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Front. Immunol. | doi: 10.3389/fimmu.2018.02198

Epstein Barr Virus Interleukin 10 Suppresses Anti-inflammatory Phenotype in Human Monocytes

 Neelakshi R. Jog1, Eliza F. Chakravarty1, Joel M. Guthridge1 and  Judith A. James1, 2*
  • 1Oklahoma Medical Research Foundation, United States
  • 2University of Oklahoma Health Sciences Center, United States

Epstein Barr virus (EBV) is a gamma herpes virus associated with certain malignancies and autoimmune diseases. EBV maintains latency in B cells with occasional reactivation, in part by overcoming the host immune response with viral homologs of several human proteins. EBV interleukin 10 (vIL-10), a lytic phase protein, is a homolog of human IL-10 (hIL-10). The effect of vIL-10 on human monocytes, which are one of the first immune cells to respond to infection, is not known. To understand the role of vIL-10, monocytes from peripheral blood mononuclear cells were stimulated with hIL-10 or vIL-10. Human IL-10 stimulated STAT3 phosphorylation, which is required for suppression of inflammatory responses. However, vIL-10 induced significantly lower phosphorylation of STAT3 compared to hIL-10, and was less efficient in downregulating inflammatory genes. vIL-10 significantly reduced the expression of scavenger receptor CD163 on monocytes, suggesting inhibition of M2 polarization. Furthermore, uptake of apoptotic cells was reduced in vIL-10-stimulated monocytes compared to hIL-10-stimulated monocytes. A neutralizing antibody to IL-10R1 inhibited STAT3 phosphorylation induced by either hIL-10 or vIL-10, suggesting that vIL-10 signals through IL-10R1. Interestingly, vIL-10 suppressed hIL-10-induced STAT3 phosphorylation and inhibited upregulation of suppressors of inflammatory response by hIL-10. We further show that vIL-10 levels were significantly higher in plasma samples from systemic lupus erythematosus (SLE) patients compared to matched unaffected controls. vIL-10 levels did not correlate with hIL-10 levels, but were associated with levels of IgA antibodies to EBV viral capsid antigen, which is an indirect measure of viral reactivation. We propose that the suppression of hIL-10- induced anti-inflammatory genes by vIL-10, together with an increase in inflammatory gene expression, may overcome the anti-inflammatory effects of hIL-10 and exacerbate autoimmune responses in systemic autoimmune diseases.

Keywords: Epstein - Barr virus, Monocytes, Interleukin-10 (IL-10), Autoimmunity, Systemic Lupus Erythamatosus (SLE), inflmmation

Received: 08 Jul 2018; Accepted: 05 Sep 2018.

Edited by:

Diana Boraschi, Istituto di biochimica delle proteine (IBP), Italy

Reviewed by:

Paola Italiani, Consiglio Nazionale Delle Ricerche (CNR), Italy
Davide Lucchesi, Queen Mary University of London, United Kingdom  

Copyright: © 2018 Jog, Chakravarty, Guthridge and James. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Judith A. James, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States, judith-james@omrf.org