Association of lactoferrin with lysozyme in granules of human polymorphonuclear leukocytes.

Lactoferrin is contained in cytoplasmic granules of human polymorphonuclear leukocytes. Upon centrifugation, it sediments in a band of granules that also contain 50% of the lysozyme activity. This granule class is distinct from others associated with alkaline phosphatase and peroxidase. The granules are latent for lactoferrin as only lysed granules have the capacity specifically to inhibit antigen binding by anti-lactoferrin serum.