title: Immunosuppression to cardiac allografts and soluble antigens by anti-vascular cellular adhesion molecule-1 and anti-very late antigen-4 monoclonal antibodies.
abstract: Effective activation of T cells in immune responses depends on two signals, one from the CD3/TCR complex and another from accessory cell surface proteins. Very late Ag-4 (VLA-4) can exert a costimulatory function upon binding with vascular cellular adhesion molecule-1 (VCAM-1). We investigated the effects of mAbs against VCAM-1 and VLA-4 on cardiac allograft survival and humoral response to soluble Ags. BALB/c hearts were transplanted into C3H/He recipients. mAbs (100 micrograms/day) were administered i.p. for the first 6 days. Graft survival in mice treated with M/K-2 (anti-VCAM-1; median survival: 20 days, n = 6) and those treated with PS/2 (anti-VLA-4; 30 days, n = 6) was greater than that in control mice (8 days, n = 7). Eight of 18 mice treated with both M/K-2 and PS/2 accepted the grafts over 65 days, and five of them accepted the grafts over 100 days. Allografts treated with the two mAbs showed scattered infiltration of leukocytes without evidence of active rejection at 65 days. Mice with long-surviving cardiac grafts were challenged with skin grafts from donor and third-party (C57BL/6) strains. Survival of the donor-type skin was significantly greater than that of the third-party skin. One mouse specifically accepted the donor-type skin indefinitely (> 150 days). FACS analysis of splenocytes at 55 days after transplantation showed complete recovery of VLA-4 expression from a down-regulation observed at day 7. In addition, mice immunized with heat-aggregated human gamma-globulin did not produce specific Ab, even after boost immunization, if PS/2 was administered at the time of the first immunization. This unresponsiveness to xenogeneic protein lasted for more than 50 days. These results indicate that in vivo administration of anti-VCAM-1 and anti-VLA-4 mAbs induces specific immunosuppression to cardiac allografts and soluble Ags.
authors.affiliation: First Department of Internal Medicine, Shinshu University, School of Medicine, Matsumoto, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Isobe
authors.forename: J
authors.initials: J
authors.lastname: Suzuki
authors.forename: H
authors.initials: H
authors.lastname: Yagita
authors.forename: K
authors.initials: K
authors.lastname: Okumura
authors.forename: S
authors.initials: S
authors.lastname: Yamazaki
authors.forename: R
authors.initials: R
authors.lastname: Nagai
authors.forename: Y
authors.initials: Y
authors.lastname: Yazaki
authors.forename: M
authors.initials: M
authors.lastname: Sekiguchi
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D015815:Cell Adhesion Molecules / Q000276:immunology*; D005434:Flow Cytometry; D006084:Graft Rejection / Q000276:immunology; D016027:Heart Transplantation / Q000276:immunology* / Q000473:pathology; D007165:Immunosuppression Therapy / Q000379:methods; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D009206:Myocardium / Q000276:immunology / Q000473:pathology; D016029:Receptors, Very Late Antigen / Q000276:immunology*; D016038:Skin Transplantation / Q000276:immunology; D014184:Transplantation, Homologous / Q000276:immunology; D019010:Vascular Cell Adhesion Molecule-1; D005719:gamma-Globulins / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D015815:Cell Adhesion Molecules; D016029:Receptors, Very Late Antigen; D019010:Vascular Cell Adhesion Molecule-1; D005719:gamma-Globulins