Lentiviral vector gene therapy protects XCGD mice from acute Staphylococcus aureus pneumonia and inflammatory response

Chronic Granulomatous Disease (CGD) is a primary immunodeficiency due to a deficiency in one of the subunits of the NADPH oxidase complex. CGD patients are characterized by an increased susceptibility to bacterial and fungal infections, and to granuloma formation due to the excessive inflammatory responses. Several gene therapy approaches with lentiviral vectors (LVs) have been proposed but there is a lack of in vivo data on the ability to control infections and inflammation. We set up a mouse model of acute infection that closely mimic the airway infection in CGD patients. It involved an intratracheal injection of a methicillin-sensitive reference strain of S. aureus. Gene therapy, with hematopoietic stem cells transduced with regulated lentiviral vectors, restored the functional activity of NADPH oxidase complex (with 20-98% of dihydrorhodamine positive granulocytes and monocytes) and saved mice from death caused by S. aureus, significantly reducing the bacterial load and lung damage, similarly to WT mice even at low vector copy number (VCN). When challenged, gene therapy- treated XCGD mice showed correction of pro-inflammatory cytokines and chemokine imbalance at levels that were comparable to WT. Examined together, our results support the clinical development of gene therapy protocols using lentiviral vectors for the protection against infections and inflammation.