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Mausser E, Nador E, Politch JA, Pauly MR, Marathe JG, Moench TR, Zeitlin L, Whaley KJ, Anderson DJ. LALAPG variant of the Human Contraception Antibody (HCA) reduces Fc-mediated effector functions while maintaining sperm agglutination activity. PLoS One 2023; 18:e0282147. [PMID: 36996137 PMCID: PMC10062632 DOI: 10.1371/journal.pone.0282147] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 02/08/2023] [Indexed: 03/31/2023] Open
Abstract
High rates of unintended pregnancies worldwide indicate a need for more accessible and acceptable methods of contraception. We have developed a monoclonal antibody, the Human Contraception Antibody (HCA), for use by women in vaginal films and rings for contraception. The divalent F(ab')2 region of HCA binds to an abundant male reproductive tract-specific antigen, CD52g, and potently agglutinates sperm. Certain other antibody activities mediated by the Fc region such as mucus trapping, complement-dependent cytotoxicity (CDC) and antibody-dependent cellular phagocytosis (ADCP) could have beneficial or negative effects. The purpose of this study was to document HCA Fc effector functions and determine whether an engineered variant of HCA with a modified Fc region, HCA-LALAPG, retains desirable contraceptive activity while minimizing Fc-mediated effects. Fab and Fc functions were compared between HCA and HCA-LALAPG. Fab activity was assessed using sperm agglutination and modified swim-up ("sperm escape") assays. Fc functions were assessed by CDC (sperm immobilization), ADCP, and cervical mucus penetration assays. HCA and HCA-LALAPG showed equivalent activity in assays of Fab function. In the assays of Fc function, HCA supported strong CDC, ADCP, and sperm trapping in cervical mucus whereas HCA-LALAPG demonstrated little to no activity. HCA and the HCA-LALAPG variant were both highly effective in the sperm agglutination assays but differed in Fc mediated functions. Use of the HCA-LALAPG variant for contraception in women could reduce antibody-mediated inflammation and antigen presentation but may have reduced contraceptive efficacy due to much weaker sperm trapping in mucus and complement-dependent sperm immobilization activity.
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Affiliation(s)
- Emilie Mausser
- Division of Medical Sciences, Boston University Aram V. Chobanian & Edward Avedisian School of Medicine, Boston, Massachusetts, United States of America
| | - Ellena Nador
- Division of Medical Sciences, Boston University Aram V. Chobanian & Edward Avedisian School of Medicine, Boston, Massachusetts, United States of America
| | - Joseph A Politch
- Department of Medicine, Boston University Aram V. Chobanian & Edward Avedisian School of Medicine, Boston, Massachusetts, United States of America
| | - Michael R Pauly
- ZabBio, Inc., San Diego, California, United States of America
| | - Jai G Marathe
- Department of Medicine, Boston University Aram V. Chobanian & Edward Avedisian School of Medicine, Boston, Massachusetts, United States of America
| | - Thomas R Moench
- Mapp Biopharmaceutical, Inc., San Diego, California, United States of America
- Mucommune, Chapel Hill, North Carolina, United States of America
| | - Larry Zeitlin
- ZabBio, Inc., San Diego, California, United States of America
- Mapp Biopharmaceutical, Inc., San Diego, California, United States of America
| | - Kevin J Whaley
- ZabBio, Inc., San Diego, California, United States of America
- Mapp Biopharmaceutical, Inc., San Diego, California, United States of America
| | - Deborah J Anderson
- Department of Medicine, Boston University Aram V. Chobanian & Edward Avedisian School of Medicine, Boston, Massachusetts, United States of America
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