The Immune system - Bulwark against Disease

When the body recognises foreign elements, it fights them by means of various defence cells and plasma proteins circulating in the bloodstream. These components, both cellular and humoral - which means present in the blood - can destroy the cell walls of the invaders or activate scavenger cells, which then "devour" the pathogens. Which cells and proteins participate specifically depends mainly on the type and site of the Infection because pathogens are very diverse. Researchers presume that 90 percent of all infections are successively controlled by the innate Immune defence.

Specific immune defence - A specific match for the pathogen 

If the pathogen successfully overcomes the first line of defence and spreads, the specific Immune defence gets involved. This system adapts individually to certain pathogens, matches them and develops a corresponding immune response. This is also called adaptive immune response. It gets involved when the foreign elements invade into the lymphatic tissue, a part of the lymphatic system, which pervades the entire body. This is where the Pathogens encounter B cells, which recognise the features of the pathogen by means of receptors. Based on these features, also called Antigens, Antibodies can be produced. By means of T-cells the B cells differentiate into more specialised Plasma cells that produce large amounts of highly specific Antibody and spread across the entire body.

The Antibodies prevent the pathogen from spreading further and limit its mobility and support the scavenger cells by "marking" the germs. These measures allow the Infection to be overcome.

Smart pathogens

However, despite this sophisticated defence mechanism, humans do still get ill. Mainly because pathogens are smart, adaptable and mutable. There are still many unanswered questions that are being addressed by researchers throughout the world.

Researchers at the HZI also investigate the interaction between Immune defence and pathogens. For these studies, the researchers develop new models that are adapted to the human immune system, and then study the mechanisms of immune response. They also look at the aging of the immune system and develop adjuvant substances to improve the efficacy of vaccines. The successes achieved in the past highlight how important it is for infection research to understand the complex mechanisms of the immune system. For this reason, immune response and immune interventions have moved into the focus of the HZI and are one of the three key topics at the centre.