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The induction of antibody production by IL-6 is indirectly mediated by IL-21 produced by CD4+ T cells.

Dienz O, Eaton SM, Bond JP, Neveu W, Moquin D, Noubade R, Briso EM, Charland C, Leonard WJ, Ciliberto G, Teuscher C, Haynes L, Rincon M - J. Exp. Med. (2009)

Bottom Line: IL-21 production by CD4(+) T cells is required for IL-6 to promote B cell antibody production in vitro.Thus, IL-6 promotes antibody production by promoting the B cell helper capabilities of CD4(+) T cells through increased IL-21 production.IL-6 could therefore be a potential coadjuvant to enhance humoral immunity.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine/Immunobiology Program, University of Vermont, Burlington, VT 05405, USA.

ABSTRACT
Interleukin (IL) 6 is a proinflammtory cytokine produced by antigen-presenting cells and nonhematopoietic cells in response to external stimuli. It was initially identified as a B cell growth factor and inducer of plasma cell differentiation in vitro and plays an important role in antibody production and class switching in vivo. However, it is not clear whether IL-6 directly affects B cells or acts through other mechanisms. We show that IL-6 is sufficient and necessary to induce IL-21 production by naive and memory CD4(+) T cells upon T cell receptor stimulation. IL-21 production by CD4(+) T cells is required for IL-6 to promote B cell antibody production in vitro. Moreover, administration of IL-6 with inactive influenza virus enhances virus-specific antibody production, and importantly, this effect is dependent on IL-21. Thus, IL-6 promotes antibody production by promoting the B cell helper capabilities of CD4(+) T cells through increased IL-21 production. IL-6 could therefore be a potential coadjuvant to enhance humoral immunity.

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IL-6 is sufficient and necessary to induce IL-21 expression during the activation of naive and memory CD4+ T cells. (A and B) FACS-sorted CD4+ T cells were activated with anti-CD3 and anti-CD28 mAbs in the absence or presence of the indicated cytokines (A) or the indicated IL-6 concentrations (B). After 3 d, cell-culture supernatants were analyzed for IL-21 production by ELISA. The means ± SEM of three (A) or four (B) experiments are shown. (C) FACS-purified CD4+ T cells were activated with anti-CD3 and anti-CD28 mAbs in the presence of medium alone, LPS, conditioned media (CM) from LPS-stimulated mouse splenocytes, CM plus 10 μg/ml of a neutralizing anti–IL-6 (αIL-6) mAb, or CM from LPS-stimulated IL-6−/− splenocytes. IL-21 expression was measured by quantitative real-time RT-PCR. One representative experiment out of two is shown (error bars represent SD). (D) C57BL/6 and IL-6−/− mice were immunized s.c. with 200 μg OVA in CFA. CD4+ T cells prepared from spleens and lymph nodes were analyzed 6 d later for the frequency of IL-21–producing cells by ELISPOT. The means ± SD of three immunizations are shown (P < 0.05). (E) FACS-purified CD4+ CD25− NK1.1− CD44low naive cells were activated with anti-CD3 and anti-CD28 mAbs in the absence or presence of IL-6 for the indicated periods of time. IL-21 expression was measured by quantitative real-time RT-PCR. One representative experiment out of two is shown (error bars represent SD). (F) CD4+ T cells were isolated from AND TCR transgenic mice, and activated with 5 μM cyt c peptide and APCs in the absence or presence of IL-6 for the indicated periods of time. IL-21 production was examined by ELISA. One representative experiment out of two is shown (error bars represent SD of a triplicate determination). (G) FACS-purified CD4+ CD25− NK1.1− CD44high memory cells were activated with anti-CD3 and anti-CD28 mAbs in the absence or presence of IL-6 for 24 h. Cytokine expression was measured by quantitative real-time RT-PCR. Values are presented as fold induction over naive CD4+ T cells activated for 24 h. One representative experiment out of two is shown.
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fig2: IL-6 is sufficient and necessary to induce IL-21 expression during the activation of naive and memory CD4+ T cells. (A and B) FACS-sorted CD4+ T cells were activated with anti-CD3 and anti-CD28 mAbs in the absence or presence of the indicated cytokines (A) or the indicated IL-6 concentrations (B). After 3 d, cell-culture supernatants were analyzed for IL-21 production by ELISA. The means ± SEM of three (A) or four (B) experiments are shown. (C) FACS-purified CD4+ T cells were activated with anti-CD3 and anti-CD28 mAbs in the presence of medium alone, LPS, conditioned media (CM) from LPS-stimulated mouse splenocytes, CM plus 10 μg/ml of a neutralizing anti–IL-6 (αIL-6) mAb, or CM from LPS-stimulated IL-6−/− splenocytes. IL-21 expression was measured by quantitative real-time RT-PCR. One representative experiment out of two is shown (error bars represent SD). (D) C57BL/6 and IL-6−/− mice were immunized s.c. with 200 μg OVA in CFA. CD4+ T cells prepared from spleens and lymph nodes were analyzed 6 d later for the frequency of IL-21–producing cells by ELISPOT. The means ± SD of three immunizations are shown (P < 0.05). (E) FACS-purified CD4+ CD25− NK1.1− CD44low naive cells were activated with anti-CD3 and anti-CD28 mAbs in the absence or presence of IL-6 for the indicated periods of time. IL-21 expression was measured by quantitative real-time RT-PCR. One representative experiment out of two is shown (error bars represent SD). (F) CD4+ T cells were isolated from AND TCR transgenic mice, and activated with 5 μM cyt c peptide and APCs in the absence or presence of IL-6 for the indicated periods of time. IL-21 production was examined by ELISA. One representative experiment out of two is shown (error bars represent SD of a triplicate determination). (G) FACS-purified CD4+ CD25− NK1.1− CD44high memory cells were activated with anti-CD3 and anti-CD28 mAbs in the absence or presence of IL-6 for 24 h. Cytokine expression was measured by quantitative real-time RT-PCR. Values are presented as fold induction over naive CD4+ T cells activated for 24 h. One representative experiment out of two is shown.

Mentions: Given the high induction of IL-21 by IL-6, we examined whether other cytokines have a similar effect. CD4+ T cells were activated in the presence of IL-4, IL-12, or IFN-γ, but none of those cytokines were able to promote IL-21 production (Fig. 2 A). Neither growth and survival factors such as IL-2 and IL-7 (Fig. 2 A and not depicted) nor other proinflammatory cytokines such as TNF-α and IL-1 were able to up-regulate IL-21 production (Fig. 2 A and not depicted). IL-11, another cytokine that signals through gp130 (1), also failed to promote IL-21 production (Fig. S3, available at http://www.jem.org/cgi/content/full/jem.20081571/DC1). Moreover, IL-6 is a very efficient inducer of IL-21 expression, as a dose–response analysis revealed that IL-6 levels as low as 0.3–0.8 ng/ml were able to readily induce measurable IL-21 production (Fig. 2 B).


The induction of antibody production by IL-6 is indirectly mediated by IL-21 produced by CD4+ T cells.

Dienz O, Eaton SM, Bond JP, Neveu W, Moquin D, Noubade R, Briso EM, Charland C, Leonard WJ, Ciliberto G, Teuscher C, Haynes L, Rincon M - J. Exp. Med. (2009)

IL-6 is sufficient and necessary to induce IL-21 expression during the activation of naive and memory CD4+ T cells. (A and B) FACS-sorted CD4+ T cells were activated with anti-CD3 and anti-CD28 mAbs in the absence or presence of the indicated cytokines (A) or the indicated IL-6 concentrations (B). After 3 d, cell-culture supernatants were analyzed for IL-21 production by ELISA. The means ± SEM of three (A) or four (B) experiments are shown. (C) FACS-purified CD4+ T cells were activated with anti-CD3 and anti-CD28 mAbs in the presence of medium alone, LPS, conditioned media (CM) from LPS-stimulated mouse splenocytes, CM plus 10 μg/ml of a neutralizing anti–IL-6 (αIL-6) mAb, or CM from LPS-stimulated IL-6−/− splenocytes. IL-21 expression was measured by quantitative real-time RT-PCR. One representative experiment out of two is shown (error bars represent SD). (D) C57BL/6 and IL-6−/− mice were immunized s.c. with 200 μg OVA in CFA. CD4+ T cells prepared from spleens and lymph nodes were analyzed 6 d later for the frequency of IL-21–producing cells by ELISPOT. The means ± SD of three immunizations are shown (P < 0.05). (E) FACS-purified CD4+ CD25− NK1.1− CD44low naive cells were activated with anti-CD3 and anti-CD28 mAbs in the absence or presence of IL-6 for the indicated periods of time. IL-21 expression was measured by quantitative real-time RT-PCR. One representative experiment out of two is shown (error bars represent SD). (F) CD4+ T cells were isolated from AND TCR transgenic mice, and activated with 5 μM cyt c peptide and APCs in the absence or presence of IL-6 for the indicated periods of time. IL-21 production was examined by ELISA. One representative experiment out of two is shown (error bars represent SD of a triplicate determination). (G) FACS-purified CD4+ CD25− NK1.1− CD44high memory cells were activated with anti-CD3 and anti-CD28 mAbs in the absence or presence of IL-6 for 24 h. Cytokine expression was measured by quantitative real-time RT-PCR. Values are presented as fold induction over naive CD4+ T cells activated for 24 h. One representative experiment out of two is shown.
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fig2: IL-6 is sufficient and necessary to induce IL-21 expression during the activation of naive and memory CD4+ T cells. (A and B) FACS-sorted CD4+ T cells were activated with anti-CD3 and anti-CD28 mAbs in the absence or presence of the indicated cytokines (A) or the indicated IL-6 concentrations (B). After 3 d, cell-culture supernatants were analyzed for IL-21 production by ELISA. The means ± SEM of three (A) or four (B) experiments are shown. (C) FACS-purified CD4+ T cells were activated with anti-CD3 and anti-CD28 mAbs in the presence of medium alone, LPS, conditioned media (CM) from LPS-stimulated mouse splenocytes, CM plus 10 μg/ml of a neutralizing anti–IL-6 (αIL-6) mAb, or CM from LPS-stimulated IL-6−/− splenocytes. IL-21 expression was measured by quantitative real-time RT-PCR. One representative experiment out of two is shown (error bars represent SD). (D) C57BL/6 and IL-6−/− mice were immunized s.c. with 200 μg OVA in CFA. CD4+ T cells prepared from spleens and lymph nodes were analyzed 6 d later for the frequency of IL-21–producing cells by ELISPOT. The means ± SD of three immunizations are shown (P < 0.05). (E) FACS-purified CD4+ CD25− NK1.1− CD44low naive cells were activated with anti-CD3 and anti-CD28 mAbs in the absence or presence of IL-6 for the indicated periods of time. IL-21 expression was measured by quantitative real-time RT-PCR. One representative experiment out of two is shown (error bars represent SD). (F) CD4+ T cells were isolated from AND TCR transgenic mice, and activated with 5 μM cyt c peptide and APCs in the absence or presence of IL-6 for the indicated periods of time. IL-21 production was examined by ELISA. One representative experiment out of two is shown (error bars represent SD of a triplicate determination). (G) FACS-purified CD4+ CD25− NK1.1− CD44high memory cells were activated with anti-CD3 and anti-CD28 mAbs in the absence or presence of IL-6 for 24 h. Cytokine expression was measured by quantitative real-time RT-PCR. Values are presented as fold induction over naive CD4+ T cells activated for 24 h. One representative experiment out of two is shown.
Mentions: Given the high induction of IL-21 by IL-6, we examined whether other cytokines have a similar effect. CD4+ T cells were activated in the presence of IL-4, IL-12, or IFN-γ, but none of those cytokines were able to promote IL-21 production (Fig. 2 A). Neither growth and survival factors such as IL-2 and IL-7 (Fig. 2 A and not depicted) nor other proinflammatory cytokines such as TNF-α and IL-1 were able to up-regulate IL-21 production (Fig. 2 A and not depicted). IL-11, another cytokine that signals through gp130 (1), also failed to promote IL-21 production (Fig. S3, available at http://www.jem.org/cgi/content/full/jem.20081571/DC1). Moreover, IL-6 is a very efficient inducer of IL-21 expression, as a dose–response analysis revealed that IL-6 levels as low as 0.3–0.8 ng/ml were able to readily induce measurable IL-21 production (Fig. 2 B).

Bottom Line: IL-21 production by CD4(+) T cells is required for IL-6 to promote B cell antibody production in vitro.Thus, IL-6 promotes antibody production by promoting the B cell helper capabilities of CD4(+) T cells through increased IL-21 production.IL-6 could therefore be a potential coadjuvant to enhance humoral immunity.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine/Immunobiology Program, University of Vermont, Burlington, VT 05405, USA.

ABSTRACT
Interleukin (IL) 6 is a proinflammtory cytokine produced by antigen-presenting cells and nonhematopoietic cells in response to external stimuli. It was initially identified as a B cell growth factor and inducer of plasma cell differentiation in vitro and plays an important role in antibody production and class switching in vivo. However, it is not clear whether IL-6 directly affects B cells or acts through other mechanisms. We show that IL-6 is sufficient and necessary to induce IL-21 production by naive and memory CD4(+) T cells upon T cell receptor stimulation. IL-21 production by CD4(+) T cells is required for IL-6 to promote B cell antibody production in vitro. Moreover, administration of IL-6 with inactive influenza virus enhances virus-specific antibody production, and importantly, this effect is dependent on IL-21. Thus, IL-6 promotes antibody production by promoting the B cell helper capabilities of CD4(+) T cells through increased IL-21 production. IL-6 could therefore be a potential coadjuvant to enhance humoral immunity.

Show MeSH
Related in: MedlinePlus