Issue 1
Vol. 42
2000

Direct nervous action on immunocompetent organs
B. Wolf, G. Novotny

There is now overwhelming evidence that the nervous system is concerned with immune system function or regulation. One question, that leads to new horizons, concerns the nature of the nervous system action. Here a primary point of interest is whether the nervous system acts globally, or whether it is capable of specific, localised regulatory activity. This is a rather interesting topic, since there are numerous known mechanisms for mounting an immune response, but there does not seem to be a similar multitude of mechanisms for its termination. It is a well known fact that the antibody titre, induced by inoculation with an infective agent, is gradually reduced with time. The generally implicated mechanisms are the limited life span of the effector cells and apoptosis of most of the remaining cells capable of division. By what mechanisms this apoptosis is induced is not clear. In this experiment the innervation of lymph nodes was investigated after an immune challenge. By specific application of antigen to only one group of nodes, it is possible to compare the effect on the stimulated nodes with the situation in nodes not directly stimulated. Additionally, there are no non-immunological functions known for the adult lymph node under normal conditions. It is an interesting outcome of the study on the effect of antigen on the innervation of axillary nodes that the density of innervation only increases in the late stages of the immune response, when the production of antibodies is being down-regulated. At the same time, there is also a marked increase in the number of axonal profiles only incompletely ensheathed by Schwann cell processes. It is only these portions of the axons that are capable of interacting with cells. It should be noted that these “open areas” increase to a greater extent than the nerves themselves. This suggests that there must be an intense interaction taking place between the nervous system and the immunocompetent cells at this time. The fact that such an increase in innervation, with the possibility for interaction between the nerves and cells, is confined to the stimulated axillary lymph nodes, and is not to be observed in the unstimulated cervical nodes, is of considerable importance.

Key words: immunocompetent cells, nervous system.

Psychologische Beiträge, Band 42, 2000, S. 130-143

Dr. B. Wolf
Institut für Neuroanatomie
Heinrich-Heine-Universität Düsseldorf
Universitätsstr. 1
D-40225 Düsseldorf