The development of safer and more accessible contraceptive options is necessary to reduce the high number of unintended pregnancies worldwide. As monoclonal antibody engineering continues to revolutionize drug development, a variety of strategies are being harnessed to establish antibody-based contraceptives. Human Contraception Antibody (HCA), an immunoglobulin G1 (IgG1) monoclonal antibody that potently agglutinates human sperm, is a promising candidate for nonhormonal immunocontraception in women. Our group recently established the safety and efficacy of a topical IgG1 HCA-formulated dissolvable vaginal film. Though successful, we are currently working to further optimize and improve the HCA product. In this study, we characterized engineered variants of HCA. Bioactivities, specifically agglutination and effector functions, of multimeric and fragment crystallizable (Fc)-mutated variants were compared and inform further engineering of an optimal clinical profile. We then established an atomized mRNA mechanism for delivery of HCA to the female reproductive tract (FRT). The use of mRNA could provide several advantages including: efficiency, reversibility, safety, durability, and cost-effectiveness. mRNA-encoded HCAs were expressed in several models of the FRT and were functional, sperm-specific, and safe. We also analyzed Fc N-glycans at the conserved glycosylation site on IgGs that regulate effector functions and compared the site-specific glycosylation on antibodies generated by two HCA expression platforms of interest, namely Nicotiana benthamiana and mRNA-transfected vaginal cells. Disparities in glycan site occupancy and glycoform populations between the two platforms were observed. Platform-specific HCA glycans resulted in differing levels of sperm phagocytosis, an Fc function. In summary, these studies provide a clearer understanding of engineered variants and delivery platforms to further advance the development of HCA as a novel, antibody-based female contraceptive.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/47962 |
| Date | 25 January 2024 |
| Creators | Nador, Ellena |
| Contributors | Anderson, Deborah |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
| Rights | Attribution 4.0 International, http://creativecommons.org/licenses/by/4.0/ |
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