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Expansion of melanoma-specific cytolytic CD8+ T cell precursors in patients with metastatic melanoma vaccinated with CD34+ progenitor-derived dendritic cells.

Paczesny S, Banchereau J, Wittkowski KM, Saracino G, Fay J, Palucka AK - J. Exp. Med. (2004)

Bottom Line: Cancer vaccines aim at inducing (a) tumor-specific effector T cells able to reduce/eliminate the tumor mass, and (b) long-lasting tumor-specific memory T cells able to control tumor relapse.Thus, CD34-DC vaccines can expand melanoma-specific CTL precursors that can kill melanoma antigen-expressing targets.These results justify the design of larger follow-up studies to assess the immunological and clinical response to peptide-pulsed CD34-DC vaccines.

View Article: PubMed Central - PubMed

Affiliation: Baylor Institute for Immunology Research, Dallas, TX 75204, USA.

ABSTRACT
Cancer vaccines aim at inducing (a) tumor-specific effector T cells able to reduce/eliminate the tumor mass, and (b) long-lasting tumor-specific memory T cells able to control tumor relapse. We have shown earlier, in 18 human histocompatibility leukocyte antigen (HLA)-A*0201 patients with metastatic melanoma, that vaccination with peptide-loaded CD34-dendritic cells (DCs) leads to expansion of melanoma-specific interferon gamma-producing CD8+ T cells in the blood. Here, we show in 9 out of 12 analyzed patients the expansion of cytolytic CD8+ T cell precursors specific for melanoma differentiation antigens. These precursors yield, upon single restimulation with melanoma peptide-pulsed DCs, cytotoxic T lymphocytes (CTLs) able to kill melanoma cells. Melanoma-specific CTLs can be grown in vitro and can be detected in three assays: (a) melanoma tetramer binding, (b) killing of melanoma peptide-pulsed T2 cells, and (c) killing of HLA-A*0201 melanoma cells. The cytolytic activity of expanded CTLs correlates with the frequency of melanoma tetramer binding CD8+ T cells. Thus, CD34-DC vaccines can expand melanoma-specific CTL precursors that can kill melanoma antigen-expressing targets. These results justify the design of larger follow-up studies to assess the immunological and clinical response to peptide-pulsed CD34-DC vaccines.

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CTL activity against melanoma peptide–pulsed T2 cells before and after vaccination. Purified CD8+ T cells after a single stimulation with peptide-pulsed DCs are used as effectors in a standard 4-h 51Cr assay with T2 cells pulsed with either a control PSA peptide, or with viral peptides (Flu-MP, CMV), or with a mix of the four melanoma peptides (GP100, MART-1/Melan A, tyrosinase, and MAGE-3) at indicated E/T ratios. (a) CD8+ T cells from patient number 9 (see Table I, after fourth DC vaccine) are capable of specific lysis (ordinate) of T2 cells pulsed with viral (CMV) or melanoma peptides at several E/T ratios (abscissa). (b) CD8+ T cells from patient number 13 (see Table I, after fourth DC vaccine) are capable of specific lysis (ordinate) of T2 cells pulsed with Flu-MP peptide at several E/T ratios (abscissa), but not of melanoma peptide–pulsed T2 cells. (c) Killing of melanoma peptide–pulsed T2 cells (a mix of four melanoma peptides) by cultured CD8+ T cells from all tested patients at baseline (Pre) and after fourth DC vaccination (Post). Ordinate/specific lysis at the E/T ratio of 30–25:1, after subtraction of values obtained with PSA peptide–loaded T2 (see Table S1), patient number (see Table I). All experiments are shown.
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fig1: CTL activity against melanoma peptide–pulsed T2 cells before and after vaccination. Purified CD8+ T cells after a single stimulation with peptide-pulsed DCs are used as effectors in a standard 4-h 51Cr assay with T2 cells pulsed with either a control PSA peptide, or with viral peptides (Flu-MP, CMV), or with a mix of the four melanoma peptides (GP100, MART-1/Melan A, tyrosinase, and MAGE-3) at indicated E/T ratios. (a) CD8+ T cells from patient number 9 (see Table I, after fourth DC vaccine) are capable of specific lysis (ordinate) of T2 cells pulsed with viral (CMV) or melanoma peptides at several E/T ratios (abscissa). (b) CD8+ T cells from patient number 13 (see Table I, after fourth DC vaccine) are capable of specific lysis (ordinate) of T2 cells pulsed with Flu-MP peptide at several E/T ratios (abscissa), but not of melanoma peptide–pulsed T2 cells. (c) Killing of melanoma peptide–pulsed T2 cells (a mix of four melanoma peptides) by cultured CD8+ T cells from all tested patients at baseline (Pre) and after fourth DC vaccination (Post). Ordinate/specific lysis at the E/T ratio of 30–25:1, after subtraction of values obtained with PSA peptide–loaded T2 (see Table S1), patient number (see Table I). All experiments are shown.

Mentions: Maturation of CD8+ T cells into CTLs was first assessed in a standard 4-h 51Cr release assay using as targets T2 cells pulsed with either the four melanoma peptides used in the vaccine, i.e., MelanA/MART-1, gp100, tyrosinase, and MAGE-3, or with a control peptide. Fig. 1, a and b, shows the CTL activity of cultured CD8+ T cells isolated from post-DC vaccination blood of two patients. Patient number 9 restimulated CD8+ T cells killed melanoma peptide–pulsed T2 cells with 40% lysis at the E/T ratio of 50:1 (Fig. 1 a). In contrast, restimulated CD8+ T cells from patient number 13 were not able to kill melanoma peptide–loaded T2 cells (Fig. 1 b). Killing was specific as no lysis of PSA peptide–pulsed T2 cells could be detected. Control cultures, in which CD8+ T cells were restimulated with CMV peptide–pulsed DCs (Fig. 1 a, Pt#9) or Flu-MP peptide–loaded DCs (Fig. 1 b, Pt#13), yielded highly efficient specific CTLs with ∼80% lysis at the E/T ratio of 50:1. These results suggested that some of the vaccinated patients do not display circulating melanoma-specific T cells able to mature into melanoma-specific CTLs, whereas they show functional virus-specific CD8+ T cells.


Expansion of melanoma-specific cytolytic CD8+ T cell precursors in patients with metastatic melanoma vaccinated with CD34+ progenitor-derived dendritic cells.

Paczesny S, Banchereau J, Wittkowski KM, Saracino G, Fay J, Palucka AK - J. Exp. Med. (2004)

CTL activity against melanoma peptide–pulsed T2 cells before and after vaccination. Purified CD8+ T cells after a single stimulation with peptide-pulsed DCs are used as effectors in a standard 4-h 51Cr assay with T2 cells pulsed with either a control PSA peptide, or with viral peptides (Flu-MP, CMV), or with a mix of the four melanoma peptides (GP100, MART-1/Melan A, tyrosinase, and MAGE-3) at indicated E/T ratios. (a) CD8+ T cells from patient number 9 (see Table I, after fourth DC vaccine) are capable of specific lysis (ordinate) of T2 cells pulsed with viral (CMV) or melanoma peptides at several E/T ratios (abscissa). (b) CD8+ T cells from patient number 13 (see Table I, after fourth DC vaccine) are capable of specific lysis (ordinate) of T2 cells pulsed with Flu-MP peptide at several E/T ratios (abscissa), but not of melanoma peptide–pulsed T2 cells. (c) Killing of melanoma peptide–pulsed T2 cells (a mix of four melanoma peptides) by cultured CD8+ T cells from all tested patients at baseline (Pre) and after fourth DC vaccination (Post). Ordinate/specific lysis at the E/T ratio of 30–25:1, after subtraction of values obtained with PSA peptide–loaded T2 (see Table S1), patient number (see Table I). All experiments are shown.
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fig1: CTL activity against melanoma peptide–pulsed T2 cells before and after vaccination. Purified CD8+ T cells after a single stimulation with peptide-pulsed DCs are used as effectors in a standard 4-h 51Cr assay with T2 cells pulsed with either a control PSA peptide, or with viral peptides (Flu-MP, CMV), or with a mix of the four melanoma peptides (GP100, MART-1/Melan A, tyrosinase, and MAGE-3) at indicated E/T ratios. (a) CD8+ T cells from patient number 9 (see Table I, after fourth DC vaccine) are capable of specific lysis (ordinate) of T2 cells pulsed with viral (CMV) or melanoma peptides at several E/T ratios (abscissa). (b) CD8+ T cells from patient number 13 (see Table I, after fourth DC vaccine) are capable of specific lysis (ordinate) of T2 cells pulsed with Flu-MP peptide at several E/T ratios (abscissa), but not of melanoma peptide–pulsed T2 cells. (c) Killing of melanoma peptide–pulsed T2 cells (a mix of four melanoma peptides) by cultured CD8+ T cells from all tested patients at baseline (Pre) and after fourth DC vaccination (Post). Ordinate/specific lysis at the E/T ratio of 30–25:1, after subtraction of values obtained with PSA peptide–loaded T2 (see Table S1), patient number (see Table I). All experiments are shown.
Mentions: Maturation of CD8+ T cells into CTLs was first assessed in a standard 4-h 51Cr release assay using as targets T2 cells pulsed with either the four melanoma peptides used in the vaccine, i.e., MelanA/MART-1, gp100, tyrosinase, and MAGE-3, or with a control peptide. Fig. 1, a and b, shows the CTL activity of cultured CD8+ T cells isolated from post-DC vaccination blood of two patients. Patient number 9 restimulated CD8+ T cells killed melanoma peptide–pulsed T2 cells with 40% lysis at the E/T ratio of 50:1 (Fig. 1 a). In contrast, restimulated CD8+ T cells from patient number 13 were not able to kill melanoma peptide–loaded T2 cells (Fig. 1 b). Killing was specific as no lysis of PSA peptide–pulsed T2 cells could be detected. Control cultures, in which CD8+ T cells were restimulated with CMV peptide–pulsed DCs (Fig. 1 a, Pt#9) or Flu-MP peptide–loaded DCs (Fig. 1 b, Pt#13), yielded highly efficient specific CTLs with ∼80% lysis at the E/T ratio of 50:1. These results suggested that some of the vaccinated patients do not display circulating melanoma-specific T cells able to mature into melanoma-specific CTLs, whereas they show functional virus-specific CD8+ T cells.

Bottom Line: Cancer vaccines aim at inducing (a) tumor-specific effector T cells able to reduce/eliminate the tumor mass, and (b) long-lasting tumor-specific memory T cells able to control tumor relapse.Thus, CD34-DC vaccines can expand melanoma-specific CTL precursors that can kill melanoma antigen-expressing targets.These results justify the design of larger follow-up studies to assess the immunological and clinical response to peptide-pulsed CD34-DC vaccines.

View Article: PubMed Central - PubMed

Affiliation: Baylor Institute for Immunology Research, Dallas, TX 75204, USA.

ABSTRACT
Cancer vaccines aim at inducing (a) tumor-specific effector T cells able to reduce/eliminate the tumor mass, and (b) long-lasting tumor-specific memory T cells able to control tumor relapse. We have shown earlier, in 18 human histocompatibility leukocyte antigen (HLA)-A*0201 patients with metastatic melanoma, that vaccination with peptide-loaded CD34-dendritic cells (DCs) leads to expansion of melanoma-specific interferon gamma-producing CD8+ T cells in the blood. Here, we show in 9 out of 12 analyzed patients the expansion of cytolytic CD8+ T cell precursors specific for melanoma differentiation antigens. These precursors yield, upon single restimulation with melanoma peptide-pulsed DCs, cytotoxic T lymphocytes (CTLs) able to kill melanoma cells. Melanoma-specific CTLs can be grown in vitro and can be detected in three assays: (a) melanoma tetramer binding, (b) killing of melanoma peptide-pulsed T2 cells, and (c) killing of HLA-A*0201 melanoma cells. The cytolytic activity of expanded CTLs correlates with the frequency of melanoma tetramer binding CD8+ T cells. Thus, CD34-DC vaccines can expand melanoma-specific CTL precursors that can kill melanoma antigen-expressing targets. These results justify the design of larger follow-up studies to assess the immunological and clinical response to peptide-pulsed CD34-DC vaccines.

Show MeSH
Related in: MedlinePlus