Comparative analysis of the morphological, cytochemical, immunophenotypical, and functional characteristics of normal human peripheral blood lineage(-)/CD16(+)/HLA-DR(+)/CD14(-/lo) cells, CD14(+) monocytes, and CD16(-) dendritic cells.
Human peripheral blood (PB) CD14(lo)/HLA-DR(+) cells were initially described as a subset of mature monocytes. Recently, it has been suggested that these represent a part of a new subset of dendritic cells (DC), characterized by the coexpression of MDC-8/HLA-DR/CD16. The aim of the present paper was to analyze the morphological, cytochemical, phenotypical, and functional characteristics of PB CD16(+)/HLA-DR(+) cells compared to both PB CD14(+) monocytes and CD16(-) DC. In contrast to CD14(+) monocytes, purified CD16(+)/HLA-DR(+) cells displayed cytoplasmic veils and lacked cytoplasmic myeloperoxidase and alpha-naphthyl acetate esterase. Normal human PB CD16(+)/HLA-DR(+) cells also displayed phenotypic characteristics different from those of CD14(+) monocytes: they lacked the CD64 Fcgamma receptor, showed lower levels of CD32, and expressed higher amounts of CD16 compared to CD14(+) monocytes. They also displayed a different pattern of expression of other antigens, including CD14, HLA-DR, CD45RA, CD45RO, complement receptors and complement regulatory surface proteins, adhesion and costimulatory molecules, and cytokine receptors, among others. When compared to CD16(-) DC, CD16(+)/HLA-DR(+) cells showed reactivity for CD16, dim positivity for CD14, higher expression of both Ig- and complement-receptors and lower reactivity for HLA-DR, adhesion, and costimulatory molecules (with the exception of CD86). The CD16(+)/HLA-DR(+) cell subset displayed a higher Ig/complement-mediated phagocytic/oxidative activity than CD16(-) DC, although this activity was significantly lower than that of mature monocytes. Regarding cytokine production at the single cell level, LPS plus IFN-gamma-stimulated PB CD16(+)/HLA-DR(+) cells produced significant amounts of IL1beta, IL6, IL12, TNFalpha, and IL8; however, the percentage of cytokine-producing cells and the amount of cytokine/cell were lower in CD16(+)/HLA-DR(+) cells than in CD14(+) monocytes. In addition, upon comparing CD16(+)/HLA-DR(+) cells with CD33(+++)/CD16(-) DC, we found that the percentage of cytokine-producing cells and the amount of cytokine/cell were significantly different in both cell subsets. In summary, our results show that CD16(+)/HLA-DR(+) cells clearly display different morphologic, cytochemical, immunophenotypical, and functional characteristics compared to both mature monocytes and CD16(-) DC. Interestingly, these cells are more frequent than other DC in normal human adult PB and cord blood samples, while they are less represented in normal bone marrow.
Almeida
J
J
Servicio General de Citometría y Departamento de Medicina, Universidad de Salamanca, Salamanca, Madrid.
Bueno
C
C
Algueró
M C
MC
Sanchez
M L
ML
de Santiago
M
M
Escribano
L
L
Díaz-Agustín
B
B
Vaquero
J M
JM
Laso
F J
FJ
San Miguel
J F
JF
Orfao
A
A
D000328:Adult; D019070:Cell Lineage; D016207:Cytokines / Q000096:biosynthesis; D003713:Dendritic Cells / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006684:HLA-DR Antigens / Q000032:analysis*; D006651:Histocytochemistry; D006801:Humans; D016130:Immunophenotyping; D018950:Lipopolysaccharide Receptors / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology*; D010084:Oxidation-Reduction; D010587:Phagocytosis; D017452:Receptors, IgG / Q000032:analysis*
D016207:Cytokines; D006684:HLA-DR Antigens; D018950:Lipopolysaccharide Receptors; D017452:Receptors, IgG