Transgenic Animal Gene Conversion for Same-Light-Chain Antibodies

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Solution Overview

Problem

Producing antibodies with the same light chain is challenging due to somatic hyper-mutation, which changes the light chain variable region coding sequence during affinity maturation in B cells, leading to diverse light chains in engineered animals.

Innovation Solution

Implementing a transgenic animal with a modified immunoglobulin light chain locus containing functional light chain genes and pseudogenes that encode the same amino acid sequence, using gene conversion to repair mutations and maintain light chain uniformity through pseudogene donation of nucleotide sequences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If somatic hyper-mutation is allowed to occur during affinity maturation in B cells, then antibody affinity is improved, but light chain diversity increases

Engineering Contradiction:

Improveantibody affinityVSAvoidlight chain sequence uniformity

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent converts the harmful effect of somatic hyper-mutation (light chain diversity) into a beneficial process by using gene conversion from pseudogenes. The same mutational mechanism that causes diversity is harnessed to restore uniformity, as pseudogenes donate wild-type sequences back to the functional light chain gene during affinity maturation, thereby maintaining light chain consistency while allowing affinity improvement.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent implements a recovery mechanism where the functional light chain gene discards accumulated mutations during affinity maturation and recovers the original wild-type sequence from pseudogenes. This discarding and recovering process ensures that light chains remain uniform across different B cells while still allowing the heavy chains to diversify for affinity maturation.

Inventive Principle:

Principle #34Discarding and recovering

2Stability of the object's composition

If pseudogenes are used for gene conversion to maintain light chain uniformity, then light chain diversity is reduced, but the mechanism complexity increases

Engineering Contradiction:

Improvelight chain sequence uniformityVSAvoidimmunoglobulin locus structure

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent implements a self-service mechanism where the immunoglobulin locus contains its own repair system. Pseudogenes are embedded within the locus itself and automatically donate sequences to functional genes during normal B cell development and affinity maturation processes, without requiring external intervention or complex artificial systems.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent merges the functional light chain genes with non-functional pseudogenes into a single operable locus. This merging allows the pseudogenes to serve as a built-in sequence reservoir that can be accessed during gene conversion, simplifying the overall system by integrating the repair mechanism directly into the existing genomic structure rather than adding separate external components.

Inventive Principle:

Principle #5Merging (Combining)

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

The transgenic animal produces polyclonal antisera with reduced light chain diversity, ensuring a diversified population of antibodies with the same light chain variable region, suitable for bi-specific antibodies with consistent binding specificity.

Implementation Method 1

a plurality of pseudogenes that are operably linked to the functional immunoglobulin light chain gene and that donate, by gene conversion, nucleotide sequence to the nucleic acid encoding a light chain variable region

Methodology Applied

Scientific EffectGene conversion:

Data Source

PatentUS12408640B2Transgenic animal for producing diversified antibodies that have the same light chain I

Publication Date: 2025.09.09 CRYSTAL BIOSCIENCE INC

AI summary

This disclosure provides, among other things, strategies for minimizing antibody diversification in a transgenic animal that uses gene conversion for antibody diversification. In some embodiments, the animal may comprise a genome comprising an endogenous immunoglobulin light chain locus comprising: (a) a functional immunoglobulin light chain gene comprising a nucleic acid encoding a light chain variable region; and (b) a plurality of pseudogenes that are operably linked to the functional immunoglobulin light chain gene and that donate, by gene conversion, nucleotide sequence to the nucleic acid encoding a light chain variable region, wherein the pseudogenes are upstream or downstream of the functional immunoglobulin light chain gene and encode the same amino acid sequence as the light chain variable region of the functional immunoglobulin light chain gene of (a). In other embodiments, the locus may have a tandem array of coding sequences for the light chain.