Autologous tumour-specific cytotoxic T-cell clone established from tumour-infiltrating lymphocytes (TIL) of malignant ascites in the absence of recombinant interleukin 2(rIL2): activation by autologous tumour cell alone

Spontaneous regression of neoplasms: new possibilities for immunotherapy

In mammalian cells, neoplastic transformation is directly associated with the expression of oncogenes, loss or simple inactivation of the function of tumour suppressor genes and the production of certain growth factors. Genes for suppression of the development of the neoplastic cellular immunophenotype, as well as inhibitory growth factors, have regulatory functions within the normal processes of cell division and differentiation. Telomerase (a ribonucleoprotein polymerase) activation is frequently detected in various neoplasms. Telomerase activation is regarded as essential for cell immortalisation and its inhibition may result in spontaneous regression of neoplasms. This phenomenon of neoplasms occurs when the malignant tissue mass partially or completely disappears without any treatment or as a result of a therapy considered inadequate to influence systemic neoplastic growth. This definition makes it clear that the term 'spontaneous regression' applies to neoplasms in which the overall malignant disease is not necessarily cured and to cases where the regression may not be complete or permanent. A number of possible mechanisms of spontaneous regression are reviewed, with the understanding that no single mechanism can completely account for this phenomenon. The application of the newest immunological, molecular biological and genetic insights for more individualised and adequate antineoplastic immunotherapy (alternative biotherapy) is also discussed.

Cytotoxic T lymphocyte mediated recognition of human pancreatic cancer cells

T lymphocytes play an important role in tumor rejection and their response to human malignant melanoma has been well documented. In contrast, the existence of cytotoxic T lymphocytes (CTL) to pancreatic cancer remains unclear. Tumor-associated lymphocytes (TAL) and peripheral blood monocytes (PBMC) were isolated from pancreatic cancer patients. Tumor-specific CTL were generated from TAL and PBMC using solid-phase anti-CD3, low-dose IL-2 (50 IU/ml) and repetitive autologous tumor stimulation. The specificity of CTL was tested in standard cytotoxicity assays using autologous tumor cells, autologous fibroblasts when available, several allogeneic pancreatic tumor cells and the NK-sensitive cell line K562. Anti-HLA-Class I MAb, W6/32, was used to demonstrate that tumor-specific CTL were HLA-Class I restricted. HLA-molecules of human pancreatic cancer cells were washed out using acid elution. Eight consecutive, histologically confirmed pancreatic cancer specimen as well as peripheral blood mononuclear cells were analyzed. CTL were capable of lysing autologous tumor cells significantly after 3 stimulations with autologous tumor cells. T cell mediated recognition was HLA-Class I restricted as shown by incubation with MAb anti-HLA-Class I. In case of HLA-A2 positivity, incubation of tumor cells in cytotoxicity assays resulted in significant inhibition. Autologous fibroblasts or K562 cells were lysed significantly less. HLA-Class I molecule elution resulted in significantly lower recognition of these cells by CTL. These results show for the first time in a larger series the possibility of generating CTL in human pancreatic cancer. The identification of new tumor associated antigens or tumor antigens will be crucial for establishing new treatment strategies.

Lack of evidence for MHC-unrestricted (atypical) recognition of mucin by mucinous pancreatic tumour-reactive T-cells

Cytotoxic T-cells generated against heterologous, mucinous pancreatic tumour cells were shown to recognize mucin in a major histocombatibility complex (MHC)-unrestricted fashion. In contrast, the present study demonstrates a typical allogeneic response of heterologous cytotoxic T-cells established against mucin-expressing pancreatic tumour cells. Heterologous cytotoxic T cells lysed targets that were used as stimulators and other targets that shared human leucocyte antigen (HLA) with the stimulator. These cytotoxic T-cells lysed mucin-expressing stimulator cells but not autologous tumour cells in spite of expressing mucin on their surface. Likewise, tumour-infiltrating CD4+ T-cells proliferated against its own tumour cell target, while such T-cells did not respond to heterologous, mucin-expressing pancreatic tumour cells. Culturing heterologous tumour-specific cytotoxic T-cells with purified pancreatic tumour cell-mucin rendered them unresponsive to their target cells. Furthermore, purified mucin did not produce a mucin-specific response in mucinous pancreatic tumour patients' primary T-cells even in the presence of antigen-presenting cells. Our study finds no evidence for MHC-unrestricted recognition of mucin by pancreatic cancer patients' T-cells.

Tumor-associated lympho-monocytes from neoplastic effusions are immunologically defective in comparison with patient autologous PBMCs but are capable of releasing high amounts of various cytokines

We studied several in vitro activities of tumor-associated lympho-monocytes (TALMs) and the concentrations of interleukin (IL)-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-10, tumor necrosis factor (TNF)alpha, interferon (IFN)gamma and soluble IL-2 receptor (slL-2R) in neoplastic effusions and in the serum of advanced stage cancer patients. Comparisons were made with autologous peripheral blood mononuclear cells (PBMCs). Autologous PBMCs were compared with PBMCs from normal subjects used as controls. TALMs were collected from 13 peritoneal and 18 pleural neoplastic effusions, secondary to primary tumors of different sites. After PHA stimulation, concentrations of IL-1alpha, IL-1beta and TNF alpha in culture media of TALMs both from peritoneal and pleural effusions were lower than those of autologous PBMCs and, similarly, concentrations of IL-4 and IL-10 in culture media of TALMs from peritoneal effusions were lower than those of autologous PBMCs, whereas concentrations of IL-4 and IL-10 in culture media of TALMs from pleural effusions were in the same range as those of autologous PBMCs. On the contrary, IL-2, IL-6 and IFN gamma amounts (only from pleural effusions) were significantly higher. IL-1alpha, IL-1beta, IL-2, IL-6 and TNF alpha production from patient PBMCs was lower than that of control PBMCs, whereas production of IL-4, IL-10 and IFN gamma was higher than that of control PBMCs. Both in peritoneal and in pleural effusions concentrations of IL-1alpha, IL-1beta and IL-4 were not different from those measured in autologous serum, whereas those of IL-6, IL-10, TNF alpha, IFN gamma and sIL-2R were significantly higher. The amounts of IL-2 in pleural effusions were not different from those of autologous serum, but in peritoneal effusions they were higher than those of autologous serum. The amounts of IL-1alpha, IL-1beta, IL-2, IL-6, TNF alpha and sIL-2R were higher in patient than in control sera, whereas those of IL-4, IL-10 and IFN gamma were in the same range in patient and in control sera. Cell cycle analysis of cultured TALMs and PBMCs (from 3 patients) showed a significant accumulation of TALMs in the non-cycling G0/G1 cell population compared with autologous PBMCs.