Nature Immunology pp 165 - 172

New light is shed on the mechanisms of infection-induced immunosuppression, in February's edition of Nature Immunology. Immunosuppression is when the body's immune system is disabled and is unable to fight off subsequent infections and is often caused by malaria and other viruses. Why this occurs is not well understood, but because many people suffer from these so-called 'systemic infections', understanding the mechanism would be beneficial.

Following infection, specialized immune cells called dendritic cells (DCs) can alert the immune system to the presence of the infectious agent by ingesting elements of the pathogen from its immediate environment in a process called cross-presentation. Jóse Villadangos and colleagues, show if infectious agents excessively trigger receptors expressed on DCs, the 'over-stimulated' DCs can no longer cross-present foreign material, thereby shutting down this critical alarm system. Unraveling how cross-presentation is switched off following systemic infection may help develop treatments to overcome immune suppression induced by severe infections such as malaria.