title: A monoclonal antibody (8H3) that binds to rat T lineage cells and augments in vitro proliferative responses.
abstract: A murine monoclonal antibody, designated 8H3, recognizes a cell surface antigen expressed exclusively on rat T lineage cells. 8H3 antibody immunoprecipitated 180-, 120-, and 90-kD components from rat thymocytes as well as splenic T cells under nonreducing conditions. 8H3 antibody specifically inhibited the binding of thymocytes to fibronectin. Furthermore, binding of rat thymocytes to immobilized synthetic peptide Gly-Arg-Gly-Asp-Ser-Pro-Cys-BSA was inhibited by 8H3 antibody as was Gly-Arg-Gly-Asp-Ser-Pro-Cys, but not by Gly-Arg-Ala-Asp-Ser-Pro-Lys or Gly-Arg-Gly-Glu-Ser-Pro. Crosslinking of 8H3 antigen on double-negative thymocytes and adult thymocytes, as well as splenic T lymphocytes by 8H3 antibody and F(ab')2 fragments of goat antibodies to mouse immunoglobulin, led to an increase in the concentration of cytoplasmic free Ca2+ due to the release of Ca2+ from intracellular stores as well as the influx of Ca2+ from extracellular sources. Expression of interleukin 2 receptor and subsequently cell proliferation was observed upon incubation of thymocytes and splenic T cells with 8H3 antibody. Furthermore, 8H3 antibody induced the proliferation of double-negative thymocytes. These data collectively indicated that a cell surface antigen, 8H3, is involved in not only cell adhesion but also involved in the expression of immature as well as mature thymocytes.
authors.affiliation: Department of Pathology, Sapparo Medical College, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Torimoto
authors.forename: M
authors.initials: M
authors.lastname: Kinebuchi
authors.forename: A
authors.initials: A
authors.lastname: Matsuura
authors.forename: K
authors.initials: K
authors.lastname: Kikuchi
authors.forename: T
authors.initials: T
authors.lastname: Uede
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000911:Antibodies, Monoclonal / Q000032:analysis / Q000378:metabolism*; D000954:Antigens, Surface / Q000032:analysis / Q000276:immunology; D002455:Cell Division / Q000502:physiology; D005353:Fibronectins / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology / Q000502:physiology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010455:Peptides / Q000032:analysis; D051381:Rats; D011917:Rats, Inbred Lew; D011919:Rats, Inbred Strains; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000648:ultrastructure; D013950:Thymus Gland / Q000166:cytology / Q000378:metabolism
chemical_list: D000596:Amino Acids; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D005353:Fibronectins; D010455:Peptides