Different Induction of PD-L1 (CD274) and PD-1 (CD279) Expression in THP-1-Differentiated Types 1 and 2 Macrophages

Chun-Yi Lai; Po-Chun Tseng; Chia-Ling Chen; Rahmat Dani Satria; Yung-Ting Wang; Chiou-Feng Lin

doi:10.2147/JIR.S329921

Different Induction of PD-L1 (CD274) and PD-1 (CD279) Expression in THP-1-Differentiated Types 1 and 2 Macrophages

J Inflamm Res. 2021 Oct 13:14:5241-5249. doi: 10.2147/JIR.S329921. eCollection 2021.

Authors

Chun-Yi Lai^#^{1

2}, Po-Chun Tseng^#^{1

2}, Chia-Ling Chen³, Rahmat Dani Satria^{2

4

5

6}, Yung-Ting Wang², Chiou-Feng Lin^{1

2

7

8}

Affiliations

¹ Core Laboratory of Immune Monitoring, Office of Research & Development, Taipei Medical University, Taipei, 110, Taiwan.
² Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, 110, Taiwan.
³ School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, 110, Taiwan.
⁴ International Ph.D. Program in Medicine, College of Medicine, Taipei Medical University, Taipei, 110, Taiwan.
⁵ Department of Clinical Pathology and Laboratory Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia.
⁶ Clinical Laboratory Installation, Dr. Sardjito Central General Hospital, Yogyakarta, 55281, Indonesia.
⁷ Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, 110, Taiwan.
⁸ International Ph.D. Program in Cell Therapy and Regenerative Medicine, College of Medicine, Taipei Medical University, Taipei, 110, Taiwan.

^# Contributed equally.

Abstract

Background: Phorbol 12-myristate 13-acetate (PMA)-induced differentiation of human monocytic THP-1 cells is an experimental model for preparing resting macrophages (M₀) for cell polarization toward the different functional specializations of macrophages.

Methods: In this study, we examined the expression of immune checkpoints by using flow cytometry following multicolor staining. The blockade of immune checkpoint by using neutralizing antibodies was performed to assess their role in PMA-induced THP-1-differentiated macrophages.

Results: Upon the inducible macrophage differentiation caused by PMA, increased expression levels of CD11b and CD68 were measured and characterized according to their adherent phenotype accompanied by the generation of cellular complexity. While the cell growth rate was abolished post-differentiation, some cells underwent cell death. Notably, we found increases in the expression of programmed cell death protein 1, also known as PD-1 (CD279), and its ligand PD-L1 (CD274), mainly in differentiated M₀ (CD68⁺CD11b⁺) macrophages. However, neutralizing PD-L1/PD-1 neither blocked THP-1 cell differentiation toward macrophages nor inhibited macrophage polarization in M₁ and M₂. In specializing macrophages, a decrease both in CD274 and CD279 was found in M₂.

Conclusion: These results revealed the inducible expression of PD-L1/PD-1 in PMA-induced THP-1-differentiated M₀ macrophages followed by a decrease in M₂ macrophages.

Keywords: PD-1; PD-L1; PMA; THP-1; differentiation; macrophage.

Grants and funding

This work was financially supported by grants from the Ministry of Science and Technology (MOST 108-2320-B-038-026, 109-2320-B-038-050, 110-2320-B-038-064-MY3 and 110-2314-B-038-141), Taiwan.