Date of Award
12-1984
Document Type
Dissertation - Restricted
Degree Name
Doctor of Philosophy (PhD)
Department
Biological Sciences
First Advisor
Helmut Ankel
Second Advisor
Walter Fredricks
Third Advisor
Peter Abramoff
Abstract
The murine leukemia cell line L1210S and a subline, L1210R, are sensitive and resistant to (alpha)/(beta) -interferon respectively. The L1210R cells are thought to differ from the L1210S in only two properties: (1) they lack the high affinity binding sites (receptors) present for (alpha)/(beta)-interferon on the L1210S, and (2) they are more sensitive to the cytotoxicity of, and bind more of a carbohydrate binding protein from Phaseolus vulgaris (PHA-L) than the L1210S cells. Both of these differences are hypothesized to be related to the same difference in carbohydrate structure(s) present in the L1210R and L1210S cell lines. Here the role of carbohydrate in the response of L1210S and L1210R cells to (alpha)/(beta)-interferon and PHA-L is examined. It was found that the L1210S cell line is less sensitive to PHA-L due to a subpopulation that is completely resistant to PHA-L, although the majority of the L1210S cells are as sensitive to PHA-L as are the L1210R cells. Furthermore, it is the presence of the ASN-linked oligosaccharides that accounts for the sensitivity of L1210S and L1210R cells to PHA-L. Indeed, the entire group of ASN-linked complex type oligosaccharides which includes the PHA-L specific oligiosaccharides can be absent from the L1210S cells without effect on their response to (alpha)/(beta)-interferon. This was shown by growing the L1210S cells in the presence of swainsonine, a compound which prevents normal processing of the precursor high-mannose type into the complex type of ASN-linked oligosaccharides. Growth in the presence of swainsonine ablated the toxicity of PHA-L and prevented the biosynthesis of the ASN-linked oligosaccharides, but response to (alpha)/(beta)-interferon remained normal. These results significantly indicate that the entire group of complex type ASN-linked oligosaccharides, including those that bind as well as those that do not bind to PHA-L, does not contain the carbohydrate structure(s) which is involved in the mechanism of action of (alpha)/(beta)-interferon. In addition, another polypeptide with hormone-like action, interleukin 2 (T cell growth factor) was found to bind to gangliosides, sialic acid containing glycolipids which are present at the cell surface and perhaps this binding is normally involved in the response of T cells to this molecule.