New anti-cancer vaccine development to be presented at iSBTC meeting

(Milwaukee)-Vladia Monsurrò, PhD will present "Effectiveness of Anti-cancer Vaccines Limited by Low T cell Activity" at the 18th Annual Meeting of the International Society for Biological Therapy of Cancer (iSBTc) being held October 30-November 2, 2003 in Bethesda, Maryland. This presentation is based on an abstract "Quiescent Phenotype of Tumor-Specific CD8+ T Cells Following Immunization by Vladia Monsurro1, Ena Wang1, Yoshisha Yamano2, Stephen Migueles3, Monica Panelli1, Kina Smith1, Dirk Nagorsen1, Mark Connors3, Steven Jacobson2, Francesco Marincola1. 1Immunogenetic Section of the Department of Transfusion Medicine, CC/NIH, Bethesda, MD; 2Viral Immunology Section, Neuroimmunology Branch, NINDS/NIH, Bethesda, MD; 3The Laboratory of Immunoregulation, NIAID/NIH, Betehsda, MD." Traditional anti-cancer treatments kill normal-healthy cells as well as tumor cells. The research in this abstract will demonstrate the development of vaccination-induced T cells which will recognize and kill cancer cells without killing normal-healthy cells in patients with cancer. "The gene activated vaccination-induced T cells are special because they can specifically recognize and kill cancer cells and not kill other cells in the human body. This could be a very promising advance for anti-cancer vaccines as cancer therapy." said Dr. Monsurrò, who works in a lab directed by Francesco M. Marincola, MD at the National Institutes of Health. Monsurrò and her co-workers began their research by addressing the ongoing issue of why anti-cancer vaccinations have not yet achieved full efficacy. They studied the activation of genes in vaccination-induced T cells identifiable in blood. Their research found that current vaccination-induced T cells could recognize cancer cells, but did not have the expected properties of normal T cells to kill cells as well. Normally, T cells have the ability to recognize and kill cells. An unexpected result, before completion of this project, was that the generation of T cells after vaccination is not sufficient to destroy cancer deposits. Monsurrò and co-workers pursued this problem by researching studies done on the activation of genes in vaccination-induced T cells identifiable in blood. Monsurrò and her team found that vaccination induced T cells appear to have a "memory" feature that recognizes cancer cells. These vaccination induced T cells are inactive or remain still, thus are not efficient to kill a tumor on their own. Monsurrò et all discovered that if they exposed the vaccination induced T cells to antigens present on the cancer cells along with immune-stimulating substances such as interleukin-2, the vaccination induced T cells would use their "memory" feature to reactivate and thus recognize and kill cancer cells without killing normal-healthy cells. Monsurrò and co-workers conclude the abstract with a note of importance-anti-cancer immunization is a very important first step that leads to generation of cancer-specific T cells, an important and natural reagent against cancer, but regulating the timing and quantity of administration of immune stimulating substances is critical to activate vaccination induced T cells at the tumor site and exploit their full potential. The results of this exciting research present the opportunity for new schemes of vaccination to be devised and produce further advances in anti-cancer vaccines

Immunotracking of specific cancer vaccine CD8 lymphocytes

not abstract availabl

Characterization of CD8(-) HLA class I/epitope tetrameric complexes binding T cells

Antigen-specific CD8-expressing T cells play a crucial role in the host's defense against viral disease and malignancy. Epitope-specific CD8(+)T cell responses to malignant and viral disease can be accurately measured using tetramers (tHLA) of HLA class I molecules loaded with antigenic peptides. In addition, tHLA have been used to evaluate immune responses to antigen-specific immunization. tHLA bind specifically to complementary T-cell receptor (TCR) structures on the surface of T cells expressing the CD8 coreceptor. Surprisingly, however, CD8(-) cells binding tHLA are often observed. This study uses four-color flow cytometry to show that HLA-A*0201-tHLA-stained CD8(-) cells can be divided into two subsets: 87% represent B-lymphocytes (CD19(+), CD45RA(+), HLA-DR(+), and CD20(+)), and 13% represent T-helper cells (CD3(+), CD4(+), CD45RA(+), and CD27(+)). This phenomenon is not HLA-restricted because it could be observed even in peripheral blood mononuclear cells (PBMC) from a non HLA-A*0201-expressing healthy donor. In addition, no T-cell receptor was detected on the B-lymphocytes. Retrospective enumeration of vaccine-induced CD8(-) tHLA cells in 243 PBMC samples from 36 patients with melanoma undergoing peptide vaccination revealed that tHLA staining is not dependent on immunization status or the presence of CD8(+) tHLA(+) T cells. These findings, suggest that the nonspecific binding of tHLA to non-TCR-expressing T cells requires a careful interpretation of results and further steps in preparation of sample for tHLA-based sorting of epitope specific T cells

Lack of correlation between Flu/HLA-A*0201 or A*0205 tetrameric complexes staining and immunogenicity of Flu-M1 (58-66) in HLA-A*0201 and A*0205 bearing individuals

Lack of correlation between Flu/HLA-A*0201 or A*0205 tetrameric complexes staining and immunogenicity of Flu-M1 (58-66) in HLA-A*0201 and A*0205 bearing individual

Immune performance profile in pancreatic adenocarcinoma patients.

Cancer patients immuneprofile can discriminate subgroups of patients with a different fit of the immunesystem either functionally or phenotypically

IFN-γ induced by PHA stimulation as new marker for GVHD prediction in patients undergoing Allogeneic Hematopoietic Stem Cell Transplantation

Background: IFN-γ is crucial in the pathogenesis of GVHD and higher levels are reported to be elevated in patients with active chronic GVHD. Immune-monitoring of INF-levels after alloHSCT could help in the management of GVHD. A recent ELISA based test (QuantiFERON®-CMV) could measure specific (anti-CMV) and aspecific production of IFN-γ in whole blood. Preliminary data suggests that aspecific production of IFN-γ should be associated with GVHD. The aim of this study is to confirm the reliability of QuantiFERON®-CMV for association and prediction of GVHD. Methods: the study was performed in 2 phases. In the fisrt phase of the study, 92 whole blood specimen were collected and analyzed from 29 patients undergoing alloHSCT in order to confirm the preliminary data. QuantiFERON® CMV is an in vitro diagnostic test that use an antigenic human cytomegalovirus proteins (CMV) peptide cocktail to stimulate cells from whole blood. Detection of interferon-γ (IFN-γ) by ELISA is used to identify responses to these peptide antigens. The IFN-γ response in the CMV Ag tube is considered positive if > 0.2 UI/mL as defined by the manufacturer. The Mitogen-stimulated (PHA) plasma sample is used as an IFN-γ positive control for each specimen tested. In order to assess the association between IFN-γ response due to PHA stimulation and GVHD, the positivity of the test was determined according to 2 different cut-off: #1) 0,5 IU/mL as defined by manufacturer, #2) 9 IU/mL as experimentally defined by the median of the observations in our data set. GVHD extension was defined by Seattle criteria and/or the number of involved sites, Chi-square test was used to assess the statistical correlation between IFN-γ production and clinical outcomes. In the second phase 10 patients were observed prospectively with collection of blood samples every 2-3 weeks since engraftment until 4-6 months after SCT in order to study the PHA stimulated IFN-γ production in relationship with the onset of chronic GVHD. Results: among 92 samples 70 were positive for the PHA stimulated IFN-γ production according to the cut-off #1; 61% (43/70) were associated with GVHD whereas 27% (6/22) with lower PHA stimulated IFN-γ production were associated with GVHD: this difference was proved to be significant (p=0.005). Among 92 samples 46 were positive for the PHA stimulated IFN-γ production according to the cut-off #2; 71% (33/46) were associated with GVHD whereas 34% (16/46) with lower PHA stimulated IFN-γ production were associated with GVHD: this difference was proved to be significant (p=0.000). Among the 10 patients observed prospectively during the first 6 months after alloHSCT 7 became positive for the PHA stimulated IFN-γ production: 6/7 developed GVHD in a median time of 100 days according to the cutoff #1 and after a median time of 33 days according the cutoff#2. Four patients received steroid treatment for extensive chronic GVHD and their PHA stimulated IFN-γ production dropped after treatment (figure 1). Conclusions: The PHA stimulated IFN-γ production is strictly associated to GVHD, seems to predict its onset and could help in the modulation of immunesuppressive treatment. However, larger prospective studies are needed

MicroRNAs linking inflamm-aging, cellular senescence and cancer

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Immunoglobulin-like transcript 2 (ILT2) is a biomarker of therapeutic response to oncolytic immunotherapy with vaccinia viruses

Background: Oncolytic viruses represent a novel form of cancer immunotherapy. Vaccinia viruses encoding humanT cell co-stimulatory molecules have demonstrated clinical activity in phase I clinical trials in patients with advancedmelanoma. However, predictive biomarkers of therapeutic response have not yet been identified.Methods: A customized microarray was performed to identify changes in peripheral blood mononuclear cell(PBMC) gene expression upon exposure to recombinant oncolytic vaccinia viruses. Up-regulated and downregulatedgenes were identified and selected for further analysis using PBMC samples from normal donors andoncolytic virus-treated patients before and after viral injection. Quantitative PCR and flow cytometry of defined T cellsubsets was performed to evaluate expression patterns and clinical correlations.Results: The microarray identified 301 genes that were up-regulated and 960 genes that were down-regulated in Tcells after exposure to oncolytic vaccinia virus. The B7.1 gene was highly up-regulated and the immunoglobulin-liketranscript 2 (ILT2) gene was highly down-regulated by vaccinia-B7.1, which was consistent with the known inverseregulation of these two genes. We observed an inverse association between ILT2 expression in the tumor microenvironmentand clinical response and further identified ILT2 as a marker of regulatory CD4+ and suppressor CD8+T cell responses and whose down-regulation was predictive of therapeutic responses in patients treated with oncolyticvirus immunotherapy.Conclusions: ILT2 is a new putative biomarker of T cell and clinical response in patients treated with oncolyticvaccinia virus immunotherapy. Further confirmation of ILT2 as a biomarker requires prospective validation in alarger series of clinical trials

Antitumor vaccines, immunotherapy and the immunological constant of rejection

Anticancer vaccines have not matched the clinical expectations projected from their ability to induce consistently systemic anticancer T-cell responses. Thus, a dichotomy is observed between the immunological and clinical endpoints of anticancer immunization. Anticancer vaccines have clearly demonstrated that highly specific T-cell responses can be induced that can recognize autologous cancer antigens in patients with cancer. This ability is an outstanding achievement of modern biotechnology, yielding one of the most specific types of potential anticancer reagents. However, systemic, vaccine-induced anticancer responses exemplify a broader immunological paradox: cytotoxic T-cells can coexist within the same organism with their target cells not only in the context of cancer, but also in the context of chronic infections, well-controlled allo-transplant reactions and autoimmunity. According to this view, anticancer immune responses are a facet of a tissue-specific autoimmune phenomenon specific for cancer tissue that may or may not result in the successful immune-destruction of target cells, depending on an assortment of genetic factors related to the background of the host or evolving phenotypes of a heterogeneous cancer environment. This feature article summarizes the current understanding of the mechanisms leading to tumor rejection in humans as well as in experimental models, in the context of the broader immunological phenomenon leading to tissue-specific destruction. Anticancer vaccines that may not induce clinically significant anticancer responses independently could function as a unique tool to enhance the specificity of the response of the host against cancer, provided that strategies are implemented to amplify the immune reaction initiated by vaccine-induced antibodies and/or T-cell