FIG. 4.

RP-HPLC chromatograms of ovine BAL fluid (A) and ovine epithelial-cell extracts (B), showing peak fraction 5, eluted in 13 to 14% acetonitrile, with antimicrobial activity and evidence of AP by competitive ELISA with antibody 1G9-1C2. BSA-DDDDDDD-OH conjugate (50 ng of conjugate/well) was used as the adsorbed antigen, and RP-HPLC fractions were used as the competitive antigens in the presence of antibody 1G9-1C2 (1.0 μg/ml). To confirm the presence of AP, fractions were examined by MALDI mass spectrometry. H-DDDDDDD-OH [(M + H)⁺; 824.4 Da], H-GDDDDDD-OH [(M + H)⁺; 766.1 Da], and H-GADDDDD-OH [(M + H)⁺; 718.24 Da] were detected.