Atacicept is a recombinant fusion protein that was designed to inhibit B cells, and which was investigated as an intervention in autoimmune diseases [2
]. Mechanistically atacicept neutralises the function of two important B-cell activating factors, BAFF (BLyS) and APRIL. Structurally atacicept contains the BLyS/APRIL-binding extracellular portion of the TACI receptor fused to a modified Fc from human IgG1 [4
]. One of the important functions of these two factors in autoimmune disease is their ability to induce proliferation of plasma cells and thus increase Ig production, in particular the production of destructive anti-self antibodies. However, this modality has proven ineffective in autoimmune diseases in clinical studies. As of June 2021 atacicept was being deployed for IgA nephropathy.
Peptide sequences and structural information for this peptide are available from its IMGT/mAb-DB entry. The peptide sequence for atacicept is claimed in patent WO2002094852 [8