BCMA Extracellular Marker for Engineered Immune Cell Detection and Removal
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Solution Overview
Problem
Current methods for detecting and removing genetically engineered immune cells, such as CAR-T cells, lack specificity and sensitivity, and large molecular weight marker genes can reduce vector transduction efficiency and affect tumor killing effects.
Innovation Solution
Utilize a gene tBCMA encoding a BCMA extracellular domain, a smaller polypeptide of 54 amino acids, which is naturally expressed in the human body and linked to CAR-T cells for detection and removal, using recombinant expression vectors and genetic engineering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large molecular weight marker genes (such as CD19, CD34, EGFR) are used for detecting and removing genetically engineered immune cells, then the detection and removal capability is achieved, but the vector packaging capacity is reduced and transduction efficiency decreases
Solution Approach 1:
The patent extracts only the essential extracellular domain of the BCMA protein (54 amino acids) to serve as the marker gene, eliminating the need for the full-length protein while maintaining the detection and removal functionality. This extracted fragment is sufficiently small to fit within vector packaging limits and achieve high transduction efficiency, while still providing the necessary epitope for antibody-based detection and removal strategies.
2Reliability
If large molecular weight marker genes are used, then the marker function is achieved, but the expression density of the gene modified protein on T cells is reduced
Solution Approach 1:
The patent uses only the extracellular domain (54 amino acids) of BCMA as the marker, which is sufficiently small to allow high expression density on the T cell surface without burdening the protein synthesis machinery. This small size enables multiple copies to be expressed per cell, enhancing the marker signal strength and detection sensitivity while maintaining full marker functionality.
3Reliability
If large molecular weight marker genes are used, then the marker capability is achieved, but the target antigen binding ability is affected
Solution Approach 1:
The patent extracts the extracellular domain of BCMA that contains the antibody binding epitopes while removing the transmembrane and intracellular domains. This extracted portion retains the ability to bind with high specificity to anti-BCMA antibodies, enabling precise detection and removal. The small size actually enhances binding efficiency by reducing steric hindrance and allowing better antibody access to the epitopes.
Data Source
AI summary
A gene using a BCMA extracellular domain as a marker, a polypeptide, a recombinant expression vector, a genetically engineered cell, and use thereof are provided. The gene tBCMA is a gene encoding a complete or partial sequence of the BCMA extracellular domain, or a gene encoding a sequence at least 85% identical to the complete or partial sequence. An extracellular domain polypeptide (tBCMA) of the B cell maturation antigen is used as a marker for the technology of detecting and removing the genetically engineered immune cells. The gene using the BCMA extracellular domain as the marker can be widely used for the detection of various genetically engineered immune cells, thereby effectively solving the problems of detection of the genetically engineered immune cells after preparation and infusion, and providing a feasible strategy when these cells need to be removed due to serious toxic and side effects in clinical therapy.