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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 allogenic tumor cell lines. Purified CD8+ T cells after single stimulation are used as effectors in a standard 4-h 51Cr assay with control (K562 and MCF-7) and HLA-A*0201 melanoma (Me275 and Me290) cell lines at the indicated E/T ratios. (a) Purified CD8+ T cells from patient number 12 (see Table I, after fourth DC vaccine) are capable of specific lysis (ordinate) of two melanoma cells lines, but do not kill control targets at several E/T ratios (abscissa). (b) Killing of Me275 cells is restricted by MHC class I expression on targets cells. Me275 cells are used without pretreatment or are preincubated with either an isotype control or anti–HLA class I W6/32 mAb and used as targets. Specific lysis (ordinate) at two E/T ratios (abscissa) representative of three independent experiments with T cells from three patients is shown.
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fig2: CTL activity against allogenic tumor cell lines. Purified CD8+ T cells after single stimulation are used as effectors in a standard 4-h 51Cr assay with control (K562 and MCF-7) and HLA-A*0201 melanoma (Me275 and Me290) cell lines at the indicated E/T ratios. (a) Purified CD8+ T cells from patient number 12 (see Table I, after fourth DC vaccine) are capable of specific lysis (ordinate) of two melanoma cells lines, but do not kill control targets at several E/T ratios (abscissa). (b) Killing of Me275 cells is restricted by MHC class I expression on targets cells. Me275 cells are used without pretreatment or are preincubated with either an isotype control or anti–HLA class I W6/32 mAb and used as targets. Specific lysis (ordinate) at two E/T ratios (abscissa) representative of three independent experiments with T cells from three patients is shown.

Mentions: Fig. 2 shows the CTL activity of restimulated CD8+ T cells from patient number 12, which killed two melanoma cell lines, Me290 and Me275 (25% specific lysis), even at a relatively low E/T ratio of 25:1 (Fig. 2 a). No killing of control targets, the HLA-A*0201 MCF7 breast cancer cell line, and the NK-sensitive K562, was observed. Killing of melanoma cells was restricted by the expression of HLA class I, as the pretreatment of target cells with the HLA class I–blocking mAb W6/32 resulted in >90% inhibition of Me275 killing at different E/T ratios (Fig. 2 b, Pt#12). In line with the results observed with melanoma peptide–pulsed T2 cells, patient number 13's CD8+ T cells did not kill melanoma cell lines (Table S1).


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 allogenic tumor cell lines. Purified CD8+ T cells after single stimulation are used as effectors in a standard 4-h 51Cr assay with control (K562 and MCF-7) and HLA-A*0201 melanoma (Me275 and Me290) cell lines at the indicated E/T ratios. (a) Purified CD8+ T cells from patient number 12 (see Table I, after fourth DC vaccine) are capable of specific lysis (ordinate) of two melanoma cells lines, but do not kill control targets at several E/T ratios (abscissa). (b) Killing of Me275 cells is restricted by MHC class I expression on targets cells. Me275 cells are used without pretreatment or are preincubated with either an isotype control or anti–HLA class I W6/32 mAb and used as targets. Specific lysis (ordinate) at two E/T ratios (abscissa) representative of three independent experiments with T cells from three patients is shown.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2211788&req=5

fig2: CTL activity against allogenic tumor cell lines. Purified CD8+ T cells after single stimulation are used as effectors in a standard 4-h 51Cr assay with control (K562 and MCF-7) and HLA-A*0201 melanoma (Me275 and Me290) cell lines at the indicated E/T ratios. (a) Purified CD8+ T cells from patient number 12 (see Table I, after fourth DC vaccine) are capable of specific lysis (ordinate) of two melanoma cells lines, but do not kill control targets at several E/T ratios (abscissa). (b) Killing of Me275 cells is restricted by MHC class I expression on targets cells. Me275 cells are used without pretreatment or are preincubated with either an isotype control or anti–HLA class I W6/32 mAb and used as targets. Specific lysis (ordinate) at two E/T ratios (abscissa) representative of three independent experiments with T cells from three patients is shown.
Mentions: Fig. 2 shows the CTL activity of restimulated CD8+ T cells from patient number 12, which killed two melanoma cell lines, Me290 and Me275 (25% specific lysis), even at a relatively low E/T ratio of 25:1 (Fig. 2 a). No killing of control targets, the HLA-A*0201 MCF7 breast cancer cell line, and the NK-sensitive K562, was observed. Killing of melanoma cells was restricted by the expression of HLA class I, as the pretreatment of target cells with the HLA class I–blocking mAb W6/32 resulted in >90% inhibition of Me275 killing at different E/T ratios (Fig. 2 b, Pt#12). In line with the results observed with melanoma peptide–pulsed T2 cells, patient number 13's CD8+ T cells did not kill melanoma cell lines (Table S1).

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