Efficient methods for generation and expansion of, and gene delivery to Rhesus Macaque plasma B cells

Engineered long lived plasma cells have the potential to be a new area of cell therapy. A key step in developing this cell therapy is testing in a model with an intact immune system similar to humans. To that end, we have developed methods to purify, expand, and differentiate non-human primate (NHP; rhesus macaque) B cells ex vivo. By comparing several media types and conditions, we consistently achieved 10-fold expansion of NHP B cells using a readily available commercial supplement. After only seven days in culture, large percentages of cells in NHP B cell cultures were differentiated. These cells expressed surface markers found in human antibody secreting cells (CD38 and CD138) and secreted immunoglobulin G. We also identified the serotypes (2.5 and D-J) and conditions necessary for efficient transduction of NHP B cells with AAV vectors for the purposes of producing a secreted protein (BAFF). We hope that this work will accelerate proof-of-concept in vivo studies using engineered protein-secreting B cells in an NHP model.