Autoantibody Recognition of Natural and Homocysteinylated Alpha-1 Antitrypsin: Indirect Enzyme-Linked Immunosorbent Assay (ELISA) Quantification in Sera

In this chapter, indirect enzyme-linked immunosorbent assays (ELISAs) to quantitatively measure autoantibodies directed to human natural and homocysteinylated alpha-1 antitrypsin (anti-AATA and anti-HAATA, respectively) in serum are described. The illustrated ELISA protocols are slightly different, since the two protein forms have different biochemical features and, consequently, different affinity for the matrix (polystyrene microplate wells), so that specific experimental conditions have to be performed for the quantification of the serum antibody recognition. These procedures can be carried out to evaluate the anti-AATA and the anti-HAATA levels, testing serum samples, for research use.