Construction of Human OX40 Transfectant and Its Potency to Induce Differentiation of Dendritic Cells

The cDNA fragment encoding the human OX40 was obtained from the mRNA of PHA-activated T cells of tonsil by using RT-PCR and cloned into the pMD18-T vector. By DNA sequencing,the cDNA was consistent with the reported human OX40 cDNA in the GenBank,and then was inserted into the eukaryotic expression vector pcDNA3.1. The recombinant plasmid was transfected into L929 cell line with lipofectine,selected by G418 after transfection,a stable cell line expressing the human OX40 was established. The expression stability and efficiency of the target molecule was assayed by immunophenotyping and flow cytometry analysis. It was found that the positive rate of expression was 89.1%. In the presence of sCD40L,OX40 transfectant was evidenced to have a potency to induce the differentiation of dendritic cells in vitro and to up-regulate the expression of maturation markers,such as CD40,CD86 and CD83.