Modified Elispot

Modifications of the Elispot Assay for T Cell Monitoring in Cancer Vaccine Trials Laboratory of Cell-Mediated Immunity, Clinical Services Program, SAIC-Frederick, Inc., National Cancer Institute at Frederick, Frederick, MD, USA Abstract The use of the IFN-y ELISPOT assay to evaluate cellular immune responses has gained increasing popularity, especially as a surrogate measure for CTL responses. We developed and validated some modifications of the IFN-y ELISPOT assay to optimize immunological...

Clinical Observations

These findings indicate that expanded populations of T cells reactive with a wide variety of tumor antigens are present in cancer patients. The failure of these T cells to control tumor cell growth may result from a variety of factors that include the expression of immunosuppressive factors by tumor cells, as well as the lack of appropriate inflammatory signals within the tumor environment. Approaches utilizing active tumor antigen immunization have to date met with only limited success, and...

Mechanisms Underlying The Lack Of Correlation Between Clinical And Immune Responses

To date, a large number of TA-specific immunotherapy trials have been conducted in patients with malignant disease. It is clear from these studies that the various types of tumor vaccines i) have limited or no toxicity and ii) are able to induce TA-specific immune responses and or augment already established TA-specific immune responses in immunized patients. Nevertheless, the results of these studies have highlighted two challenges facing tumor immunologists and clinical oncologists. The first...

Antigenic changes on malignant cells

Tumor cells can evade the host's immune response by being poor stimulators of T cells or being poor targets for effector CTL. Because of their genetic instability (24), malignant cells may change in the expression of molecules such as TA, HLA class I antigens as well as APM components, each of which plays a crucial role in the generation of the HLA class I antigen-TA peptide complex (20,21). The latter mediates the recognition of tumor cells by the host's CTL. Abnormalities in TA expression as...

Novel Method To Identify Tumorreactive T Cells Cd107 Mobilization

We developed a novel method to isolate pure, viable populations of tumor-cytolytic T cells directly ex vivo from patient blood samples using flow cytometric quantification of the surface mobilization of CD 107 - an integral membrane protein within cytolytic granules - as a marker for degranulation upon tumor stimulation (26). We showed that tumor-cytolytic T cells are indeed elicited in patients post-cancer vaccination, and that tumor-reactivity is strongly correlated with recognition...

Methodology Of Intracellular Cytokine Staining

There are a several methodological variations of the ICC assay described 2, 8-11 . T cells are typically stimulated with peptide epitopes for 6 to 18 hours. We usually stimulate cells with 10 g ml of the peptide and use an irrelevant peptide as negative control, e.g., HIV in HIV-seronegative subjects, binding to the corresponding HLA-A allele. PBMC stimulated with 1 g ml pokeweed mitogen can be used as positive control. After two hours a secretion inhibitor, mostly, brefeldin A Sigma,...