Normal human enthesis harbours conventional CD4+ and CD8+ T cells with regulatory features and inducible IL-17A and TNF expression

Abdulla Watad, Hannah Rowe, Tobias Russell, Qiao Zhou, Lisa K. Anderson, Almas Khan, Robert Dunsmuir, Peter Loughenbury, Vishal Borse, Abhay Rao, Peter A. Millner, Nicola Luigi Bragazzi, Howard Amital, Richard Cuhtbert, Miriam Wittmann, Kassem Sharif, Tony Kenna, Matthew A. Brown, Darren Newton*, Charlie BridgewoodDennis G. McGonagle

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Background The human enthesis conventional T cells are poorly characterised. Objectives To study the biology of the conventional T cells in human enthesis. Methods CD4+ and CD8+ T cells were investigated in 25 enthesis samples using immunofluorescence, cytometrically, bulk RNAseq and quantitative real-time PCR following anti-CD3/CD28 bead stimulation to determine interleukin (IL)-17A and tumour necrosis factor (TNF) levels. T-cell receptor (TCR) repertoires were characterised and a search for putative T-cell reactivity was carried out using TCR3 database. The impact of pharmacological antagonism with retinoic acid receptor-related orphan nuclear receptor gamma t inhibitor (ROR 3ti), methotrexate and phosphodiesterase type 4 inhibitor (PDE4i) was investigated. Results Immunofluorescence and cytometry suggested entheseal resident CD4+ and CD8+ T cells with a resident memory phenotype (CD69+/CD45RA-) and tissue residency gene transcripts (higher NR4A1/AhR and lower KLF2/T-bet transcripts). Both CD4+ and CD8+ T cells showed increased expression of immunomodulatory genes including IL-10 and TGF-β compared with peripheral blood T cells with entheseal CD8+ T cells having higher CD103, CD49a and lower SIPR1 transcript that matched CD4+ T cells. Following stimulation, CD4+ T cells produced more TNF than CD8+ T cells and IL-17A was produced exclusively by CD4+ T cells. RNAseq suggested both Cytomegalovirus and influenza A virus entheseal resident T-cell clonotype reactivity. TNF and IL-17A production from CD4+ T cells was effectively inhibited by PDE4i, while ROR 3ti only reduced IL-17A secretion. Conclusions Healthy human entheseal CD4+ and CD8+ T cells exhibit regulatory characteristics and are predicted to exhibit antiviral reactivity with CD8+ T cells expressing higher levels of transcripts suggestive of tissue residency. Inducible IL-17A and TNF production can be robustly inhibited in vitro.

Original languageEnglish
Pages (from-to)1044-1054
Number of pages11
JournalAnnals of the Rheumatic Diseases
Volume79
Issue number8
DOIs
StatePublished - 1 Aug 2020

Keywords

  • T cells
  • ankylosing spondylitis
  • spondyloarthritis

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