Materials and Reagents

1. Boric acid (Sigma-Aldrich, catalog number: B6768 )
   
2. Disodium tetraborate (Borax) (Sigma-Aldrich, catalog number: 71996 )
   
3. NaCI (Sigma-Aldrich, catalog number: S3014 )
   
4. Polyethylene glycol (PEG 8000) (Sigma-Aldrich, catalog number: 89510 )
   
5. Phosphate buffer saline (Life Technologies, Gibco^®, catalog number: 20012-027 )
   
6. NaHCO₃ (Sigma-Aldrich, catalog number: S6014 )
   
7. Na₂CO₃ (Sigma-Aldrich, catalog number: 330361 )
   
8. BSA (Sigma-Aldrich, catalog number: A7030 )
   
9. Tween 20 (Sigma-Aldrich, catalog number: P9416 )
   
10. Antihuman affinipure IgG/lgA/lgM HRP [The Jackson Laboratory, USA, catalog number: 709-036-149 (IgG); 109-036-011 (IgA); 309-036-043 (IgM)]
    
11. Na₂HPO₄ (Sigma-Aldrich, catalog number: S3264 )
    
12. Citric acid (Sigma-Aldrich, catalog number: 251275 )
    
13. O-Phenylenediamine (OPD) (Sigma-Aldrich, catalog number: P5412 )
    
14. H₂SO₄ (Sigma-Aldrich, catalog number: 320501 )
    
15. 0.1 M borate buffer (pH 8.4) (see Recipes)
    
16. 7% polyethylene glycol (PEG) (see Recipes)
    
17. Phosphate buffer saline (PBS) (see Recipes)
    
18. 0.06 M Carbonate buffer (pH 9.6) (see Recipes)
    
19. Blocking solution (see Recipes)
    
20. Primary antibody (see Recipes)
    
21. Secondary antibody (see Recipes)
    
22. Substrate buffer (see Recipes)
    
23. Substrate (see Recipes)
    
24. Stop solution (see Recipes)
    

Equipment

1. Refrigerated bench-top centrifuges
   
2. 96 wells flat bottom ELISA plates (Nunc^®, catalog number: 44-2404-21 )
   
3. ELISA washer (Organon Teknika)
   
4. Spectromax ELISA reader (Molecular Devices)
   

Procedure