[Influence of TLR2 and TLR4 agonists on migration of cord blood CD34(+) cells].

This study was aimed to investigate the influence of TLR2 and TLR4 agonists on the migration and adhesion activity of umbilical cord blood(UCB) CD34+ cells and to explore the underlying mechanism.The expression of TLR2 and TLR4 on UCB CD34+ cells was detected with flow cytometry.The effect of TLR2 agonist(PAM3CSK4) and TLR2 agonist(LPS) on the migration and adhesion ability of UCB CD34+ cells was evaluated with chemotaxis and adhesion assays.The results indicated that expression levels of TLR2 and TLR4 were(14.2±3.8)%,(19.6±4.1)% respectively.Compared with the control group,the migration activity of UCB CD34+ cells toward SDF-1 decreased significantly in LPS group(p0.01).The adhesion activity was not altered significantly in LPS group.However,both the migration activity towards SDF-1 and the adhesion activity of UCB CD34+ cells were not changed significantly in PAM3CSK4 group.Further study found that LPS did not affect the expression level of CXCR4 on CD34+ cells,but could inhibit the spontaneous migration ability of CD34+ cells.It is concluded that TLR4 activation can decrease the chemota-xis function of CD34+ cells towards SDF-1,which may associate with the decreased spontaneous migration ability of CD34+ cells.