Combined CLEC2d Expression and CD58 Loss Mitigate Rejection of Allogeneic T Cells

Area of Science:

• Immunology
• Cell Therapy
• Genetic Engineering

Background:

• Allogeneic chimeric antigen receptor (CAR) T cell therapies face immunogenicity challenges, limiting their effectiveness.
• Genetic knockout of beta-2-microglobulin (B2M) in T cells prevents HLA class I presentation but can trigger natural killer (NK) cell-mediated 'missing-self' responses.

Purpose of the Study:

• To develop strategies to overcome NK cell-mediated rejection of allogeneic B2M knockout (B2MKO) T cells.
• To assess the combined efficacy of engineered CLEC2d expression and CD58 loss in mitigating NK cell responses.

Main Methods:

• Allogeneic T cells underwent genetic engineering for B2M knockout.
• Engineered T cells were modified to express chimeric membrane-bound CLEC2d and to lose CD58 expression.
• In vitro assays assessed NK cell-dependent lysis of engineered T cells.
• In vivo studies evaluated the persistence of engineered T cells in humanized mice.

Main Results:

• The combination of CLEC2d expression and CD58 loss significantly reduced in vitro NK cell-mediated lysis of B2MKO T cells compared to single strategies.
• This dual genetic modification enhanced the in vivo persistence of allogeneic T cells in NK cell-replete humanized mice.

Conclusions:

• Orthogonal genome engineering approaches, including CLEC2d expression and CD58 loss, effectively mitigate NK cell rejection of allogeneic T cells.
• This strategy holds promise for improving the clinical implementation and durability of allogeneic CAR T cell therapies.