Antibody-mediated Inhibition of Global HLA/LILR Interactions Breaks Innate ImmuneSystemTolerance and Unleashes Potent Anti-Tumor Immunity

We have conducted a study to investigate how blocking HLA/LILR affects the activation of immune cells in the tumor microenvironment. We perfused a freshly isolated primary colon cancer biopsy sample with hIgG1 LALAPG or DX17 LALAPG for 48 hours. We then isolated CD45+ leukocytes from the tumor sample using magnetic cell sorting. Subsequently, we processed the resulting tumor-infiltrating lymphocytes (TILs) for single-cell RNA-seq and Cite-seq analysis. We compared the transcriptomes of NK cells, monocytes, and memory T cells under the two different culture conditions Overall design: We utilized an oxygenated ex vivo perfusion circuit (Patent No. PCT/US2021/021525) to maintain tumors that were removed from patients in near-physiological conditions. We perfused the tumor samples with autologous patient plasma and hIgG1 LALAPG and DX17-LALAPG (5ug/ml) for 48 hours. After the perfusion was complete, we isolated tumor-infiltrated lymphocytes (TILs) by dissociating the tumor explants into a single-cell suspension. We then analyzed the TILs, including NK cells, monocytes, and T cells, in tumor microenvironments using sc-RNA-seq and CITE-seq.