title: CD3 directed bispecific antibodies induce increased lymphocyte-endothelial cell interactions in vitro.
abstract: Bispecific antibody (BsMAb) BIS-1 has been developed to redirect the cytolytic activity of cytotoxic T lymphocytes (CTL) to epithelial glycoprotein-2 (EGP-2) expressing tumour cells. Intravenous administration of BIS-1 F(ab')2 to carcinoma patients in a phase I/II clinical trial, caused immunomodulation as demonstrated by a rapid lymphopenia prior to a rise in plasma tumour necrosis factor-alpha and interferon-gamma levels. Yet, no lymphocyte accumulation in the tumour tissue and no anti-tumour effect could be observed. These data suggest a BsMAb-induced lymphocyte adhesion to blood vessel walls and/or generalized redistribution of the lymphocytes into tissues. In this study, we describe the effects of BIS-1 F(ab')2 binding to peripheral blood mononuclear cells (PBMC) on their capacity to interact with resting endothelial cells in vitro. Resting and pre-activated PBMC exhibited a significant increase in adhesive interaction with endothelial cells when preincubated with BIS-1 F(ab')2, followed by an increase in transendothelial migration (tem). Binding of BIS-1 F(ab')2 to PBMC affected the expression of a number of adhesion molecules involved in lymphocyte adhesion/migration. Furthermore, PBMC preincubated with BIS-1 F(ab')2 induced the expression of endothelial cell adhesion molecules E-selectin, VCAM-1 and ICAM-1 during adhesion/tem. These phenomena were related to the CD3 recognizing antibody fragment of the BsMAb and dependent on lymphocyte-endothelial cell contact. Possibly, in patients, the BIS-1 F(ab')2 infusion induced lymphopenia is a result of generalized activation of endothelial cells, leading to the formation of a temporary sink for lymphocytes. This process may distract the lymphocytes from homing to the tumour cells, and hence prevent the occurrence of BIS-1 F(ab')2 - CTL-mediated tumour cell lysis.
authors.affiliation: Groningen University Institute for Drug Exploration, Department of Pathology and Lab Medicine, The Netherlands.
authors.forename: G
authors.initials: G
authors.lastname: Molema
authors.forename: J W
authors.initials: JW
authors.lastname: Tervaert
authors.forename: B J
authors.initials: BJ
authors.lastname: Kroesen
authors.forename: W
authors.initials: W
authors.lastname: Helfrich
authors.forename: D K
authors.initials: DK
authors.lastname: Meijer
authors.forename: L F
authors.initials: LF
authors.lastname: de Leij
mesh_terms: D018033:Antibodies, Bispecific / Q000276:immunology*; D017252:CD3 Complex / Q000276:immunology*; D002448:Cell Adhesion / Q000276:immunology*; D002450:Cell Communication / Q000276:immunology; D002465:Cell Movement; D004727:Endothelium / Q000166:cytology / Q000276:immunology; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology; D007167:Immunotherapy; D066298:In Vitro Techniques; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology*; D008231:Lymphopenia / Q000276:immunology; D019010:Vascular Cell Adhesion Molecule-1 / Q000276:immunology
chemical_list: D018033:Antibodies, Bispecific; D017252:CD3 Complex; D007140:Immunoglobulin Fab Fragments; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1