STUDIES ON THE CLASS I GLYCOPROTEINS OF THE MURINE MAJOR HISTOCOMPATIBILITY COMPLEX (TRANSPLANTATION ANTIGEN, LYMPHOCYTE, CELL SURFACE MOLECULE)

A series of studies were undertaken to analyze and compare various aspects of murine class I glycoproteins. An initial area of investigation characterized the Qa-1 alloantigens using two-dimensional gel electrophoresis. Analysis of the products of the Qa-1('b), Qa-1('c) and Qa-1('d) alleles indicated that these were distinct molecules as determined by their lack of comigration upon comparative two-dimensional gel analysis. The importance of asparagine-linked glycosylation in the cell surface expression of class I molecules was also examined. These studies employed tunicamycin, an inhibitor of N-linked glycosylation. Tunicamycin treatment of activated T lymphocytes diminished the surface expression of Qa-1 to undetectable levels; the levels of other class I molecules exhibited little or no decrease. These results indicated that N-linked glycosylation has a differential importance in the cell surface expression of various class I molecules. The molecular weight diversity of class I molecules was also investigated. Molecular weight determination of both the fully glycosylated and unglycosylated forms of H-2 and Qa/Tla region encoded molecules established that there is a significant variation in the sizes of these forms of various class I molecules. The most significant difference ((TURN)9,000 daltons) exists between the unglycosylated forms of H-2K('b) and Qa-2, suggesting that the structural organization of these two molecules may be very different. A comparative two-dimensional gel analysis of various class I glycoproteins isolated from resting and activated T and B lymphocytes indicated that class I molecules expressed on activated T cells exhibited an isoelectrophoretic pattern that was distinct from the isoelectrophoretic pattern of class I molecules expessed on the other cell populations. This difference was attributed to a lower sialic acid content of the molecules expressed on activated T cells. Analysis of cell homogenates determined that activated T cells contained a higher level of endogenous neuraminidase activity than was detected in the other populations, suggesting that this may be the basis of the lower sialic acid content. The relationship of the Qa-4 and Qa-2 alloantigens was also examined. It was established that upon mitogen activation, the expression of Qa-4 was greatly decreased, whereas Qa-2 expression was not decreased. However, an anti-Qa-2 monoclonal antibody blocked the binding of an anti-Qa-4 monoclonal antibody to resting cells. These studies established that Qa-4 is a determinant restricted to resting cells, which is closely associated on the surface with the Qa-2 molecule. ^

The rose of Castille : opera in three acts ; ... and performed in the presence of Her Majesty and the Court (by Royal command) on the occasion of the festival performances at Her Majesty's Theatre, in honor of the nuptials of The Princess Royal and The Prince of Prussia, January 21, 1858

the music (composed expressly for the Pyne and Harrison English opera Company) by M. W. Balfe. [Text] by A. Harris and E. Falconer

Table I: Schedule of the drilling operation and lengths of the recovered core material for the boreholes on Vernagtferner in 1979

In 1979 a core drilling project was carried out on Vernagtferner in the Oetztal Alps (Austria). This report describes the field work of the drilling project, the recovered core material and the occurrence of water in the boreholes and compiles the succeding investigation program.