Exosome Derived from Human Umbilical Cord Mesenchymal Cell Exerts Immunomodulatory Effects on B Cells from SLE Patients

Figure 2

Isolation and identification of hucMSCs and hucMSC-Exo. (a, b) Osteogenic differentiation of hucMSCs was performed in the differentiation medium, while the control cells were grown in a regular medium. Both were dyed with Alizarin Red S staining. Most hucMSCs were Alizarin red-positive. (c) Oil red O staining was used to stain hucMSCs after adipogenic differentiation, showing the Oil red O-positive lipid droplets (bar = 100 μm). (d) Flow cytometry analysis of the phenotypic markers of hucMSCs showed that hucMSCs were positive for CD73, CD90, and CD105 and negative for CD34, CD45, and human leukocyte antigen (HLA)-DR. (e) Transmission electron microscopic images of typical hucMSC-Exo. Scale bar = 100 nm. (f) The size distribution of the hucMSC-Exo was determined using a nanoparticle tracking analysis. hucMSC-Exo had an original concentration of 2.0e + 10 particles/mL, a mean size of 145.1 nm with a peak of 137.7 nm. (g) Expression of positive markers, CD63 and CD81, was mainly expressed in hucMSC-Exo using flow cytometry analysis.

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