[Mechanisms of tumor escape from immunologic response]

Leukemic cell products down-regulate human dendritic cell differentiation

The microenvironment produced by solid tumors is inhibitory to the immune system, inducing dendritic cell (DC) alterations, but there is a paucity of information regarding haematological malignances. The aim of this study was to investigate DC differentiation under the influence of leukemic cell products. Monocytes from healthy volunteers were cultured in the presence of IL-4 and GM-CSF for the generation of immature DCs. Supernatants from leukemic cultures were added to monocyte cultures during differentiation. The lineages used were K562, a chronic myeloid leukemia, HL-60, a promyelocytic leukemia and DAUDI, originated from Burkitt lymphoma. It was observed that the expression of CD14 remained high and the CD1a was low in the presence of tumor supernatants, while non-malignant supernatants did not affect these parameters. Furthermore, IL-1beta and TNF-alpha production by monocytes during differentiation was increased by the presence of tumor supernatants. The modifications on CD14 and CD1a expressions could be mimicked by the addition of exogenous IL-1beta and partially inhibited by the neutralization of IL-1beta. These results suggest that soluble products from leukemic cells interfere with DC differentiation and, in the present work, this effect could be mediated by monocyte-derived IL-1beta in response to tumor supernatants.

Treatment of Intracerebral Glioblastomas with G422 Tumour Cell Vaccine in a Mouse Model

The aim of this study was to develop a tumour vaccine with the ability to induce and expand higher affinity cytotoxic T lymphocytes and stimulate an effective antitumour immune response. The hypothesis tested was that G422 glioblastoma cells modified with B7-1 and interferon (IFN)-γ genes could serve as a tumour vaccine. It was found that therapeutic subcutaneous immunizations with this tumour vaccine significantly induced a cytotoxic T-cell response and prolonged the survival of female Kuming mice with intracerebral G422 tumour isografts. The data collectively suggested that G422 glioblastoma cells genetically modified with B7-1 and IFN-γ genes could serve as a tumour vaccine.

The role of interleukin 10 in the pathogenesis and potential treatment of skin diseases

Interleukin 10 (IL-10) is a key cytokine produced by a multitude of immune effector cells and possesses distinct regulatory effects on immune functioning in the skin. In this article we report the current understanding of the immunobiology of IL-10 and identify the role of IL-10 in cutaneous infection as well as in autoimmune and neoplastic processes. We reviewed the literature to examine the function of IL-10 in different cutaneous disorders. IL-10 can influence and potentially treat T1/T2 differentiation, antigen-presenting cell functioning, antigen-presenting cell-mediated T-cell activation, and T-cell, B-cell, and mast cell growth and differentiation that is aberrant in various disease processes. The literature consensus is that the multitude of effects of IL-10 contribute to the pathogenesis of different skin disorders. In certain circumstances IL-10 could represent novel therapeutic approaches to treating cutaneous diseases.

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should be acquainted with the role of IL-10 in many infectious diseases, autoimmune skin disease, inflammatory processes, and malignancy. Its possible role in the resolution of various skin diseases should be better understood.

Induction of heat shock protein gp96 by immune cytokines

Cytokines play a major role in regulating both humoral and cell-mediated immune responses. Recent advances in our understanding of cell-mediated immune responses have focused on the antigen presentation machinery and the proteins in the endoplasmic reticulum (ER). These proteins help the formation and stabilization of the major histocompatibility complex (MHC)-peptide interaction. A 96-kDa, ER-resident glycoprotein (gp96) is being evaluated as a therapeutic agent in cancer because of its ability to associate with a vast number of cellular peptides irrespective of size or sequence. Because the antigen presentation complex is assembled in the ER and a number of ER-resident proteins are modulated by cytokines, it is important to examine the regulation of gp96 in response to immune cytokines interferon gamma (IFN-gamma), and interleukin 2 (IL-2). Defects in signaling pathway in either of the cytokines can result in suboptimal immune response. We examined the effect of the cytokines IFN-gamma and IL-2 on the induction of gp96 in different cancer cell lines and examined the induction of DNA-binding proteins that recognize gamma interferon-activating sequence (GAS), present in the promoter region of gp96. The induction of GAS binding protein correlated with the induction of STAT 1 protein, a transcriptional regulator and mediator of IFN-gamma-mediated gene expression. The use of cytokines in inducing gp96 levels may have significance in maintaining high levels of gp96 for a sustained immune response.

Psychosocial interventions and cancer patients: psychological and immune responses may depend on cancer type

Psychological and immunological responses of cancer patients to a psychosocial intervention program will be assessed over time. Previously it has been proposed that there are two large divisions in cancer histology (type I and II) and that the psychobiology of patients will vary accordingly.