title: Bispecific antibody-mediated immunotherapy of the BCL1 lymphoma: increased efficacy with multiple injections and CD28-induced costimulation.
abstract: The BCL1 lymphoma in Balb/c mice can be successfully treated with bispecific (anti-CD3 x anti-idiotype) antibodies (BSABs). In these experiments, animals were injected intraperitoneally (IP) with 5 x 10(3) tumor cells (day 0) and treated with one single intravenous (IV) injection of 5 micrograms BSAB (day 9). Because cross-linking of the CD3 complex is not in itself sufficient to activate resting T cells, the therapeutic success was mainly based on the progressive retargeting of the relatively small cytotoxic T-lymphocyte effector cell pool already in existence in vivo. For this reason, the therapy lost its effectiveness at higher tumor loads. Two possibilities were explored to treat mice with a higher tumor load (10(5) tumor cells). First multiple injections of BSABs were used, but a dose-related monovalent anti-CD3 immunosuppression was induced. This approach was only beneficial when the immune system was able to recover from the previous injection of BSAB. As a second approach, CD28 costimulation together with BSABs were used in an attempt to activate resting T cells, ultimately enlarging the effector T-cell pool. However, we were repeatedly unsuccessful in attempts to improve our in vivo results using young, naive animals in which the majority of T cells are of the naive phenotype. Only when animals were primed to induce the memory T-cell type was a significantly better outcome observed, and then only with multiple injections of BSABs and anti-CD28 monoclonal antibodies (MoAbs), rather than with BSAB or anti-CD28 MoAb alone. These results suggest that this combination was able to activate memory and effector T cells and to focus them on the tumor, but was unable to activate naive T cells fully. The in vivo potency of the BSAB and CD28 costimulation was shown by the fact that one-tenth of the quantity of BSAB was required to cure animals with 20 times the tumor load.
authors.affiliation: Physiology Department of the Medical Faculty of Brussels Free University, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Demanet
authors.forename: J
authors.initials: J
authors.lastname: Brissinck
authors.forename: J
authors.initials: J
authors.lastname: De Jonge
authors.forename: K
authors.initials: K
authors.lastname: Thielemans
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000008:administration & dosage / Q000276:immunology / Q000627:therapeutic use*; D018033:Antibodies, Bispecific / Q000008:administration & dosage / Q000276:immunology / Q000627:therapeutic use*; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000627:therapeutic use; D018106:CD28 Antigens / Q000276:immunology; D002452:Cell Count; D006224:Cricetinae; D004306:Dose-Response Relationship, Immunologic; D007156:Immunologic Memory; D007167:Immunotherapy; D007275:Injections, Intravenous; D008213:Lymphocyte Activation; D016393:Lymphoma, B-Cell / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D016853:Muromonab-CD3 / Q000008:administration & dosage / Q000276:immunology / Q000627:therapeutic use*; D009368:Neoplasm Transplantation; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D018033:Antibodies, Bispecific; D000911:Antibodies, Monoclonal; D018106:CD28 Antigens; D016853:Muromonab-CD3