255 Impact of Pre Existing Neutralizing Antibodies (NAbs) on Expression of a SIV Antibody Following Intramuscular (IM) Administration of AAV2/8 Molecular Therapy Volume 20, Supplement 1, May 2012 Copy[.]
IMMUNOLOGIC & HOST RESPONSES IN GENE & CELL THERAPY I – AAV in PBS-MGO and GFP-MGO groups, immunofluorescence staining revealed decreased expression of epithelial marker E-cadherin and increased expression of mesenchymal marker vimentin, suggesting the induction of MMT by MGO In IL-10-MGO group, these changes were suppressed Our findings suggest that AAV vector-mediated systemic IL-10 delivery inhibits the progression of PF, through the suppression of inflammation and MMT induction in the peritoneum and give important information on the treatment of PF 253 Deficiency in MyD88 Signaling Results in Decreased Antibody Responses to AdenoAssociated Virus Vector Containing a CMV Enhancer/Chicken β-Actin Cassette in Murine Pompe Disease Ping Zhang,1 Andrew Bird,1 Songtao Li,1 Dwight D Koeberl.1 Pediatrics/Medical Genetics, Duke University Medical Center, Durham, NC Innate immune responses to adeno-associated virus (AAV) vectors have been shown to influence the adaptive immune responses that have complicated both preclinical experiments and clinical trials with AAV vectors Gene therapy experiments in acid a-glucosidase knockout (GAA-KO) mice have provided useful insight in the immune responses in Pompe disease, because these mice express no residual GAA protein and mount immune responses to introduced GAA Previously we developed an AAV2/8 vector containing the universally active CMV enhancer/chicken b-actin regulatory cassette (AAV2/8-CBhGAA) Ubiquitous expression of GAA with AAV2/8-CBhGAA has been shown to be inefficacious due to T cell and antibody responses against GAA Furthermore, we demonstrated that GAA-KO mice given AAV2/8-CBhGAA developed robust anti-GAA antibody responses and T cell proliferation following immunization with rhGAA It has been shown that the innate immune responses to AAV2 vectors are primarily through the TLR9-MyD88 pathway The role of MyD88/TRIF signaling pathway in shaping the antibody responses to our AAV2/8-CBhGAA vector is unknown, and therefore we investigated how MyD88/TRIF signaling affects antibody responses to AAV2/8-CBhGAA MyD88 KO mice (n=5), TRIF KO mice (n=5) and wildtype (WT) mice (n=4) were injected with AAV2/8-CBhGAA Plasma was collected at wk and wk and anti-GAA IgG1 was analyzed by Elisa WT mice developed robust anti-GAA IgG1 responses at wk TRIF KO mice had a trend towards decreased anti-GAA IgG1 responses (p=0.0765) Importantly, MyD88 KO mice had diminished anti-GAA IgG1 responses (p=0.025) Vector genomes were significantly higher in the liver of MyD88 KO mice than in WT mice (p