Polyoma enhancer

Anionic polyelectrolytes have been shown to enhance resistance to bacteria and fungi, enhance immune response, inhibit adjuvent arthritis and either depress or stimulate phagocytic activity of the reticuloendothelial system [458,459]. Carboxylic acid polymers have shown interferon induction, antiviral activity, and tumor growth inhibition [460]. The effects include inhibition of sarcoma, leukemia, polyoma and vesicular stomatitis virus. In one application, the cytotoxicity of bleomycin toward cultured mammalian cells was synergisti-cally enhanced by stirring in the presence of high molecular weight polyfacrylic acid) [461]. 

Virus-receptor interactions have also been shown to be affected by these ManN derivatives [154,155]. Treatment of human B-lymphoma BJA-B cells or African green monkey kidney epithelium cells with either ManProp, ManBut, or ManPent resulted in structural modification of about 50% of total cell surface sialic acids. Polyoma viruses, which use sialic acids as ligands for binding prior to infection, show either reduced or enhanced ability to infect cells carrying these modified sialic... 

Immunoglobulin enhancers differ from previously identified viral enhancers in their spectrum of activity, enhancers from SV40 or polyoma virus being active in a variety of cell types [87,115,161,162]. Transfection experiments have established that both the IgH [81,82], and the k enhancers [84] are preferentially active in plasmacytoma cells. Although weak activity has been described in fibroblasts, this weak activity manifests a strong dependence on distance [88,89], The fact that some deletions of the IgH enhancer increase its activity in non-lymphoid transfectants has been used to infer the existence of repressor molecules in non-lymphoid cells... 

That enhancer regions may be more or less effective in different cell types was originally suggested by studies on polyoma virus. Wild-type virus normally multiplies well in mouse cells of many types but will not propagate in undifferentiated embryonal carcinoma cell lines due to a block in the initiation of viral transcription (Dandolo et al.,... 

With the recognition that certain antibodies can protect tumor cells against the host s immune response thereby resulting in tumor enhancement, therapy with unblocking antibodies has been attempted. Bansal and Sjogren96 studied a rat polyoma tumor system and found unblocking activity... 

Liu, Y., Borchert, G.L., and Phang, J.M. (2004). Polyoma enhancer activator 3, an ets transcription factor, mediates the induction of cyclooxygenase-2 by nitric oxide in colorectal cancer cells. J. Biol. Chem. 279 18694-18700. 

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