Combination of C. parvum and specific immunization against artificial pulmonary metastases in mice

Preclinical Rationale and Clinical Considerations for Radiotherapy Plus Immunotherapy: Going Beyond Local Control

The use of radiation for cancer therapy has expanded and sparked interest in possible synergistic effects by combining it with current immunotherapies. In this review, we present a case of a patient who responded to programmed cell death 1 (PD1) blockade and radiation therapy and discuss possible mechanisms. We provide background on the blockade of the cytotoxic T-lymphocyte antigen 4 (CTLA-4) and PD1 checkpoints and highlight future immune-based therapies that may synergize with radiation, including cytosine-phosphate-guanine vaccines, OX40 agonists, CD40 agonists, regulatory T-cell depletion, and metabolic "rewiring" of cancer cells. Clinical considerations are noted for combining radiation with immunotherapies to extend the benefit of immunotherapy to more patients. New trials are needed to appropriately investigate the best sequencing and radiation dose to prime an immune response and to identify predictive biomarkers of such responses.

Proportion of infiltrating IgG-binding immune cells predict for tumour hypoxia

Macrophages can account for up to 50% of tumour mass and secrete many angiogenic factors. Furthermore, tumour hypoxia is thought to play a major role in the activation of macrophages and the regulation of angiogenesis. In this paper, we demonstrate a strong correlation between hypoxia and the recruitment of immune cells binding to IgG in 8 experimental tumours. We provide evidence that IgG binding immune cells in 3 tumour lines are predominately composed of macrophages. Reduced oxygenation may act as a stimulus for recruitment of immune cells to the tumour mass, and the detection of either IgG-positive host cells or macrophages may offer an alternative method for monitoring tumour hypoxia.

Enhancement of lung colony formation by admixing irradiated with viable tumor cells: dependence on host status

The study was designed to determine whether whole-body irradiation or stimulation of the reticuloendothelial system of mice influences the ability of heavily irradiated tumor cells to enhance formation of artificial metastases when given simultaneously with viable tumor cells. Experiments were performed with a nonimmunogenic sarcoma syngeneic to C3Hf/Kam mice. Whole-body irradiation augmented and stimulation of the reticuloendothelial system abolished the metastasis-enhancing effect of tumor cells. Another observation was that heavily irradiated tumor cells can enhance formation of metastases if given i.v. within several hours before or after i.v. injection of tumor cells.

Increase in radiosensitivity of lung micrometastases by hyperbaric oxygen

Four-day-old artificial pulmonary micrometastases of two murine fibrosarcomas, designated FSA and NFSA, showed increased sensitivity to ionizing radiation by a factor of 1.13 when animals were exposed to hyperbaric oxygen breathing before and during irradiation, implying the presence of hypoxia in the micrometastases. At the time of irradiation the diameter of FSA and NFSA metastases was smaller than 200 and 100 microns, respectively, which, on the basis of oxygen diffusion, could not be responsible for hypoxia. It is assumed that hypoxia of micrometastases is passive, reflecting the radiobiological hypoxia of lung tissue that could exist under normal breathing conditions.

Local immunotherapy of stomach and intestinal carcinoma by Propionibacterium granulosum

The effect of cell suspension of Propionibacterium granulosum strain KP-45 injected intratumorally was estimated in patients with advanced malignant neoplastic disease of the upper and lower part of the digestive tract. These patients received no other anticancer treatment, and results of therapy with P. granulosum were compared with a control group of nontreated patients. In the course of immunotherapy, general clinical state, dynamics of tumor growth as judged by endoscopy and morphologic, biochemical and immunologic parameters of the peripheral blood, were evaluated. Treatment with KP-45 preparation usually resulted in partial regression of tumor growth, accompanied by improvement of the clinical state of these patients, as well as reappearance of normal values of blood picture and biochemical parameters. Enhancement of cellular immune response, evaluated by increased number of peripheral blood T lymphocytes and increased skin reactivity to PHA and PPD, was observed. No serious side effects or complications of local immunotherapy were noted. No patients who had immunotherapy suffered from bacterial infection; this was not the case in the control group.

Activation of pleural macrophages by intrapleural application of Corynebacterium parvum

A single ipl injection of 0.25 mg CP into CBA mice led to accumulation of macrophages in the pleural cavity, but it did not influence RES as an injection given iv ipl CP caused a three-to-five-fold increase in the number of nucleated cells in the pleural cavity which persisted at least 14 days. Of these cells 86% were macrophages as shown by their esterase activity. Less than 30% of cells from the pleural cavity of normal mice were esterase positive. Macrophages from the pleural cavity of CP-treated mice were capable of destroying in vitro cultures of a syngeneic mammary carcinoma, while normal pleural macrophages exerted no effect; the former were not cytotoxic for either syngeneic or allogeneic embryo fibroblasts. Ipl CP protected mice against iv injected mammary carcinoma cells; given to mice 7 days after iv inoculation of tumor cells it significantly reduced the number of tumor nodules in their lungs.

Active specific immunotherapy of murine leukemia. I. Irradiated tumor cell vaccine

This report describes a new animal model for active, specific, systemic immunotherapy of leukemia. Mice were challenged (day 0) with 10(3) viable LSTRA cells and treated later with a vaccine containing 10(7) irradiated LSTRA cells. Four intraperitoneal or intravenous vaccine injections, on days 2, 9, 16 and 23, caused significant prolongation of survival; single injections by the same routes had inconsistent effects. Vaccine was not effective against a higher initial challenge dose, when given later in the course of tumor growth, when given intradermally or when used in weanling mice. The therapeutic effect was specific since a vaccine composed of an antigenically unrelated leukemia was ineffective. These results suggest that LSTRA is suitable for studying active, systemic, specific immunotherapy.