Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

Human Ia antigens were extensively purified (1390-fold increase in specific activity) in 32% yield from BRI 8 cells, a lymphoblastoid B-cell line. Purification was monitored by using allogeneic antisera arising by foetal-maternal stimulation. The product, a glycoprotein fraction, contained the Ia antigens, the HLA-A and -B antigens, and a glycoprotein of unknown function. The glycoprotein fraction was composed of four glycosylated polypeptides with molecular weights of 43,000, 39,000, 33,000, and 28,000, and beta2-microglobulin; no polypeptide was linked to another by disulphide bridges. The A and B antigens only were absorbed by antibody against beta2-microglobulin. The Ia antigens comprised one each of the 33,000 and 28,000 molecular weight glycosylated polypeptides noncovalently linked together. Thus, only these chains were absorbed by xenogeneic anti-Ia antisera and were cross-linked by dimethyl-3-3'-dithiobispropionimidate dihydrochloride. The dimeric molecule bound deoxycholate (0.26 g/g of protein) and, when solubilized in deoxycholate, has a molecular weight of 77,000. The Ia allo- and xeno-antigenic activities were labile to heating and proteolysis and are probably determined by the polypeptide structure. Xenogeneic specific anti-Ia antisera were raised in rabbits and mice by immunizing with the glycoprotein fraction. These antisera reacted with B lymphocytes and monocytes but not T lymphocytes and fibroblasts. Their Fab fragments blocked the cytotoxicity of the allogeneic antisera for B lymphocytes and were potent inhibitors of the mixed lymphocyte reaction.

Type

Journal article

Journal

Scand J Immunol

Publication Date

1977

Volume

6

Pages

439 - 452

Keywords

Antigens, Cell Line, Cytotoxicity Tests, Immunologic, Epitopes, Glycoproteins, Humans, Immune Sera, Isoantigens, Molecular Conformation, Molecular Weight, Peptides, beta 2-Microglobulin