Transduction of murine lung with vectors based on various AAV serotypes encoding hPALP. Vectors were intranasally administered undiluted (3 × 10¹¹ GCs per mouse, upper panels) or diluted 1:5 (6 × 10¹⁰ GCs per mouse, lower panels) to immunocompetent animals (n = 5 per group). (a) Histochemical detection of PALP in the lung 4 weeks after vector delivery. Positive cells are present in both alveolar and airway cells when AAV2/5 and AAV2/1 are given. No transduction is observed with AAV2. (b) Quantification by ELISA of hPALP activity in lung homogenates 4 weeks after vector delivery. The specific serotypes and dilution factors used are shown at the bottom. Values shown are mean ± SD. Equivalent results were obtained with the chemiluminescent assay (not shown).