Truncated BCMA-CAR Intracellular Domains for Surface Expression
Solution Overview
Problem
Current third-generation chimeric antigen receptors (CARs) that combine co-stimulatory signaling domains from CD28 and TNFR families for enhanced T cell function suffer from reduced cell surface expression, limiting their therapeutic potential in cancer treatment.
Innovation Solution
A chimeric antigen receptor (CAR) that binds to B cell maturation antigen (BCMA) is developed, incorporating a BCMA nanobody and a third-generation chimeric T cell co-stimulatory molecule with a CD28 family signaling domain and a TNFR family signaling domain, specifically designed to enhance T cell activation and proliferation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If third-generation chimeric antigen receptors combine two co-stimulatory signaling domains from CD28 and TNFR families to enhance T cell function, then T cell activation and proliferation are improved, but cell surface expression of the chimeric proteins is reduced
Solution Approach 1:
The patent extracts only the essential signaling domains from the full-length CD28 and TNFR family proteins, using truncated versions that retain co-stimulatory function while reducing steric hindrance and improving surface expression. Specifically, the CD28 intracellular domain is truncated to residues 1-170, and the 4-1BB intracellular domain is truncated to residues 1-160, removing portions that may interfere with receptor folding or surface trafficking while preserving the critical signaling motifs.
Solution Approach 2:
The patent modifies the structural parameters of the chimeric antigen receptor by changing the length and composition of intracellular signaling domains. By truncating the CD28 and 4-1BB intracellular domains to specific residue lengths, the receptor achieves optimal balance between signaling capability and cell surface expression. The ICOS extracellular stalk length is also optimized at 100 residues to improve receptor positioning and surface stability.
2Productivity
If chimeric antigen receptors use full-length co-stimulatory signaling domains to maximize signaling potential, then T cell therapeutic potential is enhanced, but cell surface expression is reduced preventing realization of functional potential
Solution Approach 1:
The patent extracts only the essential signaling domains from the full-length CD28 and TNFR family proteins, using truncated versions that retain co-stimulatory function while reducing steric hindrance and improving surface expression. Specifically, the CD28 intracellular domain is truncated to residues 1-170, and the 4-1BB intracellular domain is truncated to residues 1-160, removing portions that may interfere with receptor folding or surface trafficking while preserving the critical signaling motifs.
Solution Approach 2:
The patent applies partial action by using truncated versions of the co-stimulatory domains rather than full-length proteins. The truncations are carefully designed to include only the minimal necessary residues for signaling function (CD28 residues 1-170, 4-1BB residues 1-160), providing sufficient therapeutic potential while eliminating regions that reduce surface expression. This partial inclusion strategy optimizes the balance between function and expression.
Data Source
AI summary
The present application relates to functionally improved third generation BCMA-CARs comprising modified intracellular co-stimulatory domains, which can be used in adoptive cell therapy, e.g., in treatment of diseases and disorders such as cancer.