GLYCOPROTEIN ALTERATIONS IN DIFFERENTIATION

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The overall goal of this study is to define the biochemical alterations that occur in oligosaccharides of cell surface glycoproteins during differentiation and during the functional expression of T lymphocytes and natural killer cells. The expression of N-linked oligosaccharides will be examined from whole cells as well those from specific glycoproteins, Thy1 and Ly5/T200, which exhibit differentiation related alterations. The highest priority of the study is the characterization of oligosaccharides containing polylactosamine structures because they have been recognized to be associated with differentiation and maturation in a number of biological systems, most notably the hematopoietic system. The cell types to be used in the current study will encompass T lymphoid and natural killer (NK) cells at various stages of differentiation and maturation. Cloned T and NK cells with different cytolytic or helper functions will also be studied. The biochemical characterization of cell surface glycoproteins will be accomplished using serial lectin chromatography, polylactosamine specific Datura stramonium and tomato lectins, and binding to anti-Ii affinity columns. Cell surface polylactosamine expression will be related to oligosaccharide alterations observed during ontogeny and maturation in the hematopoietic system. The role of oligosaccharides will be studied in anti-Thy1 induced T cell proliferation and NK-tumor cell adhesion and subsequent lysis. The identification of specific oligosaccharide alterations in discrete subsets of cells that have specific biological roles will be an important step in our understanding of differentiation, development and transformation.