Peripheral Denervation Suppresses the Late Phase of Delayed-Type Hypersensitivity

Abstract

The impact of peripheral denervation on antigen-specific immune responses was analysed on the B and T cell levels. Delayed-type hypersensitivity (DTH) response to sheep red blood cells (SRBC) or oxazolone was used in mice as a model system of in vivo T cell reactivity. Serum antibody levels to SRBC, measured by an enzyme-linked immunosorbent assay (ELISA), were evaluated to analyse the B cell response. The effect of peripheral denervation on immune responsiveness was studied both at the point of sensitization and elicitation. The results show that peripheral denervation significantly suppresses the local DTH response. The late, inflammatory phase but not the early phase of the DTH reaction was reduced after denervation (p less than 0.01). The DTH suppression by denervation was similar irrespective of whether the neurectomy was performed 1 or 4 weeks prior to sensitisation. Even in the contralateral limb, with intact innervation, the inflammatory DTH reactivity was decreased. We believe that this phenomenon might be due to abrogation of the reflex arch since the denervation procedure did not give rise to a significant systemic downregulation of DTH. Also, peripheral denervation significantly suppressed footpad swelling induced by local administration of cholera toxin, a potent phlogistic compound. The antibody response against the same immunogen was not influenced by denervation. Our results suggest that denervation of a mixed peripheral sensory/motor nerve abrogates the formation of both T cell-dependent and independent inflammatory responses.