salivary secreted immunoglobulin

The immunoglobulins in saliva are mainly SIgA and SIgG. The SIg content in resting saliva is often higher than that of irritating saliva. It is often measured by RIA and one-way diffusion. The SIgA and SIgG levels in children's saliva are significantly lower than those in adults, increasing with age and approaching adult levels after age 16. Basic Information Specialist classification: Oncology examination classification: immune examination Applicable gender: whether men and women apply fasting: fasting Tips: Try to eat less and eat as much as possible, and arrange your diet reasonably. Normal value The SIgA and SIgG levels in children's saliva are significantly lower than those in adults, increasing with age and approaching adult levels after age 16. Clinical significance (1) Ig increases inflammation of the salivary gland, malignant tumors and the like can destroy the blood-saliva barrier, allowing Ig in the blood to enter the saliva, so that SIgA, SIgG, and SIgM can be increased. Certain viral infections, such as early measles, can detect specific SIgA-type antibodies from saliva, which is helpful for diagnosis. Sjogren syndrome is an autoimmune disease that mainly invades the exocrine glands and increases SIgA in saliva. Local inflammation in the mouth can also be increased. (2) Ig reduces pathological salivation Ig reduction seen in primary or secondary immunodeficiency diseases such as congenital gamma globulin deficiency, primary selective SIgA deficiency, application of immunosuppressive agents and radiation therapy, caries SIgA can also be reduced in children and large numbers of smokers. Low results may be diseases: measles virus pneumonia results may be high disease may be: measles, congenital gamma globulin hypoxia, positive results may be diseases: measles, congenital all-gammaglobulin hypolipidemia, measles virus pneumonia Radioimmunoassay has sensitivity (which can measure sodium or even picogram levels), strong specificity (resolvable antigens with similar structure) and good accuracy (recovery of sodium gram amount is close to 100%). 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 concentration of the specimen and the presence or absence of the anticoagulant 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 is no inappropriate crowd. Adverse reactions and risks It is a safe check and is harmless to the body.