Gene expression profiling of CD3γ, δ, ϵ, and ζ chains in CD4⁺ and CD8⁺ T cells from human umbilical cord blood

Abstract

In order to elucidate the feature of T-cell immune status in umbilical cord blood (CB) from humans, the expression levels of CD3γ, δ, ϵ, and ζ chain genes in CD4⁺ and CD8⁺ T cells of CB were analysed by real-time PCR. CD4⁺ and CD8⁺ T cells sorted from 12 cases of CB and 10 peripheral blood (PB) samples from healthy adults were used in the study. The β2-microglobulin gene was used as an endogenous reference, and the evaluations of mRNA expression level of each CD3 gene were used by the 2^−ΔC_t × 100% method. In CD4⁺ T cells, the expression levels of CD3γ, δ, and ζ genes (16·54±6·49, 3·53±1·15, and 5·48±1·10%) from CB were significantly higher than those from PB (P=0·001, P=0·017, and P=0·000, respectively). Higher expression levels of CD3δ and ζ genes (3·43±1·19 and 5·24±1·42%) in CD8⁺ T cells from CB were found than those from PB (P=0·000 and P=0·004). Moreover, the expression level of CD3ϵ gene in CD4⁺ T cells from CB (13·29±5·72%) was significantly different from that in CD8⁺ T cells (7·81±4·72%, P=0·018). Thus, the expression pattern of four CD3 genes were γ>ϵ>ζ>δ in both CD4⁺ and CD8⁺ T cells from CB, while similar expression pattern was found in CD8⁺ T cells from PB samples. In contrast, the expression pattern was presented as ϵ>γ>ζ>δ in CD4⁺ T cells from PB. In conclusion, the present study characterized the expression pattern of CD3γ, δ, ϵ, and ζ chain genes in CD4⁺ and CD8⁺ T cells from CB, which might be very useful for further understanding the feature of T-cell immune status in umbilical cord blood. Higher expression of CD3 genes in CD4⁺ T cells might relate to the strong ability of activation of TCR-mediated signals, and suggests that this is one of the features responsible for the low allo-reactivity of CB T cells.

Keywords:

• T CELLS
• CORD BLOOD
• CD3GAMMA DELTA EPSI AND ZETA CHAIN
• GENE EXPRESSION