Purificaton and characterization of a new antigen from human polymorphonuclears.

A new antigen was isolated from human tissue extracts. By immunofluorescence it was found only in granulocytic cells both in the cytoplasm and on the surface of these cells. It is an alpha-globulin having a molecular weight of approximately 47,000. It is unglycosylated and does not bind to various lectins. Due to its electrophoretic mobility and its cellular localization, it was named alpha-G (for granulocytes) globulin.

Quantitative variations of three different lectin receptors as a function of establishment and metabolism of normal and leukaemic human cell lines.

Lectin binding on the cell surface was measured by the method of Kornfeld [16] using three tritiated lectins: Robinia pseudo acacia, Concanavalin A and Ricinus. It has been shown that the number of binding sites for Robinia and Con A decreases after the establishment of a leukaemic cell line, whereas the affinity constant increases for Robinia. The relationship between lectin binding and cell growth was carried out on 5 cell lines, 3 of leukaemic and 2 of normal origin. In all cases the maximum number of sites was determined at the time of doubling for the cell population; the affinity constant reciprocally decreases at this moment. For Robinia, a difference was found in both cell growth and the number of sites between an Epstein-Barr virus (EBV) negative leukaemic cell line and the other EBV positive cell lines. Lectins offer a quantitative method for measuring membrane structure variations during and after establishment of cell lines.