PMID: 7543522Aug 1, 1995Paper

Variation of LPS-binding capacity, epitope expression, and shedding of membrane-bound CD14 during differentiation of human monocytes

The Journal of Immunology : Official Journal of the American Association of Immunologists
T PedronR Chaby

Abstract

The myeloid differentiation Ag CD14 is considered to play a critical role in the binding of LPS to monocytes. To determine if differences in LPS-binding capacities of cells could reflect a variability of CD14 molecules, we analyzed the interactions of various reagents with these molecules in human blood monocytes and in promyelocytic (HL60) and monocytic (THP-1) cell lines. The expression of CD14 epitopes was analyzed with the fluorescent anti-CD14 mAbs My4 and LeuM3. Expression of LPS-binding sites (LPS+ molecules) was detected with LPS-FITC. THP-1 cells stimulated with calcitriol (VitD3), as well as the majority of blood monocytes (50-90%) were My4+/LPS+. However, untreated THP-1 cells, and a substantial population (10-50%) of human monocytes from healthy donors, were My4+/LPS-, thus suggesting the existence of CD14 isoforms with different LPS-binding capacities. In line with this assumption, monocytes stimulated with PMA selectively shed LeuM3+ molecules, but almost no My4+ and LPS+ constituents. Analysis of monocytes after treatment with phosphatidylinositol-specific phospholipase C indicated that among CD14 molecules with LPS-binding capacity, some are susceptible and others are resistant to the enzyme, each type being mai...Continue Reading

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