Single infusion of engineered T-cells achieves lasting asthma remission in mice

A recent study published in Nature Immunology demostrates that durable asthma remission can be achieved with engineered and long-lived chimeric antigen receptor (CAR) T-cell treatment in mice.

Study: A single infusion of engineered long-lived and multifunctional T cells confers durable remission of asthma in mice. Image Credit: Nemes Laszlo / Shutterstock.com

Expanding the indications for cell therapies

Cell therapies can lead to durable remission of some cancers with a single infusion, which is comparable to protein- or small molecule-based therapies that require repeated or chronic administration.

CAR T-cell therapy, for example, has cured patients with B-cell malignancies. This has led researchers to become increasingly interested in determining whether T-cells could be engineered for long-term remission of non-cancerous diseases as well.

Nearly 50% of patients with asthma exhibit the type-2 high signature, which is characterized by eosinophilia, immunoglobulin E (IgE) production, bronchial hyperresponsiveness, and mucus hypersecretion. Although biologic agents targeting interleukin-4 (IL-4), IL-5, and IL-13 have been approved for asthma, these require lifelong administration and are not cost-effective or curative. Furthermore, there remains a lack of treatments available for asthma that can confer durable remission with a single dose/infusion.

Study findings

A CAR was initially developed with mouse IL-5 as the antigen-binding moiety. T-cells expressing this IL-5 CAR, which were eventually referred to as 5T cells, were found to effectively deplete IL-5 receptor-α (IL-5Rα⁺) cells and eosinophils in vitro.

Thereafter, 5T cells were administered into mice and assessed for their conditioning-free expansion and eosinophil elimination. After one week, 5T cells were not detected in the peripheral blood and eosinophils were unaffected, thus demonstrating that 5T cells do not expand or deplete eosinophils in vivo.

Immortal-like and functional 5T (5T_IF ) cells were then generated by knocking out BCL6 corepressor (BCOR) and zinc finger CCCH-type containing 12A (ZC3H12A). These 5T_IF cells exhibited robust expansion, depleted eosinophils, and persisted for at least one year. Although eosinophils reemerged one month after infusion, their proportions were lower than in control mice and expressed low/negative levels of IL-5Rα.

The researchers then engineered 5T_IF cells to express IL-4 mutein, which is an IL-4 or IL-13 antagonist, that were then referred to as 5T_IF 4 cells. Mice were then administered 5T_IF, 5T_IF 4, or phosphate-buffered saline (PBS) and subsequently immunized with ovalbumin to elicit a type 2 response.

To this end, 5T_IF 4 cells reduced IL-5 and IL-13 levels, whereas 5T_IF treatment led to slightly lower levels of IL-5 alone. Both 5T_IF and 5T_IF 4 cells exhibited a central memory-like phenotype.

Mice receiving 5T_IF 4, 5T_IF, or PBS were monitored for up to one year, none of which experienced significant weight loss nor succumbed to any adverse effects during this period. Eosinophils were depleted or absent in the bone marrow and spleens of 5T_IF 4 and 5T_IF recipients. Furthermore, there was no aberrant activation of endogenous T-cells or abnormalities in 5T_IF 4 or 5T_IF recipients.

The efficacy of 5T_IF 4 and 5T_IF cells against asthma was then assessed. In an acute asthma model, 5T_IF 4 and 5T_IF cells exhibited expansion and were detected in asthmatic lungs, thus demonstrating suppressed inflammation.

Eosinophils were also absent in the lungs and bronchoalveolar lavage fluid of treated mice and T-cell infiltration was reduced. Additionally, 5T_IF 4 cells were more effective in curbing IgE and IL-13 production.

A chronic asthma mouse model was generated by repeated intranasal challenges of house dust mites (HDMs) for eight weeks. These mice were then treated with 5T_IF 4, 5T_IF, or IL-4 mutein for four weeks.

Mice with chronic asthma that were treated with 5T_IF 4 and 5T_IF cells, but not IL-4 mutein, experienced improved airway hypersensitivity. Additionally, 5T_IF 4 cell treatment led to potent inhibition of HDM-specific and total IgE and IgG1 antibodies.

In a second chronic asthma experiment, mice received 5T_IF 4, 5T_IF, or PBS and were subsequently challenged with HDMs several times after a 10-week resting period to induce asthma recurrence. While both cell types reduced lung inflammation, 5T_IF 4 cells were more effective.

The researchers also explored the efficacy of human 5T_IF 4 (h5T_IF 4) cells using mouse IL-5 as the antigen-binding moiety for human IL-5Rα. To this end, h5T_IF 4 cell treatment in immunodeficient mice led to their expansion, eosinophil elimination, IL-4 mutein secretion, and persistence.

Single-cell ribonucleic acid (RNA) sequencing confirmed the presence of CD4⁺ and CD8⁺ h5T_IF 4 cells that formed nine clusters based on differential gene expression, six of which co-expressed genes related to stemness, exhaustion, and function. Moreover, h5T_IF 4 cells expressed interferon-gamma and no other inflammatory cytokine.

Conclusions

The current study provided proof-of-concept and preclinical data for long-term asthma remission using engineered and multifunctional T-cells. More specifically, 5T_IF 4 cells provided robust and durable effects against IL-4, IL-5, and IL-13.