| Objective To observe the effects of cryopreservation on cord blood monounclear cells (CBMC), and to provide evidences for placental-blood transplant. Methods The CBMC were separated from 18 cord bloods on 1.077 Ficoll-Hypaque gradients , and were divided into three groups: fresh sample control, fresh sample to contain 10% DMSO control and cryopreservation group. After cryopreservated to the CBMC of cryopreservation group in-196℃ liguid nitrogon for 30 days and thawed at 40℃, the cell viability of CBMC and the CD4~+ and CD8~+ T lymphocyte were analysed by Typan blue exclusion and with monoclonal antibody technique and flow cytometry in cord blood monounclear cells of three groups. After stimulated to CBMC with phytohemagglutinin(PHA), and cultured for 72 hours in vitro, the levels of Interleukin-6 (IL-6), Interleukin-2 (IL-2) , granulocyte-macrophage-cology-stimulating factor (GM-CSF) and Interferon-γ (IFN-γ) in the supernatants of CBMC were detected by ELISA respectively. Results First, the CD4~+ cells percentage, IFN-γ and IL-2 of cryopreservation group were higher than that of two controls(t=-2.83~-2.73, P<0.05 and t=-7.91~-2.60, P<0.01 or P<0.05). Second, IL-6 of cryopreservation group was significantly higher than that of fresh sample to contain 10% DMSO control(t=-4.29, P<0.01), but that was no difference to fresh sample control(t=-1.78, P>0.05). The last, the level of GM-CSF in the supernatants of cryopreservation group was decreased significantly than that of the fresh control (t=7.74, P<0.01), but that was no significant change to contain 10% DMSO control(t=4.45 , P>0.05). Conclusions After cryopreservation , the ratio of CD4~+ cell and the levels of cytokines were increased. This phenomenon was shown that cryopreservation raised the immuno-activitis of CBMC, and that maybe accelerated the early immune reconstitution which would advance resistance against infectious agents and tumor cells in recipient undergoing cord blood stem cell transplantation(CBSCT). |
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