Expression Pattern of CD3γ, δ, ε and ζ Chain Genes in CD4+ and CD8+ T-Cell From Umbilical Cord Blood.

Abstract 4739

The CD3 molecular of the T cell receptor complex contains at least four different CD3 polypeptide chains, termed CD3γ, δ, ε and ζ chain, which are required for cell surface expression of the TCR heterodimers on mature T lymphocytes and have a key role in signal transduction. Umbilical cord blood (UCB), as a source of allogeneic transplantation, which showed a different expression pattern of TCRαβ/γδ and CD3ζ from peripheral blood (PB) mononuclear cells in our previous studies. To further realize the feature of other CD3 subunits expression pattern of T-lymphocyte subsets in UCB, CD3γ, 104, ε and ζ chain genes expression level in purified CD4+ and CD8+ T cells sorted by MACs were detected by real-time PCR with SYBR Green I technique, CD4+ and CD8+ T cells from both 12 cases UCB and 10 healthy adults PB were selected to analyze in this study, β2-microglobulin gene was used as an endogenous reference. Evaluation of relative mRNA expression level of each CD3 chain were used by the 2^-ΔCt+100% method. In CD4+T cells, the relative mRNA expression level of CD3γ, δ and ζ chain genes (16.54% ± 6.49%, 3.53% ± 1.15%, 5.48% + 1.10%) from UCB were significantly higher than that from PB(P=0.001, P=0.017, P=0.000, respectively). Compared with the CD8+T cells form PB, the expression level of CD3δ and ζ chain genes (3.43% ± 1.19%, 5.24% ± 1.42%) in UCB CD8+T cells were also apparently up-regulated (P=0.000, P=0.004). Moreover, the expression level of CD3ε chain gene in CD4+T cells of UCB(13.29%±5.72%)was obviously higher than that in CD8+ T cells(7.81%±4.72%, P=0.018)and was 1.67±0.72 times as much as PB. The expression pattern of four CD3 chains were γ>ε>ζ>δ in both CD4+ and CD8+ T cells from UCB, similar expression pattern was found in CD8+ T cells from PB, in contrast, in CD4+ T cells from PB, the CD3 gene expression pattern presented as εγ>ζ>δ.As the CD3γ and CD3δ chains are highly homologous, especially in the cytoplasmic domain, our results indicated that, the ratios of CD3γ/CD3δ in CD4+ T cells and CD8+ T cells from UCB were 3.55 and 4.69, respectively. In conclusion, this is to our knowledge, the first description of CD3γ, δ, ε and ζ chain genes expression pattern in CD4+ and CD8+ T cells from UCB, which might provide new data for further understanding the feature of T cell immune state in umbilical cord blood.