“Immune system-on-a-chip” helps predict vaccine response
Scientists at the Wyss Institute for Biologically Inspired Engineering (Wyss), Harvard University, have successfully modelled the human immune system on microfluidic chips. Most medical innovations such as vaccines sometimes fall short of expectations in live human experiments – instead of relying on lab cultures and animal studies, cells on chips mimic the physical conditions as in a human organ/body and are hoped to provide a more accurate representation.
When Wyss scientists cultured human B and T cells inside a microfluidic “organ chip” device, the cells began to organise themselves into three-dimensional structures that resembled lymphoid follicles (LFs). LFs are masses of tissue found in lymph nodes and other tissues that mediate immune responses.
In this case, the LFs were secreting a chemical called CXCL13, produced in response to chronic inflammation. The self-assembled B cells were also found to express an enzyme called activation-induced cytidine deaminase (AID), which is critical for activating B cells against specific antigens.
However, AID is not present in B cells that are circulating in the blood. Neither were CXCL13 nor AID present in cells that were cultured in a standard lab dish, suggesting that the scientists had indeed successfully created functional LFs.
In addition to probing the normal function of the immune system, the scientists used the LF chips to predict immune responses to various vaccines, offering significant improvement over existing preclinical models. In experiments, vaccinated LF chips were noticed to produce far more immune cells than those grown in flat cell cultures. Similar results were seen when the scientists repeated the experiment with commercially available flu vaccines.
“Animals have been the gold-standard research models for developing and testing new vaccines, but their immune systems differ significantly from our own and do not accurately predict how humans will respond to them,” said Wyss senior staff scientist Girija Goyal. “Our LF chip offers a way to model the complex choreography of human immune responses to infection and vaccination, and could significantly speed up the pace and quality of vaccine creation in the future.”
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