Soluble PD-1 (sPD-1) is expressed in human macrophages

TY - JOUR

T1 - Soluble PD-1 (sPD-1) is expressed in human macrophages

AU - Antonsen, Kristian W

AU - Hviid, Claus V B

AU - Hagensen, Mette K

AU - Sørensen, Boe S

AU - Møller, Holger J

N1 - Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.

PY - 2021/11

Y1 - 2021/11

N2 - The PD-1/PD-L1 axis plays a crucial role in regulating the anti-tumour immune response. A soluble PD-1 protein (sPD-1) has previously been observed, which could block the binding of PD-L1 to PD-1. Tumour associated macrophages are abundant in tumours, and evidence suggest they express PD-1. However, whether they also express sPD-1 remains unclear. The objective of this study was to investigate expression of sPD-1 in two in vitro models of human macrophages: THP-1 cells and monocyte-derived macrophages (MDM). Cells were polarised with either LPS + IFN-γ or IL-4 + IL-13 or left unpolarised. PD-1 and sPD-1 mRNAs were measured using droplet digital PCR, sPD-1 protein by electrochemiluminescence immunoassay and PD-1 by flow cytometry. sPD-1 mRNA was induced in both THP-1 cells and MDM after polarisation with LPS + IFN-γ, while IL-4 + IL-13 induced sPD-1 mRNA in MDM only. sPD-1 protein was measurable in culture supernatants. These findings show that macrophages can be induced to express sPD-1.

AB - The PD-1/PD-L1 axis plays a crucial role in regulating the anti-tumour immune response. A soluble PD-1 protein (sPD-1) has previously been observed, which could block the binding of PD-L1 to PD-1. Tumour associated macrophages are abundant in tumours, and evidence suggest they express PD-1. However, whether they also express sPD-1 remains unclear. The objective of this study was to investigate expression of sPD-1 in two in vitro models of human macrophages: THP-1 cells and monocyte-derived macrophages (MDM). Cells were polarised with either LPS + IFN-γ or IL-4 + IL-13 or left unpolarised. PD-1 and sPD-1 mRNAs were measured using droplet digital PCR, sPD-1 protein by electrochemiluminescence immunoassay and PD-1 by flow cytometry. sPD-1 mRNA was induced in both THP-1 cells and MDM after polarisation with LPS + IFN-γ, while IL-4 + IL-13 induced sPD-1 mRNA in MDM only. sPD-1 protein was measurable in culture supernatants. These findings show that macrophages can be induced to express sPD-1.

KW - Macrophages

KW - PD-1

KW - Soluble PD-1

KW - Tumor associated macrophages

KW - Tumor immunology

U2 - 10.1016/j.cellimm.2021.104435

DO - 10.1016/j.cellimm.2021.104435

M3 - Journal article

C2 - 34482260

SN - 0008-8749

VL - 369

JO - Cellular Immunology

JF - Cellular Immunology

M1 - 104435

ER -