CELA1 antibody validation. A: an immunoblot for CELA1 (green) and β-actin (red) demonstrated the lack of nonspecific bands but an unexpectedly high molecular mass for CELA1, approximately double the expected molecular mass of 28 kDa. B: with the use of PN 8 wk lung homogenate and pancreatic homogenate, adsorption of the generated antibody with the antigenic peptide prevented antibody-antigen interaction with loss of the band. Pancreatic homogenate generated a CELA1 band at the expected 28 kDa, and this band was also lost with adsorption. The protein concentration of pancreatic homogenate was 0.1% that of the lung homogenates; thus, there is no visible β-actin band. C: there was no signal apparent after incubating PND14 elastin in situ zymography lung sections with fluorophore-conjugated anti-guinea pig secondary antibody. D: in contrast, CELA1+ cells were visualized with the use of the generated anti-CELA1 antibody before secondary antibody incubation.