Detection and isolation of an Ia glycoprotein antigen from mouse serum

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..