TABO8: “first-in-class”, humanized IgG4 monoclonal antibody specific for the human T-lymphocyte co-stimulatory receptor CD28
CD28 is expressed on most human CD4 and on approximately half of CD8 T-cells where it efficiently co-stimulates the activation and expansion of T-cells. Antibody requires only weak tonic T-cell receptor signaling and activates human T-cells solely by CD28 engagement. This unique capability of TAB08 has been described as “agonistic” T-cells stimulation. This propriety is intimately linked to the recognition of a specific epitope of the extracellular domain of CD28, the C’’D loop.
A proposed clinical application of TAB08 will be the temporary polyclonal activation and expansion of T-cells and the induction of a T-cell-mediated anti-tumor immune response in patients with B-cell chronic lymphocytic leukaemia (B-CLL).
In addition, TAB08 is being developed for the treatment of rheumatoid arthritis (RA). As a proposed mechanistic mode-of-action, TAB08 has the property of improving quantitative balance and functions of regulatory T-cells and induction of anti-inflammatory mechanisms to suppress progression of autoimmune disease.