A strategy for rapidly isolating rare, naturally occurring antibodies is reported this week in a study published in Communications Biology, a new selective, open access journal from Nature Research. The strategy could aid in developing biological therapeutics and vaccines in the future.
During an infection, B cells (a type of white blood cell) produce antibodies against specific protein fragments, called antigens, present on a pathogen. B cells producing antibodies that successfully recognize an antigen will remain in the total pool of an individual’s antibodies, called their B cell repertoire, at very low levels long after the infection has passed. Naturally produced antibodies could be a potential source of drugs to treat diseases; however, identifying specific antibodies from a pool of possibly billions of B cells is extremely challenging, and existing methods for selecting antibodies are expensive and labour-intensive.
Saravanan Rajan and colleagues developed a new strategy for identifying rare antibodies from large pools of human B cells. By using a glass microfluidic chip that can generate evenly sized, microscopic water droplets the authors loaded each droplet with a single B cell from a healthy donor. Using this strategy, one million B cells can be individually encapsulated in droplets within 40 minutes. The new approach allows researchers to select and purify antigen-specific antibodies within four weeks from an initial pool of millions of naturally occurring antibodies.
The authors used their system to screen for antibodies able to recognize multiple subtypes of the influenza virus. This approach led to the identification of seven rare antibodies that existing strategies would be unlikely to detect. The authors believe this approach will be useful for developing therapeutics in the future, particularly for rapidly spreading or emerging infections.