Effects of human DAF and CD59 co-expression in vascular endothelia in transgenic mice on heart work during human plasma peffasion / 中华器官移植杂志

ABSTRACT

Objective To construct transgenic mice tissue-specifically co-expressing human DAF/CD59 in the vascular endothelia and to investigate the ability to protect against human comple- ment-mediated attack.Methods Transgenic mice were generated by co-microinjection of hDAF/CD59 expression constructs driven by the human intercellular adhesion molecule-2(ICAM-2)promoter.PCR and Southern blot of genomic DNA were used to assess the presence of hDAF/CD59 in the genome of the founders,and the expression at protein level was measured by flow cytometry.Immunohistochemis- try was used to detect the distribution of hDAF/CD59.An ex vivo perfusion model was used to com- pare hearts from these hDAF/CD59 transgenic mice with hDAF hearts.Results After microinjection of genes,11 of 135 mice born were shown to be double-transgenic,and human DAF/CD59 were ex- pressed on the surface of leucocytes in 6 of the 11 DAF/CD59-integrated mice.Expression levels of 6 founders ranged from 80% to 95% of that in human leucocytes.Human DAF/CD59 were strongly expressed in the vascular endothelia of heart,kidney,with little or no positive staining observed in non- endothelial cells.Compared to hDAF hearts that maintained approximately 20% maximum work during perfusion with 20% human plasma,these endothelial-specific hDAF/CD59 hearts were further protected with work maintained at 40% of the maximum level during 60 min.Conclusion The intro- duced hDAF/CD59 genes have been integrated and specifically expressed in the vascular endothelia. The endothelial co-expression of hDAF/CD59 can provide greater protection against human complement-mediated attack than the expression of hDAF alone.