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Modulation of Kv channel expression and function by TCR and costimulatory signals during peripheral CD4(+) lymphocyte differentiation.

Liu QH, Fleischmann BK, Hondowicz B, Maier CC, Turka LA, Yui K, Kotlikoff MI, Wells AD, Freedman BD - J. Exp. Med. (2002)

Bottom Line: However, how Kv channels cooperate with other signaling pathways involved in T cell activation and differentiation is unknown.Effector CD4(+) cells generated by optimal TCR and costimulation exhibit only Kv1.3 current, but at approximately sixfold higher levels than naive cells.To determine if Kv channels contribute to the distinct functions of naive, effector, and anergized T cells, we tested their role in immunoregulatory cytokine production.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104, USA.

ABSTRACT
Ionic signaling pathways, including voltage-dependent potassium (Kv) channels, are instrumental in antigen-mediated responses of peripheral T cells. However, how Kv channels cooperate with other signaling pathways involved in T cell activation and differentiation is unknown. We report that multiple Kv channels are expressed by naive CD4(+) lymphocytes, and that the current amplitude and kinetics are modulated by antigen receptor-mediated stimulation and costimulatory signals. Currents expressed in naive CD4(+) lymphocytes are consistent with Kv1.1, Kv1.2, Kv1.3, and Kv1.6. Effector CD4(+) cells generated by optimal TCR and costimulation exhibit only Kv1.3 current, but at approximately sixfold higher levels than naive cells. CD4(+) lymphocytes anergized through partial stimulation exhibit similar Kv1.1, Kv1.2, and/or Kv1.6 currents, but approximately threefold more Kv1.3 current than naive cells. To determine if Kv channels contribute to the distinct functions of naive, effector, and anergized T cells, we tested their role in immunoregulatory cytokine production. Each Kv channel is required for maximal IL-2 production by naive CD4(+) lymphocytes, whereas none appears to play a role in IL-2, IL-4, or IFN-gamma production by effector cells. Interestingly, Kv channels in anergized lymphocytes actively suppress IL-4 production, and these functions are consistent with a role in regulating the membrane potential and calcium signaling.

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Functional characterization of CD4+ Vβ8.1 lymphocytes. FACS® analysis was performed to determine the percentage of 3G11 expressing CD4+ cells on indicated days after inoculation. (A) The percentage of 3G11+ lymph node lymphocytes decreases during the first few days after Mls-1a superantigen inoculation and maximum steady-state number and percentage (∼50%) of 3G11− cells is observed on day 3 after antigen inoculation, after which the proportion of CD4+ 3G11− cells progressively decreases. (B) CD4+ lymph node lymphocytes from control Vβ8.1 TCR transgenic mice or from mice stimulated with Mls-superantigen in vivo were restimulated with soluble αCD3 mAb (145–2C11) and splenic APC's in vitro. Proliferation was assessed by measuring the amount of [3H]thymidine (counts per minute) incorporation on day 4 of culture for naive and cells previously primed in vivo for 3 (▪) or 14 (▴) days. The proliferative capacity of day 14 lymphocytes was markedly decreased. Each value is the mean (±SD) of triplicate cultures and the experiment shown is typical of three similar experiments.
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fig1: Functional characterization of CD4+ Vβ8.1 lymphocytes. FACS® analysis was performed to determine the percentage of 3G11 expressing CD4+ cells on indicated days after inoculation. (A) The percentage of 3G11+ lymph node lymphocytes decreases during the first few days after Mls-1a superantigen inoculation and maximum steady-state number and percentage (∼50%) of 3G11− cells is observed on day 3 after antigen inoculation, after which the proportion of CD4+ 3G11− cells progressively decreases. (B) CD4+ lymph node lymphocytes from control Vβ8.1 TCR transgenic mice or from mice stimulated with Mls-superantigen in vivo were restimulated with soluble αCD3 mAb (145–2C11) and splenic APC's in vitro. Proliferation was assessed by measuring the amount of [3H]thymidine (counts per minute) incorporation on day 4 of culture for naive and cells previously primed in vivo for 3 (▪) or 14 (▴) days. The proliferative capacity of day 14 lymphocytes was markedly decreased. Each value is the mean (±SD) of triplicate cultures and the experiment shown is typical of three similar experiments.

Mentions: To determine whether Kv currents are modulated by antigen stimulation of CD4+ lymphocytes, we used an Mls-superantigen–specific Vβ8.1 TCR transgenic mouse model to generate both anergized and productively primed effector cells in vivo. In these mice, superantigen induces a large proportion of CD4+ lymphocytes to enter the cell cycle and proliferate, and the resulting expansion is evident as a large increase in CD4+ cells within 2–3 d. T cells isolated on day 3 contain productively primed cells that are identified ex vivo according to their expression levels of a disialoganglioside antigen termed 3G11 (Fig. 1 A). 3G11 expressed on naive T lymphocytes is irreversibly down-modulated from the membrane of productively primed effector T cells (27, 28). Importantly, 2 wk after the initiation of an immune response with superantigen in Vβ8.1 TCR+ mice, virtually all surviving CD4+ T cells, which express 3G11, are anergic by virtue of a diminished capacity to produce IL-2 and proliferate (Fig. 1 B; reference 24).


Modulation of Kv channel expression and function by TCR and costimulatory signals during peripheral CD4(+) lymphocyte differentiation.

Liu QH, Fleischmann BK, Hondowicz B, Maier CC, Turka LA, Yui K, Kotlikoff MI, Wells AD, Freedman BD - J. Exp. Med. (2002)

Functional characterization of CD4+ Vβ8.1 lymphocytes. FACS® analysis was performed to determine the percentage of 3G11 expressing CD4+ cells on indicated days after inoculation. (A) The percentage of 3G11+ lymph node lymphocytes decreases during the first few days after Mls-1a superantigen inoculation and maximum steady-state number and percentage (∼50%) of 3G11− cells is observed on day 3 after antigen inoculation, after which the proportion of CD4+ 3G11− cells progressively decreases. (B) CD4+ lymph node lymphocytes from control Vβ8.1 TCR transgenic mice or from mice stimulated with Mls-superantigen in vivo were restimulated with soluble αCD3 mAb (145–2C11) and splenic APC's in vitro. Proliferation was assessed by measuring the amount of [3H]thymidine (counts per minute) incorporation on day 4 of culture for naive and cells previously primed in vivo for 3 (▪) or 14 (▴) days. The proliferative capacity of day 14 lymphocytes was markedly decreased. Each value is the mean (±SD) of triplicate cultures and the experiment shown is typical of three similar experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2194034&req=5

fig1: Functional characterization of CD4+ Vβ8.1 lymphocytes. FACS® analysis was performed to determine the percentage of 3G11 expressing CD4+ cells on indicated days after inoculation. (A) The percentage of 3G11+ lymph node lymphocytes decreases during the first few days after Mls-1a superantigen inoculation and maximum steady-state number and percentage (∼50%) of 3G11− cells is observed on day 3 after antigen inoculation, after which the proportion of CD4+ 3G11− cells progressively decreases. (B) CD4+ lymph node lymphocytes from control Vβ8.1 TCR transgenic mice or from mice stimulated with Mls-superantigen in vivo were restimulated with soluble αCD3 mAb (145–2C11) and splenic APC's in vitro. Proliferation was assessed by measuring the amount of [3H]thymidine (counts per minute) incorporation on day 4 of culture for naive and cells previously primed in vivo for 3 (▪) or 14 (▴) days. The proliferative capacity of day 14 lymphocytes was markedly decreased. Each value is the mean (±SD) of triplicate cultures and the experiment shown is typical of three similar experiments.
Mentions: To determine whether Kv currents are modulated by antigen stimulation of CD4+ lymphocytes, we used an Mls-superantigen–specific Vβ8.1 TCR transgenic mouse model to generate both anergized and productively primed effector cells in vivo. In these mice, superantigen induces a large proportion of CD4+ lymphocytes to enter the cell cycle and proliferate, and the resulting expansion is evident as a large increase in CD4+ cells within 2–3 d. T cells isolated on day 3 contain productively primed cells that are identified ex vivo according to their expression levels of a disialoganglioside antigen termed 3G11 (Fig. 1 A). 3G11 expressed on naive T lymphocytes is irreversibly down-modulated from the membrane of productively primed effector T cells (27, 28). Importantly, 2 wk after the initiation of an immune response with superantigen in Vβ8.1 TCR+ mice, virtually all surviving CD4+ T cells, which express 3G11, are anergic by virtue of a diminished capacity to produce IL-2 and proliferate (Fig. 1 B; reference 24).

Bottom Line: However, how Kv channels cooperate with other signaling pathways involved in T cell activation and differentiation is unknown.Effector CD4(+) cells generated by optimal TCR and costimulation exhibit only Kv1.3 current, but at approximately sixfold higher levels than naive cells.To determine if Kv channels contribute to the distinct functions of naive, effector, and anergized T cells, we tested their role in immunoregulatory cytokine production.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104, USA.

ABSTRACT
Ionic signaling pathways, including voltage-dependent potassium (Kv) channels, are instrumental in antigen-mediated responses of peripheral T cells. However, how Kv channels cooperate with other signaling pathways involved in T cell activation and differentiation is unknown. We report that multiple Kv channels are expressed by naive CD4(+) lymphocytes, and that the current amplitude and kinetics are modulated by antigen receptor-mediated stimulation and costimulatory signals. Currents expressed in naive CD4(+) lymphocytes are consistent with Kv1.1, Kv1.2, Kv1.3, and Kv1.6. Effector CD4(+) cells generated by optimal TCR and costimulation exhibit only Kv1.3 current, but at approximately sixfold higher levels than naive cells. CD4(+) lymphocytes anergized through partial stimulation exhibit similar Kv1.1, Kv1.2, and/or Kv1.6 currents, but approximately threefold more Kv1.3 current than naive cells. To determine if Kv channels contribute to the distinct functions of naive, effector, and anergized T cells, we tested their role in immunoregulatory cytokine production. Each Kv channel is required for maximal IL-2 production by naive CD4(+) lymphocytes, whereas none appears to play a role in IL-2, IL-4, or IFN-gamma production by effector cells. Interestingly, Kv channels in anergized lymphocytes actively suppress IL-4 production, and these functions are consistent with a role in regulating the membrane potential and calcium signaling.

Show MeSH
Related in: MedlinePlus