HEALTH NEWS

Study Title:

Liver has Lymph Function as Well for Mounting Immune Response

Study Abstract

The intricacies of the adaptive immune system are a wonder to behold. Perceived invaders bearing surface characteristics, known as antigens, are picked up by ever-vigilant, widely circulating antigen-presenting cells (APCs). APCs carry the antigens to lymph nodes and other secondary lymphoid tissues (SLTs), where they are used as templates for mobilizing large numbers of lymphocytes—T cells and B cells—that have receptors designed to recognize that particular antigen.

It's long been thought that this kind of immune response depends on the ability of APCs and lymphocytes to meet in the SLT. Indeed, specific areas within the lymph nodes called germinal centers demarcate where B cells divide in response to the presence of an antigen, creating high-affinity antibodies to flood the body and battle the invader. Yet cold-blooded vertebrates, which lack lymph nodes, are still able to respond robustly to the introduction of antigens by T cell proliferation. Is there a mystery participant in the immune response that might provide an alternate venue where lymphocytes and antigen-bearing APCs might interact and initiate the adaptive immune responses in the absence of SLTs? Using strategic combinations of various mutant mice, disease-mimicking injections, and artful experiments, Melanie Greter, Janin Hofmann, and Burkhard Becher concluded that in the case of T cells, the liver plays just such a role.