PubMed Health⌕ Search

Biomedical subjects

A Sharif

Publications and source records attributed to A Sharif.

4 recordsLinked to original sources
PubMed1978

Modifications of lectin binding on human leukemic cells after neuraminidase treatment.

Cell surface modifications after vibrio cholerae neuraminidase treatment were investigated using three different tritiated lectins: Concanavalin A, Ricinus sanguineus agglutinin (R.S.A.) and Robinia pseudoacacia lectin. Lectin binding measurements were performed on untreated and enzyme treated cells. The cells used were from chronic and acute leukemic donors. After neuraminidase treatment, a significant increase in the number of receptor sites, from 1 to 3 times, was found in all cases tested and for all three lectins utilized with only one exception. The affinity constant was generally decreased after neuraminidase treatment. The increase in number lectin binding sites, indicating extensive modification of the cell surface, is completely consistant with the known importance of sialic acid in determining immunogenicity.

Binding Sites↗
PubMed1978

Activation of human B lymphocytes induced by Robinia pseudoacacia lectin in the presence of T cells.

Robinia pseudoacacia seed lectin is a potent human lymphocyte activator which is capable of activating pure T cells but not pure B lymphocytes. However, when B and T cells were cultured together, the thymidine incorporation was found to be higher than that expected from B- or T-cell cultures alone. Killing of T cells by anti-human-T-lymphocyte antigen (HTLA) serum and complement at the time of thymidine incorporation was found to be unable to suppress completely the thymidine uptake whereas treatment by anti-human-B-lymphocyte and monocyte antigen (HBLMA) serum reduced the response to some extent. Moreover, stimulated lymphoblasts were shown to bear B-cell markers (surface Ig and complement receptors) in about the same proportion as B lymphocytes present in the cultures. These results show that B cells proliferate in the presence of T cells and Robinia lectin. Finally, activation of B cells by Robinia lectin in the presence of T cells led to their maturation to plasma cells in the same way as PWM.

Antilymphocyte Serum↗
PubMed1976

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.

Animals↗