Epitope determination of anti rat thy-1 monoclonal antibody that regulates neurite outgrowth.
Glycosylphosphatidylinositol-anchored protein Thy-1 is abundantly expressed on the cell surface of neurons and T lymphocytes in rodents. Although Thy-1 is known to bind integrins as a ligand and to mediate neurite outgrowth and immune responses, its precise function is not fully understood. Previously we produced several anti rat Thy-1 monoclonal antibodies and identified one, 2E11, which induces PC12 cell neurite outgrowth. Here we screened antibodies that inhibit 2E11-induced neurite outgrowth and stimulate or inhibit rat thymocyte aggregation. Since Thy-1 lacks an intracellular region, it requires other membrane-bound molecules for the signal transduction. Hence these antibodies are hypothesized to play key roles in the interaction between Thy-1 and signaling molecules. To elucidate the mechanisms of antibody-induced Thy-1 functions, antibody characterization and epitope determination were carried out. Thy-1 cleavage and mutation revealed that the antibodies recognize not only amino acid sequences, but also the three-dimensional structures consisting of immunoglobulin-like domains. Two antibodies were suggested to bind spatially close to the integrin binding site and crosslink Thy-1 molecules, while a third antibody is believed to inhibit Thy-1 crosslinking and subsequent Thy-1 signaling. The antibodies reported here may therefore function as crosslinkers, agonists, or antagonists that modify Thy-1 signaling.
Department of Biochemistry, Jichi Medical University, Tochigi, Japan. kkuroiwa@jichi.ac.jp
Kenji
K
Kuroiwa
Yusuke
Y
Torikai
Mafumi
M
Osawa
Takaaki
T
Nakashima
Mitsuhiro
M
Nakashima
Hitoshi
H
Endo
Takao
T
Arai
D000595:Amino Acid Sequence; D000818:Animals; D058846:Antibodies, Monoclonal, Murine-Derived / Q000276:immunology / Q000494:pharmacology; D001665:Binding Sites; D001667:Binding, Competitive; D002449:Cell Aggregation / Q000187:drug effects; D018604:Epitope Mapping; D000939:Epitopes / Q000276:immunology / Q000378:metabolism; D006825:Hybridomas; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D016501:Neurites / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D016716:PC12 Cells; D051381:Rats; D017208:Rats, Wistar; D018800:Thy-1 Antigens / Q000276:immunology* / Q000378:metabolism; D060168:Thymocytes / Q000187:drug effects / Q000502:physiology
D058846:Antibodies, Monoclonal, Murine-Derived; D000939:Epitopes; D018800:Thy-1 Antigens