Immunohistochemical Analysis of Programmed Death-Ligand 1 Expression in Equine Sarcoids

J Equine Vet Sci. 2021 Feb:97:103338. doi: 10.1016/j.jevs.2020.103338. Epub 2020 Dec 3.


The aim of the study was to assess the expression of the immune checkpoint inhibitor programmed death-ligand 1 (PD-L1) in equine sarcoids (ES). Programmed death-ligand 1 is expressed by various cancer cells to block T cell-mediated elimination of tumor cells. Antibodies targeting human PD-L1 were tested by immunohistochemistry for their cross-reactivity with equine PD-L1 using formalin-fixed, paraffin-embedded tissues. Our results do not support an important role of PD-L1-mediated immune evasion in ES disease and hence do not offer a rationale for anti-PD-1/PD-L1-based immunotherapy against ES.

Keywords: Equine sarcoids; Immune checkpoint inhibition; Immune evasion; Immunohistochemistry; PD-L1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • B7-H1 Antigen / genetics
  • Horse Diseases*
  • Horses
  • Immunohistochemistry
  • Immunotherapy / veterinary
  • Neoplasms* / veterinary


  • B7-H1 Antigen