Immunology is the study of the immune system. At the Malaghan Institute the focus of our research is the immune system and its relationship to our health. Through understanding the immune system our scientists are finding new and better ways to prevent, treat and cure disease.
The immune system is a complex network of cells, tissues and organs spread throughout the body. These communicate, coordinate and collaborate, providing natural defences that keep us healthy and safe from threats like bacteria, viruses – even cancer cells – and to remove them as quickly as possible.
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There are two main branches of the immune system: the innate immune system and the adaptive immune system.
The innate immune system
We are born with innate immunity – a layer of defence that is activated once a pathogen (or disease-causing organism) attacks. Its main purpose is to immediately prevent the spread and movement of foreign invaders and prevent them from causing damage.
The innate immune system reacts to the presence of antibodies to provide a generalised, non-specific layer of defence against common pathogens. It triggers inflammation and increases blood flow to the area in order to recruit other immune cells to the site and limit the spread of the invader as well as speed up repair to any damaged cells.
The innate immune system also includes physical barriers to infection such as the skin, mucus, bile and stomach acid.
The adaptive immune system
By contrast, the adaptive immune system – also known as acquired immunity – is highly specific to the type of pathogen it’s targeting. It responds more slowly than the non-specific innate immune system, but its advantage lies creating a tailored response (antigens) that perfectly matches the threat.
The adaptive immune system allows immune cells to launch a more effective, coordinated and longer-lasting attack. We develop adaptive immunity as our body is exposed to new pathogens. What’s more, the adaptive immune system retains a ‘memory’ of pathogens it encounters, so if it were to appear a second time, the immune system is already primed to quickly remove it, often before we even know we’re sick.
Working together, the innate and adaptive immune responses provide all-round protection, dealing with both the everyday threats as well as anything more serious that comes our way.
Immunotherapy
Our immune system is our closest ally in the fight against infection and disease. However, it isn’t perfect.
On the rare occasion, the immune system fails to recognise a pathogen (or disease-causing organism), or doesn’t properly respond to it, allowing the pathogen to run rampant in the body. Other times, the immune system may inaccurately label something harmless (such as a food particle, pollen, even healthy cells) as dangerous, causing things like allergies and autoimmune disease. Environmental and genetic factors also can influence whether the immune system behaves ‘correctly’.
Immunotherapy is often thought of as ‘tipping the balance’ – helping to nudge the immune system in a direction that is beneficial rather than harmful. This might mean helping the immune system identify a pathogen (like a cancer cell), or help suppress an aggressive immune reaction to a harmless peanut. Almost all human diseases are immune-mediated in some way, which means that the majority of human disease may one day be cured or managed through immunotherapy.
