Plasticity of innervation of the medulla of axillary lymph nodes in the rat after antigenic stimulation

Abstract

The purpose of this investigation was to test the hypothesis that activation of the immune system in rats will lead to changes in the density of innervation in lymph nodes. In order to reduce the variability between animals, the rats were reared under sterile conditions and immunostimulation was effected by subcutaneous application of bovine albumin in a region draining to the axillary lymph nodes of both sides. Control animals received an equivalent application of sterile physiological saline. The animals were sacrificed 10 days and 27 days and 4 months after immunostimulation. The nerves in the axillary lymph nodes were quantified by light microscopy in silver impregnated sections and at the ultrastructural level on ultrathin sections. The survival times were chosen so that the first group was in the ascending phase of antibody production, the second group at the peak, and the third group in the declining phase. Both at the light and ultrastructural levels, there were statistically significant differences in the density of innervation of medulla between the groups, with a particularly pronounced increase in the group 4 months after immunostimulation. At the ultrastructural level, there was also an increase in the density of incompletely ensheathed axonal profiles in the parenchyma of the medulla, while the nerves associated with blood vessels were not increased. We conclude that immunostimulation leads to morphological changes in the innervation of the medulla of axillary lymph nodes, that are consistent with the concept of functional activation of the autonomic nervous system through the immune system.

Plasticity of GAP-43 Innervation of the Spleen during Immune Response in the Mouse

“…The result of our study on the plasticity of the GAP-43-LI innervation of the spleen is in good consistency with the reported immune-stimulated nerve growth in lymphoid nodes [30] and is supported by an in vitro study showing that inflammation enhanced lymphoid tissueinduced neurite outgrowth [31]. The mechanism of neurite outgrowth, however, remains unclear.…”

Histological, histochemical, and fine structural observations on the lymph node of the common seal (Phoca vitulina) and the grey seal (Halichoerus grypus)

“…Plasma cells are another very common feature of this region, and in experimental studies their number in the medullary region of lymph nodes increases after antigenic stimulation (Novotny et al, 1994), again arguing for the immunologically active nature of these lymph nodes. A similarly high content of plasma cells was described in the spleen of Weddell seals in which it was interpreted as a high antigen exposure (Schumacher and Welsch, 1987), a conclusion which seems also justified in this study.…”

“…Most of the follicles appear as germinal centers which are indicative of an active humoral immune response since the priming and maturation of B-cells takes place in this location (Stein et al, 1982). Indeed, quantitative studies of the immune response in sterile-reared rats revealed that germinal centers were absent in nontreated control groups, while they formed after antigen administration (Novotny et al, 1994). Four months after immunostimulation, germinal centers could be found only in a few lymph nodes (Novotny et al, 1994).…”

“…Indeed, quantitative studies of the immune response in sterile-reared rats revealed that germinal centers were absent in nontreated control groups, while they formed after antigen administration (Novotny et al, 1994). Four months after immunostimulation, germinal centers could be found only in a few lymph nodes (Novotny et al, 1994). The presence of an active immune response in the mesenteric lymph nodes of P. vitulina and H. grypus, which directly drain the paracolic lymph nodes, is in accordance with quantitative immunohistochemical data from human lymph nodes, indicating that paracolic lymph nodes are immunologically more active than axillary lymph nodes (Horny and Horst, 1984).…”

Clinical Implications of Basic Science Discoveries: Nociceptive Neurons as Targets to Control Immunity—Potential Relevance for Transplantation

“…Involvement of neurologic control in graft rejection is supported by the facts that the most frequently transplanted organs (before excision from the donor) are innervated by afferent nociceptive fibers, and that T cells make contact with nociceptive fibers in the lymph node paracortex (8). These observations suggest that activation of nociceptors and the immediate release of pro-inflammatory neuropeptides in the grafts (i.e.…”