Method of altering the immundominance hierarchy of HIV gag by DNA vaccine expressing conserved regions
Inventors
Pavlakis, George • Felber, Barbara • Mullins, James
Assignees
University of Washington Center for Commercialization • US Department of Health and Human Services
Publication Number
US-9415099-B2
Publication Date
2016-08-16
Expiration Date
2033-03-04
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
The invention provides methods and compositions for eliciting broad immune responses. The methods employ nucleic acid vaccines that encodes highly conserved elements from a virus.
Core Innovation
The invention provides methods and compositions for eliciting broad immune responses against highly diverse viral proteins, such as HIV-1, by employing nucleic acid vaccines encoding highly conserved elements within the viral proteins. These conserved elements are selected segments of the proteome that are nearly invariable across different viral strains and are essential for viral function, thus less prone to mutational escape.
The problem addressed arises from the high variability of HIV-1 strains, which challenges vaccine design by limiting cross-clade protection. Immunodominant epitopes within variable regions can act as decoys, diverting immune responses and allowing the virus to escape immunity. The invention focuses on excluding variable segments and immunodominant decoy epitopes by using conserved elements-only vaccines, which are more likely to induce immune responses that prevent virus acquisition or propagation.
The invention describes vaccination regimens employing DNA constructs encoding several (e.g., three to seven) conserved elements from HIV-1 p24gag, arranged collinearly and separated by linkers, sometimes fused with sequences like GM-CSF signal peptide or LAMP-1 to enhance antigen processing and immune presentation. The regimen involves administering the conserved element DNA vaccine followed by administration of a DNA vaccine encoding the full-length Gag protein. This sequential or co-immunization strategy broadens immune responses, including both cellular and humoral, overcoming the limitations of responses generated by full-length Gag alone and generating cross-clade reactive immunity.
Claims Coverage
The claims encompass methods primarily related to immunization strategies involving nucleic acids encoding conserved elements from HIV Gag protein and subsequent administration of full-length Gag nucleic acid. The main inventive features relate to the composition of conserved elements, their variants, administration sequences, fusion to signal peptides, and delivery methods.
Use of nucleic acids encoding multiple conserved Gag elements
Methods comprising administering a first nucleic acid encoding six conserved elements from Gag, each 12 to less than 30 amino acids in length and non-contiguous, and a second nucleic acid encoding variant conserved elements differing by up to three amino acids.
Sequential administration followed by full-length Gag nucleic acid
Administering the conserved element nucleic acids followed by a nucleic acid encoding only the full-length Gag protein to induce immune responses.
Conserved elements derived from HIV-1 p24gag with specific sequences
Conserved element polypeptides comprising sequences set forth in SEQ ID NOS:1-7, 32, or 33, arranged in particular configurations as presented in the sequence listings and figures.
Fusion of conserved element polypeptides to GM-CSF signal peptide
Encoding polypeptides fused to signal peptides like GM-CSF to enhance expression or immune processing.
Administration of conserved element nucleic acids in same or separate vectors
Conserved element sequences may be encoded on the same vector or separate vectors and administered either sequentially or concurrently.
Delivery by intramuscular injection followed by electroporation
Nucleic acid constructs encoding conserved elements and full-length Gag are administered intramuscularly and enhanced by in vivo electroporation to improve immune response.
Utilization of variant conserved elements differing by 1-3 amino acids
Use of nucleic acids encoding variant conserved element polypeptides differing slightly from the first set, covering over 99% of naturally occurring variants.
Specific sequence embodiments for conserved elements and full-length Gag
Methods employing nucleic acids encoding polypeptides such as SEQ ID NO:15 and SEQ ID NO:16 or their variants (p24CE1c, p24CE2c, p24CE1d, p24CE2d) combined with a nucleic acid encoding p55 Gag protein.
The claims cover immunization methods using nucleic acids encoding selected conserved elements of HIV Gag proteins and their variants, followed by administration of full-length Gag nucleic acid, with specifics on sequence identity, polypeptide fusion to signal peptides, delivery methods, and sequence arrangements to induce broad and enhanced immune responses.
Stated Advantages
The vaccine strategy increases the breadth and magnitude of immune responses to conserved HIV elements compared to full-length Gag immunization alone.
It induces both CD4+ and CD8+ T cell responses, including polyfunctional and cytotoxic T cells, which are associated with better viral control.
The approach overcomes immunodominance of variable regions and immunodominant decoy epitopes that impair effective immune responses.
It generates cross-clade reactive humoral and cellular immune responses against highly conserved viral regions.
Fusion to signal peptides or lysosomal targeting sequences stabilizes the conserved element proteins and improves secretion and processing, enhancing immunogenicity.
Documented Applications
Use as a DNA vaccine approach to induce broad and cross-clade immune responses against HIV-1, particularly targeting conserved regions of the p24gag protein.
Vaccination of mammals including humans and non-human primates to induce cellular and humoral immunity against HIV infection.
Application of the conserved element vaccine strategy to other highly diverse viral proteins to focus immune responses on conserved, functionally critical proteome segments.
Use of nucleic acid vaccines delivered by intramuscular injection followed by electroporation, viral vector-based vaccines, or other delivery modalities to enhance immune responses.
Interested in licensing this patent?