Human mesenchymal stromal cells express CD14 cross‐reactive epitopes

Abstract

Mesenchymal stromal cells (MSCs) do not express a unique definite epitope or marker gene. As such, minimal criteria were recently established for defining multipotent MSC. These criteria include expression of CD73, CD90, CD105, and a lack of hematopoietic marker expression. However, we detected binding of a CD14 antibody on bone marrowand placenta-derived MSC and investigated the staining of CD14 antibodies on these MSC in more detail. The MSC were isolated from human bone marrow and placenta tissue, expanded, characterized by quantitative RT-PCR, flow cytometry, and immunocytochemistry and differentiated to generate osteoblasts, chondrocytes, and adipocytes. The CD14-cross-reactive MSCs were enriched by cell sorting. Human peripheral blood mononuclear cells, fibroblasts, and hematopoietic cell lines served as controls. Utilizing four different clones of CD14 monoclonal antibodies, we found that three CD14 reagents stained the MSC. Two CD14 antibodies (HCD14 and M5E2) clearly marked the CD90 1 MSC population with distinct intensities, clone 134 620 generated a shift in flow cytometry histograms, but clone MFP9 did not stain MSC. Transcripts encoding CD14 or the CD14 protein were not detected in MSC. We confirm that bone marrow-and placentaderived MSC do not express CD14 and that the CD14 antibody MFP9 discriminates between monocytes and MSC more efficiently than the other antibodies employed here. This investigation does not contradict previous work but provides a more accurate characterization of MSC. ' 2011 International Society for Advancement of Cytometry

Enhanced osteoblastic differentiation and bone formation in co-culture of human bone marrow mesenchymal stromal cells and peripheral blood mononuclear cells with exogenous VEGF

“…However, we did not observe any differences between the plain MSCs cultured in OB-medium, or OB-medium supplemented with VEGF, indicating that the mechanism requires the presence of cells from the MNCfraction, such as CD34+ or CD14+ cells. MSCs have indeed been described to have a CD14-crossreactive epitope [24] demonstrating a cell-cell contact dependent interaction mechanism.…”

Human Placenta-Derived CD146-Positive Mesenchymal Stromal Cells Display a Distinct Osteogenic Differentiation Potential

“…Expression of cell surface antigens on MSC was explored by flow cytometry as described recently [6]. The cells were detached by mild proteolysis (Accutase, Sigma-Aldrich), counted by aid of a hematocytometer and 2x10 5 The samples were analyzed by flow cytometry (LSRII, BD Biosciences).…”

“…They express a variety of cell surface antigens, including CD29, CD73, CD90, CD140b, CD105, CD146 and CD166, but lack expression of antigens characteristic for hematopoietic or endothelial cells such as CD11b, CD14, CD34, CD31, CD45, or CD133 [3][4][5][6][7][8]. Widely used protocols for preparation of MSC from bone marrow (bmMSC) start with a crude mix of cells and debris in suspension.…”

Characterization of Human Adipose Tissue-Resident Hematopoietic Cell Populations Reveals a Novel Macrophage Subpopulation with CD34 Expression and Mesenchymal Multipotency

“…In this regard, we should consider that some epitopes of antigens may have a cross reaction with doubtful antibodies. For example, it was reported that human mesenchymal stromal cells expressed CD14 cross-reactive epitopes depending on the clone of antibody [50].…”