Properties of human blood monocytes. I. CD91 expression and log orthogonal light scatter provide a robust method to identify monocytes that is more accurate than CD14 expression

Abstract

Background: This study was designed to improve identification of human blood monocytes by using antibodies to molecules that occur consistently on all stages of monocyte development and differentiation.Methods: We examined blood samples from 200 healthy adults without clinically diagnosed immunological abnormalities by flow cytometry (FCM) with multiple combinations of antibodies and with a hematology analyzer (Beckman LH750).Results: CD91 (a 2 -macroglobulin receptor) was expressed only by monocytes and to a consistent level among subjects [mean median fluorescence intensity (MFI) 5 16.2 6 3.2]. Notably, only 85.7 6 5.82% of the CD91 1 monocytes expressed high levels of the classical monocyte marker CD14, with some CD91 1 CD16 1 cells having negligible CD14, indicating that substantial FCM under-counts will occur when monocytes are identified by high CD14. CD33 (receptor for sialyl conjugates) was co-expressed with CD91 on monocytes but CD33 expression varied by nearly ten-fold among subjects (mean MFI 5 17.4 6 7.7). In comparison to FCM analyses, the hematology analyzer systematically over-counted monocytes and eosinophils while lymphocyte and neutrophil differential values generally agreed with FCM methods.Conclusions: CD91 is a better marker to identify monocytes than CD14 or CD33. Furthermore, FCM (with anti-CD91) identifies monocytes better than a currently used clinical CBC instrument. Use of anti-CD91 together with anti-CD14 and anti-CD16 supports the identification of the diagnostically significant monocyte populations with variable expression of CD14 and CD16.

Quantitative whole-cell MALDI-TOF MS fingerprints distinguishes human monocyte sub-populations activated by distinct microbial ligands

“…Finally, our mass spectrometry profiles were confronted to grouping based on the current monocyte nomenclature and the expression of CD16 and CD14 surface markers [ 2 ]. In the future, this classification might be refined based on the differential expression of surface antigens such as Fc gamma receptor I (CD64) [ 41 ], P-selectin glycoprotein ligand-1 (PSGL-1) [ 31 ], the low-density lipoprotein receptor-related protein (LRP1) [ 42 ] or the α2-macroglobulin receptor [ 43 ]. This would give rise to new clusters that could be further phenotypically discriminated by whole-cell MALDI-TOF MS profiling.…”

Properties of human blood monocytes. II. Monocytes from healthy adults are highly heterogeneous within and among individuals

“…The methods used in these studies were described in detail in "Properties of human blood monocytes I. CD91 expression and log orthogonal light scatter provide a robust method to identify monocytes that is more accurate than CD14 expression" (18). The procedures are briefly summarized below with additional details included in the Supporting Information Methods.…”

Issue Highlights ‐ November 2016

“…Palmeira and colleagues offer evidence about the role of CD45 ‐ B‐NHL. A previous publication by Hudig et al reveals how side scatter combined with CD91 immunophenotyping works for monocyte identification .…”