The Effect Of Exosomes From Umbilical Cord Blood On T Cells In The Elderly

The number and the function of the T lymphocytes in the elderly change with age,and the proportion and dysfunction of these cells can affect the body’s immune function,leading to autoimmune diseases,and may be an important factor of aging.Because of its special origin,umbilical cord blood contains many active ingredients and has a great potential for regulating T cell function.In this paper,we studied the regulation effect of exosomes from cord blood plasma and cord blood T cells on the T lymphocytes of the elderly,and obtained the following innovative results:1.We initially studied the possible effects of exosomes that were obtained from human umbilical cord blood plasma(Pexo),on proliferation,apoptosis and related immune factors expression of the PBMCs in the elderly.This was done by co-culturing Pexo with PBMCs,followed by detecting its regulation effect on the Treg sub-population and CD4+ and CD8+ memory T cells of the T lymphocytes in the elderly.Our results showed that Pexo can maintain the cell viability and can lower the expression of TNF-α、IFN-γ notably within 24 h and there was no significant effect found on Treg cells or memory T cell subgroups in the peripheral blood of the elderly.Thus it showed that Pexo can down-regulate the inflammatory factors and retard the cells apoptosis without influencing the T lymphocytes functions,which helps to adjust the low-grade inflammation state in the elderly,slow down cellular aging to a certain degree.2.We next explored the immuno-regulatory function of exosomes that were obtained from the umbilical cord blood T cells(Texo),on the T cells of the elderly by co-culturing them as mentioned above.Our results showed that Texo can promote the proliferation of T cells in the PBMCs and the proliferated cells were proved to be the Treg cell subgroups.Texo can activate the T cells in PBMCs of the elderly with promoting the CD4+CD25-subpopulation into CD4+CD25+ subpopulation.Further,the Texo reduced the TGF-β expression and increased the IFN-γ expression.It also didn’t show any obvious effect on CD4+ and CD8+ memory T cells.Results of this part of our work showed that Texo can enhance the inhibitory effect of T lymphocytes on foreign antigens by increasing the proportion of induced Treg cells in elderly T cells,and it also has the potential to exert some effect to treat the related immune diseases.