LACTOFERRIN - A PROMOTER OF POLYMORPHONUCLEAR LEUKOCYTE ADHESIVENESS

  • 1 January 1981
    • journal article
    • research article
    • Vol. 57  (5) , 939-945
Abstract
Polymorphonuclear leukocytes (PMN) degranulate, adhere to vascular endothelium or aggregate to each other following exposure of the cells to high concentrations of chemotactic stimuli such as formly-methionyl-leucyl phenylalanine (FMLP). PMN released the specific granule product lactoferrin more readily in response to chemotactic stimuli, which correlated with promotion of PMN aggregation as measured by light transmission and enhanced PMN adherence. Both concanavalin A (Con-A) and phorbol myristate acetate (PMA), agents that lead to specific granule discharge, induced and sustained human PMN aggregation. Supernatants, generated from Con-A-treated PMN, aggregated fresh PMN in the presence of .alpha.-methylmannoside, a competitive inhibitor of the lectin. Anti-human lactoferrin IgG but not normal goat IgG blunted the aggregation elicited by both PMA and FMLP. Both human milk lactoferrin and rabbit PMN lactoferrin aggregated human PMN in a dose dependent fashion. Human lactoferrin promoted PMN adherence to endothelial cells. The enhanced PMN stickiness was correlated with the early phases of degranulation. PMN lactoferrin serves an autoregulatory role to retain PMN at inflammatory sites to amplify the inflammatory response.