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SummaryClosely similar but nonidentical NH2-terminal amino acid sequences have been reported for a protein or proteins in human neutrophils whose bioactivities is/are diverse (as a serine protease, antibiotic, and Wegener's granulomatosis autoantigen) but that share(s) several features: localization in the azurophil granules, a molecular mass of ti29 kD, reactivity with diisopropylfluorophosphate, and the ability to degrade elastin. We previously purified one such entity, termed p29b. Using a monospecific antibody, we have cloned from human bone marrow a cDNA encoding the complete p29b protein in its mature form, along with pre-and pro-sequences . The predicted amino acid sequence agrees closely with the NH2-terminal sequence obtained previously from purified p29b, as well as with sequences newly obtained from CNBr fragments . The primary structure is highly homologous to elastase, cathepsin G, T cell granzymes, and other serine proteases, and shares both the catalytic triad and substrate binding pocket of elastase. Hybridization ofthe full-length cDNA with restriction enzyme digests of human genomic DNA revealed only one fragment. This suggests that the closely related species described previously are the same, and can be subsumed by the term used for the first-described activity, proteinase 3. Proteinase 3 is more abundant in neutrophils than elastase and has a similar proteolytic profile and specific activity. Thus, proteinase 3 may share the role previously attributed to neutrophil elastase in tissue damage, and has the potential to function as an antimicrobial agent .

Cetuximab elicits effective ADCC activity against a wide range of tumor cells in vitro. This activity is dependent on antibody glycosylation and IgG1 isotype as well as tumor-cell EGFR expression. These findings suggest that ADCC may contribute to the antitumor activity of cetuximab.

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