Changes in the expression of lectins in human T lymphocyte membrane upon mitogenic stimulation

Abstract Surface lectins, specific for given sugar structures, are expressed on human T cells, as shown by flow cytofluorometry using F-neoglycoproteins bearing either β- and α- d -galactosyl, β- d -galactosyl 6-phosphate, or α- l -rhamnosyl groups, but not by F-neoglycoproteins bearing other sugar groups (such as δ- d -mannosyl groups). After simulation with Phaseolus vulgaris mitogen, the number of cells that bind β- d -galactosyl 6-phosphate groups (6- P -β- d Gal p lec + cells) increased fourfold during the first five days; these cells are helper (CD4 + ) T cells. Conversely, cells that bin dα- l -Rha groups belong to the T suppressor (CD8 + ) family and their number moderately increased. Upon stimulation by concanavalin A, the number of cells expressing the lectin recognizing α- l -Rha groups increased during the first two days and then decreased within the next two days. These results are discussed with regard to the implication of lymphocyte membrane lectins in the suppressor mechanisms and in the homing process.