C1q Binding Assay

Creative Biolabs has made long-term commitment to the discovery and development of therapeutic antibodies. To bring our customers impeccable service of antibody function validation, our seasoned scientific team has developed an integrated C1q binding assay platform in the aim of comprehensively profiling Fc characteristics regarding CDC activity.

Fig 1. Classical complement pathway activation by antibodies. (González-Molina M, Ruiz-Esteban P, et al. 2016)

Complement-dependent cytotoxicity, aka CDC, plays a broad role in antibody-based anti-cancer and anti-infection therapies, especially for microbe invasion. It is a sophisticated process involving over twenty tightly-regulated complement proteins in serum, ranging from C1 to C9. Amongst, C1, which is composed of a single C1q molecule with 2 smaller C1r and C1s, is responsible for initial binding with Fc regions of at least two target-bound antibodies, thereby activating subsequent complement cascade. Generally, CDC is considered as a non-cellular killing mechanism, via formation of membrane-attack complex (MAC) to destruct target cells. Recent evidence suggests that CDC displays a synergistic effect with FcγR-mediated ADCC, which can greatly enhance the overall cytotoxicity of lead antibodies. Therefore, evaluating the potency of antibody Fc domain to recruit complement and mediate effector functions (i.e. CDC) has become an essential part of Fc profiling and in vivo function estimation during early discovery stage.

Based on leading-edge facilities and profound knowledge in antibody functional mechanisms, Creative Biolabs introduces our world-class platform of C1q binding assay. C1q is the predominant component to interact with antibody Fc, and high affinity towards C1q can directly lead to higher CDC potential. We take advantage of the well-recognized surface plasmon resonance (SPR, from Biacore) technique to conduct full kinetic analysis, using recombinant C1q or purified human serum. This platform is highly versatile and flexible, which can be tailored to meet different custom requirements. C1q binding assay can be an excellent supplement for cell-based CDC assay, providing extra mechanistic insight.

Creative Biolabs is pleased to provide one-stop service using our comprehensive Fc assessment portfolio, including FcγR binding assay and FcRn binding assay. Furthermore, we are also the long-term expert in conducting Fc engineering to obtain antibodies with enhanced cytotoxicity. Of note, it has been proven that beneficial FcγR and C1q mutations within Fc regions can be combined additively, yielding optimized antibodies with greater ADCC and CDC bioactivities. This implies enormous potential for developing next-generation antibody therapies. For more detailed information, please feel free to contact us or directly sent us an inquiry.

References

1. González-Molina M, Ruiz-Esteban P, et al. (2016) “Immune response and histology of humoral rejection in kidney transplantation.” Nefrologia. 36(4):354-67.
2. Moore GL, Chen H, et al. (2010) “Engineered Fc variant antibodies with enhanced ability to recruit complement and mediate effector functions.” MAbs. 2(2):181-9.

For Research Use Only.