Engineering Natural Killer Cells to Secrete Engager Molecules Targeting B7-H3 — ASN Events
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  2. Poster Session Two
  3. Engineering Natural Killer Cells to Secrete Engager Molecules Targeting B7-H3

Engineering Natural Killer Cells to Secrete Engager Molecules Targeting B7-H3 (#250)

Nicholas A Zorko 1 , Rih-Sheng Huang 1 , Jacob Rugloski 1 , Madison Shackelford 1 , Melissa Khaw 1 , Shee-Kwan Phung 1 , John R Lozada 1 , Terran Stenger 1 , Justin H Hwang 1 , Emmanuel S Antonarakis 1 , Martin Felices 1 , Jeffrey S Miller 1
  1. University of Minnesota, Minneapolis, MINNESOTA, United States

Background:

We have shown natural killer (NK) cells infiltrate prostate cancer (PCa) at high levels. We developed a novel dual camelid (cam) Tri-specific Killer Engager (TriKE) molecule containing WT IL-15 and two cam engagers targeting CD16 on NK cells and B7H3 on tumors.  We also developed a dual camelid Bispecific Killer Engager (BiKE) that lacks WT IL-15.  B7H3 (CD276) is an immune checkpoint inhibitor that is associated with poorer prognosis and is highly-expressed on PCa. To deliver BiKE or TriKE (engager) directly to the tumor microenvironment, we sought to develop lentivirus to transduce NKs capable of secreting engagers.

Methods:

Second-generation lentivirus was generated containing camB7-H3 BiKE, camB7-H3 TriKE, or empty vector, all with mNeongreen reporter. Healthy donor NK cells were expanded then transduced with lentiviral constructs.  Cells were then sorted and expanded for an additional 21 days   The presence of BiKE or TriKE on transduced NK cells evaluated by flow cytometry.  NK cell degranulation (CD107a), inflammatory cytokine production (interferon-gamma or tumor necrosis factor-alpha), and NK proliferation will be compared.    

Results:

Expanded normal donor NK cells were transduced with BiKE or TriKE and mNeongreen expression persisted through the 21-day expansion.  Secreted engager was detected on the surface of transduced, expanded NK cells and B7-H3+ tumor targets.  Functional and killing assays to evaluate whether adequate concentrations of engager to induce target killing will be presented. 

Conclusions:

We have successfully developed a method to efficiently transduce and expand normal donor NK cells to secrete engager molecules targeting the tumor antigen B7-H3.  We have shown that transduced NK cells secrete functional engager that binds to the surface of both NK cells and tumor targets.  This study demonstrates the feasibility of efficient lentiviral transduction of peripheral blood NK cells as a source of local and continuous immune engager production for the treatment of PCa.