A novel bispecific antibody, BiSS, with potent anti-cancer activities.

One of the most active fields in cancer immunotherapyis the study of bispecific antibodies, which engage immune cells to kill cancer cells. However, a variety of issues are associated with most of current bispecific antibodyformats. In this study, we present a novel bispecific antibody, BiSS (Bispecific antibodywith Single domain, Single domain antibodies), which was constructed by linking 2 single domain antibodies, anti-CEA and anti- CD16, in tandem. Unlike most other bispecific antibodies, the BiSS antibodycan be expressed and purified from E.coli in large quantities. By recruiting natural killer cells(NK cells) to CEA-positive cancer cells, BiSS led to cancer cell death in vitro. In xenograft models, the BiSS protein blocked cancer progression. The data suggested that the single domain-based bispecific antibodyBiSS was functional and can be potentially applied to a broad range of immunotherapies.