Figure 4

EC continue to express β-gal in transgenic VWF-lacZ and TIE2-lacZ mice mounting strong immune responses against β-gal. A. EC in cardiac vessels of immunized, transgenic mice continue to make β-gal. Control, unimmunized mice and mice immunized and boosted with β-gal protein were sacrificed and their hearts were harvested and stained with X-gal. Representative fields are shown. Similar results were obtained in four independent experiments, two analyzing mice immunized with β-gal protein and two analyzing mice immunized with β-gal expression vectors. B. Dermal EC of immunized, transgenic TIE2-lacZ mice continue to express β-gal. Mice were sacrificed and full-thickness portions of their skins were stained with X-gal. The underside is shown. Unimmunized TIE2-lacZ mice expressed equivalent levels of β-gal, as assessed by X-gal staining (not shown).