N-formylmethionyl-leucyl-[3H]phenylalanine binding, superoxide release, and
chemotactic responses of human blood monocytes that repopulate the
circulation during leukapheresis
E Alteri and EJ Leonard
Human blood monocytes comprise two subpopulations: one migrates to the
chemoattractant, N-formylmethionyl-leucyl-phenylalanine (fMet-Leu-Phe), and
has saturable binding sites for this peptide; the other does not migrate
and exhibits little peptide binding. To determine if expression of binding
sites was a function of monocyte maturation, we depleted human subjects of
blood monocytes by leukapheresis so that the circulation was repopulated by
monocytes released from the bone marrow. Pre- and postleukapheresis
monocytes were then compared for fMet-Leu- [3H]Phe binding, superoxide
generation, and chemotactic responses. No significant differences in
peptide binding curves were found, suggesting that receptor expression was
stable over the maturational span represented by these two groups of cells.
This supports the hypothesis that there are two distinct lineages of
monocytes with respect to expression of receptors for fMet-Leu-Phe. An
additional finding of interest was that the number of chemotactically
responsive cells immediately postleukapheresis was half the control. This
was a transient state; monocyte responses were normal 3 hr after
termination of leukapheresis, suggesting that they rapidly become
functionally mature.
Volume 62,
Issue 4,
pp. 918-923,
10/01/1983
Copyright © 1983 by The American Society of Hematology
