EXPRESSION OF HUMAN CD59 ANTIGEN ON MOUSE NIH3T3 AND EL-4 CELLS CONFERS PROTECTION AGAINST HUMAN COMPLEMENT ATTACK / 免疫学杂志

ABSTRACT

CD59 antigen is a widely expressed cell surface glycosylphosphatidyl-inositol (GPI) anchored glycoprotein.It acts as an inhibitor to the assembly of the membrane attack complex of homologous complement,binds to CD2,and also transduces activation signals with T cells.In this report,a 396bp DNA fragment was amplified by RT-PCR method from the total RNA of Jurkat cells.The fragment was cloned into pUC18 and pUC19 plas-mids,and further sequenced by Sanger′s-dideory-mediated chain termination.The results showed that this cDNA fragment included 384bp open reading fragment and its sequence was identical to the published sequence encoding human CD59 antigen.Furthermore,the cDNA of CD59 was subcloned into retroviral vector pLXSN and transfec-ted into packaging cell line PA317 to generate stable virus-producing cell lines.Then,mouse thymotase cell line EL-4 and fibroblasts cell line NIH3T3 were infected with the virus resulting in stable expression of CD59 on the cell surface.The transfected cells were tested for their susceptibility to human complement-mediated cytolysis.It was found that the transfected cells expressing CD59 antigen were far less susceptible than the controls,indicating that the gene for CD59 can be expressed in xenotypic cells stably to confer protection against human serum complement.