Anti-LAYN monoclonal antibody, clone 439003

Tregs are crucial for maintaining maternal immunotolerance against the semiallogeneic fetus. We investigated the elusive transcriptional profile and functional adaptation of human uterine Tregs (uTregs) during pregnancy. Uterine biopsies, from placental bed (materno-fetal interface) and incision site (control) and blood were obtained from women with uncomplicated pregnancies undergoing cesarean section. Tregs and CD4(+) non-Tregs were isolated for transcriptomic profiling by Cel-Seq2. Results were validated on protein and single cell levels by flow cytometry. Placental bed uTregs showed elevated expression of Treg signature markers, including FOXP3, CTLA-4, and TIGIT. Their transcriptional profile was indicative of late-stage effector Treg differentiation and chronic activation, with increased expression of immune checkpoints GITR, TNFR2, OX-40, and 4-1BB; genes associated with suppressive capacity (HAVCR2, IL10, LAYN, and PDCD1); and transcription factors MAF, PRDM1, BATF, and VDR. uTregs mirrored non-Treg Th1 polarization and tissue residency. The particular transcriptional signature of placental bed uTregs overlapped strongly with that of tumor-infiltrating Tregs and was remarkably pronounced at the placental bed compared with uterine control site. In conclusion, human uTregs acquire a differentiated effector Treg profile similar to tumor-infiltrating Tregs, specifically at the maternofetal interface. This introduces the concept of site-specific transcriptional adaptation of Tregs within 1 organ.

The clinical success of immune checkpoint blockade provides great hope for curing cancers. However, the patient responses are not even. Precise understanding of tumor immunity is necessary to improving the current cancer immunotherapies and to developing new treatment options. Here we applied full-length single cell RNA-seq (scRNA-seq) to three cancer types and provide a comprehensive single T cell data resource for understanding various characteristics of tumor-infiltrating T cells. We also developed an analytical framework named as STARTRAC to quantitatively characterize the dynamic properties of various T cell subsets including tissue preference, clonal expansion, migration, and state transitions from the scRNA-seq snapshots of tumor immune microenvironments. Conserved and cancer type-specific T cell subsets and developmental patterns were revealed, and detailed molecular portrait of the tumor immunity-relevant T cell clusters were provided, shedding lights into the cellular and molecular mechanisms underlying the composition, heterogeneity, and formation of tumor immune microenvironments. Important genes such as LAYN and IGFLR1 also provided new options for future development of cancer therapeutics.