Table 2.

Summary of durability of IN-vector-delivered gene expression

Vector	Cell origin	Week analyzed	Therapeutic gene expression	Total no. of mice
LTR-LacZ	NL	4	Yes	4
LTR-LacZ	NL	8	Yes	3
LTR-LacZ	NL	12	Yes	3
LTR-LacZ/GFP	JEB(4) LI (2)	4	No*	6
IN β3/TG1	JEB(8) LI (3)	4	Yes	11
IN β3/TG1	JEB(2) LI (0)	6	Yes	2
IN β3/TG1	JEB(2) LI (1)	8	Yes	3
IN β3/TG1	JEB(0) LI (3)	12	Yes	3

Human skin tissue from either JEB or LI patients as well as normal control (NL) was regenerated after gene transfer in vitro with the IN retroviral vector backbone driving expression of laminin 5 β3 (β3) or transglutaminase 1 (TG1), respectively. Xenograft tissue was excised and analyzed at either 4, 6, 8, or 12 weeks after grafting. The total number of mice analyzed at each timepoint is noted with the number of independent xenografts analyzed at each timepoint for each genodermatosis shown in parentheses under the column labeled “Cell origin.” Each entry at each timepoint represents a separately grafted and analyzed mouse. β3 and TGase1 expression was determined by immunohistochemistry as noted in the Methods section. No significant variability in the levels of delivered gene expression were detected; expression was either at levels similar to normal control (Yes) or not detectable (No). 

^*Therapeutic gene expression is defined as expression of β3 protein in JEB tissue or TGase1 protein in LI tissue.