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T helper subset differentiation in the absence of invariant chain.

Brown DR, Swier K, Moskowitz NH, Naujokas MF, Locksley RM, Reiner SL - J. Exp. Med. (1997)

Bottom Line: We wished to determine whether this unexpected efficiency of T helper subset induction despite inefficient T cell stimulation could be modeled in vitro.In the presence of rIL-12 or rIL-4 naive parasite-specific transgenic T cells could mature into IFN-gamma-or IL-4-secreting T helper cells, respectively, even when antigen presentation was suboptimal or antigen dose was submitogenic.These experiments demonstrate that activation of T helper cells to a threshold required for IL-2 production or proliferation is not required to achieve induction of disease-regulating T helper cell effector functions, and that pathogen-associated secondary activation signals may facilitate the full differentiation of T helper subsets during limiting presentation of antigenic peptides.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Gwen Knapp Center for Lupus & Immunology Research, University of Chicago, Illinois 60637, USA.

ABSTRACT
The outcome of murine infection with Leishmania major is regulated by major histocompatibility complex class II-restricted T helper cells. Invariant chain-deficient (Ii -/-) mice have impaired ability to present major histocompatibility complex class II-restricted antigens, and reduced numbers of CD4+ T cells. Despite these deficits, C57BL/6 Ii -/- mice controlled L. major infection comparably to wild-type mice. As assessed by mRNA analysis and in vitro antigen restimulation for IFN-gamma, Ii -/- mice had normal induction of Th1 subset differentiation even though antigen-dependent proliferation of their lymph node cells was substantially compromised. In addition, BALB/c Ii -/- mice exhibited a progressive course of infection and Th2 effector cell development that were comparable to that seen in wild-type BALB/c mice. We wished to determine whether this unexpected efficiency of T helper subset induction despite inefficient T cell stimulation could be modeled in vitro. In the presence of rIL-12 or rIL-4 naive parasite-specific transgenic T cells could mature into IFN-gamma-or IL-4-secreting T helper cells, respectively, even when antigen presentation was suboptimal or antigen dose was submitogenic. These experiments demonstrate that activation of T helper cells to a threshold required for IL-2 production or proliferation is not required to achieve induction of disease-regulating T helper cell effector functions, and that pathogen-associated secondary activation signals may facilitate the full differentiation of T helper subsets during limiting presentation of antigenic peptides.

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IL-12 induces IFN-γ  production from TCR transgenic T cells at suboptimal levels  of stimulation. Splenocytes from  Ii+ mice were incubated in either the absence (0) or presence  of increasing amounts of the  LACK peptide epitope, in the  absence (open symbols) or presence of increasing amounts of  rIL-12 (filled symbols), as designated on the lower axis. Each  well contained 2 × 105 Ii +  APCs and 2 × 105 TCR transgenic lymph node T cells. After  48 h, supernatants were collected  and assayed for IL-2 and IFN-γ  by ELISA. Data points represent  means and standard deviations  from duplicate determinations,  and are representative of three  separate experiments.
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Figure 6: IL-12 induces IFN-γ production from TCR transgenic T cells at suboptimal levels of stimulation. Splenocytes from Ii+ mice were incubated in either the absence (0) or presence of increasing amounts of the LACK peptide epitope, in the absence (open symbols) or presence of increasing amounts of rIL-12 (filled symbols), as designated on the lower axis. Each well contained 2 × 105 Ii + APCs and 2 × 105 TCR transgenic lymph node T cells. After 48 h, supernatants were collected and assayed for IL-2 and IFN-γ by ELISA. Data points represent means and standard deviations from duplicate determinations, and are representative of three separate experiments.

Mentions: The striking preservation of the IFN-γ response in vivo and in vitro suggested that costimulatory signals triggered by the organisms might compensate for the Ii −/− defect in antigen presentation. IL-12, induced by the intracellular forms of L. major (22), is required for optimal IFN-γ production and control of infection (30–32), and is required for Th1 effector cell development (33, 34). Stimulation of transgenic T cells (Fig. 6) with LACK peptide at levels >0.1 μM presented by normal Ii + APCs, allowed the ready recovery of IL-2, but not IFN-γ, from culture supernatants. Below this concentration of peptide, neither IL-2 nor proliferation was induced. Using suboptimal concentrations of the peptide, however, the addition of recombinant IL-12 (rIL-12) induced the dose-dependent production of IFN-γ by transgenic T cells not accompanied by IL-2 recovery in the supernatants (Fig. 6).


T helper subset differentiation in the absence of invariant chain.

Brown DR, Swier K, Moskowitz NH, Naujokas MF, Locksley RM, Reiner SL - J. Exp. Med. (1997)

IL-12 induces IFN-γ  production from TCR transgenic T cells at suboptimal levels  of stimulation. Splenocytes from  Ii+ mice were incubated in either the absence (0) or presence  of increasing amounts of the  LACK peptide epitope, in the  absence (open symbols) or presence of increasing amounts of  rIL-12 (filled symbols), as designated on the lower axis. Each  well contained 2 × 105 Ii +  APCs and 2 × 105 TCR transgenic lymph node T cells. After  48 h, supernatants were collected  and assayed for IL-2 and IFN-γ  by ELISA. Data points represent  means and standard deviations  from duplicate determinations,  and are representative of three  separate experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196096&req=5

Figure 6: IL-12 induces IFN-γ production from TCR transgenic T cells at suboptimal levels of stimulation. Splenocytes from Ii+ mice were incubated in either the absence (0) or presence of increasing amounts of the LACK peptide epitope, in the absence (open symbols) or presence of increasing amounts of rIL-12 (filled symbols), as designated on the lower axis. Each well contained 2 × 105 Ii + APCs and 2 × 105 TCR transgenic lymph node T cells. After 48 h, supernatants were collected and assayed for IL-2 and IFN-γ by ELISA. Data points represent means and standard deviations from duplicate determinations, and are representative of three separate experiments.
Mentions: The striking preservation of the IFN-γ response in vivo and in vitro suggested that costimulatory signals triggered by the organisms might compensate for the Ii −/− defect in antigen presentation. IL-12, induced by the intracellular forms of L. major (22), is required for optimal IFN-γ production and control of infection (30–32), and is required for Th1 effector cell development (33, 34). Stimulation of transgenic T cells (Fig. 6) with LACK peptide at levels >0.1 μM presented by normal Ii + APCs, allowed the ready recovery of IL-2, but not IFN-γ, from culture supernatants. Below this concentration of peptide, neither IL-2 nor proliferation was induced. Using suboptimal concentrations of the peptide, however, the addition of recombinant IL-12 (rIL-12) induced the dose-dependent production of IFN-γ by transgenic T cells not accompanied by IL-2 recovery in the supernatants (Fig. 6).

Bottom Line: We wished to determine whether this unexpected efficiency of T helper subset induction despite inefficient T cell stimulation could be modeled in vitro.In the presence of rIL-12 or rIL-4 naive parasite-specific transgenic T cells could mature into IFN-gamma-or IL-4-secreting T helper cells, respectively, even when antigen presentation was suboptimal or antigen dose was submitogenic.These experiments demonstrate that activation of T helper cells to a threshold required for IL-2 production or proliferation is not required to achieve induction of disease-regulating T helper cell effector functions, and that pathogen-associated secondary activation signals may facilitate the full differentiation of T helper subsets during limiting presentation of antigenic peptides.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Gwen Knapp Center for Lupus & Immunology Research, University of Chicago, Illinois 60637, USA.

ABSTRACT
The outcome of murine infection with Leishmania major is regulated by major histocompatibility complex class II-restricted T helper cells. Invariant chain-deficient (Ii -/-) mice have impaired ability to present major histocompatibility complex class II-restricted antigens, and reduced numbers of CD4+ T cells. Despite these deficits, C57BL/6 Ii -/- mice controlled L. major infection comparably to wild-type mice. As assessed by mRNA analysis and in vitro antigen restimulation for IFN-gamma, Ii -/- mice had normal induction of Th1 subset differentiation even though antigen-dependent proliferation of their lymph node cells was substantially compromised. In addition, BALB/c Ii -/- mice exhibited a progressive course of infection and Th2 effector cell development that were comparable to that seen in wild-type BALB/c mice. We wished to determine whether this unexpected efficiency of T helper subset induction despite inefficient T cell stimulation could be modeled in vitro. In the presence of rIL-12 or rIL-4 naive parasite-specific transgenic T cells could mature into IFN-gamma-or IL-4-secreting T helper cells, respectively, even when antigen presentation was suboptimal or antigen dose was submitogenic. These experiments demonstrate that activation of T helper cells to a threshold required for IL-2 production or proliferation is not required to achieve induction of disease-regulating T helper cell effector functions, and that pathogen-associated secondary activation signals may facilitate the full differentiation of T helper subsets during limiting presentation of antigenic peptides.

Show MeSH
Related in: MedlinePlus