Limits...
T cell costimulation through CD28 depends on induction of the Bcl-xgamma isoform: analysis of Bcl-xgamma-deficient mice.

Ye Q, Press B, Kissler S, Yang XF, Lu L, Bassing CH, Sleckman BP, Jansson M, Panoutsakopoulou V, Trimble LA, Alt FW, Cantor H - J. Exp. Med. (2002)

Bottom Line: The molecular basis of CD28-dependent costimulation of T cells is poorly understood.We report that Bcl-xgamma-deficient (Bcl-xgamma-/-) T cells display defective proliferative and cytokine responses to CD28-dependent costimulatory signals, impaired memory responses to proteolipid protein peptide (PLP), and do not develop PLP-induced experimental autoimmune encephalomyelitis (EAE).These findings identify the Bcl-xgamma cytosolic protein as an essential downstream link in the CD28-dependent signaling pathway that underlies T cell costimulation.

View Article: PubMed Central - PubMed

Affiliation: Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.

ABSTRACT
The molecular basis of CD28-dependent costimulation of T cells is poorly understood. Bcl-xgamma is a member of the Bcl-x family whose expression is restricted to activated T cells and requires CD28-dependent ligation for full expression. We report that Bcl-xgamma-deficient (Bcl-xgamma-/-) T cells display defective proliferative and cytokine responses to CD28-dependent costimulatory signals, impaired memory responses to proteolipid protein peptide (PLP), and do not develop PLP-induced experimental autoimmune encephalomyelitis (EAE). In contrast, enforced expression of Bcl-xgamma largely replaces the requirement for B7-dependent ligation of CD28. These findings identify the Bcl-xgamma cytosolic protein as an essential downstream link in the CD28-dependent signaling pathway that underlies T cell costimulation.

Show MeSH

Related in: MedlinePlus

Expression and proliferation profiles of Bcl-xγ in cells derived from Tg mice. (A) Expression of Bcl-xγ and Bcl-xL in different murine tissues from Tg mice (see Materials and Methods). Immunoblot analysis was performed as described in Materials and Methods and is representative of data in one of two independent experiments; the level of actin serves as a control for protein loading. (B) Proliferation of activated T cells from wt and Tg mice. T cells were isolated from Tg or wt mice and cultured for 48 h in the presence of plate-bound anti-CD3 and/or anti-CD28 antibodies. Cells were then pulsed with 3[H]thymidine and cultured for an additional 18 h before harvesting. In the absence of antibody-dependent activation, survival of T cells from Bcl-xγ Tg and wt mice was not significantly different after 24–72 h in culture. (C) Time-course of IL-2 production from activated T cells. Supernatants from T cells activated as described above were harvested at the indicated times and analyzed for IL-2 by ELISA. All values are the average of triplicate determinations (±SEM) from one of four representative and independent experiments. (D) Proliferative response of T cells from Bcl-xγ and DO11.10 TCR Tg to OVA peptide (323–339). Purified Bcl-xγ transgenic and wt T cells (4 × 104) from DO11.10+ littermates (B6.129 × Balb/c genotype) were incubated with irradiated (5 × 105) splenocytes from either Balb/c mice or from B7.1−/−B7.2−/−Balb/c mice for 48 h before addition of 1 μCi 3[H]thymidine to each well. Proliferation (cpm) of triplicate cultures was measured after 16 h.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2194014&req=5

fig3: Expression and proliferation profiles of Bcl-xγ in cells derived from Tg mice. (A) Expression of Bcl-xγ and Bcl-xL in different murine tissues from Tg mice (see Materials and Methods). Immunoblot analysis was performed as described in Materials and Methods and is representative of data in one of two independent experiments; the level of actin serves as a control for protein loading. (B) Proliferation of activated T cells from wt and Tg mice. T cells were isolated from Tg or wt mice and cultured for 48 h in the presence of plate-bound anti-CD3 and/or anti-CD28 antibodies. Cells were then pulsed with 3[H]thymidine and cultured for an additional 18 h before harvesting. In the absence of antibody-dependent activation, survival of T cells from Bcl-xγ Tg and wt mice was not significantly different after 24–72 h in culture. (C) Time-course of IL-2 production from activated T cells. Supernatants from T cells activated as described above were harvested at the indicated times and analyzed for IL-2 by ELISA. All values are the average of triplicate determinations (±SEM) from one of four representative and independent experiments. (D) Proliferative response of T cells from Bcl-xγ and DO11.10 TCR Tg to OVA peptide (323–339). Purified Bcl-xγ transgenic and wt T cells (4 × 104) from DO11.10+ littermates (B6.129 × Balb/c genotype) were incubated with irradiated (5 × 105) splenocytes from either Balb/c mice or from B7.1−/−B7.2−/−Balb/c mice for 48 h before addition of 1 μCi 3[H]thymidine to each well. Proliferation (cpm) of triplicate cultures was measured after 16 h.

Mentions: Then, we asked whether enforced expression of Bcl-xγ in T cells might replace the need for CD28-dependent costimulation. Expression of a Bcl-xγ transgene under the control of the Lck distal promoter resulted in constitutive overexpression of Bcl-xγ in peripheral T cells independent of overt activation (Fig. 3 A). Enforced Bcl-xγ expression did not enhance survival of unstimulated T cells, in contrast to the reported effects of Bcl-xL (Fig. 3 B, legend). However, proliferative and IL-2 responses of T cells from Bcl-xγ Tg+ mice after CD3 ligation were 3–4-fold greater than T cells from nontransgenic littermates and were not significantly increased by CD28 coligation (Fig. 3, B and C). Moreover, enforced expression of Bcl-xγ restored the response of CD4 DO11.10+ T cells to OVA peptide presented by B7.1/B7.2−/− APC to levels provoked by B7.1/B7.2+ APC (Fig. 3 D).


T cell costimulation through CD28 depends on induction of the Bcl-xgamma isoform: analysis of Bcl-xgamma-deficient mice.

Ye Q, Press B, Kissler S, Yang XF, Lu L, Bassing CH, Sleckman BP, Jansson M, Panoutsakopoulou V, Trimble LA, Alt FW, Cantor H - J. Exp. Med. (2002)

Expression and proliferation profiles of Bcl-xγ in cells derived from Tg mice. (A) Expression of Bcl-xγ and Bcl-xL in different murine tissues from Tg mice (see Materials and Methods). Immunoblot analysis was performed as described in Materials and Methods and is representative of data in one of two independent experiments; the level of actin serves as a control for protein loading. (B) Proliferation of activated T cells from wt and Tg mice. T cells were isolated from Tg or wt mice and cultured for 48 h in the presence of plate-bound anti-CD3 and/or anti-CD28 antibodies. Cells were then pulsed with 3[H]thymidine and cultured for an additional 18 h before harvesting. In the absence of antibody-dependent activation, survival of T cells from Bcl-xγ Tg and wt mice was not significantly different after 24–72 h in culture. (C) Time-course of IL-2 production from activated T cells. Supernatants from T cells activated as described above were harvested at the indicated times and analyzed for IL-2 by ELISA. All values are the average of triplicate determinations (±SEM) from one of four representative and independent experiments. (D) Proliferative response of T cells from Bcl-xγ and DO11.10 TCR Tg to OVA peptide (323–339). Purified Bcl-xγ transgenic and wt T cells (4 × 104) from DO11.10+ littermates (B6.129 × Balb/c genotype) were incubated with irradiated (5 × 105) splenocytes from either Balb/c mice or from B7.1−/−B7.2−/−Balb/c mice for 48 h before addition of 1 μCi 3[H]thymidine to each well. Proliferation (cpm) of triplicate cultures was measured after 16 h.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2194014&req=5

fig3: Expression and proliferation profiles of Bcl-xγ in cells derived from Tg mice. (A) Expression of Bcl-xγ and Bcl-xL in different murine tissues from Tg mice (see Materials and Methods). Immunoblot analysis was performed as described in Materials and Methods and is representative of data in one of two independent experiments; the level of actin serves as a control for protein loading. (B) Proliferation of activated T cells from wt and Tg mice. T cells were isolated from Tg or wt mice and cultured for 48 h in the presence of plate-bound anti-CD3 and/or anti-CD28 antibodies. Cells were then pulsed with 3[H]thymidine and cultured for an additional 18 h before harvesting. In the absence of antibody-dependent activation, survival of T cells from Bcl-xγ Tg and wt mice was not significantly different after 24–72 h in culture. (C) Time-course of IL-2 production from activated T cells. Supernatants from T cells activated as described above were harvested at the indicated times and analyzed for IL-2 by ELISA. All values are the average of triplicate determinations (±SEM) from one of four representative and independent experiments. (D) Proliferative response of T cells from Bcl-xγ and DO11.10 TCR Tg to OVA peptide (323–339). Purified Bcl-xγ transgenic and wt T cells (4 × 104) from DO11.10+ littermates (B6.129 × Balb/c genotype) were incubated with irradiated (5 × 105) splenocytes from either Balb/c mice or from B7.1−/−B7.2−/−Balb/c mice for 48 h before addition of 1 μCi 3[H]thymidine to each well. Proliferation (cpm) of triplicate cultures was measured after 16 h.
Mentions: Then, we asked whether enforced expression of Bcl-xγ in T cells might replace the need for CD28-dependent costimulation. Expression of a Bcl-xγ transgene under the control of the Lck distal promoter resulted in constitutive overexpression of Bcl-xγ in peripheral T cells independent of overt activation (Fig. 3 A). Enforced Bcl-xγ expression did not enhance survival of unstimulated T cells, in contrast to the reported effects of Bcl-xL (Fig. 3 B, legend). However, proliferative and IL-2 responses of T cells from Bcl-xγ Tg+ mice after CD3 ligation were 3–4-fold greater than T cells from nontransgenic littermates and were not significantly increased by CD28 coligation (Fig. 3, B and C). Moreover, enforced expression of Bcl-xγ restored the response of CD4 DO11.10+ T cells to OVA peptide presented by B7.1/B7.2−/− APC to levels provoked by B7.1/B7.2+ APC (Fig. 3 D).

Bottom Line: The molecular basis of CD28-dependent costimulation of T cells is poorly understood.We report that Bcl-xgamma-deficient (Bcl-xgamma-/-) T cells display defective proliferative and cytokine responses to CD28-dependent costimulatory signals, impaired memory responses to proteolipid protein peptide (PLP), and do not develop PLP-induced experimental autoimmune encephalomyelitis (EAE).These findings identify the Bcl-xgamma cytosolic protein as an essential downstream link in the CD28-dependent signaling pathway that underlies T cell costimulation.

View Article: PubMed Central - PubMed

Affiliation: Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.

ABSTRACT
The molecular basis of CD28-dependent costimulation of T cells is poorly understood. Bcl-xgamma is a member of the Bcl-x family whose expression is restricted to activated T cells and requires CD28-dependent ligation for full expression. We report that Bcl-xgamma-deficient (Bcl-xgamma-/-) T cells display defective proliferative and cytokine responses to CD28-dependent costimulatory signals, impaired memory responses to proteolipid protein peptide (PLP), and do not develop PLP-induced experimental autoimmune encephalomyelitis (EAE). In contrast, enforced expression of Bcl-xgamma largely replaces the requirement for B7-dependent ligation of CD28. These findings identify the Bcl-xgamma cytosolic protein as an essential downstream link in the CD28-dependent signaling pathway that underlies T cell costimulation.

Show MeSH
Related in: MedlinePlus