Purification, immunochemical, and biologic characterization of the Schistosoma circulating M antigen
Carlier, Y.; Bout, D.; Strecker, G.; Debray, H.; Capron, A.
Journal of Immunology 124(5): 2442-2450
1980
ISSN/ISBN: 0022-1767 PMID: 6988517 Document Number: 154417
Circulating M antigen (M ag) soecific for the genus Schistosoma was purified from S. mansoni soluble antigenic extract using trichloracetic acid solubility, DEAE Sephadex and immunoadsorption. The M ag showed a neutral electric charge, a molecular weight heterogeneity and was only stained by periodic acid-Schiff. The M ag was shown to be a glycoprotein with a polysaccharide moiety (63% of the molecules) particularly rich in galactose, fructose, glucosamine and mannose, and with a high molecular ratio of serine and threonine. These properties and the presence of an O-glycosidic linkage suggested that the M ag is a mucin or mucus glycoprotein-like component. Studies on the immunogenicity of M ag showed that rabbits were unable to synthesize anti-M ag antibodies. By contrast, 96 (20%) of 469 sera from Africans infected with S. mansoni gave a precipitation line against M ag, indicating that humans are able to synthesise anti- M ag antibodies. Immunofluorescence studies indicated that M ag is present within the cell wall of the gut of adult S. mansoni.