Professional development session for early career scientists at SITC 2012.

The Society for Immunotherapy of Cancer (SITC) 2012 Professional Development Session was held as part of the SITC 27th Annual Meeting, Washington, DC, on October 24, 2012. The session was designed as a new opportunity for early career investigators to learn about relevant career development topics in a didactic setting.

Cutting Edge: Tumor-specific CD8+ T cells infiltrating prostatic tumors are induced to become suppressor cells.

We previously reported that naive, tumor-specific CD8(+) (TcR-I) T cells transferred into prostate tumor-bearing mice traffic to the prostate where they become tolerized. We now report that TcR-I cells suppress the proliferation of naive T cells. This suppression is mediated at least in part by secreted factors, and the suppressive activity can be blocked by Abs directed against TGF-beta.

Immunity to murine prostatic tumors: continuous provision of T-cell help prevents CD8 T-cell tolerance and activates tumor-infiltrating dendritic cells.

We reported previously that tumor-specific CD8(+) T cells (TcR-I) become tolerant in the transgenic adenocarcinoma of the mouse prostate (TRAMP) model. In this study, we show that CD4(+) TcR transgenic (TcR-II) T cells transferred into TRAMP mice became activated in lymph nodes, trafficked to the prostate, and initially functioned as T(H)1 cells. Although a single cotransfer of TcR-II cells delayed TcR-I cell tolerization, repeated transfer of TcR-II cells was required to prevent TcR-I cell tolerization and significantly slowed progression of TRAMP prostate tumors.

Application of a flow cytometric cytotoxicity assay for monitoring cancer vaccine trials.

In this study, we evaluated the applicability of a flow cytometry-based cytotoxicity (FC) assay previously developed by our laboratory, for monitoring cancer vaccine trials. The assay simultaneously measures effector cell degranulation and target cell death. Clinically relevant samples consisted of frozen peripheral blood mononuclear cells (PBMC) from vaccinated melanoma patients with known response to the melanoma peptide g209.

A novel flow cytometric assay for evaluating cell-mediated cytotoxicity.

Comprehensive evaluation of cell-mediated cytotoxicity is very important, especially in the clinical setting, when a surrogate immunologic endpoint that correlates with a clinical outcome needs to be defined. With the objective of simultaneously evaluating target cell death and effector cell frequency, the authors combined the measuring of the expression of the degranulation marker CD107a by effector cells with the apoptosis marker annexin V binding to target cells. Using human cytotoxic T lymphocytes, the authors found a significant incubation time-dependent increase of surface CD107a expression on effector cells due to degranulation.

Evaluating the cytotoxicity of innate immune effector cells using the GrB ELISPOT assay.

BACKGROUND: This study assessed the Granzyme B (GrB) ELISPOT as a viable alternative to the 51Cr-release assay for measuring cytotoxic activity of innate immune effector cells. We strategically selected the GrB ELISPOT assay because GrB is a hallmark effector molecule of cell-mediated destruction of target cells. METHODS: We optimized the GrB ELISPOT assay using the human-derived TALL-104 cytotoxic cell line as effectors against K562 target cells.

A modified human ELISPOT assay to detect specific responses to primary tumor cell targets.

BACKGROUND: The desired outcome of cancer vaccination is to induce a potent T cell response which can specifically recognize and eliminate autologous tumor cells in vivo. Accordingly, immunological assays that demonstrate recognition of native tumor cells (tumor-specific) may be more clinically relevant than assays that demonstrate recognition of tumor protein or peptide (antigen-specific). METHODS: Towards this goal, we adapted the IFN-gamma ELISPOT assay to measure immune responses against autologous primary tumor cells in vaccinated cancer patients.