Complement-dependent Cytotoxicity (CDC) Assay

Creative Biolabs is an indubitable pioneer in the bispecific antibodies (BsAbs) development and manufacture. With professional scientists and years of rich experience, we offer highly reproducible NK cell complement-dependent cytotoxicity (CDC) assays for the analysis and interpretation of the cytotoxic effects of your BsAbs. With our full-scale antibody analysis platform, we can rapidly evaluate the cytotoxicity profile of your therapeutic candidates in a high throughput manner.

The development of antibody therapy is a promising anti-cancer treatment which targets antigens mostly expressed in tumor cells, therefore enhancing the specificity of the therapy. Antibodies directed against TAA are able to induce the natural antitumor responses, including CDC. CDC is very crucial for the optimal function of therapeutic antibodies and is extremely conserved even after a chemotherapy treatment. Nevertheless, this activity is produced by some antibodies but not all of them.

Figure 1. This sketch map shows the CDC and antibody-dependent cellular cytotoxicity (ADCC) of tumor cells (Kourtzelis, I., 2016).

CDC Mechanism

CDC is mediated by the C1 complex-initiated complement activation that leads to anaphylatoxin generation and deposition of C3b fragments on the target cells. C3b, together with C4b and C2a, constitute the C5 convertase (C4b2a3b) which in turn cleaves C5 to C5a and C5b. C5b then takes part in the production of the C5b-C6-C7-C8-C9 complex, which is the subunit component of the membrane attack complex (MAC). MAC formation on the target cell’s surface results in subsequent cell lysis. As cancer therapeutic antibodies activate the typical complement pathway, they induce the production of MAC on cancer cells, thus causing the killing of cancer cells through CDC.

CDC Assays

CDC assays are often applied to measure the efficacy of antibody- and protein-based therapeutics. They evaluate the efficacy of candidates to initiate a multi-pathway attack which is mediated by the complement immune system to kill specific target cells. The classical approach for CDC is to mix serum comprising the components of the complement system (usually human serum), with target cells bound by the antibody being detected, and then to determine cell death. A common CDC assay determines cell death via pre-loading the target cells with a radioactive compound. As cells die, the radioactive compound is released from them. Hence, the efficacy of the antibody to mediate cell death is determined by the radioactivity level. Unlike radioactive CDC assays, non-radioactive CDC assays often determine the release of abundant cell components, such as GAPDH, with fluorescent or luminescent determination.

With our well-established CDC assay platform, the experienced scientists at Creative Biolabs are dedicated to helping you develop therapeutic BsAbs. Our high-quality CDC assay services will greatly contribute to the successes of your projects. We also provide various other services regarding BsAbs development. Please feel free to contact us for more information and a detailed quote.

References

1. Kourtzelis, I.; Rafail S. The dual role of complement in cancer and its implication in anti-tumor therapy. Annals of translational medicine. 2016, 4(14): 265.
2. Akalin, E.; et al. Intravenous immunoglobulin and thymoglobulin facilitate kidney transplantation in complement-dependent cytotoxicity B-cell and flow cytometry T-or B-cell crossmatch-positive patients. Transplantation. 2003, 76(10): 1444-1447.