Table 2

 Surrogate cell types

Cell typeAdvantagesDisadvantages
Transformed cell linesEasily obtained, cultured and manipulated. Survive after transplantHigh degree of malignant transformation of cells after transplant. Unsafe
Primary cell culturesDecreased risk of transformation. Relatively easy to infectCan be difficult to obtain or culture. May not survive long term after transplant
Adult stem cellsPlasticity of cell type with ability to potentially incorporate into target organ tissueDifficult to maintain in culture and to infect while maintaining stem cell status
Fetal stem cellsPlasticity of cell type has potential for incorporation and regenerating target tissueOften heterogeneous and difficult to purify. Moral and ethical problems remain a major impedence to availability. Heterologous transplant only