University of Leicester researchers have released evidence substantiating an unexpected dual role of an important component of the immune system.
Findings by researchers at the University's Department of Infection, Immunity and Inflammation including three PhD graduates are published in a paper for the journal 'Medical Microbiology and Immunology'.
The paper presents significant new findings about the protein properdin an important part of the immune system. It is a positive regulator in the alternative pathway of complement activation which means it plays a key part in one of the body's main techniques for tackling infections and foreign bodies known as antigens.
The new findings show that in some situations a lack of properdin can actually have major benefits while in others it can be a big disadvantage.
Using mouse models, the researchers investigated the differences in immune responses between individuals deficient in properdin and those with normal amounts of the protein.
When individuals were infected with Streptococcus pneumoniae - bacteria which can cause sepsis and pneumonia in humans those deficient in properdin had higher survival rates than those with normal levels.
But when individuals were infected with Listeria monocytogenes which cause an infection called listeriosis in humans those deficient in properdin had lower levels of survival.
Cellular analysis by the researchers suggests that properdin-deficiency is likely to cause the body to use more of a type of white blood cell known as M2 macrophages involved in tissue repair rather than M1 macrophages, whose main role is to kill pathogens.
This allowed the researchers to conclude that properdin controls the strength of the body's immune response by affecting the role of macrophages during infection and inflammation.
Principal investigator and corresponding author, Dr Cordula Stover, Senior
|Contact: Cordula Stover|
University of Leicester