PT  - JOURNAL ARTICLE
AU  - Joshua Johnson
AU  - Peter Ka Sam
AU  - Rengasamy Asokan
AU  - Evelyn Llerena Cari
AU  - Elise S. Bales
AU  - Thanh-Ha Luu
AU  - Lauren Perez
AU  - Amanda N. Kallen
AU  - Liesl Nel-Themaat
AU  - Alex J. Polotsky
AU  - Miriam D. Post
AU  - David J. Orlicky
AU  - Kimberly R. Jordan
AU  - Benjamin G. Bitler
TI  - Expression and T cell Regulatory Action of the PD-1 Immune Checkpoint in the Ovary and Fallopian Tube
AID  - 10.1101/2020.06.06.138123
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.06.06.138123
4099  - http://biorxiv.org/content/early/2020/06/07/2020.06.06.138123.short
4100  - http://biorxiv.org/content/early/2020/06/07/2020.06.06.138123.full
AB  - The Programmed Cell Death Protein-1 (PD-1/PDCD-1/CD279) checkpoint has powerful immunomodulatory action, including in the context of cancer. PD-1 receptor activation by its ligands (PD-L1/2) is associated with downregulated immune response, and tumor cells can avoid surveillance via PD-1 and/or ligand expression. While receptor expression is largely limited to lymphoid, myeloid, and tumor cells, we show that membrane bound and soluble variants of PD-1 and ligands are also expressed by permanent constituent cell types of the human ovary and fallopian tube, including granulosa cells and oocytes. PD-1 and soluble ligands were highly enriched in exosome fractions in human follicular fluid at bioactive levels that can control T cell PD-1 activation. PD-1 checkpoint signaling may be involved in physiological ovarian functions including follicle, and ultimately, germline and embryo immune-privilege.Competing Interest StatementThe authors have declared no competing interest.