Anti-CD105 Antibody [MEM-229] (PE) (A85493)

BACKGROUND:

Stem cells are capable of unlimited self-renewal and are able to remain undifferentiated for extended periods of time prior to their differentiation into specific cell lineages. Because of the issues (ethical and religious) involved in the use of embryonic stem cells and the limited plasticity of adult stem cells, an alternative cell source could be foetal stem cells derived from extra-embryonic tissue, which are highly proliferative, grow in vitro and possess interesting immunogenic characteristics. As a result, the amniotic membrane of several species has been studied as an important new source of stem cells.

METHODS:

Here, we cultured and characterized mesenchymal progenitor cells derived from the rabbit amniotic membrane, and investigated their differentiation potential. In total, amniotic membranes were collected from eight rabbit foetuses and were isolated by the explant technique. The obtained cells were cultured in DMEM-HIGH glucose and incubated at 37 °C in a humidified atmosphere with 5% CO₂.

RESULTS:

The cells adhered to the culture plates and showed a high proliferative capacity with fibroblast-like morphologies. The cells showed a positive response for markers for the cytoskeleton, mesenchymal stem cells and proliferation, pluripotency and haematopoietic precursor stem cells. However, the cells were negative for CD45, a marker of haematopoietic cells. Furthermore, the cells had the capacity to be induced to differentiate into osteogenic, adipogenic and chondrogenic lineages. In addition, when the cells were injected into nude mice, we did not observe the formation of tumours.

CONCLUSIONS:

In summary, our results demonstrate that multipotent mesenchymal stem cells can be obtained from the rabbit amniotic membrane for possible use in future cell therapy applications.

The aim of the present study was to investigate the effect of programmed cell death 1 (PD-1) on osteosarcoma (OD) stem cells and T cells, and to determine their correlation. OS stem cells were sorted and identified from OS MG63 cells. Flow cytometry was used to detect the PD-1 expression of the OS tumor stem cell membrane surface. The expression of PD-1 mRNA was detected by reverse transcription-polymerase chain reaction (RT-PCR). MTT was used to detect the effect of PD-1 signals on T-cell proliferation. The results indicated that the cancer cells (cultured in DMEM medium containing 10% fetal bovine serum) exhibited clear proliferation within 1 week of cell culture, which showed their strong proliferation and aggressive ability. The formation of tumor cell spheres was dependent on the support of serum nutrition. The proliferation of MG63 cells in the serum culture medium was significantly higher than the number of OS cell spheres in serum-free suspension culture (P<0.05). Pluripotent stem cells in cancer cell spheres exhibited significantly higher cluster of differentiation 133 expression compared with the MG63 cells. The PD-1 expression levels of the cancer cell spheres was significantly increased compared with the MG63 cells, which is consistent with the results of the RT-PCR. In conclusion, the MG63 cell line possesses the features of OS stem cells. The MG63 cell line can express the certain cancer-associated cell markers. The expression of PD-1 in spheres was also increased significantly compared to the MG63 cells, which can reduce the immune function of patients and may be closely associated with the occurrence and development of tumors.

Mesenchymal stem cells (MSCs) are multipotent progenitor cells exerting immunomodulatory effects on cells of the innate and adaptive immune system. It has been shown that an inflammatory milieu is required for the activation of MSC-mediated immunomodulation, and interferon-γ (IFN-γ) plays an important role in this process. We determined the influence of IFN-γ on human adipose-derived stem cells (ASCs) and human amniotic mesenchymal stromal cells (hAMSCs). We further evaluated the effect of MSCs on stimulated T-cells and peripheral blood mononuclear cells (PBMCs) in a cell-contact independent setting. On IFN-γ treatment, ASCs and hAMSCs possessed significantly higher antiproliferative properties and showed surface characteristics of nonprofessional antigen presenting cells (HLA-DR(+)CD40(med+)CD54(high)) with a possible regulatory phenotype (PD-L1(+)PD-L2(+)). The effect of ASCs and hAMSCs on cytokine secretion and T-cell activation was dependent on stimulation method and cellular context. Although ASCs and hAMSCs highly inhibited cytokine secretion of stimulated PBMCs, this was not observed in the case of purified T-cells. The presence of ASCs even favored the secretion of pro-inflammatory cytokines including IFN-γ by T-cells, although T-cell proliferation was efficiently inhibited. Further, ASCs enhanced the number of CD69(+) T-cells independent of the stimuli and cellular context. Interestingly, ASCs significantly suppressed CD25 expression on phytohemagglutinin stimulated PBMCs but had no effect on αCD3/αCD28 stimulated cells. Depending on the stimulation method and cellular context, immune cells create a specific cytokine milieu in vitro, thus differently influencing MSCs and, in turn, affecting their action on immune cells.