Conditionally Replication Defective Herpesvirus Vaccine Design
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Solution Overview
Problem
Current live VZV vaccines provide long-lived protective immunity but are susceptible to reactivation, leading to serious neurological diseases like zoster and shingles, and existing herpesvirus vaccines fail to prevent reactivation after initial infection.
Innovation Solution
Development of conditionally replication defective herpesvirus strains, such as varicella virus mutants with destabilization domains fused to essential genes like ORF 63 or 70, which only replicate under defined conditions, preventing reactivation and allowing for long-lived immunity without the risk of viral reactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If live VZV vaccines are used to provide long-lived protective immunity, then immunity duration is improved, but reactivation risk increases leading to zoster and shingles
Solution Approach 1:
The vaccine virus is engineered with conditional replication control mechanisms that segment the replication process into controlled phases. The virus contains destabilization domains fused to essential genes (ORF 63, 70, 62, or 71) that can be conditionally stabilized by antibiotics like trimethoprim, allowing controlled replication only when needed for immune response while preventing uncontrolled reactivation
Solution Approach 2:
The patent changes the replication parameter of the virus from constitutive to conditional by introducing destabilization domains. The virus replication capability is modified to depend on the presence of specific antibiotics that stabilize essential viral proteins, thereby controlling when and where the virus can replicate - during vaccination when antibiotics are present, but not during latency or reactivation phases
2Reliability
If herpesvirus vaccines allow viral replication to induce immunity, then immune response is improved, but neurological disease risk worsens due to reactivation
Solution Approach 1:
Antibiotics serve as intermediary molecules that mediate between the vaccine virus and the host immune system. The antibiotics temporarily stabilize essential viral genes during the vaccination period, enabling controlled replication and immune response induction, then are withdrawn to prevent subsequent reactivation and neurological complications
Solution Approach 2:
The vaccine design incorporates preliminary anti-replication measures through destabilization domains that prevent viral gene expression. These domains are engineered to be unstable by default, blocking viral replication unless stabilized by antibiotics, thereby preventing harmful reactivation before it can occur
3Reliability
If destabilization domains are fused to essential viral genes to prevent reactivation, then reactivation prevention is improved, but viral replication capability worsens under normal conditions
Solution Approach 1:
The viral replication system is made dynamic and adjustable through the antibiotic-responsive destabilization domains. The virus transitions between a non-replicating latent state (when antibiotics are absent) and an active replicating state (when antibiotics are present), allowing the replication capability to be tuned dynamically based on therapeutic needs
Data Source
AI summary
The present invention is directed to a mutated recombinant herpesvirus, e.g., varicella zoster virus (VZV) and simian varicella virus strains or HSV-1 or HSV-2 strains, vaccines containing, and methods for the construction and use thereof to elicit protective immunity in susceptible individuals, wherein the particular herpesvirus is modified to render the virus replication deficient, i.e., the virus substantially or only replicates under defined conditions, by the incorporation of at least one destabilization domain in or fused to a gene essential for herpesvirus replication. The invention particularly relates to the use of the resultant conditionally replication defective herpesviruses, e.g., a mutated VZV strains in vaccine compositions in order to immunize individuals against herpesvirus infection, e.g., in the case of VZV chickenpox and to protect against shingles and zoster, or to prevent the reactivation of VZV or other herpesvirus reactivation and the onset of shingles or another condition relating to the reactivation of another herpesvirus infection, e.g., as a consequence of advanced age, stress, inflammation, drug or other therapy, cancer, or immunodeficiency such as in HIV-AIDS or other diseases resulting in impaired T and/or B cell immunity.