Solid phase-bound elastase-binding assay for the measurement of alpha

1. A method for the measurement of active alpha 1 -proteinase inhibitor (A1PI) in a sample, comprising the steps of

(a) binding elastase to a solid phase, wherein the elastase bound to the solid phase retains its enzymatic activity;

(b) incubating the solid phase from step (a) with the sample; and then washing the solid phase;

(c) incubating the solid phase from step (b) with a detection reagent specifically binding to A1PI, wherein the detection reagent comprises an A1PI epitope binding domain, and then washing the solid phase;

(d) determining the amount of detection reagent bound to the solid phase in step (c); and

(e) thereby determining the amount of active A1PI in the sample.

2. The method according to claim 1 , further comprising the step of blocking the solid phase with bovine serum albumin prior to step (b).

3. The method according to claim 1 , further comprising the step of diluting the sample prior to incubation with the solid phase in step (b).

4. The method according to claim 1 , wherein the elastase is porcine elastase.

5. The method according to claim 1 , wherein the solid phase is a microplate.

6. The method according to claim 1 , wherein the detection reagent is conjugated to peroxidase.

7. The method according to claim 1 , wherein the detection reagent is selected from an antibody, an antibody fragment, a camelized antibody, a camelized antibody fragment, a Fv fragment, a single chain Fv (scFv) fragment, a Fab′fragment, a F(ab′)2 fragment, a chimeric antibody and a multivalent version or a combination thereof.

8. The method according to claim 7 , wherein the detection reagent is conjugated to peroxidase.