Live-Attenuated Junín Virus GPC Mutations for Reversion Resistance
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Solution Overview
Problem
The existing Junín virus (JUNV) vaccine strain, Candid#1, is prone to genetic reversion, posing a risk of losing its attenuated pathogenicity, which is a concern for live attenuated viral vaccines, as seen in the oral poliovirus vaccine.
Innovation Solution
Introduce specific mutations in the GPC protein of JUNV, including altering the NxT/S glycosylation motif in residues 150-175, mutating residue 33 to a non-positively charged amino acid, and maintaining the F427I mutation to enhance resistance to genetic reversion, thereby stabilizing attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Candid#1 vaccine strain is used, then protective immunity against JUNV is achieved, but the virus is prone to genetic reversion to virulence
Solution Approach 1:
The patent introduces specific amino acid substitutions in the GPC protein (N166Q, N166D, N166E, A168G, A168V, T168A, T168G, T168V) to alter the glycosylation motif and stabilize the attenuated phenotype. These parameter changes in the protein sequence prevent genetic reversion while maintaining vaccine efficacy, directly resolving the contradiction between vaccine safety and genetic stability.
Solution Approach 2:
The patent creates a composite mutation profile combining multiple amino acid substitutions in the GPC protein rather than relying on a single mutation. This composite approach (combining F427I with additional glycosylation motif mutations) provides synergistic stabilization against reversion, addressing the genetic instability issue while preserving the attenuated state.
2Stability of the object's composition
If multiple mutations are introduced in GPC protein, then resistance to genetic reversion is enhanced, but the complexity of the vaccine development increases
Solution Approach 1:
The patent systematically evaluates specific parameter changes (amino acid substitutions) at defined positions (166, 168, 427) in the GPC protein. By focusing mutations on specific residues with known functional importance (glycosylation motifs and transmembrane domain), the complexity is managed through targeted rather than random mutagenesis, making the multi-mutation approach feasible.
Solution Approach 2:
The patent uses reverse genetics to copy and propagate specific mutation combinations in a controlled manner. By creating plasmids containing the desired amino acid substitutions and using them to generate virus stocks, the complex multi-mutation profile is efficiently propagated without requiring complex serial passage procedures, reducing developmental complexity.
Data Source
AI summary
The present disclosure relates to a novel live-attenuated Junín virus (JUNV), which exhibits reduced likelihood for virulence reversion compared to the Candid#1 vaccine strain. The live-attenuated JUNV comprises at least three mutations in its GPC protein compared to a pathogenic strain of JUNV. One mutation is a substitution mutation at residue 427 like the Candid#1 vaccine strain. The live-attenuated JUNV comprises at least one mutation altering a NxT/S glycosylation motif in a region spanning residues 150-175 of the Junín virus GPC protein to inactivate the glycosylation site. In some embodiments, the live-attenuated JUNV further comprises a substitution mutation at residue 33. Compositions comprising the variant JUNV and methods of using the JUNV and compositions are also described herein.