Monocyte enriched apheresis for preparation of dendritic cells (DC) to be used in cellular therapy.

We describe that with one leukapheresis procedure it is feasible to obtain sufficient numbers of monocytes to be utilized in dendritic cell therapies. Twenty-two leukaphereses were performed on eight healthy volunteers and 13 cancer patients, using Cobe Spectra. An on-line sample was drawn as soon as a stable interface was established. The concentration of monocytes in the sample was used to calculate the volume to be collected to reach target numbers of monocytes. A recovery unit was used to calculate the efficacy of the leukaphereses and we demonstrate an efficacy for monocytes correlating with the amount of processed blood.

Naturally occurring peptides associated with HLA-A2 in ovarian cancer cell lines identified by mass spectrometry are targets of HLA-A2-restricted cytotoxic T cells.

Identifying naturally occurring peptides bound to HLA class I molecules recognized by HLA-restricted cytotoxic T lymphocytes (CTL) is both relevant and central to the development of effective immunotherapeutic strategies against cancer. Several cancer-related genes have been reported for ovarian cancer, but very few are known to be naturally processed T cell epitopes. In the present study we used mass spectrometry to identify 16 novel HLA-A2-bound peptides from HLA-A2(+) ovarian cancer cell lines. All 16 peptides are derived from source proteins with diverse functions and marked homology to known proteins found in public databases. Synthetic peptide analogues of identified sequences were found to stabilize HLA-A2.1, albeit with varying affinities. The peptides were found to be antigenic in that a primary CD8(+) CTL response could be elicited from normal donor blood. The CTL generated were not only peptide specific, but failed to recognize targets pulsed with control peptides. In addition, recognition of shared HLA-A2-restricted epitopes by these CTL is suggested by their reactivity with a subset of HLA-A2(+) tumor lines and freshly isolated cancer cells or cell lines established from peritoneal ascites. These results were further corroborated by competitive inhibition of lysis of an otherwise susceptible cell line in the presence of cold peptide-pulsed targets. Furthermore, lack of recognition of several HLA-A2(+) control cell lines or cells isolated from normal ovaries suggests that these peptides are cancer related. These findings broaden the list of CTL-defined antigens that could lead to the development of multi-epitope vaccines for the treatment of ovarian cancer.

A short-term dietary supplementation of high doses of vitamin E increases T helper 1 cytokine production in patients with advanced colorectal cancer.

PURPOSE: Patients with advanced cancer exhibit multifaceted defects in their immune capacity, which are likely to contribute to an increased susceptibility to infections and disease progression and to constitute a barrier to immunotherapeutic interventions. A chronic inflammatory condition associated with increased oxidative stress has been suggested as one of the responsible mechanisms behind the tumor-induced immune suppression. We, therefore, speculated that supplementation with the antioxidant vitamin E could enhance the immune functions in patients with advanced cancer. EXPERIMENTAL DESIGN: This hypothesis was here tested in twelve patients with colorectal cancer (Dukes' C and D) who, prior to intervention with chemo- or radiotherapy, received a daily dose of 750 mg of vitamin E during a period of 2 weeks. RESULTS: Short-term supplementation with high doses of dietary vitamin E leads to increased CD4:CD8 ratios and to enhanced capacity by their T cells to produce the T helper 1 cytokines interleukin 2 and IFN-gamma. In 10 of 12 patients, an increase of 10% or more (average, 22%) in the number of T cells producing interleukin 2 was seen after 2 weeks of vitamin E supplementation, as compared with peripheral blood monocyte samples taken before treatment (P = 0.02). Interestingly, there seemed to be a more pronounced stimulatory effect by vitamin E on naïve (CD45RA(+)) T helper cells as compared with T cells with a memory/activated phenotype. CONCLUSIONS: Dietary vitamin E may be used to improve the immune functions in patients with advanced cancer, as a supplement to more specific immune interventions.

Immunization with heat shock protein 70 from methylcholanthrene-induced sarcomas induces tumor protection correlating with in vitro T cell responses.

The cytosolic members of the heat shock protein 70 (hsp70) family have in recent years been shown to elicit protective immunity mediated via binding to antigenic peptides in tumor and viral animal models. In this study we have used the methylcholanthrene (MC)-induced sarcomas MC57S and MC57X, previously shown to express individually distinct MHC-I associated peptides recognized by tumor necrosis factor-alpha (TNF-alpha) producing CD8(+) T cells. With hsp70 purified from tumor or liver tissue, we were able to confirm that tumor-derived hsp70 elicited in vivo protection against a challenge with the same tumor as that used for hsp70 isolation. We also observed that immunizing with hsp70 isolated from tumor tissue resulted in a significantly better protection than immunizing with hsp70 isolated from the liver tissue of healthy mice. In two out of three experiments however, immunization with liver-derived hsp70 as well as tumor-derived hsp70 resulted in a significantly delayed tumor outgrowth as compared to saline-injected controls. In vitro, T cell lines from mice immunized with tumor-derived hsp70 could recognize tumor cells from the same MC57 tumor as that used for the hsp70 purification, resulting in TNF-alpha production. In sera from hsp70-immunized mice we observed undetectable or only very low levels of anti-hsp70 antibodies, suggesting that it is possible to repeatedly immunize the mice with no significant interference from neutralizing antibodies. We therefore conclude that hsp70 immunization can lead to protection against the tumor it was purified from, with a low risk of eliciting neutralizing antibodies that could affect further immunizations.