The present invention relates to methods and compositions for the reduction of 
xenotransplantation rejection. Specifically, the present invention relates, first, to transgenic cells, tissues, organs and animals containing transgenic 
nucleic acid molecules that direct the expression of 
gene products, including, but not limited to enzymes, capable of modifying, either directly or indirectly, 
cell surface 
carbohydrate epitopes such that the 
carbohydrate epitopes are no longer recognized by natural human antibodies or by the 
human cell-mediated immune response, thereby reducing the human 
immune system response elicited by the presence of such 
carbohydrate epitopes. In a preferred embodiment, the transgenic cells, tissues, organs and animals express 
nucleic acid molecules encoding functional recombinant alpha-Galactosidase A (alphaGalA) 
enzyme which modifies the carbohydrate 
epitope Galalpha(1,3)Gal. In a more preferred embodiment, the transgenic cells, tissues, organs and animals expressing the functional recombinant alphaGalA are transgenic pig cells, organs, tissues and / or animals. Second, the present invention relates to methods for 
xenotransplantation comprising introducing the transgenic cells, tissues and / or organs into human recipients so that a lower level of hyperacute rejection (HAR) is observed in the human recipients relative to the level of HAR observed in human recipients having received non-transgenic cells, tissues and / or organs.