USDA-Licensed Plate Antigens for Plate Agglutination Test
|Mycoplasma gallisepticum Antigen
SPAFAS MG Plate Antigen for Plate Agglutination Test (Material No. 10100760)
This antigen is a suspension of killed, stained A5969 strain of Mycoplasma gallisepticum (MG) for serum plate agglutination testing of chicken and turkey flocks.
|Mycoplasma meleagridis Antigen
SPAFAS MM Plate Antigen for Plate Agglutination Test (Material No. 10100825)
This antigen is a suspension of killed Mycoplasma meleagridis (MM) for serum plate agglutination testing of turkey flocks.
|Mycoplasma synoviae Antigen
SPAFAS MS Plate Antigen for Plate Agglutination Test (Material No. 10100761)
This antigen is a suspension of killed, stained WVU1853 strain of Mycoplasma synoviae (MS) for serum plate agglutination testing of chicken flocks.
Stained Antigen Polyvalent for Plate Agglutination Test (Material No. 10105346)
This antigen is a suspension of five (5) killed, stained strains (4, 11, 77, 79 and 296) of Salmonella pullorum for use in the whole-blood or serum plate agglutination test for the detection of pullorum disease and fowl typhoid in poultry flocks.
Serum Plate Antiserum/Antibody
Positive and negative control antibodies are available for MG, MM, MS, and Salmonella polyvalent (Groups B & D).
|Serum Plate Antiserum/Antibody||Material No.*|
|Salmonella polyvalent (Group B & D)||10100702|
|*1 ml per vial (liquid; store at 4 °C)|
Confirmatory Testing Reagents
|Mycoplasma gallisepticum Whole Organism||10100704|
|Mycoplasma synoviae Whole Organism||10100707|
|Mycoplasma gallisepticum Antiserum||10100478|
|Mycoplasma synoviae Antiserum||10100482|
|*1 ml per vial|
Serum Plate Agglutination Test Principle
The serum plate agglutination (SPA) test is used to detect specific antibodies that will bind to an antigen and cause visible “clumping” or agglutination. The antigen is prepared from cultures of Mycoplasma gallisepticum (MG), Mycoplasma meleagridis (MM), Mycoplasma synoviae (MS), or Salmonella pullorum and a dye is added to improve visibility of the reactions. A prescribed amount of antigen is placed on a solid support, such as a glass plate or mirror, keeping each drop of antigen separate. An equal amount of test serum is placed next to the antigen and these are then mixed together. After a short incubation, the mixture is examined for evidence of agglutination, which appears as discrete clumps of the stained particles with a clearer background. If no antibodies are detected, the mixture will remain opaque.
Standard Procedure for Performing the SPA Test
- Prewarm all components (solid plate, antigen, control sera and test sera) to room temperature before use.
- Vortex the antigen well for 15-20 seconds to mix.
- Always use the antigen undiluted.
- Use positive and negative controls each time the assay is performed.
- Use only 0.04 ml of antigen or one drop from the dispensing tip and 0.04 – 0.05 ml of serum sample.
- Mix the serum with the antigen, keeping each mixture within one square.
- Start the timer set for 2 minutes.
- Gently rotate the plate for a few seconds, then let stand. After one minute, the plate may be rotated again and allowed to stand. After 2 minutes, the reactions can be read.
- A positive reaction shows formation of discrete clumps of stained material, normally starting at the edge of the mixture. The quality of the serum can affect the appearance, and only stained clumps should be considered suspect. Negative reactions show little change in the opaque serum antigen mixture after 2 minutes.
- Reagents and sera should never be frozen.
Indications for Antigen Use
These antigens are used in a screening test for the presence of MG, MS, MM, and Salmonella pullorum in a flock and should not be used as a final determination of the infection status of individual birds. When used on a flock basis, these antigens provide a simple method for detecting the presence of antibodies in the population. As in all serologic assays, positive reactions should be followed by other tests to confirm the infection status of the flock. It is strongly advised that flocks that give positive reactions in the SPA test be sampled for confirmatory testing before the infection status is verified. Repeated testing is also needed to continue certification that the flock is negative. Consult your poultry veterinarian in case of any clinical signs or questionable reactions. DO NOT DESTROY ANY FLOCK BASED UPON RESULTS OF TESTING WITH THESE ANTIGENS.