Selection of intracellular antibodies.

The intracellular expression of antibodies in mammalian cells is a strategy to inhibit in vivo the function of selected molecules. One limitation of this technology is represented by the unpredictable behaviour of antibodies, under conditions of intracellular expression. Recent advances in the field of antibody expression in E. coli show that the introduction of mutations inspired by sequence comparisons or by educated guesses can improve the properties of some antibody domains, but the general applicability of this approach to intracellular antibodies remains to be proven. As a complement to rational approaches, selection schemes whereby antibodies are selected on the basis of their performance in vivo as intracellular antibodies can be exploited. (Fig. 3, Ref. 44.)