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Tonsilar NK cells restrict B cell transformation by the Epstein-Barr virus via IFN-gamma.

Strowig T, Brilot F, Arrey F, Bougras G, Thomas D, Muller WA, Münz C - PLoS Pathog. (2008)

Bottom Line: CD56(bright)CD16(-) NK cells, which are enriched in human secondary lymphoid tissues, responded primarily to this DC activation.DCs elicited 50-fold stronger interferon-gamma (IFN-gamma) secretion from tonsilar NK cells than from peripheral blood NK cells, reaching levels that inhibited B cell transformation by EBV.The high IFN-gamma concentrations, produced by tonsilar NK cells, delayed latent EBV antigen expression, resulting in decreased B cell proliferation during the first week after EBV infection in vitro.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Viral Immunobiology, The Rockefeller University, New York, New York, United States of America.

ABSTRACT
Cells of the innate immune system act in synergy to provide a first line of defense against pathogens. Here we describe that dendritic cells (DCs), matured with viral products or mimics thereof, including Epstein-Barr virus (EBV), activated natural killer (NK) cells more efficiently than other mature DC preparations. CD56(bright)CD16(-) NK cells, which are enriched in human secondary lymphoid tissues, responded primarily to this DC activation. DCs elicited 50-fold stronger interferon-gamma (IFN-gamma) secretion from tonsilar NK cells than from peripheral blood NK cells, reaching levels that inhibited B cell transformation by EBV. In fact, 100- to 1,000-fold less tonsilar than peripheral blood NK cells were required to achieve the same protection in vitro, indicating that innate immune control of EBV by NK cells is most efficient at this primary site of EBV infection. The high IFN-gamma concentrations, produced by tonsilar NK cells, delayed latent EBV antigen expression, resulting in decreased B cell proliferation during the first week after EBV infection in vitro. These results suggest that NK cell activation by DCs can limit primary EBV infection in tonsils until adaptive immunity establishes immune control of this persistent and oncogenic human pathogen.

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IFN-γ Secreted by NK Cells Restricts EBV-mediated B Cell Transformation(A) Sorted NK cell subsets from blood, spleen, tonsil, and lymph node were cultured alone or with DC1s, and IFN-γ levels were quantified by ELISA after 20 h.(B) IFN-γ secreted by tonsilar NK cells after activation by differently matured DCs was detected in supernatants of B cell transformation assays by ELISA. (Tonsil–T, tonsilar cultures depleted of T cells; Tonsil–T-NK, tonsilar cultures depleted of T and NK cells.)(C) IFN-γ secreted by peripheral blood NK cells and NK cell subsets was detected in supernatants of B cell transformation assays by ELISA.(D) IFN-γ secreted by purified tonsilar NK cell subsets was detected in supernatants of B cell transformation assays by ELISA.(E) Peripheral blood B cells were infected with EBV and increasing concentrations of IFN-γ were added. Restriction of B cell transformation was analyzed after 12 d by comparing numbers of transformed B cells with and without IFN-γ.(F) Blocking antibodies against IFN-γ were added to B cell transformation assays with B cells, NK cells, and DC1s from peripheral blood. Where indicated, NK cells were separated from B cells and DCs by transwell membranes. Results from at least three independent experiments were summarized (mean ± standard deviation) (*, p < 0.03).
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ppat-0040027-g004: IFN-γ Secreted by NK Cells Restricts EBV-mediated B Cell Transformation(A) Sorted NK cell subsets from blood, spleen, tonsil, and lymph node were cultured alone or with DC1s, and IFN-γ levels were quantified by ELISA after 20 h.(B) IFN-γ secreted by tonsilar NK cells after activation by differently matured DCs was detected in supernatants of B cell transformation assays by ELISA. (Tonsil–T, tonsilar cultures depleted of T cells; Tonsil–T-NK, tonsilar cultures depleted of T and NK cells.)(C) IFN-γ secreted by peripheral blood NK cells and NK cell subsets was detected in supernatants of B cell transformation assays by ELISA.(D) IFN-γ secreted by purified tonsilar NK cell subsets was detected in supernatants of B cell transformation assays by ELISA.(E) Peripheral blood B cells were infected with EBV and increasing concentrations of IFN-γ were added. Restriction of B cell transformation was analyzed after 12 d by comparing numbers of transformed B cells with and without IFN-γ.(F) Blocking antibodies against IFN-γ were added to B cell transformation assays with B cells, NK cells, and DC1s from peripheral blood. Where indicated, NK cells were separated from B cells and DCs by transwell membranes. Results from at least three independent experiments were summarized (mean ± standard deviation) (*, p < 0.03).

Mentions: Human NK cells from secondary lymphoid organs such as tonsils produce IFN-γ rapidly upon activation and this antiviral cytokine contributes directly to control early infection in murine models of herpes virus infection [33]. When we compared the production of IFN-γ upon NK cell/DC coculture, we observed that NK cells from tonsil and lymph node produced significantly more IFN-γ than their equivalents from blood or spleen (Figure 4A). Comparing CD56brightCD16− NK cells, tonsilar and lymph node cells produced 5-fold more IFN-γ than peripheral blood cells, which amounted to a 50-fold difference when bulk NK cell cultures were analyzed due to the enrichment of CD56brightCD16− NK cells in these organs. It had recently been reported that IL-18 exposed blood NK cells develop into a CD56brightCD83+CCR7+ NK cell subset with superior IFN-γ production [35]. In order to test if an enrichment of this NK cell subset could account for the superior ability of tonsilar NK cells to produce IFN-γ, we analyzed CD83 and CCR7 expression on tonsilar NK cells (Figure S4). Confirming our previously published data [28], we found no CCR7 expression on tonsilar NK cells, and only a minor population expressed CD83. Therefore, an enrichment of CD83+CCR7+ NK cells with superior IFN-γ production does not explain why NK cells from secondary lymphoid organs produce more IFN-γ than their peripheral blood counterparts.


Tonsilar NK cells restrict B cell transformation by the Epstein-Barr virus via IFN-gamma.

Strowig T, Brilot F, Arrey F, Bougras G, Thomas D, Muller WA, Münz C - PLoS Pathog. (2008)

IFN-γ Secreted by NK Cells Restricts EBV-mediated B Cell Transformation(A) Sorted NK cell subsets from blood, spleen, tonsil, and lymph node were cultured alone or with DC1s, and IFN-γ levels were quantified by ELISA after 20 h.(B) IFN-γ secreted by tonsilar NK cells after activation by differently matured DCs was detected in supernatants of B cell transformation assays by ELISA. (Tonsil–T, tonsilar cultures depleted of T cells; Tonsil–T-NK, tonsilar cultures depleted of T and NK cells.)(C) IFN-γ secreted by peripheral blood NK cells and NK cell subsets was detected in supernatants of B cell transformation assays by ELISA.(D) IFN-γ secreted by purified tonsilar NK cell subsets was detected in supernatants of B cell transformation assays by ELISA.(E) Peripheral blood B cells were infected with EBV and increasing concentrations of IFN-γ were added. Restriction of B cell transformation was analyzed after 12 d by comparing numbers of transformed B cells with and without IFN-γ.(F) Blocking antibodies against IFN-γ were added to B cell transformation assays with B cells, NK cells, and DC1s from peripheral blood. Where indicated, NK cells were separated from B cells and DCs by transwell membranes. Results from at least three independent experiments were summarized (mean ± standard deviation) (*, p < 0.03).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2233668&req=5

ppat-0040027-g004: IFN-γ Secreted by NK Cells Restricts EBV-mediated B Cell Transformation(A) Sorted NK cell subsets from blood, spleen, tonsil, and lymph node were cultured alone or with DC1s, and IFN-γ levels were quantified by ELISA after 20 h.(B) IFN-γ secreted by tonsilar NK cells after activation by differently matured DCs was detected in supernatants of B cell transformation assays by ELISA. (Tonsil–T, tonsilar cultures depleted of T cells; Tonsil–T-NK, tonsilar cultures depleted of T and NK cells.)(C) IFN-γ secreted by peripheral blood NK cells and NK cell subsets was detected in supernatants of B cell transformation assays by ELISA.(D) IFN-γ secreted by purified tonsilar NK cell subsets was detected in supernatants of B cell transformation assays by ELISA.(E) Peripheral blood B cells were infected with EBV and increasing concentrations of IFN-γ were added. Restriction of B cell transformation was analyzed after 12 d by comparing numbers of transformed B cells with and without IFN-γ.(F) Blocking antibodies against IFN-γ were added to B cell transformation assays with B cells, NK cells, and DC1s from peripheral blood. Where indicated, NK cells were separated from B cells and DCs by transwell membranes. Results from at least three independent experiments were summarized (mean ± standard deviation) (*, p < 0.03).
Mentions: Human NK cells from secondary lymphoid organs such as tonsils produce IFN-γ rapidly upon activation and this antiviral cytokine contributes directly to control early infection in murine models of herpes virus infection [33]. When we compared the production of IFN-γ upon NK cell/DC coculture, we observed that NK cells from tonsil and lymph node produced significantly more IFN-γ than their equivalents from blood or spleen (Figure 4A). Comparing CD56brightCD16− NK cells, tonsilar and lymph node cells produced 5-fold more IFN-γ than peripheral blood cells, which amounted to a 50-fold difference when bulk NK cell cultures were analyzed due to the enrichment of CD56brightCD16− NK cells in these organs. It had recently been reported that IL-18 exposed blood NK cells develop into a CD56brightCD83+CCR7+ NK cell subset with superior IFN-γ production [35]. In order to test if an enrichment of this NK cell subset could account for the superior ability of tonsilar NK cells to produce IFN-γ, we analyzed CD83 and CCR7 expression on tonsilar NK cells (Figure S4). Confirming our previously published data [28], we found no CCR7 expression on tonsilar NK cells, and only a minor population expressed CD83. Therefore, an enrichment of CD83+CCR7+ NK cells with superior IFN-γ production does not explain why NK cells from secondary lymphoid organs produce more IFN-γ than their peripheral blood counterparts.

Bottom Line: CD56(bright)CD16(-) NK cells, which are enriched in human secondary lymphoid tissues, responded primarily to this DC activation.DCs elicited 50-fold stronger interferon-gamma (IFN-gamma) secretion from tonsilar NK cells than from peripheral blood NK cells, reaching levels that inhibited B cell transformation by EBV.The high IFN-gamma concentrations, produced by tonsilar NK cells, delayed latent EBV antigen expression, resulting in decreased B cell proliferation during the first week after EBV infection in vitro.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Viral Immunobiology, The Rockefeller University, New York, New York, United States of America.

ABSTRACT
Cells of the innate immune system act in synergy to provide a first line of defense against pathogens. Here we describe that dendritic cells (DCs), matured with viral products or mimics thereof, including Epstein-Barr virus (EBV), activated natural killer (NK) cells more efficiently than other mature DC preparations. CD56(bright)CD16(-) NK cells, which are enriched in human secondary lymphoid tissues, responded primarily to this DC activation. DCs elicited 50-fold stronger interferon-gamma (IFN-gamma) secretion from tonsilar NK cells than from peripheral blood NK cells, reaching levels that inhibited B cell transformation by EBV. In fact, 100- to 1,000-fold less tonsilar than peripheral blood NK cells were required to achieve the same protection in vitro, indicating that innate immune control of EBV by NK cells is most efficient at this primary site of EBV infection. The high IFN-gamma concentrations, produced by tonsilar NK cells, delayed latent EBV antigen expression, resulting in decreased B cell proliferation during the first week after EBV infection in vitro. These results suggest that NK cell activation by DCs can limit primary EBV infection in tonsils until adaptive immunity establishes immune control of this persistent and oncogenic human pathogen.

Show MeSH
Related in: MedlinePlus