Abstract: Genetically engineered cells are provided which can serve as universal donor cells in such applications as reconstruction of vascular linings or the administration of therapeutic agents. The cells include a coding region which provides protection against complement-based lysis, i.e., hyperacute rejection. In addition, the cell's natural genome is changed so that functional proteins encoded by either the class II or both the class I and the class II major histocompatibility complex genes do not appear on the cell's surface. In this way, attack by T-cells is avoided. Optionally, the cells can include a self-destruction mechanism so that they can be removed from the host when no longer needed.

Abstract: Genetically engineered cells are provided which can serve as universal donor cells in such applications as reconstruction of vascular linings or the administration of therapeutic agents. The cells include a coding region which provides protection against complement-based lysis, i.e., hyperacute rejection. In addition, the cell's natural genome is changed so that functional proteins encoded by either the class II or both the class I and the class II major histocompatibility complex genes do not appear on the cell's surface. In this way, attack by T-cells is avoided. Optionally, the cells can include a self-destruction mechanism so that they can be removed from the host when no longer needed.

Abstract: An intact, assembled T cell receptor (TcR) in soluble form is provided. The soluble TcR is prepared by splicing the extracellular domains of a T cell receptor to the glycosyl phosphatidylinositol (GPI) membrane anchor sequences of Thy-1. The molecule is expressed in the absence of CD3 on the cell surface, and can be cleaved from the membrane by treatment with phosphatidylinositol specific phospholipase C (PI-PLC). The .alpha. and .beta. chains of the soluble molecule are paired in the native conformation as judged by reactivity with the anti-V.sub..beta. 8 monoclonal antibody F23.1, and with the anti-clonotypic monoclonal antibody 1B2. The soluble TcR is a disulfide linked dimer with a molecular mass of 95 kDa on SDS-PAGE under nonreducing conditions, and 47 kDa after reduction.

Abstract: A method and means for protecting cells and transplanted organs for the effects of activated complement proteins generated in blood serum or plasma by introducing the gene for CD59 into the cells to be protected is described. In an example of the method, protection against the pore-forming activity of the human C5b-9 proteins was conferred on CHO cells by transfection with cDNA encoding the human complement regulatory protein CD59.