Ascorbate recycling in human neutrophils: Induction by bacteria

Yaohui Wang, Thomas A. Russo, Oran Kwon, Stephen Chanock, Steven C. Rumsey, Mark Levine

Research output: Contribution to journalArticlepeer-review

100 Scopus citations


Ascorbate (vitamin C) recycling occurs when extracellular ascorbate is oxidized, transported as dehydroascorbic acid, and reduced intracellularly to ascorbate. We investigated microorganism induction of ascorbate recycling in human neutrophils and in microorganisms themselves. Ascorbate recycling was determined by measuring intracellular ascorbate accumulation. Ascorbate recycling in neutrophils was induced by both Gram-positive and Gram-negative pathogenic bacteria, and the fungal pathogen Candida albicans. Induction of recycling resulted in as high as a 30-fold increase in intracellular ascorbate compared with neutrophils not exposed to microorganisms. Recycling occurred at physiologic concentrations of extracellular ascorbate within 20 min, occurred over a 100-fold range of effector/target ratios, and depended on oxidation of extracellular ascorbate to dehydroascorbic acid. Ascorbate recycling did not occur in bacteria nor in C. albicans. Ascorbate did not enter microorganisms, and dehydroascorbic acid entry was less than could be accounted for by diffusion. Because microorganism lysates reduced dehydroascorbic acid to ascorbate, ascorbate recycling was absent because of negligible entry of the substrate dehydroascorbic acid. Because ascorbate recycling occurs in human neutrophils but not in microorganisms, it may represent a eukaryotic defense mechanism against oxidants with possible clinical implications.

Original languageEnglish
Pages (from-to)13816-13819
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number25
StatePublished - 9 Dec 1997


Dive into the research topics of 'Ascorbate recycling in human neutrophils: Induction by bacteria'. Together they form a unique fingerprint.

Cite this