Aim: The objective of this study was compare the in vivo distribution of different preparations of dendritic cells (DC) from a single donor after intradermal (ID) administration and correlate FACS analysis of excised tissue and imaging findings.

The primary goal of cancer vaccines is to induce CD8+ T cells specific for tumor-associated antigens (TAA) but the characterization of these cells has been difficult because of the low sensitivity of ex vivo assays. Here, we focused on TAA-specific CD8+ T-cell responses in melanoma patients after vaccination with autologous dendritic cells loaded with lysates derived from allogeneic tumor-cell lines (Lysate-DC). Out of 40 patients treated, 16 patients developed immune response to tumor-cell lysate and/or CD8+ T cells specific for differentiation and cancer-testis antigens. TAA-specific CD8+ T-cell responses were detected by interferon (IFN)-γ enzyme-linked immunospot after in vitro sensitization and were, either transient during the treatment period or delayed, that is, observed after completion of all vaccinations. We could not correlate these immune responses to clinical data as none of the patients achieved an overall objective response according to Response Evaluation Criteria in Solid Tumors criteria. Three patients were reported as stable disease and 10 patients presented evidence of antitumor activity. We found that TAA-specific T cells characterized in 4 patients produced perforin ex vivo, but no IFN-γ in enzyme-linked immunospot. Differential expression of IFN-γ and perforin was also observed for viral-specific T cells. Altogether, our results show that Lysate-DC therapy elicited tumor-specific CD8+ T cells nonlimited to human leukocyte antigen-A2+ patients, with some T cells secreting perforin ex vivo and IFN-γ only after restimulation. The differential expression of perforin and IFN-γ by antitumor and antiviral CD8+ T cells supports that the sole use of IFN-γ production to monitor T cells overlooks functional T-cell subpopulations triggered by vaccines.

Radio-labelling of blood cells is an established technique for evaluating in vivo migration of normal cells to sites of pathology such as infection and haemorrhage. A limitation of cellular immunotherapies to induce anti-tumour responses is in part due to the uncertain ability of cellular effectors to reach their intended target. We extended the approach of cell radiolabelling to accurately examine the in vivo distribution of cellular immunotherapy with ex-vivo macrophage activated killer (MAK) cells. We describe the use of two methods of cell labelling for tracking the destination of autologous-derived macrophage activated killer (MAK®) cells linked to the bi-specific antibody MDX-H210 delivered either by intravenous (i.v.) or intraperitoneal (i.p.) injection in ten patients with peritoneal relapse of epithelial ovarian carcinoma. Our results demonstrate the feasibility of generating high numbers and purity of GMP quality MAK cells, which can be radiolabelled with 18F-FDG or 111In-oxime. MAK cell administration produced minimal infusional toxicity and demonstrated a reproducible pattern of in vivo distribution and active in vivo tracking to sites of known tumour following 8 of 16 i.v. infusions or 4 of 6 i.p. infusions. However, the leakage of 18F-FDG limited the ability to confidently confirm the tracking of MAK cells to tumour in all cases and improved PET labels are required. The addition of MDX-H210 bispecific antibody did not alter the distribution of cells to tumour sites, but did accelerate the clearance of i.v. administered MAK cells from the pulmonary circulation. This data demonstrates that cellular cancer immunotherapies may be successfully delivered to the sites of active tumour following either i.v. or i.p. injection in a proportion of patients with metastatic cancer. Incorporation of tracking studies in early cycles of cellular immunotherapy may allow selection of patients who demonstrate successful targeting of the immunotherapy for ongoing treatment.

The aim of the present phase I/II study was to evaluate the safety, immune responses and clinical activity of a vaccine based on autologous dendritic cells (DC) loaded with an allogeneic tumor cell lysate in advanced melanoma patients. DC derived from monocytes were generated in serum-free medium containing GM-CSF and IL-13 according to Good Manufacturing Practices. Fifteen patients with metastatic melanoma (stage III or IV) received four subcutaneous, intradermal, and intranodal vaccinations of both DC loaded with tumor cell lysate and DC loaded with hepatitis B surface protein (HBs) and/or tetanus toxoid (TT). No grade 3 or 4 adverse events related to the vaccination were observed. Enhanced immunity to the allogeneic tumor cell lysate and to TAA-derived peptides were documented, as well as immune responses to HBs/TT antigens. Four out of nine patients who received the full treatment survived for more than 20 months. Two patients showed signs of clinical response and received 3 additional doses of vaccine: one patient showed regression of in-transit metastases leading to complete remission. Eighteen months later, the patient was still free of disease. The second patient experienced stabilization of lung metastases for approximately 10 months. Overall, our results show that vaccination with DC loaded with an allogeneic melanoma cell lysate was feasible in large-scale and well-tolerated in this group of advanced melanoma patients. Immune responses to tumor-related antigens documented in some treated patients support further investigations to optimize the vaccine formulation.

Dendritic cell (DC) immunotherapy is being actively studied in multiple myeloma (MM). We aimed to use positron emission tomography or single positron emission tomography to determine the in vivo distribution of monocyte-derived nonmatured DC or matured DC (mDC) administered to patients with MM. Eligible patients had stable or slowly progressive MM and elevated serum MUC-1 or MUC-1 expression on marrow plasma cells. DCs were derived from granulocyte-macrophage colony-stimulating factor+ interleukin-13 stimulated autologous monocytes, pulsed with mannan-MUC1 fusion protein, and matured by FMKp and interferon-gamma. Before injection, DCs were labeled with either 18fluorine-fluorodeoxyglucose, 111indium-oxine or 64copper-pyruvaldehyde-bis-N-4-methylthiosemicarbazone. Labeled DCs were given either as a single intravenous dose or by concurrent subcutaneous (SC), intradermal (ID), and intranodal routes. 18Fluorine-fluorodeoxyglucose tracking was unsuccessful owing to high radiolabel efflux. 64Copper-pyruvaldehyde-bis-N-4-methylthiosemicarbazone-labeled mDC (n=2 patients) demonstrated tracking to regional nodes but quantitation was also limited owing to cellular efflux. 111Indium-oxine, however, gave reproducible tracking of both nmDc and mDC (n=6) to regional lymph node after either SC or ID administration, with mDC revealing superior migration to regional lymph node. SC and ID routes produced similar levels of DC migration.

Introduction, - Adoptive immunotherapy was first introduced in the 1980s. This new anticancer therapeutic approach has already demonstrated promising results in both animal models and humans affected by various tumors.Current knowledge and key points. - This review summarizes the requirements of such therapies involving either activated lymphocytes, tumor-infiltrating lymphocytes or activated macrophages. It focuses more particularly on the promising approaches that represent antigen presenting cells such as macrophages and antigen-loaded dendritic cells in the development of safe and effective cancer vaccines.Future prospects and projects. - Standardized procedures for macrophages and dendritic cell generation, as well as preliminary results of clinical applications in patients with either prostate cancer or melanoma, are also discussed. (C) 2000 Editions Scientifiques et Medicales Elsevier SAS, Paris.

Apres plus de 15 annees de travaux experimentaux, l'immunociblage des tumeurs par des anticorps monoclonaux diriges contre des marqueurs tumoraux connait actuellement un developpement clinique important. Cette progression est due pour beaucoup aux resultats therapeutiques encourageants obtenus par l'injection d'anticorps recombinants en grande partie humanises, tels que le rituximab, anti-CD20, dans les lymphomes B folliculaires et l'herceptine, anti-ErbB2, dans les carcinomes du sein. Grâce a l'ingenierie genetique, il est en effet possible de greffer les regions variables ou hypervariables des anticorps murins sur des molecules d'IgG humaines, ou meme d'obtenir des anticorps entierement humains, soit chez des souris transgeniques pour une grande partie du repertoire des IgG humaines, soit par selection de domaines variables humains exprimes sur des phages. Le marquage des anticorps antitumeurs par des radio-isotopes a joue un role important dans la demonstration de la specificite de l'immunociblage tumoral et reste interessant pour le diagnostic par immunoscintigraphie, ainsi que pour la radio-immunotherapie de certains cancers. Dans cette revue, nous decrirons les progres realises et les perspectives d'utilisations diagnostiques et therapeutiques des anticorps antitumeurs et de leurs fragments. Au niveau diagnostique, l'immunoscintigraphie par les fragments Fab marques a l'iode 123 ou au technetium 99m a fourni des images tumorales tres elegantes depuis plusieurs annees, mais l'influence de cette technique sur la conduite du traitement reste limitee. L'immuno-TEP (tomographie par emission de positons) pourrait ameliorer la sensibilite et la precision de cette methode. La chirurgie radio-immunoguidee et l'immunophotodetection restent des methodes prometteuses encore a l'etude. Au niveau therapeutique, les anticorps anti-CD20 marques a l'iode 131 ont donne des resultats spectaculaires dans les lymphomes B non hodgkiniens de differents degres de malignite. Pour les tumeurs solides, moins radiosensibles, les chances d'efficacite de la radio-immunotherapie passent par l'attaque plus precoce de tumeurs de tres petite taille, par l'utilisation de strategies de ciblage en plusieurs etapes et par l'utilisation de radio-isotopes emetteurs de particules alpha. D'autres utilisations d'anticorps sont decrites comme celles des anticorps bispecifiques antitumeurs et anticellules effectrices du systeme immunitaire, ou la synthese de fragments d'anticorps exprimes sur les recepteurs de lymphocytes T appeles T bodies, ou encore l'etude biologique des intrabodies. Les resultats publies et les nombreuses etudes en cours montrent que l'immunociblage des tumeurs prendra une place toujours plus importante dans le traitement des maladies cancereuses.