Aerosol Delivery of Synthetic mRNA to Vaginal Mucosa Leads to Durable Expression of Broadly Neutralizing Antibodies against HIV

Abstract

There is a clear need for low-cost, self-applied, long-lasting approaches to prevent human immunodeficiency virus (HIV) infection in both men and women, even with the advent of pre-exposure prophylaxis (PrEP). Broadly neutralizing antibodies represent an option to improve HIV prophylaxis, but intravenous delivery, cold-chain stability requirements, low cervicovaginal concentrations, and cost may preclude their use. Here, we present an approach to express the anti-GP120 broadly neutralizing antibody PGT121 in the primary site of inoculation, the female reproductive tract, using synthetic mRNA. Expression is achieved through aerosol delivery of unformulated mRNA in water. We demonstrated high levels of antibody expression for over 28 days with a single mRNA administration in the reproductive tract of sheep. In rhesus macaques, neutralizing antibody titers in secretions developed within 4 h and simian-HIV (SHIV) infection of ex vivo explants was prevented. Persistence of PGT121 in vaginal secretions and epithelium was achieved through the incorporation of a glycosylphosphatidylinositol (GPI) anchor into the heavy chain of the antibody. Overall, we present a new paradigm to deliver neutralizing antibodies to the female reproductive tract for the prevention of HIV infections.

Safe and effective aerosolization of in vitro transcribed mRNA to the respiratory tract epithelium of horses without a transfection agent

“…Our findings are important because delivering naked mRNA to the airways greatly reduces the costs and complexity of its use for treating and preventing respiratory tract diseases. As previously noted by others 11 , the use of water alone to reconstitute mRNA for aerosol delivery to mucosal membranes offers the advantages of technical simplicity and avoiding the need for a cold-chain when lyophilized mRNA is used 35 . This is one of the major concerns about the advanced COVID-19 vaccine currently in advanced development.…”

“…For example, IVT mRNA vaccines encoding tumor-associated antigens have been injected intranodally into patients either with advanced melanoma or with hepatocellular carcinoma 3 , 21 . Intra-tracheal delivery of naked IVT-mRNA has been demonstrated by different research groups in mice 10 , 22 , and the vaginal epithelium of sheep has been locally transfected without using a transfection vehicle 11 .…”

Self-assembled mRNA vaccines

“…Another approach for vaccination is mucosal vaccine delivery, targeting non-gastrointestinal mucosal lymphoid tissues and lymph nodes. mRNA vaccines administered to the mucosal layers, such as the nasal and pulmonary mucosa, travel to the draining mucosal LNs via lymphatic systems under the epithelium [ 86 , 110 , 111 ]. Particularly, prophylactic mRNA therapeutics to prevent respiratory diseases, such as influenza [ 112 ] and RSV [ 83 ], are preferred to be delivered via intranasal (IN) administration [ 113 ] because mucosal vaccination can offer pathogen-specific antibodies to be secreted to the mucus where the antibodies can neutralize the pathogens at the early stage of infection [ 114 ].…”

Engineering monoclonal antibody-based contraception and multipurpose prevention technologies†

“…In a more recent publication [ 89 ], synthetic mRNA was again utilized, but to express PGT121, is a well-established HIV neutralizing antibody [ 90 ]. In this case the mRNA was modified with N-1-methylpseudouridine, which greatly mitigates innate immune responses [ 91 ] and was sprayed directly on the cervical and vaginal mucosa using a Teleflex off-the-shelf atomizer in water; no nanoparticle was used in this work.…”