If we imagine that our immune system is the police, then, according to the results of the work known to this day, the lymph nodes would be best suited to the role of police stations, the places where the immune response is organized. However, a new article published in PLoS Biology states that lymph nodes are not key in ordering the T-cells (the main immune infantrymen) in the mouse to respond to skin damage.. This conclusion is surprising at the same time and speaks of a new function of the liver as an alternative site for the activation of T-lymphocytes.

When a child falls off a bicycle and scratches the skin, the body responds to this with its immune system.. Macrophages at the site of damage seize antigens - small particles formed from invading microorganisms - and dirt that the body perceives as foreign bodies.. These antigens are delivered to the nearest lymph node.. T-and B-lymphocytes (immune cells) that carry the receptors appropriate for these antigens are stimulated by concentrated antigens in the lymph nodes. Then T-cells organize a protective response against invaders, whereas B-lymphocytes transform into cells that produce antibodies, filling the body with antibodies that act against hostile microorganisms..

Mice that do not have lymph nodes due to genetic mutation (alimfoplasia), have a greatly weakened immune system and struggle with infections and tumors..

Written by Melanie Grether, Janin Hofmann, and Burkhart Becher of the Institute of Experimental Immunology at the University of Zurich, it is stated that immunological deficiency associated with alimfoplasia is caused not by the absence of lymph nodes, but by genetic damage to the immune cells themselves.. The article demonstrates that in a mouse, T-lymphocyte functioning in the absence of lymph nodes is not impaired, whereas activation of B-cells and the release of antibodies are seriously affected..

It is extremely surprising that the reaction of T-lymphocytes can be caused not only in the lymph nodes, since this means that T-cells can be activated from a collision with antigens somewhere else.. Tracing the movement of fluorescent particles from the site of penetration of antigens (t. from the wound), scientists have found that the liver can also serve as a surrogate structure to activate T cells.

During embryonic development, the liver becomes the first organ supplying us with blood and immune cells..

Obviously, at least in the mouse, the liver continues to serve as an “immune organ” even in adulthood..

The paper offers an explanation of the fact that patients who have been transplanted a liver sometimes inherit allergic reactions and the immune system of its former owner.. It also assumes that the immune function of the liver has been preserved from the time preceding the development of lymph nodes in higher birds and mammals..

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