PTPN22 for global population reduction via
"==PTPN22 contributes to exhaustion of T lymphocytes
during chronic viral infection=="
Christian J. Mainea, John R. Teijaroa, Kristi Marquardta, and Linda A. Shermana
Department of Immunology and Microbial Sciences, The Scripps Research Institute, La Jolla, CA 92037
Edited by Rafi Ahmed, Emory University, Atlanta, GA, and approved October 5, 2016 (received for review March 6, 2016)
https://www.pnas.org/content/pnas/113/46/E7231.full.pdf
The protein encoded by the autoimmune-associated protein tyrosine
phosphatase nonreceptor type 22 gene, PTPN22, has wide-ranging
effects in immune cells including suppression of T-cell receptor signaling and promoting efficient production of type I interferons (IFN-I)
by myeloid cells. Here we show that mice deficient in PTPN22 resist
chronic viral infection with lymphocytic choriomeningitis virus clone
13 (LCMV cl13). The numbers and function of viral-specific CD4
T lymphocytes is greatly enhanced, whereas expression of the
IFNβ-induced IL-2 repressor, cAMP-responsive element modulator
(CREM) is reduced. Reduction of CREM expression in wild-type CD4
T lymphocytes prevents the loss of IL-2 production by CD4 T lymphocytes during infection with LCMV cl13. These findings implicate the
IFNβ/CREM/IL-2 axis in regulating T-lymphocyte function during
chronic viral infection.
Significance
Some viruses, including lymphocytic choriomeningitis virus clone
13, shut down the ability of CD4 T lymphocytes to produce IL-2, a
cytokine required for the survival and function of T lymphocytes.
This shutdown contributes to exhaustion of CD4 and CD8 T lymphocytes and chronic viral infection of the host. The underlying
mechanism responsible for the loss of cytokine production by CD4
T cells remains poorly understood. We demonstrate that the expression of a protein tyrosine phosphatase, PTPN22, contributes to
chronic viral infection. PTPN22 increases the production of IFN-β
following infection, resulting in increased expression of the cAMP
response element modulator (CREM) in CD4 T lymphocytes. CREM
prevents production of IL-2, thereby contributing to T-cell exhaustion and chronic viral infection