A subpopulation of human polymorphonuclear neutrophils contains an active form of lactoferrin capable of binding to human monocytes and inhibiting production of granulocyte-macrophage colony stimulatory activities

H. E. Broxmeyer, P. Ralph, J. Bognacki, P. W. Kincade, M. Desousa

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Abstract

Subpopulations of human peripheral blood polymorphonuclear neutrophils (PMN) differing in functional capacity were separated by a rosetting procedure by using rabbit IgG antibody-coated sheep erythrocytes (EA). EA + and EA - populations of PMN both contained lactoferrin (LF) as determined by radioimmunoassay. However, only LF (10 -16 to 10 -6 M) obtained from EA + (= FC receptor (FcR) +) PMN was able to suppress the production of granulocyte-macrophage colony stimulatory activity derived from monocytes. LF from EA - PMN was inactive at concentrations as high as 10 -5 M. Extracts of EA - PMN contained proteolytic enzymes, not apparent in FcR + PMN, that inactivated the inhibitory activity of LF obtained from FcR + PMN. These results were substantiated by immunofluorescence studies. LF from FcR + PMN bound to monocytes whereas LF from EA - PMN demonstrated negligible binding to the monocytes and extracts from EA - PMN drastically decreased the capability of LF obtained from FcR + obtained from FcR + PMN to bind to monocytes. These studies demonstrate functional heterogeneity of peripheral blood PMN and suggest a role of PMN subpopulations in the regulation of myelopoiesis.

Original languageEnglish (US)
Pages (from-to)903-909
Number of pages7
JournalJournal of Immunology
Volume125
Issue number2
StatePublished - Nov 10 1980

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ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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