Distribution of neural and neural-crest-related antigens in human dental pulp by immunohistochemistry

Human teeth (formalin-fixed, demineralized and paraffin-embedded as well as frozen sections of human dental pulp) were examined by immunohistochemistry to detect the presence and distribution of a series of neural and neural-crest-associated antigens: S-100 protein, neuron-specific enolase (NSE), glial fibrillary acid protein (GFAP), myelin basic protein (MBP) and neurofilaments (NF). Although several experimental pieces of evidence support a neural crest derivation for dental papilla and odontoblasts with the histological method used in the present study, these structures were immunonegative for most of the markers employed in the present investigation. Indeed, mesenchymal cells as fibroblasts and endothelial cells were devoid of immunostaining. Schwann cells were strongly immunostained by S-100, NSE and GFAP. Nerve fibres running in the pulp showed a positive labelling for NF, S-100 and MBP antisera. It is concluded that the lack of labelling of pulp cells (excepting nerves) by the neural and neural-crest-associated antibodies could be due to a loss of capacity to express these antigens during differentiation. However, the possibility that these antigenic determinants are expressed but outside the limits of sensitivity of immunohistochemistry cannot be ruled out. Further studies, including molecular biology techniques, are required to clarify these alternatives.