Sialyltransferase-1 in a human malignant glioma cell line. Kinetic characteristics and effect of human interferon-beta

Alteration of human melanoma gangliosides by IFN-gamma, IL-2, and IL-4

In lesions of malignant melanoma, melanoma cells are exposed to various cytokines produced by inflammatory reactions. As a result, transformation of melanoma cells is expected to occur. We studied alterations in human melanoma cell line ganglioside composition after exposing melanoma cell lines to interferon (IFN)-gamma, interleukin (IL)-2, and IL-4 by biochemical methods. IFN-gamma increases the ratio of a-series gangliosides and the ratio of GM3/GD3. This suggests an alteration of immunoreactivity, a decrease in ganglioside sialyltransferase II activity, and an decrease in the malignant character of these cells. The alteration of the ganglioside profile varied among cytokines and cell lines. The progression of malignant melanoma may be influenced by reciprocal interactions between the melanoma cells and the host immune system.

Immunobiology of brain tumors

In summary, many actual interactions between tumors in the CNS and the immune system have been demonstrated. The normal brain does not possess a lymphatic system and is partially hidden from the systemic immune system by the BBB, furthermore brain cells do not express MHC antigens which are necessary for the initiation of an immune response. In pathological conditions however, immunocompetent cells may find their way through transformed endothelial cells. Microglia and astrocytes may function as antigen presenting cells. Glioma cells when stimulated by cytokines such as IFN gamma can be induced to express MHC class I and class II antigens, thus making them more susceptible to an immune attack. In addition glioma cells are capable of secreting several cytokines including IL 1, IL 3 and IL 6 also involved in the generation of an immune response. Indeed, a functional analysis of lymphocytes infiltrating gliomas has revealed the accumulation at the tumor site of cytotoxic T lymphocytes as well as NK cells. However host-immune responses against gliomas seem to be weak in comparison to other cancers. Glioma cells are known to secrete TGF beta 2 and PGE 2 which may in part be responsible for this lack of immune response, thus shielding themselves from immune attack. In order to be recognized by the immune system the tumor cells must express TAA in addition to MHC antigens, and such TAA have been identified by MAbs. These MAbs can be used for "targeted" therapy when coupled to toxic agents or radionuclides. Preclinical studies have shown that, after intravenous or intracarotid injection, there is specific accumulation of the MAb in the tumor but in insufficient amounts for therapeutic use. The relatively small amount of MAb binding to the tumor in vivo can be due to several factors: not all the cells in a single tumor express a given tumor-associated antigens, the MAb may have a low affinity for the antigen, the BBB may hinder the passage of the MAb. Attempts have been made to overcome these drawbacks by opening the BBB for example. In addition MAbs can readily be used for the treatment of carcinomatous meningitis. There has been little success in the development of immunotherapy with IFN beta 1 and even less with adoptive immunotherapy using LAK cells plus IL 2. TIL as well as LAK cells can be expanded in vitro with IL2 and it is feasible to reinject these cells into the tumor site.(ABSTRACT TRUNCATED AT 400 WORDS)

The effects of rHuIFN-alpha A/D on brain lipids and behavior of neonatal ICR Swiss albino mice

Systemic administration of interferon (IFN) can cause reversible neurologic side effects, but there is little information on its effect on the developing nervous system. We studied the effects of daily, subcutaneous injections of recombinant human interferon-alpha A/D (rHuIFN-alpha A/D) (which has biological activity in mice) on brain development of neonatal ICR Swiss albino mice. Animals were treated daily between 8 and 20 days of age (doa) with 5 x 10(4) units (U) of rHuIFN-alpha A/D and sacrificed at 24, 62, and 111 doa following testing in an active avoidance paradigm. Results show that rHuIFN-alpha A/D causes transient decreases in body and brain weights. There were no changes in brain total lipid, ganglioside, phosphorus, or cholesterol content, but there was a transient decrease in neutral glycolipid content. In addition, treated animals exhibited decreased spontaneous activity levels and an impaired retention of a learned behavior. These results suggest that there are some long-term treatment effects on behavior following administration of rHuIFN-alpha A/D to mice during the neonatal period.