(H-294) Engineering of a Long-Term Antibody Producing Cell Therapy for anti-Human Immunodeficiency Virus Treatment

Introduction:: Acquired Immunodeficiency Syndrome (AIDS) is a chronic and life-threatening disease caused by the Human Immunodeficiency Virus (HIV). HIV/AIDS has been one of the most significant public health challenges worldwide since its discovery in the early 1980s with an estimated 38 million people living with this disease worldwide in 2021 (1). The development of antiretroviral therapy (ART) has been successful in lowering viral load and improving the quality of life of many people living with the disease, but the necessity of frequent administration and the possible resurgence of resistant virus if treatment is interrupted, highlights the pressing need for more research in this area (2). The recent discovery, development, and clinical trials of broadly neutralizing antibodies (bNAbs) targeting the CD4 binding site of HIV have created a unique opportunity for a biologic-based therapy for AIDS (3). To take advantage of these developments, a long-term therapy for HIV has been developed that consists of in situ production of these bNAbs from engineered ARPE-19 cells encapsulated in an implantable alginate hydrogel.


Materials and Methods:: Lipid-based transfection and a PiggyBac transposase system were used to stably integrate antibody heavy and light chain genes into the host genome of AERPE-19 cells. The antibody transgenes encoded for the anti-HIV antibodies: PGT121 and 3BNC117, two potent bNAbs with pre-existing clinical trial data. A library of polyclonal cell lines expressing either of these bNAbs was screened for high antibody production. The top performers then underwent monoclonal selection and expansion to isolate high-producing clones. The antibody expression and secretion productivities and quality were assessed using ELISA, ICC, and western blot. High producing clones were also encapsulated in alginate biopolymers using an electro-spraying machine to build implantable, antibody-producing cell capsules. Modified sodium alginate was synthesized using an amine coupling reaction to couple small molecules to the carboxyl groups of the alginate for anti-fibrotic functionality (4). The encapsulated antibody-producing ARPE-19 cells were then tested for continuing productivity in vitro. In vivo testing was then carried out via subcutaneous implantation in murine models to test the durability of production, and resultant ability to maintain dose-dependent Ab titers in blood.

Results, Conclusions, and Discussions:: ARPE-19 cells were successfully engineered to produce 3BNC117 and PGT121 bNAbs and per cell productivity was analyzed. Protein characterization indicates full-length, and bioactive antibodies are produced. After monoclonal isolation, these cells were able to exceed therapeutically relevant production levels of greater than 10 pg/cell/day, while maintaining a healthy cell phenotype. Cells also showed consistent production even after encapsulation and are shown to be viable post implantation. Our data therefore suggests this cell therapy platform therefore has significant potential to facilitate long term delivery of therapeutic antibodies for treatment of AIDS and other human diseases.

Acknowledgements (Optional): : Bill and Melinda Gates Foundation

References (Optional): : 1. UNAIDS/WHO estimates.

2.Dubrocq G, Rakhmanina N. Antiretroviral therapy interruptions: impact on HIV treatment and transmission. HIV AIDS (Auckl). 2018 Jun 13;10:91-101.

3.Hsu, D. C., Mellors, J. W., & Vasan, S. (2021). Can Broadly Neutralizing HIV-1 Antibodies Help Achieve an ART-Free Remission? Frontiers in Immunology, 12.

4.Vegas, A. J., Veiseh, O., Doloff, J. C., Ma, M., Tam, H. H., Bratlie, K., Li, J., Bader, A. R., Langan, E., Olejnik, K., Fenton, P., Kang, J. W., Bochenek, M. A., Chiu, A., Siebert, S., Tang, K., Jhunjhunwala, S., Dholakia, N., Thakrar, R., . . . Anderson, D. G. (2016). Combinatorial hydrogel library enables identification of materials that mitigate the foreign body response in primates. Nature Biotechnology, 34(3), 345-352.