tumor associated antigen

Twelve mouse monoclonal antibodies against human gastric cancer were developed using hybridomas. Immunohistochemistry confirmed that the corresponding antigen of this group of monoclonal antibodies existed in gastric cancer, colon cancer, and esophageal cancer tissues, but not in normal tissues and other cancer tissues. Antigen analysis indicated that the corresponding antigen of this group of monoclonal antibodies is a new tumor-associated antigen. Basic Information Specialist classification: Oncology examination classification: chest and ascites examination Applicable gender: whether men and women apply fasting: not fasting Tips: Do not eat too greasy, high-protein foods the day before the blood draw, avoid heavy drinking. The alcohol content in the blood directly affects the test results. Normal value Non-tumor disease chest and ascites <27kU / L. Clinical significance Using the mixture of monoclonal antibodies MG7, MG9, MGb1, MGc1 and MGd1 and immunoradiometric assay, the tumor-associated antigen MG-Ags in the ascites and ascites was determined. The average content and positive rate of MG-Ags in the thoracic and ascites of patients with gastric cancer and lung cancer were found. Higher than tuberculous pleurisy, portal cirrhosis. There was no increase in MG-Ags in the ascites of ovarian cancer. The first cytopathological examination of 6 cases of lung cancer pleural effusion did not find cancer cells, and immunoradiometric analysis found that 4 of them had elevated MG-Ags. It is revealed that the determination of MG-Ags in the thoracic and ascites by IRMA is helpful for the diagnosis of neoplastic serositis, and to some extent, the primary organs of tumor cells are discriminated. High results may be diseases: pleural effusion, elderly gastric cancer, familial colon polyps, elderly pancreatic cancer, small cell lung cancer, lung cancer The detection rate of lung cancer only accounted for 28.6%, but the detection rate of lung squamous cell carcinoma can account for 44.4%. Combined detection with CYFRA-21-1 can increase the positive rate. Inspection process The method is divided into three steps, namely antigen-antibody reaction, B and F separation, and radioactivity determination. (1) Reaction of antigen with antibody: The specimen (non-labeled antigen), labeled antigen and antiserum are sequentially dosed into a small test tube, and allowed to stand at room temperature (15 to 30 ° C) for 24 hours to fully compete for binding. (2) Separation of B and F: There are various separation techniques, and the precipitation method is commonly used. 1 second antibody precipitation method: also known as diabody method, after the test antigen specifically reacts with the first antibody, the corresponding second antibody is added, so that the formed antigen-first antibody-second antibody complex is co-precipitated. The labeled antigen B is separated from the free antigen F by centrifugation. This method is a specific precipitation, complete separation, low non-specific binding. However, the amount of the second antibody is large and the cost is high. In addition, the serum concentration and the presence or absence of anticoagulants can affect the results to some extent. 2 Polyethylene glycol (PEG) precipitation method: the protein is in an isoelectric point state, and the hydration layer is destroyed to cause protein precipitation. The advantage of this method is that PEG is convenient to prepare, inexpensive, and rapid to separate. The disadvantage is that there are many non-specific precipitates and the separation is incomplete. 3Second antibody-polyethylene glycol precipitation method: This method not only has the advantage of rapid precipitation of PEG method, but also maintains the effect of specific precipitation of second antibody, reduces the amount of second antibody, and reduces the concentration of PEG, so that non-specific precipitation Reduced material. 4 Activated carbon adsorption method: the free part of small molecules is adsorbed by the surface activity of activated carbon. For example, a layer of dextran is coated on the surface of the activated carbon to make a mesh having a certain pore diameter on the surface, thereby allowing small molecules of free antigen or hapten to escape and being adsorbed, while the macromolecular complex is excluded. After the antigen and the antibody are reacted, the dextran-activated carbon is added and allowed to stand for 5 to 10 minutes, so that the free antigen is adsorbed on the activated carbon particles, and the particles are precipitated by centrifugation, and the supernatant contains the labeled antigen. (3) Determination of radioactivity: After separation of B and F, the radioactivity can be measured. There are two types of measuring instruments: a liquid scintillation counter (measuring beta rays) and a crystal scintillation counter (measuring gamma rays). The unit of counting is the number of electrical pulses output by the detector in units of cpm (number of pulses/min). A standard curve is required for each measurement, and the different concentrations of the standard antigen are plotted on the abscissa, and the corresponding radioactivity measured is plotted on the ordinate. The radioactivity may be optionally B or F, and the calculated values ​​B/B+F, B/F or B/B0 may also be used. Specimens should be determined in duplicate, the average value is taken, and the corresponding antigen concentration is detected on the standard curve. Not suitable for the crowd There are no taboos. Adverse reactions and risks This test generally does not cause complications and harm.