Plasmid-Cured Chlamydia Vaccine Vectors for Attenuated Pathogens

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Solution Overview

Problem

Current methods lack effective genetic tools to characterize chlamydial genes of unknown function, hindering the understanding of chlamydial pathogenesis and development of novel methods for preventing and treating chlamydia infections.

Innovation Solution

Development of novel vectors and plasmid-cured chlamydia strains with specific gene deletions, such as the pgp4 gene, to create attenuated pathogens that can be used as vaccines or treatments, enhancing the stability and replicative capacity of attenuated pathogens and inducing protective immunity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If plasmid-deficient C. trachomatis strains are used as live-attenuated vaccines, then protective immunity is induced against challenge with virulent organisms, but the molecular basis of plasmid-mediated virulence remains poorly understood

Engineering Contradiction:

Improveprotective immunityVSAvoidmolecular basis of virulence

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The plasmid was segmented into individual open reading frames (ORFs) for separate analysis. Each ORF was individually deleted or mutated to determine its specific contribution to virulence, allowing systematic identification of virulence factors while maintaining the overall plasmid structure for immune induction

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Specific regions of the plasmid (individual ORFs) were modified to alter local properties while preserving global plasmid function. This allowed identification of which specific plasmid components contribute to virulence versus those necessary for immune protection

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If chlamydial forward and reverse genetics systems are developed, then genes of unknown function can be characterized, but there have been no reports using these tools to characterize chlamydial genes

Engineering Contradiction:

Improvegenetic characterization capabilityVSAvoidapplication implementation

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The genetic tools (forward and reverse genetics systems, transformation protocols) were developed and validated in advance before being applied to characterize specific chlamydial genes. This preliminary establishment of methodology enabled subsequent successful characterization of plasmid ORFs and chromosomal genes

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Plasmid-deficient strains served as intermediaries between the development of genetic tools and their application to study virulence. These strains provided a stable background in which to test and refine genetic manipulation techniques before applying them to broader gene characterization studies

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10258682B2Attenuated chlamydia vaccine

Publication Date: 2019.04.16 THE GOVERNMENT OF THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY DEPARTMENT OF HEALTH & HUMAN SERVICES

AI summary

The invention provides vectors, attenuated pathogens, compositions, methods, and kits for use in preventing or treating infection by an infectious pathogen, especially Chlamydia trachomatis. The vectors comprise the plasmid encoded ppg genes from Chlamydia, ppg1, ppg2, ppg3, ppg5, ppg6, ppg7 and/or ppg8, but lack ppg4, a regulator of virulence associated genes. The application also provides attenuated pathogens, especially chlamydia, which are cured of their plasmid and have additional mutations to improve the attenuation, especially mutations in the CT135 gene or in the tryptophan operon (trp promoter, trpA, or trpB). Uses of said nucleic acids and attenuated pathogens for inducing or modulating an immune response in a subject, especially for prevention or treatment of infections, are proposed.