Triggering the body's adaptive immune response can be crucial to clear an infection. In a new study, researchers have found that a subset of dendritic cells known as cDC2s is necessary and sufficient for robust Tfh cell induction, a critical act of the adaptive immune response. The work comes from researchers at The Jackson Laboratory, Yale University and Astra-Zeneca and was published in Science Immunology last week.
Using mice that lacked a protein needed for cDC2 mobility, the researchers were able to that there were no signs of Tfh cells being induced. Without Tfh cell induction, no antibodies were produced when the animals were vaccinated, even in the presence of other functional dendritic cells.
The authors used inhalants and showed that multiple types of DCs access antigens through this delivery form. They found that cDC2s successfully delivered the inhaled antigens to lung-draining lymph nodes and induced a potent Tfh response.
In contrast, scientists tried the usual method of vaccination through intramuscular injection, in which there are very few CDC2s. From older epidemiological data and a similar repertoire of cDC2s in the superficial layer of the skin, the researchers speculate that intradermal injections may be far more efficient in driving antibody production.
"Not only are dendritic cell types concentrated in different areas of the body, they also migrate to specialized areas within the lymph node. This fundamental aspect of immune architecture is lost in vitro," says senior co-author Adam Williams, Ph.D. "Having mouse models in which specific dendritic cells were disabled or deleted was essential for this work."
With a more efficient delivery, vaccines could be delivered in smaller doses, meaning that more people could be vaccinated. These findings could be important during a pandemic or when a particular vaccine is in short supply.