \"sandwich\" immunometric assay techniques for determination of the presence and/or concentration of antigenic substances in fluids using monoclonal antibodies. One monoclonal antibody is presented in a soluble labeled form and a second monoclonal antibody is presented bound to a solid carrier; the soluble and bound monoclonal antibodies may be the products of either the same or different cell lines. Each monoclonal antibody has an affinity for the antigenic substances of at least about 10 8 liters/mole.",
  "url": "https://patentbrief.org/patent/us/4376110/psa-test-for-prostate-cancer",
  "markdown_url": "https://patentbrief.org/patent/us/4376110/psa-test-for-prostate-cancer/md",
  "google_patents_url": "https://patents.google.com/patent/US4376110",
  "relatedPatents": []
}