Allergy Today Expert Article: Mapping allergic responses one cell at a time
The Malaghan Institute has uncovered differences in how the immune system responds to allergens compared to bacterial or fungal infections, potentially opening up new treatment options.
Much of the allergic response is shrouded in mystery. For the most part, we know what the causes are, and we know the effects, but what goes on in between? Which cells are responsible? What genes are involved? Importantly, what makes it different to a response to a bacterial infection or a virus? That’s the bigger picture Professor Franca Ronchese from the Malaghan Institute is seeking to understand.
Different cells for different responses
Published in the prestigious scientific journal Cell Systems, the paper ‘Single cell analysis of diverse pathogen responses defines a molecular roadmap for generating antigen-specific immunity’ uses single-cell transcriptomics to show that while on the outside an immune response to a bacterial antigen or parasite allergen may look similar, on a cell-by-cell level the steps these different pathogens go through to get there are very different.
“By following the individual cells that take up the different pathogens you can really see the make-up of the immune response. Already by 24 hours you can see the differences between the response to an allergen compared to the response to a bacterial or fungal infection.”
Specifically, Prof Ronchese explains that this research has allowed her research team to identify the different types of immune cells called in to deal with different types of responses. This is an important step in understanding how the immune system deals with different kinds of threats.
“The immune system is made up of thousands of different cells and many cell types,” says Prof Ronchese.
“In reality, only about one per cent of those cells are actually involved in taking up and dealing with allergens during the early days of an immune response. By looking at all the cells one by one, we can see where the action is. Now we can focus on the key players and ask exactly what they do, how does it impact the immune response, and what can we do to change it.”
A revolution in understanding
Single-cell transcriptomics are revolutionising our understanding of biology due to their power to provide exhaustive information of complex biological systems at a single cell level. For this reason, transcriptomics has been voted ‘2018 breakthrough of the year’ by top scientific journal Science. Transcriptomics enable scientists to track complex, overarching events or responses that may be too complex to be studied piece by piece.
By pinpointing which immune cells are responsible for starting an allergic reaction, and understanding what makes them different to a bacterial or viral response, Prof Ronchese hopes that this research will pave the way for future work interrupting these reactions, preventing allergies from developing in the first place.