EBNA1-specific CD4+ T cells in healthy carriers of Epstein-Barr virus are primarily Th1 in function
Kara Bickham, … , Nina Bhardwaj, Ralph Steinman
Kara Bickham, … , Nina Bhardwaj, Ralph Steinman
Published January 1, 2001
Citation Information: J Clin Invest. 2001;107(1):121-130. https://doi.org/10.1172/JCI10209.
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EBNA1-specific CD4+ T cells in healthy carriers of Epstein-Barr virus are primarily Th1 in function

Abstract

The Epstein-Barr virus (EBV) nuclear antigen-1 (EBNA1) maintains the viral episome in all host cells infected with EBV. Recently, EBNA1 was found to be the main EBV latency antigen for CD4+ T cells and could be recognized in cultures from all donors tested. We now identify a polarized Th1 phenotype and obtain evidence for its presence in vivo. When T cells were stimulated with dendritic cells infected with vaccinia vectors expressing EBNA1, 18 of 19 donors secreted IFN-γ, whereas only two of 19 secreted IL-4. Magnetic selection was then used to isolate cells from fresh blood based on EBNA1-induced cytokine production. Specific IFN-γ CD4+ cell lines were established from six of six donors and IL-4 lines from three of six. Only the Th1 lines specifically lysed targets expressing three different sources of EBNA1 protein. When the IgG isotype of EBNA1 plasma Ab’s was tested, most specific Ab’s were IgG1 and of a high titer, confirming a Th1 response to EBNA1 in vivo. Ab’s to other microbial antigens generally were not skewed toward IgG1. Given emerging evidence that Th1 CD4+ T cells have several critical roles in host defense to viral infection and tumors, we propose that EBNA1-specific CD4+ Th1 cells contribute to resistance to EBV and EBV-associated malignancies.

Authors

Kara Bickham, Christian Münz, Ming Li Tsang, Marie Larsson, Jean-Francois Fonteneau, Nina Bhardwaj, Ralph Steinman

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Figure 4

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EBNA1-specific Th1 cells, but not Th2 cells, lyse EBNA1-expressing DCs. ...
EBNA1-specific Th1 cells, but not Th2 cells, lyse EBNA1-expressing DCs. Cell lines were isolated from PBMCs stimulated with vvEBNA1ΔGA-infected DCs for either 7 hours (IFN-γ) or 18 hours (IL-4). The cells were then positively selected based on the secretion of IFN-γ or IL-4. EBNA1-specific IFN-γ– and IL-4–producing cells were isolated from six of six donors and three of six donors, respectively. These cells were expanded with weekly restimulations of irradiated vvEBNA1ΔGA-infected DCs alternating with DCs pulsed with a rEBNA1 protein. (a) Cells were restimulated with vvEBNA1ΔGA-infected or vvTK–-infected DCs and tested for either IFN-γ or IL-4 secretion after 3 weeks of expansion. The IFN-γ–secreting cell line isolated from donor 3 representative of all Th1 cell lines is shown in the left panel, and a representative EBNA1-specific IL-4–secreting cell line from donor 1 is illustrated in the right panel. (b) Cells were then tested for their ability to lyse vvEBNA1ΔGA-infected DCs by 51Cr-release assay. The results of the 51Cr release from cell line from donor 3 are shown with graded effector-to-target ratios and are representative of all six established IFN-γ cell lines (left panel). Results shown are from a cell line established from donor 1 and are representative of all IL-4–secreting cell lines isolated. (c) CTL assay results at an effector-to-target ratio of 10:1 are shown for five IFN-γ cell lines and three IL-4 lines for three sources of EBNA1 antigen (vvEBNA1ΔGA, rEBNA1, or the physiologically expressed protein in B-LCL) as compared with controls (vvTK, rPCNA control protein, or T2 cells, respectively). Different symbols are representative of each cell line, with Th1 cell lines as open symbols and Th2 cell lines as filled symbols. Th1 and Th2 cell lines isolated from the same donor share symbol shapes.