Antitumor Immune Mechanisms of the Anti-Complement Factor H Antibody GT103

Area of Science:

• Immunology
• Oncology
• Biotechnology

Background:

• Anti-complement factor H (CFH) autoantibodies are linked to early-stage lung cancer and favorable outcomes.
• The human monoclonal antibody (mAb) GT103, derived from a lung cancer patient, targets tumor cells and inhibits growth.
• GT103 has been shown to restructure the tumor microenvironment and initiate an antitumoral adaptive immune response.

Purpose of the Study:

• To elucidate the mechanisms by which GT103 kills tumor cells and drives the immune program.
• To confirm the tumor specificity of GT103 and its effects on the tumor microenvironment and immune cells.

Main Methods:

• In vitro and in vivo experiments were conducted to assess GT103's binding specificity, complement activation, and cellular interactions.
• Assays included complement C3 split product deposition, antibody-dependent cellular phagocytosis, calreticulin translocation, and B-cell activation.
• Tumor models were used to evaluate GT103's antitumor activity and its dependence on B-cells.

Main Results:

• GT103 demonstrated specificity for tumor cells, without binding to native soluble CFH or normal tissues.
• GT103 induced complement C3 split product deposition on tumor cells, triggered antibody-dependent cellular phagocytosis, and increased calreticulin exposure.
• GT103 stimulated B-cell activation both in vitro and in vivo, and its antitumor efficacy was dependent on B-cells.

Conclusions:

• GT103 exhibits a complex mechanism of action, killing tumor cells and stimulating an immune response.
• The antibody's tumor-specific activity and immune-modulating properties support its further development as a therapeutic for lung cancer.
• GT103 represents a promising novel therapeutic option for patients with lung cancer, potentially leading to long-term immunity.