R01AI168242

Novel Strategy to Block NABs for AAV Gene Delivery

Adeno-associated virus (AAV) vectors have been applied in clinical trials in patients with different disorders. Although successful in clinical studies, one of the major concerns for broader AAV vector application for patients is the high prevalence of neutralizing antibodies (NABs). In the general human population, over 95% of individuals have been infected by AAV, and on average, approximately 50% of them have NABs.

Several approaches have been explored to evade AAV NABs, including epitope masking with PEG or exosome, different serotype of AAV vector, rational design and combinatorial mutagenesis of the capsid in situ, as well as biological depletion of NABs (empty capsid utilization, B cell depletion, plasma-apheresis, and IgG cleavage enzymes). Generally, these approaches have low efficiency or side effects or AAV tropism change. Therefore, it is imperative to develop ideal strategies to evade NABs, but without a change in tissue tropism from capsid engineering or negative side effects from pharmacological treatment.

Recently, we have developed a vector independent protein-based strategy to universally block NABs and demonstrated that this approach is effective against a broad range of pre-existing NAB concentrations by use of a unique mycoplasma-derived protein and its analogues, termed protein-M. Protein-M is able to interact with immunoglobulin from any species without antigen dependence. We have found that protein-M protected AAV vector neutralization over 100-fold in vitro and 1000-fold in mice with adoptive transfer of NAB positive serum, so far, the most effective strategy to evade AAV NABs.

However, the wild-type protein-M is structurally unstable at body temperature (37°C), making it challenging for clinical application. The protein unfolding at body temperature may correspond with decreased NAB blockade when using the protein in vivo. In order to improve protein-M stability, we have rationally designed in silico a library of 150 individual protein mutants engineered for improved thermal stability. At least 10 mutants were identified with enhanced thermal stability and high biological activity.

In this proposal, we will further characterize the efficacy of these mutants in vitro and in mice with adoptive transfer of NAB positive serum (Aim 1). Next, we will study the role of protein-M in AAV re-dosing in mice with pre-immunization (Aim 2). Then we will move forward to a disease model to test the ability of the best protein-M variants to block AAV NABs in animals for phenotypic correction with AAV vector-mediated gene delivery (Aim 3).

The long-term objective is to develop a more effective strategy to evade NAB activity in future gene therapy with AAV vectors in patients with NABs.

University Of North Carolina At Chapel Hill

TO ASSIST PUBLIC AND PRIVATE NONPROFIT INSTITUTIONS AND INDIVIDUALS TO ESTABLISH, EXPAND AND IMPROVE BIOMEDICAL RESEARCH AND RESEARCH TRAINING IN INFECTIOUS DISEASES AND RELATED AREAS, TO CONDUCT DEVELOPMENTAL RESEARCH, TO PRODUCE AND TEST RESEARCH MATERIALS. TO ASSIST PUBLIC, PRIVATE AND COMMERCIAL INSTITUTIONS TO CONDUCT DEVELOPMENTAL RESEARCH, TO PRODUCE AND TEST RESEARCH MATERIALS, TO PROVIDE RESEARCH SERVICES AS REQUIRED BY THE AGENCY FOR PROGRAMS IN INFECTIOUS DISEASES, AND CONTROLLING DISEASE CAUSED BY INFECTIOUS OR PARASITIC AGENTS, ALLERGIC AND IMMUNOLOGIC DISEASES AND RELATED AREAS. PROJECTS RANGE FROM STUDIES OF MICROBIAL PHYSIOLOGY AND ANTIGENIC STRUCTURE TO COLLABORATIVE TRIALS OF EXPERIMENTAL DRUGS AND VACCINES, MECHANISMS OF RESISTANCE TO ANTIBIOTICS AS WELL AS RESEARCH DEALING WITH EPIDEMIOLOGICAL OBSERVATIONS IN HOSPITALIZED PATIENTS OR COMMUNITY POPULATIONS AND PROGRESS IN ALLERGIC AND IMMUNOLOGIC DISEASES. BECAUSE OF THIS DUAL FOCUS, THE PROGRAM ENCOMPASSES BOTH BASIC RESEARCH AND CLINICAL RESEARCH. SMALL BUSINESS INNOVATION RESEARCH (SBIR) PROGRAM EXPANDS AND IMPROVES PRIVATE SECTOR PARTICIPATION IN BIOMEDICAL RESEARCH. THE SBIR PROGRAM INTENDS TO INCREASE AND FACILITATE PRIVATE SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL RESEARCH AND DEVELOPMENT, TO INCREASE SMALL BUSINESS PARTICIPATION IN FEDERAL RESEARCH AND DEVELOPMENT, AND TO FOSTER AND ENCOURAGE PARTICIPATION OF SOCIALLY AND ECONOMICALLY DISADVANTAGED SMALL BUSINESS CONCERNS AND WOMEN-OWNED SMALL BUSINESS CONCERNS IN TECHNOLOGICAL INNOVATION. THE SMALL BUSINESS TECHNOLOGY TRANSFER (STTR) PROGRAM STIMULATES AND FOSTERS SCIENTIFIC AND TECHNOLOGICAL INNOVATION THROUGH COOPERATIVE RESEARCH AND DEVELOPMENT CARRIED OUT BETWEEN SMALL BUSINESS CONCERNS AND RESEARCH INSTITUTIONS, TO FOSTER TECHNOLOGY TRANSFER BETWEEN SMALL BUSINESS CONCERNS AND RESEARCH INSTITUTIONS, TO INCREASE PRIVATE SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL RESEARCH AND DEVELOPMENT, AND TO FOSTER AND ENCOURAGE PARTICIPATION OF SOCIALLY AND ECONOMICALLY DISADVANTAGED SMALL BUSINESS CONCERNS AND WOMEN-OWNED SMALL BUSINESS CONCERNS IN TECHNOLOGICAL INNOVATION. RESEARCH CAREER DEVELOPMENT AWARDS SUPPORT THE DEVELOPMENT OF SCIENTISTS DURING THE FORMATIVE STAGES OF THEIR CAREERS. INDIVIDUAL NATIONAL RESEARCH SERVICE AWARDS (NRSAS) ARE MADE DIRECTLY TO APPROVE APPLICANTS FOR RESEARCH TRAINING IN SPECIFIED BIOMEDICAL SHORTAGE AREAS. IN ADDITION, INSTITUTIONAL NATIONAL RESEARCH SERVICE AWARDS ARE MADE TO ENABLE INSTITUTIONS TO SELECT AND MAKE AWARDS TO INDIVIDUALS TO RECEIVE TRAINING UNDER THE AEGIS OF THEIR INSTITUTIONAL PROGRAM.

93.855 - Allergy and Infectious Diseases Research

National Institute of Allergy and Infectious Diseases (NIAID) [HHS - NIH]

Chapel Hill, North Carolina 27599 United States

Single Zip Code

NIH Research Project Grant (Parent R01 Clinical Trial Not Allowed) (PA-20-185)

Amendment Since initial award the total obligations have increased 418% from $578,782 to $3,000,414.