Ca. Owen et al., MONOCYTES RECRUITED TO SITES OF INFLAMMATION EXPRESS A DISTINCTIVE PROINFLAMMATORY (P) PHENOTYPE, American journal of physiology. Lung cellular and molecular physiology, 11(6), 1994, pp. 120000786-120000796
Only a minor proportion of monocytes responds to chemoattractants. To
test the possibility that chemoattractant-responsive monocytes have di
stinctive functional characteristics, we enriched or depleted monocyte
preparations for cells having a proinflammatory (P) phenotype and tes
ted their responses to biologically relevant chemoattractants. We prep
ared monocyte subpopulations by one of three independent techniques to
minimize the chances of artifacts: 1) depletion of P monocytes by adh
erence to fibronectin; 2) enrichment for P monocytes by negative selec
tion for HLA-DR antigen; and 3) flow cytometric sorting. We measured r
esponsiveness of monocyte subpopulations to N-formyl-met-Leu-Phe, C5a,
zymosan-activated serum, and monocyte chemoattractant protein-1 by th
ree parameters: 1) polarization, 2) actin polymerization, and 3) direc
ted migration. With each chemoattractant and each parameter, there was
a striking direct relationship between the responsiveness of the mono
cyte preparations and their content of P monocytes. Our data indicate
that the capacity of monocytes to be recruited rapidly from the vascul
ature into sites of inflammation is a property of a subpopulation of m
onocytes with a distinctive, neutrophil-like proinflammatory phenotype
.