After four intensive days in Berlin there are a few things, from those sessions I had time to visit, that stands out. The tumor immunology is coming strong, showing that chemotherapy is more efficient when it leads to exposure of tumor antigen to the immune system. If the chemotherapy change the tumor cells to express “eat-me-signals” to dendritic cells, it subsequently leads to clearance of the tumor by the immunes system. The better the activation of the immune system is the better the prognosis and survival after treatment becomes. Consequently the use of NOD mice as tool for cancer research was criticized, since it is not giving the right picture when the immune system is not involved (Immunogenicity of chemotherapy: A novel paradigm by L. Zitvogel from France).

On the session of innate lymphocytes Di Santo described how NK cells have different functions in different tissues, apparently shaped by the surrounding matrix. In this session I was also happy to finally hear something about trogocytosis by Moretta, who described that the NK cells acquired CCR7 by taking it from the cell-surface of myeloid DC. This rendered the NK cells capable of migrating into lymph nodes (LN).

Talking about LN there was quite a bit on this subject, introducing the lymphoid tissue inducer cells (Lti cells) that are required for formation of lymph nodes. And why do we need LN anyway? According to Becher in the symposium of “New concepts in Neuroimmunolgy” the LN are merely for the spoiled and picky B cells. In fact the LN are vital since mice without LN are immunodeficient and resistant to EAE induction. However if you do take the LN away (and the spleen as well while you are at it) immune reactions are still going on as can be seen with Becher’s fluorescence antigen model. And where does it taking place then? In the liver! Turns out that the liver is indeed the lymphoid organ in the fetus and that allergy can be transferred to recipients of liver transplants. Evolutionary T and B cells appeared already in sharks whereas affinity maturation evolved in the mice. So in conclusion LNs are not required for T cells, but for B cells.