title: A modified human ELISPOT assay to detect specific responses to primary tumor cell targets.
abstract: 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. As a model system to develop the assay, we utilized peripheral blood mononuclear cells (PBMC) directly isolated from follicular lymphoma patients vaccinated with tumor-derived idiotype protein. RESULTS: After optimizing several variables, we demonstrated that the modified IFN-gamma ELISPOT assay could be used to reliably and reproducibly determine the tumor-reactive T cell frequency in the PBMC of these patients. The precursor frequency of tumor-reactive T cells was significantly higher in the postvaccine PBMC, compared with prevaccine samples in all patients tested. Furthermore, the specificity of these T cells was established by the lack of reactivity against autologous normal B cells. CONCLUSIONS: These results demonstrate the feasibility of quantitating tumor-specific T cell responses when autologous, primary tumor cells are available as targets.
authors.affiliation: Laboratory of Cell-Mediated Immunity, SAIC-Frederick, Inc, National Cancer Institute at Frederick, Frederick, MD 21702 USA. amalyguine@ncifcrf.gov
authors.forename: Anatoli
authors.initials: A
authors.lastname: Malyguine
authors.forename: Susan L
authors.initials: SL
authors.lastname: Strobl
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Shafer-Weaver
authors.forename: Tracy
authors.initials: T
authors.lastname: Ulderich
authors.forename: Angela
authors.initials: A
authors.lastname: Troke
authors.forename: Michael
authors.initials: M
authors.lastname: Baseler
authors.forename: Larry W
authors.initials: LW
authors.lastname: Kwak
authors.forename: Sattva S
authors.initials: SS
authors.lastname: Neelapu