Dendritic cells (or "DC" ) are specialised white blood cells that patrol the body, searching for infections. DC seize and then internally break apart any infectiousorganisms that they find. These fragments are then presented on the waving branches or "dendrites" of the DC to activate the immune system's killer T cells. These activated T cells then eliminate the existing infection and resist any future attack by memorizing that infection.
DC also have an important educative role to play in preventing autoimmune diseases, such as type 1 diabetes and Multiple Sclerosis, where the body's immune system mistakes "self " for "foreign " and launches an attack. Since DC are central to many immune responses, they are potential targets for the development of new immune therapies.
Since their discovery in the US in 1975, it has been known that DC, like other white blood cells, develop from stem cells in the bone marrow. Exactly how that process happens has been a mystery ?until now. Using a mouse model, PhD student Shalin Naik, group leader Professor Ken Shortman and a team of colleagues at The Walter and Eliza Hall Institute have discovered the different " precursors " that produce DC. In doing so, they have also determined that the practical operations of DC are more specialized than previously believed. Rather than being generalized "police "within the body, it seems that DC are effectively organized as specialized squads that deal with specific problems ?just as a police force might have different departments to deal with armed robberies, homicides and fraud. These discoveries at W EHI have profoundly altered our understanding of this important aspect of the immune system.
The research received advance online publication on the Nature Immunology website on 7 May 2006.