Induction of Phagocyte Oxidase Components during Human Myeloid Differentiation: Independent Protein Expression and Discrepancy with the Function

We investigated the content of four components of the O2(-)-producing enzyme (p47, p67, p22, and gp91) and the O2(-)-producing capacity in human myeloid cell lines. The content of the four components of the phagocyte oxidase was minimal before differentiation induction. During differentiation, expression of p22 and gp91 was at consistently low levels, even when the O2(-)-producing capacity was equivalent to that of normal neutrophils. On the other hand, p47 was consistently and rapidly induced to the level comparable to normal neutrophils. The results indicate that low expression of p22 and gp91 is sufficient to obtain normal O2- production, and that p47 might play an important regulatory role in the functional differentiation.