The predominant gangliosides produced by two cultured human melanoma cell lines are GD3 and/or GD2. These gangliosides were found to be cell associated and present in substratum-attached material after cell removal by EDTA. Monoclonal antibodies directed to GD2 and GD3 specified the cell-surface distribution of these gangliosides and localized them in focal adhesion plaques at the interface of cells and their substratum. These attachment sites did not represent indiscriminant membrane fragments remaining after removal of cells with EDTA, because neither melanoma-associated proteoglycan nor class I histocompatibility antigens were detected by their respective antibodies. Our data suggest that the disialogangliosides GD2 and GD3 may be involved in the interaction between human melanoma cells and solid substrata.The development of murine monoclonal antibodies (mAbs) that react specifically with antigens on human tumor cells has led to a more complete understanding of the topography and molecular profile of these tumor cell-surface markers. Such antibodies have also aided in defining functional properties of various tumor-associated glycoproteins (1-3), proteoglycans (4, 5), as well as glycolipids (6)(7)(8)(9).Recent technological advances have facilitated the characterization of mAbs directed to the carbohydrate moieties of tumor-associated gangliosides (6-9). In this regard, mAbs that react with such molecules associated with neuroblastoma (10), melanoma (7, 9), as well as carcinoma of the colon (8) have been described. The use of mAbs specifically directed to gangliosides may help to strengthen and extend observations that implicated these molecules as putative cellular receptors for hormones (11) and toxins (12) as well as to gain further evidence for their possible role in cell-substratum interactions (13,14).Previous studies have demonstrated that the gangliosides GD3* (7) and GD2 (16) are highly enriched in tumors of neuroectodermal origin. Specifically, two murine mAbs produced against cultured melanoma cells were reported to react with GD3 (7, 17), and a recently described human mAb was shown to react with GD2 (16). In the present study, we demonstrate that GD2 and/or GD3 are major gangliosides produced by two human melanoma cell lines and that these molecules are deposited in the substratum-attached material of these tumor cells. We show that two murine mAbs (126 and MB3.6) produced in our laboratory react with GD2 and GD3, respectively. Using these mAbs, we were able to define the topographical distribution of GD2 and GD3 on the human melanoma cell surface and to localize these gangliosides in focal-adhesion plaques, thus further implicating gangliosides as important molecules in cell-substratum interactions.

We conclude that after conventional-dose VIP chemotherapy, a shortened treatment course of IL-3 (5 days) sequentially followed by GM-CSF (10 days) combines the benefits of prolonged single GM-CSF treatment on WBC count recovery in all patients and an accelerated platelet recovery only in some intensively pretreated patients.

In a prospective randomized multicentric trial, 61 patients from six hospitals with resectable pancreatic cancer were recruited between 1987 and 1989. All patients underwent a Whipple resection. Two weeks after surgery, the patients were randomized to be given either intravenous (IV) treatment with 370 mg (100 mg loading dose, 9 × 30 mg continuing within 10 days) of monoclonal antibody (MoAb) 494/32 (Behringwerke AG, Marsburg, Germany) or no additional anti‐cancer treatment. This murine immunoglobulin (Ig) G1 antibody has been shown to strongly bind to human pancreatic cancer cells and to induce an antibody‐dependent cellular cytotoxicity (ADCC). Both study groups were well matched with respect to age, sex, tumor staging, and grading. Six patients suffered from minor toxicity (vomiting and abdominal pain) after immunotherapy. Ten months after the end of the recruitment period, 65% and 53% of the patients in the treatment and control groups, respectively, had died. Of the living patients, 60% and 53% are alive with recurrent or progressive cancer disease. Median survival time was 428 days (range, 248 to 510 days) and 386 days (range, 296 to 509 days) in the treatment and control groups, respectively. The authors concluded that repeated IV treatment with the antibody 494/32 is not helpful in resectable pancreatic cancer. This study provides the first controlled data on passive immunotherapy in solid cancer.

We report on the chemotherapy plus granulocyte colony-stimulating factor (G-CSF) induced mobilization of peripheral blood progenitor cells (PBPCs) and their impact on haematopoietic recovery following high-dose chemotherapy. Twenty-four patients with advanced solid tumours or lymphomas received standard-dose chemotherapy with VP16, ifosfamide and cisplatin (VIP) followed by filgrastim (G-CSF; 5 micrograms/kg s.c. daily for 14 d) for the prevention of chemotherapy induced neutropenia and for the simultaneous mobilization of PBPCs. Maximal numbers of progenitors of different lineages were reached at day 11 (range 9-14) after VIP chemotherapy. A median of 0.415 x 10(9)/l CD34+ cells (range 0.11-1.98), 9000 CFU-GM/ml (range 2800-17,700), 3500 BFU-E/ml (range 400-10,800) and 200 CFU-GEMM/ml (range 0-4400) were recruited. One single apheresis yielded a median of 1.6 x 10(8) mononuclear cells/kg (range 0.2-5.4) or 5.4 x 10(6) CD34+ cells/kg body weight (range 0.2-24.2). Fourteen patients who showed at least a partial remission after two cycles of the standard-dose chemotherapy regimen were subjected to high-dose VIP chemotherapy (cumulative doses of 1500 mg/m2 VP16, 12 g/m2 ifosfamide and 150 mg/m2 cisplatin) with or without PBPC support. The first six patients were treated with growth factors only (IL-3/GM-CSF) and did not receive PBPCs, whereas the following eight patients were supported with PBPCs in addition to IL-3 and GM-CSF. Neutrophil recovery as well as platelet recovery were significantly faster in patients receiving PBPCs with a median of 6.5 d below 0.1 x 10(9) neutrophils/l and 3 d below 20 x 10(9) platelets/l as compared to 10.5 d and 8 d in control patients receiving growth factors only. The accelerated platelet recovery in patients supported with PBPCs might be explained--in the absence of detectable colony-forming units megakaryocyte--by the presence of glycoprotein IIb/IIIa+, non-proliferating endomitotic megakaryocytic precursor cells within G-CSF mobilized PBPCs. Our data demonstrate that chemotherapy plus G-CSF mobilized PBPCs accelerate both neutrophil and platelet recovery after high-dose VIP chemotherapy in patients with solid tumours or lymphomas.

The in vivo effect of yeast-derived recombinant human granulocyte-macrophage colony-stimulating factor (rh GM-CSF) was investigated in 30 patients with advanced malignancy in a phase Ib trial. Patients were treated at four different dose levels (120 to 1,000 micrograms/m2/d) by either daily intravenous (IV) bolus injection or 24-hour continuous infusion. Administration of rh GM-CSF resulted in a broad spectrum of dose- and schedule-dependent hematopoietic effects. Sustained infusion of rh GM-CSF elicited a maximum 17-fold average peak increase of the total WBC count with mainly neutrophils, eosinophils, and monocytes accounting for this rise, and increases in bone marrow cellularity with a shift to immature myeloid elements. Elevation of lymphocytes, platelets, and reticulocytes was not induced. Within five days after discontinuation of treatment the leukocytosis had disappeared. Adverse reactions encountered with rh GM-CSF seen in 65% of the patients studied were never life-threatening and always rapidly reversible. They included mild myalgias, facial flushing, low-grade fever, headache, bone discomfort, nausea, dyspnea, and transient decline of platelet counts. These results suggest that rh GM-CSF can be safely administered at the doses and schedules used and that it can induce in vivo some of the biological effects reported in in vitro studies. Although no objective antitumour responses have been seen, the ability of rh GM-CSF to increase number and function of leukocytes in vivo may prevent neutropenia and infections when GM-CSF is added to cytotoxic cancer therapy.