Preventative Cancer Vaccine-Elicited Human Anti-MUC1 Antibodies Have Multiple Effector Functions.

Area of Science:

• Oncology
• Immunology
• Vaccinology

Background:

• Mucin-1 (MUC1) is overexpressed in premalignant and malignant cells, serving as a potential target for cancer immunotherapy.
• A MUC1 peptide vaccine was investigated in high-risk individuals to assess its feasibility in preventing colon cancer.

Purpose of the Study:

• To evaluate the feasibility of a MUC1 peptide vaccine for colon cancer prevention.
• To clone and characterize anti-MUC1 monoclonal antibodies (mAbs) for their potential in tumor rejection.

Main Methods:

• Healthy individuals at high risk for colon cancer received a MUC1 peptide vaccine.
• Anti-MUC1 mAbs were generated from B cells and sera post-vaccination.
• Three high-binding mAbs were tested for effector functions against MUC1+ target cells.

Main Results:

• All tested mAbs mediated antibody-dependent cytokine release (ADCR), cellular cytotoxicity (ADCC), and cellular phagocytosis (ADCP).
• Two mAbs also demonstrated antibody-dependent trogocytosis/trogoptosis (ADCT).
• No complement-dependent cytotoxicity (CDC) was observed.

Conclusions:

• Antibody-dependent cellular functions (ADCP, ADCT) were more effective when antibodies targeted membrane-anchored MUC1 epitopes.
• Findings provide insights for optimizing therapeutic antibody strategies targeting MUC1.