Mutant HSV Generation via Site-Specific Recombination

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Solution Overview

Problem

The existing methods for generating recombinant Herpes Simplex Virus (HSV) mutants are slow, inefficient, and technically challenging, requiring lengthy processes such as homologous recombination and multiple rounds of plaque purification, which hinder the rapid production of second-generation oncolytic viruses for cancer treatment.

Innovation Solution

The use of a site-specific recombination system employing recombinase enzymes to exchange DNA sequences flanked by attL and attR recognition sequences, allowing for rapid and efficient generation of HSV mutants by inserting genes of interest into specific locations within the HSV genome, either in vitro or in cell culture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If homologous recombination is used to generate HSV mutants, then the mutants can be generated with accurate genetic modifications, but the process takes 3-6 months and requires multiple plaque purification rounds

Engineering Contradiction:

Improvegenetic modification accuracyVSAvoidtime to generate mutants

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent introduces a bacterial artificial chromosome (BAC) as an intermediary system to carry the HSV genome. This BAC-based system allows for more efficient manipulation and recombination compared to traditional viral DNA approaches, enabling faster generation of mutants while maintaining genetic accuracy through controlled recombination events in bacterial hosts followed by viral rescue

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent performs preliminary cloning of the entire HSV genome into a BAC vector before generating mutants. This preliminary action creates a stable, manipulable platform that allows for rapid introduction of genetic modifications through standard molecular biology techniques, eliminating the need for time-consuming multiple plaque purification rounds

Inventive Principle:

Principle #10Preliminary action

2Reliability

If traditional plaque purification methods are used to isolate recombinant viruses, then pure recombinant virus stocks can be obtained, but the process requires 6-10 purification rounds over 3-6 months

Engineering Contradiction:

Improvepurity of recombinant virusVSAvoidrate of virus production

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the mechanical, iterative process of multiple plaque purification rounds with a molecular biology-based selection system. This includes using antibiotic resistance markers, fluorescent protein markers, or other selectable markers that allow for direct identification and isolation of recombinant viruses through a single transfection and selection step, dramatically increasing productivity while maintaining purity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If the entire HSV genome is cloned into a BAC vector, then rapid generation of mutants is enabled, but the initial cloning process is technically challenging

Engineering Contradiction:

Improvespeed of mutant generationVSAvoidcomplexity of cloning process

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the complex task of HSV genome manipulation into manageable parts: first cloning the genome into a BAC vector in a single comprehensive step, then using this stable BAC platform for rapid generation of specific mutants through targeted recombination. This segmentation separates the technically challenging initial cloning from the subsequent easy mutant generation steps

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method significantly accelerates the production of HSV mutants, reducing the time from weeks to days, and increases the efficiency of recombinant virus isolation, enabling the rapid generation and screening of second-generation oncolytic viruses for enhanced tumour destruction.

Implementation Method 1

The lambda phage site-specific recombination system employs a recombinase enzyme to exchange DNA sequences flanked by site-specific DNA recognition sequences

Methodology Applied

Scientific EffectSite-specific recombination: Enzyme

Data Source

PatentUS9085777B2Mutant HSV, materials and methods for generation of mutant HSV

Publication Date: 2015.07.21 VIRTTU BIOLOGICS LTD

AI summary

The present invention includes a method of generating a mutant Herpes Simplex Virus (HSV). In one embodiment, the generated HSV genome includes nucleic acid encoding a nucleic acid sequence of interest. In one step, a nucleic acid vector is provided which includes a nucleic acid encoding first and second site specific recombination sequences and a nucleic acid encoding a nucleic acid sequence of interest between said site specific recombination sequences an HSV is provided, the genome of which comprises third and fourth site specific recombination sequences In another step, the nucleic acid vector and HSV are contacted together with one or more recombinase enzymes capable of catalyzing site specific recombination between the site specific recombination sequences of said nucleic acid vector and said HSV. Another step includes identifying HSV containing the nucleic acid sequence of interest. In some embodiments, the methods are conducted in a cell-free system.