A novel lentiviral vector-based approach to generate chimeric antigen receptor T cells targeting
Aspergillus fumigatus
Authors: Kumaresan Pappanaicken R. , Wurster Sebastian , Bavisi Karishma , da Silva Thiago Aparecido , Hauser Paul , Kinnitt Jordan , Albert Nathaniel D. , Bharadwaj Uddalak , Neelapu Sattva , Kontoyiannis Dimitrios P. 
Published: February 2024

Invasive aspergillosis (IA) is a common and deadly mold infection in immunocompromised patients. As morbidity and mortality of IA are primarily driven by poor immune defense, adjunct immunotherapies, such as chimeric antigen receptor (CAR) T cells, are direly needed. Here, we propose a novel approach to generate
Aspergillus fumigatus
(AF)-CAR T cells using the single-chain variable fragment domain of monoclonal antibody AF-269-5 and a lentiviral vector system. These cells successfully targeted mature hyphal filaments of representative clinical and reference AF isolates and elicited a potent release of cytotoxic effectors and type 1 T cell cytokines. Furthermore, AF-CAR T cells generated from peripheral blood mononuclear cells of four healthy human donors and expanded with either of three cytokine stimulation regimens (IL-2, IL-2 + IL-21, or IL-7 + IL-15) significantly suppressed mycelial growth of AF-293 after 18 hours of co-culture and synergized with the immunomodulatory antifungal agent caspofungin to control hyphal growth for 36 hours. Moreover, cyclophosphamide-immunosuppressed NSG mice with invasive pulmonary aspergillosis that received two doses of 5 million AF-CAR T cells (6 and 48 hours after AF infection) showed significantly reduced morbidity on day 4 post-infection (
P
< 0.001) and significantly improved 7-day survival (
P
= 0.049) compared with mice receiving non-targeting control T cells, even without concomitant antifungal chemotherapy. In conclusion, we developed a novel lentiviral strategy to obtain AF-CAR T cells with high targeting efficacy, yielding significant anti-AF activity
in vitro
and short-term protection
in vivo
. Our approach could serve as an important steppingstone for future clinical translation of antifungal CAR T-cell therapy after further refinement and thorough preclinical evaluation.

IMPORTANCE

Invasive aspergillosis (IA) remains a formidable cause of morbidity and mortality in patients with hematologic malignancies and those undergoing hematopoietic stem cell transplantation. Despite the introduction of several new
Aspergillus
-active antifungals over the last 30 years, the persisting high mortality of IA in the setting of continuous and profound immunosuppression is a painful reminder of the major unmet need of effective antifungal immune enhancement therapies. The success of chimeric antigen receptor (CAR) T-cell therapy in cancer medicine has inspired researchers to translate this approach to opportunistic infections, including IA. Aiming to refine anti-
Aspergillus
CAR T-cell therapy and improve its feasibility for future clinical translation, we herein developed and validated a novel antibody-based CAR construct and lentiviral transduction method to accelerate the production of CAR T cells with high targeting efficacy against
Aspergillus fumigatus
. Our unique approach could provide a promising platform for future clinical translation of CAR T-cell-based antifungal immunotherapy.