Universal donor cells

Patent Number: 6916654

This patent covers the modification of cells to make them "universal donors" and thus not be rejected by the immune system. Not only is it next to impossible to completely inhibit expression of all immunogenic MHC molecules, but even if this is accomplished, the influence of the NK cells which kill tissue not expressing MHC must also be overcome. This patent is an interesting idea but of very little practical utility.

The one independent claim covers:

A isolated genetically engineered mammalian cell for transplantation into a human or animal wherein the mammalian cell does not express in its surface proteins encoded by the class I major histocompatibility complex genes which elicit a T lymphocyte mediated reaction against the cell due to disruption of the beta2-microglobulin gene by homologous recombination and wherein the mammalian cell expresses a nucleotide molecule encoding one or more complement regulators selected from the group consisting of CD59, CD46 and CD55, wherein the nucleotide molecule is heterologous or located at a separate locus from the native complement regulator sequence, in an amount effective to inhibit complement mediated attack of the engineered cell when introduced into an animal of another species or another individual.

View this patent on the USPTO website.