Recombinant chimeric OKT3/IgM antibodies for immune suppression: evaluation in a human CD3 transgenic mouse model

Design, construction, and in vitro analyses of multivalent antibodies

Some Abs are more efficacious after being cross-linked to form dimers or multimers, presumably as a result of binding to and clustering more surface target to either amplify or diversify cellular signaling. To improve the therapeutic potency of these types of Abs, we designed and generated Abs that express tandem Fab repeats with the aim of mimicking cross-linked Abs. The versatile design of the system enables the creation of a series of multivalent human IgG Ab forms including tetravalent IgG1, tetravalent F(ab')2, and linear Fab multimers with either three or four consecutively linked Fabs. The multimerized Abs target the cell surface receptors HER2, death receptor 5, and CD20, and are more efficacious than their parent mAbs in triggering antitumor cellular responses, indicating they could be useful both as reagents for study as well as novel therapeutics.

Evolving new therapies of autoimmune hepatitis

Refinements in the understanding of the mechanisms of immunocyte activation and the emergence of new immunosuppressive agents with highly selective actions has created opportunities for improving the treatment of autoimmune hepatitis. Drugs, such as budesonide and deflazacort, may inhibit immunocyte activation and limit corticosteroid-related side effects. Agents, such as cyclosporine and tacrolimus, can impair calcineurin activity and restrict the generation of transcription factors necessary for T cell responses. Intravenous immunoglobulin can bind anti-idiotype antibodies and reduce interleukin-2 secretion, and monoclonal antibodies directed against critical components of the T cell activation cascade can dampen the immune reaction. Drugs, such as mycophenolate mofetil, cyclophosphamide, methotrexate, and KF20444, can inhibit T cell proliferation, and other interventions promise to deplete activated T cells, impair effector mechanisms, and induce self-tolerance.