Immunosuppressive effect of vestibulo-cerebellar lesion in rats.

Kainate lesion of the vestibulo cerebellum induces sympathetic hyperactivity, but the mechanism of immunosuppression observed as a result is not yet clarified. Here we report that vestibulo cerebellum lesioned (VCL) rats have depressed secretion of haematopoietic cytokines (bioimmunomodulator or BIM, a 12.7 kD peptide and thymosin FrV) in tissue cultures of bone marrow and thymus, respectively, compared with controls (P < 0.01). Peripheral blood leukocyte concentration, neutrophil myeloperoxydase response, T-SRBC rosette and antibody titre to sheep red blood cells (SRBC) are also significantly less, compared with control (P < 0.01). Injection of BIM (concentration 0.01 microg/g body weight) in VCL rats corrected the immunodeficiency. Partial restoration of immune competence is observed after injection of thymosin FrV (0.01 microg/g body weight) or after prolonged vestibular stimulation (18 rpm for 15 min/day for 21 days). The results indicate that the vestibular nodule (VN) through autonomic nerves (AN) can modulate the immune function of rats by regulating the secretion of cytokines from bone marrow and thymus.