Limits...
Regulatory CD4+CD25+ T cells restrict memory CD8+ T cell responses.

Kursar M, Bonhagen K, Fensterle J, Köhler A, Hurwitz R, Kamradt T, Kaufmann SH, Mittrücker HW - J. Exp. Med. (2002)

Bottom Line: In terms of cytokine production and cytotoxicity, the enlarged CD8+ T cell population consisted of functional effector T cells.Our results demonstrate that CD4+ T cells control the CD8+ T cell response in two directions.Initially, they promote the generation of a CD8+ T cell responses and later they restrain the strength of the CD8+ T cell memory response.

View Article: PubMed Central - PubMed

Affiliation: Max Planck Institute for Infection Biology, Department of Immunology. Deutsches Rheumaforschungszentrum, Schumannstr. 21/22, 10117 Berlin, Germany.

ABSTRACT
CD4+ T cell help is important for the generation of CD8+ T cell responses. We used depleting anti-CD4 mAb to analyze the role of CD4+ T cells for memory CD8+ T cell responses after secondary infection of mice with the intracellular bacterium Listeria monocytogenes, or after boost immunization by specific peptide or DNA vaccination. Surprisingly, anti-CD4 mAb treatment during secondary CD8+ T cell responses markedly enlarged the population size of antigen-specific CD8+ T cells. After boost immunization with peptide or DNA, this effect was particularly profound, and antigen-specific CD8+ T cell populations were enlarged at least 10-fold. In terms of cytokine production and cytotoxicity, the enlarged CD8+ T cell population consisted of functional effector T cells. In depletion and transfer experiments, the suppressive function could be ascribed to CD4+CD25+ T cells. Our results demonstrate that CD4+ T cells control the CD8+ T cell response in two directions. Initially, they promote the generation of a CD8+ T cell responses and later they restrain the strength of the CD8+ T cell memory response. Down-modulation of CD8+ T cell responses during infection could prevent harmful consequences after eradication of the pathogen.

Show MeSH

Related in: MedlinePlus

Effector functions of LLO91–99–specific CD8+ T cells after prime/boost DNA immunization. Mice were immunized with pChly using the gene gun. After 50 d, a boost immunization with the same DNA was performed. Mice were left untreated (control) or were treated with anti-CD4 mAb during the boost immunization. At day 7, mice were killed. (A) Spleen cells were stained and analyzed by flow cytometry. Dot plots depict CD62L and LLO91–99-tetramer staining of viable CD8-gated T cells and figures represent percent values calculated for CD8+ T cells only. (B) Spleen cells were cultured for 5 h with or without the peptide LLO91–99 and stained extracellularly for CD8 and intracellularly for IFN-γ and TNF-α or with isotype control mAbs. Dot blots show CD8-gated cells, and figures give percent values calculated for CD8+ T cells only. Values for isotype controls were below 0.05% (data not depicted). Dot blots in A and B show corresponding results from the same mice. (C) Spleen cells from untreated (diamonds) or anti-CD4 mAb-treated mice (triangles) were incubated for 4 h with target cells with (filled symbols) or without LLO91–99 (open symbols). After 4 h, lysis of target cells was determined. C shows results from three individually analyzed mice per group. Experiments in A–C are representative for at least two independent experiments with three individually analyzed mice per experimental group in each experiment.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2196063&req=5

fig3: Effector functions of LLO91–99–specific CD8+ T cells after prime/boost DNA immunization. Mice were immunized with pChly using the gene gun. After 50 d, a boost immunization with the same DNA was performed. Mice were left untreated (control) or were treated with anti-CD4 mAb during the boost immunization. At day 7, mice were killed. (A) Spleen cells were stained and analyzed by flow cytometry. Dot plots depict CD62L and LLO91–99-tetramer staining of viable CD8-gated T cells and figures represent percent values calculated for CD8+ T cells only. (B) Spleen cells were cultured for 5 h with or without the peptide LLO91–99 and stained extracellularly for CD8 and intracellularly for IFN-γ and TNF-α or with isotype control mAbs. Dot blots show CD8-gated cells, and figures give percent values calculated for CD8+ T cells only. Values for isotype controls were below 0.05% (data not depicted). Dot blots in A and B show corresponding results from the same mice. (C) Spleen cells from untreated (diamonds) or anti-CD4 mAb-treated mice (triangles) were incubated for 4 h with target cells with (filled symbols) or without LLO91–99 (open symbols). After 4 h, lysis of target cells was determined. C shows results from three individually analyzed mice per group. Experiments in A–C are representative for at least two independent experiments with three individually analyzed mice per experimental group in each experiment.

Mentions: Protection against secondary listeriosis is predominantly mediated by CD8+ T cells, but CD4+ T cells participate as well in the response against L. monocytogenes (3). Thus, the lack of listeria-specific CD4+ T cells could result in higher bacterial titers and delayed bacterial clearance. Consequently, the enhanced CD8+ T cell response could be due to an increase in antigen load. Although we did not observe a significant difference in bacterial titers during secondary infection between control mice and anti-CD4 mAb-treated mice, we cannot formally exclude that the enhanced CD8+ T cell response reflects compensatory mechanisms. To circumvent this problem, mice were infected with L. monocytogenes, and secondary CD8+ T cell responses were analyzed following specific DNA or peptide immunization. For DNA immunization, the plasmid pChly containing the gene for listeriolysin (hly) under the control of a eukaryotic promoter was applied with a gene gun (6). The peptide LLO91–99 was given subcutaneously in incomplete Freund's adjuvant (Fig. 2) . Prior to treatment, LLO91–99–specific CD8+ T cells comprised 0.1–0.2% of CD8+ T cells. Both DNA and peptide immunization increased frequencies of LLO91–99–specific CD8+ T cells. Depletion of CD4+ T cells drastically enlarged the frequencies and numbers of these T cells. In all experiments, CD4+ T cell depletion caused at least a 10- to 20-fold enhancement of the LLO91–99–specific CD8+ T cell response (Fig. 2, and unpublished data). DNA immunization was also used to analyze the effect of CD4+ T cell depletion in a setting independent from infection. Mice were prime/boost immunized with pChly DNA. 50 d after priming, frequencies of LLO91–99 specific-CD8+ T cells were close to the detection levels of the tetramer assay (unpublished data and Table I). Boost with the same DNA construct resulted in frequencies of ∼1.5% at day 7 after immunization. Depletion of CD4+ T cells during the boost markedly enhanced frequencies (up to 40%) and numbers of LLO91–99–specific CD8+ T cells (Figs. 3 A and 4 A).


Regulatory CD4+CD25+ T cells restrict memory CD8+ T cell responses.

Kursar M, Bonhagen K, Fensterle J, Köhler A, Hurwitz R, Kamradt T, Kaufmann SH, Mittrücker HW - J. Exp. Med. (2002)

Effector functions of LLO91–99–specific CD8+ T cells after prime/boost DNA immunization. Mice were immunized with pChly using the gene gun. After 50 d, a boost immunization with the same DNA was performed. Mice were left untreated (control) or were treated with anti-CD4 mAb during the boost immunization. At day 7, mice were killed. (A) Spleen cells were stained and analyzed by flow cytometry. Dot plots depict CD62L and LLO91–99-tetramer staining of viable CD8-gated T cells and figures represent percent values calculated for CD8+ T cells only. (B) Spleen cells were cultured for 5 h with or without the peptide LLO91–99 and stained extracellularly for CD8 and intracellularly for IFN-γ and TNF-α or with isotype control mAbs. Dot blots show CD8-gated cells, and figures give percent values calculated for CD8+ T cells only. Values for isotype controls were below 0.05% (data not depicted). Dot blots in A and B show corresponding results from the same mice. (C) Spleen cells from untreated (diamonds) or anti-CD4 mAb-treated mice (triangles) were incubated for 4 h with target cells with (filled symbols) or without LLO91–99 (open symbols). After 4 h, lysis of target cells was determined. C shows results from three individually analyzed mice per group. Experiments in A–C are representative for at least two independent experiments with three individually analyzed mice per experimental group in each experiment.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196063&req=5

fig3: Effector functions of LLO91–99–specific CD8+ T cells after prime/boost DNA immunization. Mice were immunized with pChly using the gene gun. After 50 d, a boost immunization with the same DNA was performed. Mice were left untreated (control) or were treated with anti-CD4 mAb during the boost immunization. At day 7, mice were killed. (A) Spleen cells were stained and analyzed by flow cytometry. Dot plots depict CD62L and LLO91–99-tetramer staining of viable CD8-gated T cells and figures represent percent values calculated for CD8+ T cells only. (B) Spleen cells were cultured for 5 h with or without the peptide LLO91–99 and stained extracellularly for CD8 and intracellularly for IFN-γ and TNF-α or with isotype control mAbs. Dot blots show CD8-gated cells, and figures give percent values calculated for CD8+ T cells only. Values for isotype controls were below 0.05% (data not depicted). Dot blots in A and B show corresponding results from the same mice. (C) Spleen cells from untreated (diamonds) or anti-CD4 mAb-treated mice (triangles) were incubated for 4 h with target cells with (filled symbols) or without LLO91–99 (open symbols). After 4 h, lysis of target cells was determined. C shows results from three individually analyzed mice per group. Experiments in A–C are representative for at least two independent experiments with three individually analyzed mice per experimental group in each experiment.
Mentions: Protection against secondary listeriosis is predominantly mediated by CD8+ T cells, but CD4+ T cells participate as well in the response against L. monocytogenes (3). Thus, the lack of listeria-specific CD4+ T cells could result in higher bacterial titers and delayed bacterial clearance. Consequently, the enhanced CD8+ T cell response could be due to an increase in antigen load. Although we did not observe a significant difference in bacterial titers during secondary infection between control mice and anti-CD4 mAb-treated mice, we cannot formally exclude that the enhanced CD8+ T cell response reflects compensatory mechanisms. To circumvent this problem, mice were infected with L. monocytogenes, and secondary CD8+ T cell responses were analyzed following specific DNA or peptide immunization. For DNA immunization, the plasmid pChly containing the gene for listeriolysin (hly) under the control of a eukaryotic promoter was applied with a gene gun (6). The peptide LLO91–99 was given subcutaneously in incomplete Freund's adjuvant (Fig. 2) . Prior to treatment, LLO91–99–specific CD8+ T cells comprised 0.1–0.2% of CD8+ T cells. Both DNA and peptide immunization increased frequencies of LLO91–99–specific CD8+ T cells. Depletion of CD4+ T cells drastically enlarged the frequencies and numbers of these T cells. In all experiments, CD4+ T cell depletion caused at least a 10- to 20-fold enhancement of the LLO91–99–specific CD8+ T cell response (Fig. 2, and unpublished data). DNA immunization was also used to analyze the effect of CD4+ T cell depletion in a setting independent from infection. Mice were prime/boost immunized with pChly DNA. 50 d after priming, frequencies of LLO91–99 specific-CD8+ T cells were close to the detection levels of the tetramer assay (unpublished data and Table I). Boost with the same DNA construct resulted in frequencies of ∼1.5% at day 7 after immunization. Depletion of CD4+ T cells during the boost markedly enhanced frequencies (up to 40%) and numbers of LLO91–99–specific CD8+ T cells (Figs. 3 A and 4 A).

Bottom Line: In terms of cytokine production and cytotoxicity, the enlarged CD8+ T cell population consisted of functional effector T cells.Our results demonstrate that CD4+ T cells control the CD8+ T cell response in two directions.Initially, they promote the generation of a CD8+ T cell responses and later they restrain the strength of the CD8+ T cell memory response.

View Article: PubMed Central - PubMed

Affiliation: Max Planck Institute for Infection Biology, Department of Immunology. Deutsches Rheumaforschungszentrum, Schumannstr. 21/22, 10117 Berlin, Germany.

ABSTRACT
CD4+ T cell help is important for the generation of CD8+ T cell responses. We used depleting anti-CD4 mAb to analyze the role of CD4+ T cells for memory CD8+ T cell responses after secondary infection of mice with the intracellular bacterium Listeria monocytogenes, or after boost immunization by specific peptide or DNA vaccination. Surprisingly, anti-CD4 mAb treatment during secondary CD8+ T cell responses markedly enlarged the population size of antigen-specific CD8+ T cells. After boost immunization with peptide or DNA, this effect was particularly profound, and antigen-specific CD8+ T cell populations were enlarged at least 10-fold. In terms of cytokine production and cytotoxicity, the enlarged CD8+ T cell population consisted of functional effector T cells. In depletion and transfer experiments, the suppressive function could be ascribed to CD4+CD25+ T cells. Our results demonstrate that CD4+ T cells control the CD8+ T cell response in two directions. Initially, they promote the generation of a CD8+ T cell responses and later they restrain the strength of the CD8+ T cell memory response. Down-modulation of CD8+ T cell responses during infection could prevent harmful consequences after eradication of the pathogen.

Show MeSH
Related in: MedlinePlus