978. Reduced Immune Response to Adenovirus Vector Formulated with the Anti-Inflammatory Liposome DS/DOPE

Abstract

Introduction: Successful gene transfer to lung has been hindered by immune responses elicited against gene transfer vectors and transgenes as well as inefficient gene transfer to target cells. We have previously demonstrated that, when delivered intranasally, adenoviral (AdV) vectors formulated with the anti-inflammatory cationic lipid dexamethasone-spermine (DS) and the neutral lipid dioleoylphosphatidylethanolamine (DOPE) target transgene expression to airway epithelia and reduce cellular infiltration to the lung.Methods: C57Bl/6 mice were administered with two doses of AdV vector expressing either β-galactosidase (LacZ) or human α- antitrypsin (AAT), with or without DS/DOPE, at days 0 and 14 respectively. At various time points cytokine responses, T-cell responses and B-cell responses were quantified.Results: We found that the six hour acute response to AdV vector alone has higher serum levels of many inflammatory cytokines and chemokines, such as KC/GROα(6-fold increase), TNF-α(5.7-fold increase), and IL-6 (2.7-fold increase). Furthermore, the production of neutralizing antibody against AdV at day 28 was significantly reduced when at least one dose of vector was formulated with DS/ DOPE (AdV,AdV=400; AdV+DS/DOPE,AdV=60; AdV+DS/ DOPE,AdV+DS/DOPE= 213). ELISPOT assays on splenocytes, isolated from vector treated mice, on days 14, 28, and 34 suggest altered kinetics of T-cell response based on formulation of AdV with DS/DOPE, though not necessarily a reduced response to the LacZ transgene. However, the localized pulmonary response to the vectors following double administration was significantly reduced for AdV formulated with DS/DOPE compared to AdV alone as indicated by quantification of CD4 (204.7 + 107.3 vs. 478.8 + 258.9) and CD8 (305.3 + 175.3 vs. 571.8 + 238.4) immunohistochemistry.Conclusion: Taken together our results indicate that formulating AdV vector with DS/DOPE targets transgene expression to airway epithelia while reducing the immune response to AdV. Introduction: Successful gene transfer to lung has been hindered by immune responses elicited against gene transfer vectors and transgenes as well as inefficient gene transfer to target cells. We have previously demonstrated that, when delivered intranasally, adenoviral (AdV) vectors formulated with the anti-inflammatory cationic lipid dexamethasone-spermine (DS) and the neutral lipid dioleoylphosphatidylethanolamine (DOPE) target transgene expression to airway epithelia and reduce cellular infiltration to the lung. Methods: C57Bl/6 mice were administered with two doses of AdV vector expressing either β-galactosidase (LacZ) or human α- antitrypsin (AAT), with or without DS/DOPE, at days 0 and 14 respectively. At various time points cytokine responses, T-cell responses and B-cell responses were quantified. Results: We found that the six hour acute response to AdV vector alone has higher serum levels of many inflammatory cytokines and chemokines, such as KC/GROα(6-fold increase), TNF-α(5.7-fold increase), and IL-6 (2.7-fold increase). Furthermore, the production of neutralizing antibody against AdV at day 28 was significantly reduced when at least one dose of vector was formulated with DS/ DOPE (AdV,AdV=400; AdV+DS/DOPE,AdV=60; AdV+DS/ DOPE,AdV+DS/DOPE= 213). ELISPOT assays on splenocytes, isolated from vector treated mice, on days 14, 28, and 34 suggest altered kinetics of T-cell response based on formulation of AdV with DS/DOPE, though not necessarily a reduced response to the LacZ transgene. However, the localized pulmonary response to the vectors following double administration was significantly reduced for AdV formulated with DS/DOPE compared to AdV alone as indicated by quantification of CD4 (204.7 + 107.3 vs. 478.8 + 258.9) and CD8 (305.3 + 175.3 vs. 571.8 + 238.4) immunohistochemistry. Conclusion: Taken together our results indicate that formulating AdV vector with DS/DOPE targets transgene expression to airway epithelia while reducing the immune response to AdV.