B cells as boostable factories for HIV inhibition

ABSTRACT We are developing reprogrammed B cells to secret anti-HIV molecules. We use CRISPR/Cas9 genome editing to precisely insert custom antibody cassettes at the endogenous immunoglobulin locus. In this way the engineered B cells maintain the ability to respond to a matched antigen such as the HIV Env protein, and can differentiate into both antibody-secreting plasma cells and memory phenotypes. Our reprogrammed B cells therefore provide the possibility of creating in vivo biofactories for the long-term secretion of anti-HIV antibodies, which would be present both systemically and also concentrated in the lymphoid tissues that are the sites of HIV replication. The focus of Project 2 is to now extend our ability to create engineered B cells through in vivo gene editing. To do this we will evaluate engineering of B cells or their HSC precursors using re-targeted lentiviral-like particles and helper dependent adenovirus vectors. The utility of these approaches will be evaluated in next generation humanized mouse models that support human B cell function, and expanded to NHP studies that combine Env vaccination and SHIV infection. Our overall goal is to demonstrate that reprogrammed B cells can be created in vivo following injection of the selected vectors, that they respond to both HIV Env vaccination and HIV replication, and that they can secrete antibodies and antibody-like molecules to control HIV. As a result, we expect this novel B cell therapy to contribute to our broader goal of a combination in vivo cell therapy for HIV cure, with the potential for increased access and acceptability that an in vivo engineering approach would provide.