Triple-Target FAP CAR-NKT Cells Clear Arterial Plaques Better Than Single-Target CAR-T

A research team at the University of California, Los Angeles (UCLA) has engineered a novel class of immune cells capable of attacking atherosclerotic plaques—the fatty deposits within arterial walls that drive the majority of heart attacks and strokes. These engineered cells exert their therapeutic effect by recognizing three distinct pathogenic cell populations within the plaque microenvironment. The findings were published in the journal Circulation Research.

Across mouse models, laboratory-engineered microvessels, and arterial tissues derived from patients with severe cardiovascular disease, these "triple-threat" cells consistently outperformed single-target counterparts by eliminating a broader array of cell types that keep plaques biologically active and unstable.

Atherosclerosis remains the principal driver of cardiovascular disease, which stands as the leading cause of death worldwide. Even with lipid-lowering and anti-inflammatory pharmacotherapies, the disease remains difficult to manage. This persistent challenge stems largely from plaque pathology: far from being inert clumps of fat, plaques represent complex cellular ecosystems where distinct populations continuously amplify reciprocal damage.

Dysfunctional vascular smooth muscle cells transition into an aggressive, scar-forming phenotype, while macrophages engorged with excess cholesterol become foam cells. These foam cells secrete pro-inflammatory cytokines that further stimulate vascular smooth muscle cells, fueling a pathogenic vicious cycle.

Limitations of Single-Target Approaches

An emerging strategy adapts CAR-T cell therapy—which has shown early promise in fibrosis-related conditions—to construct engineered FAP.CAR-T cells directed against fibroblast activation protein (FAP). Because FAP is expressed on aberrant vascular smooth muscle cells, it serves as a valuable surface marker for targeted ablation.

However, this paradigm carries a fundamental bottleneck: CAR-T cells targeting FAP alone leave inflammatory macrophages and foam cells untouched. Eliminating a single pathogenic subset allows other destructive lineages to perpetuate tissue injury unchecked.

A Three-Pronged Plaque Detection Mechanism

To overcome this constraint, UCLA researchers developed FAP.CAR-NKT cells. Instead of conventional T cells, the team engineered invariant natural killer T (iNKT) cells—a rarer, more versatile immune subset—by equipping them with a synthetic FAP-targeting construct.

FAP.CAR-NKT cells detect plaque-associated threats through three independent mechanisms:

• An engineered synthetic receptor directed against aberrant vascular smooth muscle cells.
• Endogenous invariant receptors that recognize lipid-associated antigens presented on macrophages and foam cells.
• Native stress sensors capable of detecting metabolic distress markers shed by dysfunctional foam cells.

The investigators evaluated FAP.CAR-NKT cells across three experimental platforms: an atherosclerotic murine model, a lab-cultured human "vessel-on-a-chip" system, and donated human arterial tissue from individuals with advanced cardiac disease. In every experimental setting, FAP.CAR-NKT cells demonstrated marked superiority over FAP.CAR-T cells.

Consistent Efficacy Across Disease Models

In atherosclerotic mice, FAP.CAR-NKT cell treatment yielded plaques that were significantly smaller and lower in lipid content compared to FAP.CAR-T cells, which had negligible impact on disease progression. This divergence was mirrored in the engineered microvessel platform: while single-target cells cleared aberrant smooth muscle cells, they spared adjacent foam cells; by contrast, the dual-action NKT cells eliminated both.

Figure 1. FAP.CAR-NKT cells mitigate atherosclerotic progression through multitarget cytotoxicity. (Zhu E, et al., 2026)

In human clinical arterial specimens, FAP.CAR-NKT cells effectively ablated aberrant smooth muscle cells, inflammatory macrophages, and foam cells, whereas standard FAP.CAR-T cells fell short.

Crucially, FAP.CAR-NKT cells showed no discernible systemic toxicity in mice—a safety profile likely attributable to the restricted expression of FAP in healthy adult tissues, which minimizes off-target collateral damage.

Durability and Dosing Considerations

To date, adoptive cell therapies have struggled to make meaningful clinical inroads against atherosclerosis. In these preclinical evaluations, FAP.CAR-NKT cells surpassed conventional single-target modalities by engaging a wider spectrum of plaque-resident cell types—offering a distinct strategic blueprint for a persistent clinical challenge.

Moving forward, the researchers aim to define the durability of therapeutic responses and identify optimal dosing regimens to sustain efficacy. This investigation represents an early yet substantive step toward next-generation atherosclerosis therapies capable of fighting arterial disease across multiple biological fronts simultaneously.