Oral Presentation CD1-MR1 2024

Adoptive cell therapy of hematological malignancies across MHC-barriers by iNKT cells engineered with a CD1c-restricted TCR (#77)

Giulia Casorati 1
  1. San Raffaele Scientific Institute, Milan, Italy

The major unmet clinical need of acute leukemia and Non-Hodgkin lymphoma (NHL) remains the frequent recurrence after the frontline treatment. For these reasons there is pressing need for alternative strategies to target T cell responses selectively against malignant cells. We have shown that primary acute myelogenous (AML) and B-lymphoblastic (B-ALL) leukemia blasts express the CD1c molecule, and that a group of human CD1c-restricted, self-reactive T cell clones kills acute leukemia blasts by recognizing the leukemia-associated lipid antigen methyl-lysophosphatidic acid (mLPA). More recently we observed that also the majority of B-cell NHL express CD1c. Because CD1c is monomorphic and expressed only by healthy mature leukocytes, we can envisage a donor-unrestricted adoptive immunotherapy approach with reduced risk of GvHD induction using iNKT cells redirected against CD1ctumor cells. iNKT cells promote GvL reaction without eliciting GvHD and modulate immunosuppressive myeloid cells in the tumor microenvironment (TME) through their TCR. Hence, we envision to generate bi-specific iNKT cells armed with a universal mLPA-specific TCR to dual target leukemia cells and the immunosuppressive myeloid TME. Furthermore, CD1d can be also expressed by cancer cells, implying the possibility for combinatorial recognition of CD1d- and CD1c-restricted antigens on the malignant target by mLPA-specific TCR engineered iNKT cells. iNKT cells from any donor can be efficiently engineered with our lead CD1c-restricted TCR DN4.99 and can kill CD1c-expressing leukemia and lymphoma cell in vitro. Our results highlight a novel approach for ACT of acute leukemia with T or iNKT cells engineered to recognize malignant cells by the transfer of a lipid-specific TCR that works across MHC-barriers like a CAR