Figure 1.

Structure of galactose-alpha 1,3-galactose (alpha-gal). Alpha-gal is an oligosaccharide found in mammalian cells of non-primates [49,50]. The alpha-gal epitope is present in beef, pork, lamb [14,47-49], and cat dander [54,55], and absent in chicken and fish [49]. Beta-galactosyl alpha 1,3 galactosyl transferase, the enzyme needed for formation of alpha-gal, is inactivated in humans and higher mammals [49,56].