Engineered natural killer (NK) cells represent a promising option for immune therapy option due to their immediate availability in allogeneic settings. Severe acute diseases, such as COVID-19, require targeted and immediate intervention. Here we show engineering of NK cells to express (1) soluble interleukin-15 (sIL15) for enhancing their survival and (2) a chimeric antigen receptor (CAR) consisting of an extracellular domain of ACE2, targeting the spike protein of SARS-CoV-2. These CAR NK cells (mACE2-CAR_sIL15 NK cells) bind to VSV-SARS-CoV-2 chimeric viral particles as well as the recombinant SARS-CoV-2 spike protein subunit S1 leading to enhanced NK cell production of TNF-α and IFN-γ and increased in vitro and in vivo cytotoxicity against cells expressing the spike protein. Administration of mACE2-CAR_sIL15 NK cells maintains body weight, reduces viral load, and prolongs survival of transgenic mice expressing human ACE2 upon infection with live SARS-CoV-2. These experiments, and the capacity of mACE2-CAR_sIL15 NK cells to retain their activity following cryopreservation, demonstrate their potential as an allogeneic off-the-shelf therapy for COVID-19 patients who are faced with limited treatment options.

Ting Lu, Rui Ma, Wenjuan Dong, Kun-Yu Teng, Daniel S. Kollath, Zhiyao Li, Jinhee Yi, Christian Bustillos, Shoubao Ma, Lei Tian, Anthony G. Mansour, Zhenlong Li, Erik W. Settles, Jianying Zhang, Paul S. Keim, Bridget M. Barker, Michael A. Caligiuri, Jianhua Yu