PD-1-specific “Blocking” antibodies that deplete PD-1+ T cells present an inconvenient variable in preclinical immunotherapy experiments

Fanny Polesso, Michael W. Munks, Katherine H. Rott, Savannah Smart, Ann B. Hill, Amy E. Moran

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Therapeutic antibodies blocking PD-1-/PD-L1 interaction have achieved remarkable clinical success in cancer. In addition to blocking a target molecule, some isotypes of antibodies can activate complement, NK cells or phagocytes, resulting in death of the cell expressing the antibody's target. Human anti-PD-1 therapeutics use antibody isotypes designed to minimize such antibody-dependent lysis. In contrast, anti-PD-1 reagents used in mice are derived from multiple species, with different isotypes, and are not engineered to reduce target cell death: few studies analyze or discuss how antibody species and isotype may impact data interpretation. We demonstrate here that anti-PD-1 therapy to promote activation and proliferation of murine PD-1-expressing CD8 T cells sometimes led instead to a loss of antigen specific cells. This phenomenon was seen in two tumor models and a model of virus infection, and varied with the clone of anti-PD-1 antibody. Additionally, we compared competition among anti-PD-1 clones to find a combination that allows detection of PD-1-expressing cells despite the presence of blocking anti-PD1 antibodies in vivo. These data bring attention to the possibility of unintended target cell depletion with some commonly used anti-mouse PD-1 clones, and should provide a valuable resource for the design and interpretation of anti-PD-1 studies in mice.

Original languageEnglish (US)
Pages (from-to)1473-1481
Number of pages9
JournalEuropean Journal of Immunology
Issue number6
StatePublished - Jun 2021


  • ADCC
  • Immune checkpoint blockade
  • Immunotherapy
  • T cell
  • αPD-1

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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