ISSN:
1432-1211
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract Ia antigenic activity is present in mouse serum and exists predominantly (〉90 percent) as a dialyzable oligosaccharide which can be purified readily. This paper describes experiments which indicate, however, that a small proportion (〈10 percent) of the Ia antigenic activity in serum, particularly from mitogen-injected mice, exists in a high molecular-weight form. Furthermore, this high molecular-weight Ia antigen, like the Ia oligosaccharide, appears to be secreted by T lymphocytes, particularly by T cells which have been activated recently by mitogens. The high molecular-weight Ia antigen was isolated from mouse serum by a procedure which utilized salt fractionation, gel filtration, density separation, and sucrose gradient sedimentation. This procedure gave a 190–260-fold increase in specific Ia antigenic activity, and up to 80 or 90 percent of high molecular-weight Ia antigenic activity detected in the original serum was recovered in the purified fraction. On the basis of sucrose gradient sedimentation studies, the high molecular-weight Ia antigen was estimated to have a molecular weight of approximately 500,000 daltons, if it is assumed that it exists as a globular protein. In addition, the protein has anα 2-macroglobulin-like electrophoretic mobility, contains little or no lipid, and, based on its ability to bind to Concanavalin A columns, is a glycoprotein. The relationship between this Ia glycoprotein antigen and other molecular forms of Ia antigen is discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01575666
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