MSC phenotype following rapid immunodepletion. When compared to isotype control, MSC stained positive for MHC class I (H-2kd), the VLA complex marker CD29, the cell adhesion receptor CD44, and the hematopoietic stem cell marker Sca-1. MSC stained negative for MHC class II (I-Ad), macrophage cell surface markers (CD11b, CD14), B cell marker (B220), lymphocytes (CD2, CD3, CD4, and CD8a), and the hematopoietic stem cell markers Thy-1 and c-kit. Histograms represent consistent findings of more than 30 independent experiments.