CRISPR arms HSPCs to resist and fight HIV-1

Matthew Porteus and colleagues at Stanford University School of Medicine have developed a CRISPR-based knockout/knock-in system targeting the CCR5 locus in CD34+ HSPCs. The system uses ribonucleoprotein (RNP) electroporation and AAV6 vectors to insert expression cassettes for broadly neutralising HIV-1 antibodies.

Efficient editing was achieved with up to 50% allelic knock-in and over 90% knockout. Small-molecule inhibition of non-homologous end joining (NHEJ) further improved integration rates. Edited HSPCs retained multilineage differentiation capacity and engrafted in immunodeficient mice, with engineered B cells maintaining antibody expression in vitro.

The use of multiple antibodies (e.g. 10-1074, Ibalizumab, CAP256V2LS) addressed the challenge of viral escape, and the antibodies secreted by modified B cells inhibited HIV-1 pseudoviruses at neutralising concentrations. While in vivo antibody production could not be confirmed due to limitations of the murine model, direct editing of adult B cells demonstrated robust secretion of functional antibodies, with potential therapeutic titres projected based on endogenous IgG output.

This work was led by William Feist, Sofia Luna, Amanda Dudek and Matthew Porteus at Stanford University School of Medicine. It was published today in Nature Communications.