Tanemura M, Maruyama S, Galili U
Department of Microbiology and Immunology, MCP Hahnemann School of Medicine, Philadelphia, Pennsylvania 19129, USA.
Transplantation. 2000 Jan 15;69(1):187-90. doi: 10.1097/00007890-200001150-00034.
Expression of the alpha-gal epitope in mice can be completely eliminated by disruption of the alpha1,3 galactosyltransferase gene. As an initial step for assessing the feasibility of this approach in the pig, it was of interest to compare the expression of alpha-gal epitopes in pig and mouse organs.
Membranes from pig and mouse organ homogenates were analyzed for alpha-gal epitope expression by Western blots, enzyme-linked immunosorbent assay (ELISA), immunostaining of tissues, and ELISA inhibition assay.
Immunostaining of Western blots with human anti-Gal detected alpha-gal epitopes on glycoproteins from pig organs but not on glycoproteins from the corresponding mouse organs. ELISA with membrane homogenates and immunostaining of tissue sections demonstrated a much higher binding of human anti-Gal to alpha-gal epitopes on pig membranes than on mouse membranes. ELISA inhibition assay with monoclonal anti-Gal indicated that alpha-gal epitope expression in pig organs is up to 500-fold higher than in mouse organs.
Expression of alpha-gal epitopes in pig organs is many fold higher than in mouse organs. The abundance of these epitopes in pigs raises the question of whether pigs can properly develop without expression of alpha-gal epitopes.
通过破坏α1,3半乳糖基转移酶基因，可完全消除小鼠体内α-半乳糖表位的表达。作为评估该方法在猪身上可行性的第一步，比较猪和小鼠器官中α-半乳糖表位的表达情况很有意义。
通过蛋白质免疫印迹法、酶联免疫吸附测定（ELISA）、组织免疫染色和ELISA抑制试验，分析猪和小鼠器官匀浆膜中α-半乳糖表位的表达。
用人抗Gal对蛋白质免疫印迹进行免疫染色，在猪器官的糖蛋白上检测到α-半乳糖表位，而在相应小鼠器官的糖蛋白上未检测到。用膜匀浆进行ELISA以及对组织切片进行免疫染色表明，人抗Gal与猪膜上α-半乳糖表位的结合比与小鼠膜上的结合高得多。用单克隆抗Gal进行ELISA抑制试验表明，猪器官中α-半乳糖表位的表达比小鼠器官中高500倍。
猪器官中α-半乳糖表位的表达比小鼠器官中高很多倍。猪体内这些表位的丰度引发了一个问题，即猪在没有α-半乳糖表位表达的情况下能否正常发育。
