Abstract

The isolation and characterization of neutralizing antibodies from infection and vaccine settings will inform future vaccine design, and methodologies that streamline the isolation of antibodies and the generation of B cell clones are of great interest. Retroviral transduction to express Bcl-6 and Bcl-xL in primary B cells has been shown to promote long-term B cell survival and antibody secretion in vitro, and can be used to isolate antibodies from memory B cells. The application of this methodology to B cell subsets from tissues and to B cells from individuals with chronic infection has not been extensively characterized. Here, we characterize Bcl-6/Bcl-xL B cell immortalization across multiple tissue types and B cell subsets in healthy and HIV-1 infected individuals, as well as individuals recovering from malaria. In HIV-1- and malaria-uninfected donors, naive and memory B cell subsets from PBMC and tonsil tissue transformed with similar efficiencies, and displayed similar characteristics after transformation with respect to their longevity and immunoglobulin secretion. In HIV-1-viremic individuals or in individuals after malaria infection, the CD27-CD21- memory B cell subsets transformed with lower efficiencies compared to the CD27+CD21+ populations, but following transformation B cells expanded and secreted IgG with similar efficiency. Using B cells from HIV-1-infected individuals, we combined Bcl-6/Bcl-xL B cell immortalization with a HIV-1 microneutralization assay to isolate broadly neutralizing antibodies related to VRC13 and VRC38.01. Overall, Bcl-6/Bcl-xL B cell immortalization can be used to isolate antibodies and generate B cell clones from multiple different B cell populations, albeit with different efficiencies.