Provided herein are genetically modified porcine cells comprising a reduced or eliminated level of ?1,3-N-acetylglucosaminyltransferase 5 (B3gnt5) activity as compared to a normal porcine cell, and methods of improving a rejection related symptom by transplanting porcine cells, tissues or organs to a subject in need thereof.

This invention relates to a method of producing one or more human milk oligosaccharides (HMOs), in particular LNT and/or LNnT, in a genetically engineered cell comprising an enhanced oligosaccharide transport capability. The genetically modified cell comprises a series of genetic modification which enable the production of one or more HMO(s), and a series of genetic modification that enhances the transport of lactose and produced HMO(s).