Glycoproteins of Cell Surfaces A COMPARATIVE STUDY OF THREE DIFFERENT CELL SURFACES OF THE RAT

https://www.cell.com/cell/pdf/0092-8674(81)90318-4.pdf

Major histocompatibility antigens: The human (HLA-A,-B,-C) and murine (H-2K, H-2D) class I molecules

Publisher Summary The carbohydrate components of cell surfaces occur in structures that are free to react with agents in the external environment of the cell, as in the antigenic reactions in which they are involved. Carbohydrates are well suited for formation of stereospecific structures. They are relatively rigid molecules in which there are many groups for hydrogen bonding and for lipophilic interaction. The shape of the molecule and the position of the reactive groups can be markedly different depending on the sugars involved, the hydroxyl position to which the nonreducing sugar is linked, and the α or β configuration of the glycosidic linkage. Glucose is rarely in the outer tier of sugars in glycoproteins or glycolipids. This is consonant with the recognition site hypothesis, because free glucose in the body fluids could otherwise inhibit recognition of specific binding or receptor sites. Sialoglycoproteins are generally poor antigens, and antibodies against glycoproteins are rarely directed toward the sialic acids, even though they are terminal sugars in glycoproteins and glycolipids.

Carbohydrates in cell surfaces.

Extraction of cultured human lymphoid cells with hypertonic salt solutions (3 molar potassium chloride) resulted in high recoveries of membrane-associated histocompatibility (HL-A) antigens in soluble form with potent activity and marked immunologic specificity. The active principle was purified by preparative acrylamide-gel electrophoresis. Application of the hypertonic salt extraction method is now yielding sufficient HL-A antigen to begin the elucidation of the molecular basis of transplantation individuality.

Salt extraction of soluble HL-A antigens.

A radiochemical technique has been used to determine the primary structure of a murine H-2Kb molecule, a 346-residue glycoprotein subunit attached to a 99-residue β2-microglobulin subunit. Comparison of this structure with those available for other murine H–2 antigens and human HLA molecules suggests an evolutionary origin of MHC products.

Primary structure of a murine transplantation antigen

Human lymphocyte (HL-A) alloantigens have been isolated from human spleen and tissue culture cell sources Solubilization was accomplished by digesting membrane extracts with papain About 20% of all the alloantigens detected on the cell membrane were recovered in soluble form Purification of these materials was achieved by Sephadex chromatography and acrylamide gel electrophoresis The final purified fraction contained similar levels of several alloantigen specificities These materials lost alloantigenic activity at low pH, low NaCl concentration, and high temperatures Comparison of the amino acid composition of alloantigen preparations from two cell sources with different HL-A specificities revealed a general similarity in amino acid content These proteins contained sialic acid and neutral sugars, but amino sugars were absent The analytic and quantitative findings indicate that the HL-A alloantigen-carrying molecules have a similar fundamental structure

Human Lymphocyte Membrane (HL-A) Alloantigens: Isolation, Purification and Properties

ISOANTIGENS, thought to be important as histocompatibility antigens, have been identified on membranes of human cells by serological techniques1. In order to interpret serological studies of histocompatibility antigens in terms of an understanding of the molecular representation of gene information, the isoantigens must be obtained in a suitable state for detailed chemical analysis. Preparation of soluble isoantigen in relatively low molecular weight form would be an important step in this direction.

Rogentine Gn

Papers

Human Lymphocyte Membrane (HL-A) Alloantigens: Isolation, Purification and Properties

Solubilization of human leucocyte membrane isoantigens.

Solubilization, properties and molecular separation of HL-A alloantigens.