Limits...
Regulation of the interleukin (IL)-12R beta 2 subunit expression in developing T helper 1 (Th1) and Th2 cells.

Szabo SJ, Dighe AS, Gubler U, Murphy KM - J. Exp. Med. (1997)

Bottom Line: Importantly, IL-4 and IFN-gamma were found to significantly modify IL-12 receptor beta 2 expression after T cell activation.IFN-gamma treatment of early developing Th2 cells maintained IL-12R beta 2 expression and restored the ability of these cells to functionally respond to IL-12, but did not directly inhibit IL-4 or induce IFN-gamma production.Controlling the expression of the IL-12R beta 2 subunit could be an important therapeutic target for the redirection of ongoing Th cell responses.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.

ABSTRACT
The developmental commitment to a T helper 1 (Th1)- or Th2-type response can significantly influence host immunity to pathogens. Extinction of the IL-12 signaling pathway during early Th2 development provides a mechanism that allows stable phenotype commitment. In this report we demonstrate that extinction of IL-12 signaling in early Th2 cells results from a selective loss of IL-12 receptor (IL-12R) beta 2 subunit expression. To determine the basis for this selective loss, we examined IL-12R beta 2 subunit expression during Th cell development in response to T cell treatment with different cytokines. IL-12R beta 2 is not expressed by naive resting CD4+ T cells, but is induced upon antigen activation through the T cell receptor. Importantly, IL-4 and IFN-gamma were found to significantly modify IL-12 receptor beta 2 expression after T cell activation. IL-4 inhibited IL-12R beta 2 expression leading to the loss of IL-12 signaling, providing an important point of regulation to promote commitment to the Th2 pathway. IFN-gamma treatment of early developing Th2 cells maintained IL-12R beta 2 expression and restored the ability of these cells to functionally respond to IL-12, but did not directly inhibit IL-4 or induce IFN-gamma production. Thus, IFN-gamma may prevent early Th cells from premature commitment to the Th2 pathway. Controlling the expression of the IL-12R beta 2 subunit could be an important therapeutic target for the redirection of ongoing Th cell responses.

Show MeSH
Activation in the  presence of IL-4 and IL-12 results in the maintenance of functional IL-12 responsiveness.  FACS®-sorted naive CD4+  DO11.10 T cells were cultured  for seven days with OVA peptide and irradiated BALB/c splenocytes under the indicated primary culture conditions. Cultures  were harvested on day 7, washed,  and restimulated at 1.25 × 105 T  cells/well with OVA peptide and  BALB/c splenocytes in the presence of the indicated cytokines  or anti-cytokine antibodies. Supernatants collected after 48 h  were analyzed by ELISA for  IFN-γ.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2196166&req=5

Figure 3: Activation in the presence of IL-4 and IL-12 results in the maintenance of functional IL-12 responsiveness. FACS®-sorted naive CD4+ DO11.10 T cells were cultured for seven days with OVA peptide and irradiated BALB/c splenocytes under the indicated primary culture conditions. Cultures were harvested on day 7, washed, and restimulated at 1.25 × 105 T cells/well with OVA peptide and BALB/c splenocytes in the presence of the indicated cytokines or anti-cytokine antibodies. Supernatants collected after 48 h were analyzed by ELISA for IFN-γ.

Mentions: We next asked what conditions controlled the maintenance of IL-12 signaling in developing Th cells. IL-4 was thought to dominate IL-12 for effects on T helper phenotype development (5, 34), since the addition of IL-4 and IL-12 together led to Th2 development both in TCR-transgenic and anti-CD3 driven systems (5, 34). We first wished to determine if it was the lack of IL-4 in primary cultures that allowed the maintenance of IL-12 responsiveness in developing Th1 cells. Thus, we activated naive T cells in the presence of IL-4 and IL-12 together in the primary culture and assessed IL-12 responsiveness on day 5 after primary stimulation (Fig. 2). Surprisingly, these T cells were able to phosphorylate Stat4 upon IL-12 treatment (Fig. 2, middle), similar to Th1 cells (Fig. 2, top), but unlike IL-12 unresponsive Th2 cells (Fig. 2, bottom). This maintenance of Stat4 phosphorylation correlated with functional IL-12 responses in these T cells as measured by IL-12–induced IFN-γ production (Fig. 3). T cells arising from stimulation in IL-4 and IL-12 together showed significant IL-12 induced IFN-γ production during restimulation (Fig. 3, top). Restimulation of these cells without exogenously added IL-12 led to production of 180 U/ml IFN-γ, while addition of IL-12 increased IFN-γ production to 400 U/ml. Because these T cells arose in IL-4, they acquired the Th2-type property of producing IL-4 and IL-10, two cytokines which inhibit IFN-γ production (35, 36). In this system, IL-10 could also be produced by other cells used as APCs. Neutralization of IL-4 and IL-10 revealed a significantly increased IL-12– mediated induction of IFN-γ, from less than 50 U/ml of IFN-γ produced upon restimulation in the absence of IL-12 to 1,300 U/ml of IFN-γ produced in the presence of IL-12 (Fig. 3, top). In contrast, the control Th2 cells produced very low amounts of IFN-γ (20 U/ml) upon restimulation in the presence of IL-12, a level which was not increased by neutralization of IL-4 and IL-10 (Fig. 3, bottom). Taken together, these results therefore suggest that the presence of IL-12 during primary T cell activation, not the absence of IL-4, was responsible for maintenance of functional responsiveness to IL-12.


Regulation of the interleukin (IL)-12R beta 2 subunit expression in developing T helper 1 (Th1) and Th2 cells.

Szabo SJ, Dighe AS, Gubler U, Murphy KM - J. Exp. Med. (1997)

Activation in the  presence of IL-4 and IL-12 results in the maintenance of functional IL-12 responsiveness.  FACS®-sorted naive CD4+  DO11.10 T cells were cultured  for seven days with OVA peptide and irradiated BALB/c splenocytes under the indicated primary culture conditions. Cultures  were harvested on day 7, washed,  and restimulated at 1.25 × 105 T  cells/well with OVA peptide and  BALB/c splenocytes in the presence of the indicated cytokines  or anti-cytokine antibodies. Supernatants collected after 48 h  were analyzed by ELISA for  IFN-γ.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196166&req=5

Figure 3: Activation in the presence of IL-4 and IL-12 results in the maintenance of functional IL-12 responsiveness. FACS®-sorted naive CD4+ DO11.10 T cells were cultured for seven days with OVA peptide and irradiated BALB/c splenocytes under the indicated primary culture conditions. Cultures were harvested on day 7, washed, and restimulated at 1.25 × 105 T cells/well with OVA peptide and BALB/c splenocytes in the presence of the indicated cytokines or anti-cytokine antibodies. Supernatants collected after 48 h were analyzed by ELISA for IFN-γ.
Mentions: We next asked what conditions controlled the maintenance of IL-12 signaling in developing Th cells. IL-4 was thought to dominate IL-12 for effects on T helper phenotype development (5, 34), since the addition of IL-4 and IL-12 together led to Th2 development both in TCR-transgenic and anti-CD3 driven systems (5, 34). We first wished to determine if it was the lack of IL-4 in primary cultures that allowed the maintenance of IL-12 responsiveness in developing Th1 cells. Thus, we activated naive T cells in the presence of IL-4 and IL-12 together in the primary culture and assessed IL-12 responsiveness on day 5 after primary stimulation (Fig. 2). Surprisingly, these T cells were able to phosphorylate Stat4 upon IL-12 treatment (Fig. 2, middle), similar to Th1 cells (Fig. 2, top), but unlike IL-12 unresponsive Th2 cells (Fig. 2, bottom). This maintenance of Stat4 phosphorylation correlated with functional IL-12 responses in these T cells as measured by IL-12–induced IFN-γ production (Fig. 3). T cells arising from stimulation in IL-4 and IL-12 together showed significant IL-12 induced IFN-γ production during restimulation (Fig. 3, top). Restimulation of these cells without exogenously added IL-12 led to production of 180 U/ml IFN-γ, while addition of IL-12 increased IFN-γ production to 400 U/ml. Because these T cells arose in IL-4, they acquired the Th2-type property of producing IL-4 and IL-10, two cytokines which inhibit IFN-γ production (35, 36). In this system, IL-10 could also be produced by other cells used as APCs. Neutralization of IL-4 and IL-10 revealed a significantly increased IL-12– mediated induction of IFN-γ, from less than 50 U/ml of IFN-γ produced upon restimulation in the absence of IL-12 to 1,300 U/ml of IFN-γ produced in the presence of IL-12 (Fig. 3, top). In contrast, the control Th2 cells produced very low amounts of IFN-γ (20 U/ml) upon restimulation in the presence of IL-12, a level which was not increased by neutralization of IL-4 and IL-10 (Fig. 3, bottom). Taken together, these results therefore suggest that the presence of IL-12 during primary T cell activation, not the absence of IL-4, was responsible for maintenance of functional responsiveness to IL-12.

Bottom Line: Importantly, IL-4 and IFN-gamma were found to significantly modify IL-12 receptor beta 2 expression after T cell activation.IFN-gamma treatment of early developing Th2 cells maintained IL-12R beta 2 expression and restored the ability of these cells to functionally respond to IL-12, but did not directly inhibit IL-4 or induce IFN-gamma production.Controlling the expression of the IL-12R beta 2 subunit could be an important therapeutic target for the redirection of ongoing Th cell responses.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.

ABSTRACT
The developmental commitment to a T helper 1 (Th1)- or Th2-type response can significantly influence host immunity to pathogens. Extinction of the IL-12 signaling pathway during early Th2 development provides a mechanism that allows stable phenotype commitment. In this report we demonstrate that extinction of IL-12 signaling in early Th2 cells results from a selective loss of IL-12 receptor (IL-12R) beta 2 subunit expression. To determine the basis for this selective loss, we examined IL-12R beta 2 subunit expression during Th cell development in response to T cell treatment with different cytokines. IL-12R beta 2 is not expressed by naive resting CD4+ T cells, but is induced upon antigen activation through the T cell receptor. Importantly, IL-4 and IFN-gamma were found to significantly modify IL-12 receptor beta 2 expression after T cell activation. IL-4 inhibited IL-12R beta 2 expression leading to the loss of IL-12 signaling, providing an important point of regulation to promote commitment to the Th2 pathway. IFN-gamma treatment of early developing Th2 cells maintained IL-12R beta 2 expression and restored the ability of these cells to functionally respond to IL-12, but did not directly inhibit IL-4 or induce IFN-gamma production. Thus, IFN-gamma may prevent early Th cells from premature commitment to the Th2 pathway. Controlling the expression of the IL-12R beta 2 subunit could be an important therapeutic target for the redirection of ongoing Th cell responses.

Show MeSH