title: Ligation of the lymphocyte homing receptor CD44 triggers T-helper and cytolytic functions of human T cells.
abstract: We show that antibodies to the CD44 molecule trigger proliferation of human CD3+/CD4+ T-cell clones. Such effect is IL2-dependent, as shown by IL2 production induced by anti-CD44 mAb and by inhibition of cell proliferation in the presence of anti-IL2 antibodies or cyclosporin A (CsA). Moreover, anti-CD44 mAb triggered human cytolytic CD4+ and CD8+ TCR α/β+ clones, and Vδ1 or Vδ2 TCR Y/δ+ clones to lyse Fc-gamma-R+ P815 cells and to release granule trypsin-like esterase enzymes. Anti-CD44 mAb-triggered proliferation and cytotoxicity were blocked by the PTK-inhibitor, genestein. In addition, ligation of the CD44 molecule induced tyrosine phosphorylation of proteins identical, by molecular weight, to those phosphorylated following anti-CD3 mAb-stimulation. Notably, anti-CD44 mAb does not induce tyrosine phosphorylation of a 21 kD protein (the phosphorylated zeta chain of the TcR molecular complex) typically observed upon anti-CD3 mAb stimulation.
authors.affiliation: Inst of Hematol, Univ of Perugia, Genova, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Galandrini
authors.forename: R
authors.initials: R
authors.lastname: Tognellini
authors.forename: N
authors.initials: N
authors.lastname: Albi
authors.forename: A
authors.initials: A
authors.lastname: Vecchiarelli
authors.forename: D
authors.initials: D
authors.lastname: Zarcone
authors.forename: C E
authors.initials: CE
authors.lastname: Grossi
authors.forename: A
authors.initials: A
authors.lastname: Velardi