Engineered B cells expressing an anti-HIV antibody enable memory retention, isotype switching and clonal expansion

Alessio D Nahmad,Iris Dotan,Itai Benhar,Adi Barzel,Tal Akriv,Miriam Horovitz-Fried,Yuval Raviv,Yaron Carmi,Ilan Sofer,Yariv Wine,Daniel Nataf,David Burstein

doi:10.1038/s41467-020-19649-1

Alessio D Nahmad, Iris Dotan + Show 10 more

Open Access

https://doi.org/10.1038/s41467-020-19649-1

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Journal: Nature Communications	Publication Date: Nov 17, 2020
Citations: 49	License type: open-access

Affiliation: Tel Aviv University

Abstract

ABSTRACTHIV viremia can be controlled by chronic antiretroviral therapy. As a potentially single-shot alternative, B cells engineered by CRISPR/Cas9 to express anti-HIV broadly neutralizing antibodies (bNAbs) are capable of secreting high antibody titers. Here, we show that, upon immunization of mice, adoptively transferred engineered B cells home to germinal centers (GC) where they predominate over the endogenous response and differentiate into memory and plasma cells while undergoing class switch recombination (CSR). Immunization with a high affinity antigen increases accumulation in GCs and CSR rates. Boost immunization increases the rate of engineered B cells in GCs and antibody secretion, indicating memory retention. Finally, antibody sequences of engineered B cells in the spleen show patterns of clonal selection. Therefore, B cells can be engineered into what could be a living and evolving drug.

Highlights

HIV viremia can be controlled by chronic antiretroviral therapy
We demonstrate that engineered B cells enable immunological memory and clonal selection that may contribute to addressing viral variability between patients and to counteracting viral escape
The VH is followed by a splice donor sequence to allow fusion to constant segments and initial expression of the broadly neutralizing antibodies (bNAbs) as a membranal B cell receptor (BCR)

Summary

Introduction

As a potentially single-shot alternative, B cells engineered by CRISPR/Cas[9] to express anti-HIV broadly neutralizing antibodies (bNAbs) are capable of secreting high antibody titers. We show that, upon immunization of mice, adoptively transferred engineered B cells home to germinal centers (GC) where they predominate over the endogenous response and differentiate into memory and plasma cells while undergoing class switch recombination (CSR). Antibodies expressed from muscle undergo neither class switch recombination (CSR) nor affinity maturation, which are necessary for long term control over diverse and continuously evolving HIV infections. These challenges might be overcome by B cell engineering. We demonstrate that engineered B cells enable immunological memory and clonal selection that may contribute to addressing viral variability between patients and to counteracting viral escape

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Conclusion