PTPN22 controls virally-induced autoimmune diabetes by modulating cytotoxic T lymphocyte responses in an epitope-specific manner

Georgia Fousteri, Tatiana Jofra, Roberta Di Fonte, Mirela Kuka, Matteo Iannacone, Manuela Battaglia

Research output: Contribution to journalArticle


Ptpn22 is one of the most potent autoimmunity predisposing genes and strongly associates with type 1 diabetes (T1D). Previous studies showed that non-obese diabetic mice with reduced expression levels of Ptpn22 are protected from T1D due to increased number of T regulatory (Treg) cells. We report that lack of Ptpn22 exacerbates virally-induced T1D in female rat insulin promoter lymphocytic choriomeningitis virus (RIP-LCMV-GP) mice, while maintaining higher number of Treg cells throughout the antiviral response in the blood and spleen but not in the pancreatic lymph nodes. GP33-41-specific pentamer-positive cytotoxic lymphocytes (CTLs) are numerically reduced in the absence of Ptpn22 at the expansion and contraction phase but reach wild-type levels at the memory phase. However, they show similar effector function and even a subtle increase in the production of IL-2. In contrast, NP396-404-specific CTLs develop normally at all phases but display enhanced effector function. Lack of Ptpn22 also augments the memory proinflammatory response of GP61-80 CD4 T cells. Hence, lack of Ptpn22 largely augments antiviral effector T cell responses, suggesting that caution should be taken when targeting Ptpn22 to treat autoimmune diseases where viral infections are considered environmental triggers.

Original languageEnglish
Pages (from-to)98-108
Number of pages11
JournalClinical Immunology
Issue number2
Publication statusPublished - Feb 1 2015



  • Cytotoxic lymphocytes (CTLs);
  • Memory CD8<sup>+</sup> T cells;
  • Ptpn22;
  • Treg cells
  • Type 1 diabetes (T1D);
  • Virally-induced T1D;

ASJC Scopus subject areas

  • Immunology
  • Immunology and Allergy
  • Medicine(all)

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