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Human CD4(+) T lymphocytes consistently respond to the latent Epstein-Barr virus nuclear antigen EBNA1.

Münz C, Bickham KL, Subklewe M, Tsang ML, Chahroudi A, Kurilla MG, Zhang D, O'Donnell M, Steinman RM - J. Exp. Med. (2000)

Bottom Line: In contrast, B-LCLs and Burkitt's lymphoma lines likely present EBNA1 after endogenous processing, as their capacity to cross-present from exogenous sources is weak or undetectable.By limiting dilution, there is a tight correlation between the capacity of CD4(+) T cell lines to recognize autologous B-LCL-expressing EBNA1 and DCs that have captured EBNA1.Therefore, CD4(+) T cells can respond to the EBNA1 protein that is crucial for EBV persistence.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Cellular Physiology and Immunology, The Rockefeller University, New York, New York 10021-6399, USA.

ABSTRACT
The Epstein-Barr virus (EBV)-encoded nuclear antigen EBNA1 is critical for the persistence of the viral episome in replicating EBV-transformed human B cells. Therefore, all EBV-induced tumors express this foreign antigen. However, EBNA1 is invisible to CD8(+) cytotoxic T lymphocytes because its Gly/Ala repeat domain prevents proteasome-dependent processing for presentation on major histocompatibility complex (MHC) class I. We now describe that CD4(+) T cells from healthy adults are primed to EBNA1. In fact, among latent EBV antigens that stimulate CD4(+) T cells, EBNA1 is preferentially recognized. We present evidence that the CD4(+) response may provide a protective role, including interferon gamma secretion and direct cytolysis after encounter of transformed B lymphocyte cell lines (B-LCLs). Dendritic cells (DCs) process EBNA1 from purified protein and from MHC class II-mismatched, EBNA1-expressing cells including B-LCLs. In contrast, B-LCLs and Burkitt's lymphoma lines likely present EBNA1 after endogenous processing, as their capacity to cross-present from exogenous sources is weak or undetectable. By limiting dilution, there is a tight correlation between the capacity of CD4(+) T cell lines to recognize autologous B-LCL-expressing EBNA1 and DCs that have captured EBNA1. Therefore, CD4(+) T cells can respond to the EBNA1 protein that is crucial for EBV persistence. We suggest that this immune response is initiated in vivo by DCs that present EBV-infected B cells, and that EBNA1-specific CD4(+) T cell immunity be enhanced to prevent and treat EBV-associated malignancies.

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DCs are efficient, and B-LCLs inefficient, in presenting EBNA1 by an exogenous pathway. (A) The EBNA1-specific HLA-DRB*0701+CD4+ T cell line BC, selected for IFN-γ secretion upon stimulation with vvEBNA1ΔGA-infected autologous DCs, responds comparably to vvEBNA1ΔGA-infected autologous DCs and vvEBNA1ΔGA-infected HLA-DRB*0701+ Ramos cells. DCs, but not Ramos cells, present recombinant EBNA1 proteins and allogenic LCL-JT. (B) The EBNA1-specific CD4+ T cell line 090199.6 recognized autologous DCs either infected with vvEBNA1DGA, or cocultured with infected allogeneic (allo) DCs. Semiallogeneic (semiallo) DCs were recognized irrespective of coculturing with autologous DCs.
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Figure 6: DCs are efficient, and B-LCLs inefficient, in presenting EBNA1 by an exogenous pathway. (A) The EBNA1-specific HLA-DRB*0701+CD4+ T cell line BC, selected for IFN-γ secretion upon stimulation with vvEBNA1ΔGA-infected autologous DCs, responds comparably to vvEBNA1ΔGA-infected autologous DCs and vvEBNA1ΔGA-infected HLA-DRB*0701+ Ramos cells. DCs, but not Ramos cells, present recombinant EBNA1 proteins and allogenic LCL-JT. (B) The EBNA1-specific CD4+ T cell line 090199.6 recognized autologous DCs either infected with vvEBNA1DGA, or cocultured with infected allogeneic (allo) DCs. Semiallogeneic (semiallo) DCs were recognized irrespective of coculturing with autologous DCs.

Mentions: Therefore, we first compared the capacity of DCs (as a positive control) and the EBV− Burkitt's lymphoma cell line, Ramos, to present EBNA1 through an exogenous pathway, either rEBNA1 protein or EBNA1 expressed by allogeneic B-LCLs (Fig. 6 A). Because of MHC class II mismatching, the allogeneic B-LCLs could not directly present EBNA1 to T cell lines that had been selected for IFN-γ secretion upon stimulation with vvEBNA1ΔGA-infected autologous DCs. The Ramos cell line as well as the autologous DCs could present vvEBNA1ΔGA to an EBNA1-specific CD4+ T cell line from a donor matched at HLA-DR7 to Ramos (Fig. 6 A). In contrast, only the DCs, and not the Ramos Burkitt's lymphoma cells, presented exogenous rEBNA1 and EBNA1 from allogeneic LCLs (having ∼20% trypan blue–positive or dead cells; Fig. 6 A).


Human CD4(+) T lymphocytes consistently respond to the latent Epstein-Barr virus nuclear antigen EBNA1.

Münz C, Bickham KL, Subklewe M, Tsang ML, Chahroudi A, Kurilla MG, Zhang D, O'Donnell M, Steinman RM - J. Exp. Med. (2000)

DCs are efficient, and B-LCLs inefficient, in presenting EBNA1 by an exogenous pathway. (A) The EBNA1-specific HLA-DRB*0701+CD4+ T cell line BC, selected for IFN-γ secretion upon stimulation with vvEBNA1ΔGA-infected autologous DCs, responds comparably to vvEBNA1ΔGA-infected autologous DCs and vvEBNA1ΔGA-infected HLA-DRB*0701+ Ramos cells. DCs, but not Ramos cells, present recombinant EBNA1 proteins and allogenic LCL-JT. (B) The EBNA1-specific CD4+ T cell line 090199.6 recognized autologous DCs either infected with vvEBNA1DGA, or cocultured with infected allogeneic (allo) DCs. Semiallogeneic (semiallo) DCs were recognized irrespective of coculturing with autologous DCs.
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Related In: Results  -  Collection

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Figure 6: DCs are efficient, and B-LCLs inefficient, in presenting EBNA1 by an exogenous pathway. (A) The EBNA1-specific HLA-DRB*0701+CD4+ T cell line BC, selected for IFN-γ secretion upon stimulation with vvEBNA1ΔGA-infected autologous DCs, responds comparably to vvEBNA1ΔGA-infected autologous DCs and vvEBNA1ΔGA-infected HLA-DRB*0701+ Ramos cells. DCs, but not Ramos cells, present recombinant EBNA1 proteins and allogenic LCL-JT. (B) The EBNA1-specific CD4+ T cell line 090199.6 recognized autologous DCs either infected with vvEBNA1DGA, or cocultured with infected allogeneic (allo) DCs. Semiallogeneic (semiallo) DCs were recognized irrespective of coculturing with autologous DCs.
Mentions: Therefore, we first compared the capacity of DCs (as a positive control) and the EBV− Burkitt's lymphoma cell line, Ramos, to present EBNA1 through an exogenous pathway, either rEBNA1 protein or EBNA1 expressed by allogeneic B-LCLs (Fig. 6 A). Because of MHC class II mismatching, the allogeneic B-LCLs could not directly present EBNA1 to T cell lines that had been selected for IFN-γ secretion upon stimulation with vvEBNA1ΔGA-infected autologous DCs. The Ramos cell line as well as the autologous DCs could present vvEBNA1ΔGA to an EBNA1-specific CD4+ T cell line from a donor matched at HLA-DR7 to Ramos (Fig. 6 A). In contrast, only the DCs, and not the Ramos Burkitt's lymphoma cells, presented exogenous rEBNA1 and EBNA1 from allogeneic LCLs (having ∼20% trypan blue–positive or dead cells; Fig. 6 A).

Bottom Line: In contrast, B-LCLs and Burkitt's lymphoma lines likely present EBNA1 after endogenous processing, as their capacity to cross-present from exogenous sources is weak or undetectable.By limiting dilution, there is a tight correlation between the capacity of CD4(+) T cell lines to recognize autologous B-LCL-expressing EBNA1 and DCs that have captured EBNA1.Therefore, CD4(+) T cells can respond to the EBNA1 protein that is crucial for EBV persistence.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Cellular Physiology and Immunology, The Rockefeller University, New York, New York 10021-6399, USA.

ABSTRACT
The Epstein-Barr virus (EBV)-encoded nuclear antigen EBNA1 is critical for the persistence of the viral episome in replicating EBV-transformed human B cells. Therefore, all EBV-induced tumors express this foreign antigen. However, EBNA1 is invisible to CD8(+) cytotoxic T lymphocytes because its Gly/Ala repeat domain prevents proteasome-dependent processing for presentation on major histocompatibility complex (MHC) class I. We now describe that CD4(+) T cells from healthy adults are primed to EBNA1. In fact, among latent EBV antigens that stimulate CD4(+) T cells, EBNA1 is preferentially recognized. We present evidence that the CD4(+) response may provide a protective role, including interferon gamma secretion and direct cytolysis after encounter of transformed B lymphocyte cell lines (B-LCLs). Dendritic cells (DCs) process EBNA1 from purified protein and from MHC class II-mismatched, EBNA1-expressing cells including B-LCLs. In contrast, B-LCLs and Burkitt's lymphoma lines likely present EBNA1 after endogenous processing, as their capacity to cross-present from exogenous sources is weak or undetectable. By limiting dilution, there is a tight correlation between the capacity of CD4(+) T cell lines to recognize autologous B-LCL-expressing EBNA1 and DCs that have captured EBNA1. Therefore, CD4(+) T cells can respond to the EBNA1 protein that is crucial for EBV persistence. We suggest that this immune response is initiated in vivo by DCs that present EBV-infected B cells, and that EBNA1-specific CD4(+) T cell immunity be enhanced to prevent and treat EBV-associated malignancies.

Show MeSH
Related in: MedlinePlus