Immunohistochemical study on antigen-presenting cells in healthy and carious human teeth

Abstract

Class II major histocompatibility complex (MHC) antigen-presenting cells are associated with the early phase of the immune response. We have studied the distribution of class II-expressing cells in developing, healthy and carious human teeth to clarify, when human pulp acquires an immunologic defense potential and how this reacts to dental caries. Antigen-expressing cells were identified immunohistochemically with the following monoclonal antibodies: HLA-DR - for dendritic cells and CD68 - for macrophages. In the pulp of unerupted developing teeth, HLA-DR-positive cells were distributed mainly in and around the odontoblast layer. A few CD68 positive cells were located more coronary around the blood vessels. In erupted teeth, HLA-DR-positive cells were located, for the most part, just beneath the odontoblast layer. CD68 positive cells were also located coronary, mainly around the blood vessels. Superficial caries lesions caused an aggregation of HLA-DR-positive cells and macrophages in the dental pulp corresponding to the lesion. These findings showed that: (1) human teeth are already equipped with an immunological defense potential prior to eruption; (2) in the initial stage of caries infection, an immuno-response mediated by class-II-expressing cells is initiated in human dental pulp (Fig. 8, Ref. 33).

The Role of Dendritic Cells during Physiological and Pathological Dentinogenesis

“…The ultrastructure of HLA-DR + cells evidenced several vesicles, a moderately developed Golgi apparatus, and mitochondria [ 82 ]. These results were consistent with other reports on HLA-DR + cells in the dental pulp of human unerupted developing teeth and human deciduous teeth during the physiological root resorption process [ 81 , 83 ].…”

“…A half-reduction of the dentin thickness directly changed the DC distribution, whereas a two-third reduction directly induced the replacement of odontoblasts with HLA-DR + cells until 1 month after treatment. Clusters of immunocompetent cells, such as DCs and T lymphocytes, and nerve fibers remained in the subodontoblastic layer under the affected area 6 months after treatment [ 83 , 102 ].…”

“…The findings obtained using infection models demonstrate the importance of DCs as initiators of the pulpal immune response and suggest another putative role during the pulpal healing process [ 46 , 48 , 98 , 103 ]. The pulpal immune responses may vary according to the local conditions and the stimuli intensity, as the antigen-presenting capacity of pulpal DCs may persist for many months, even after caries treatment [ 83 , 100 , 102 ]. During the early stages after oral exposure, an active DC recruitment is described in the dental pulp under the exposure site [ 81 , 99 ].…”

Evaluation of the Level of Salivary sHLA-G in Children Aged 3–5 Years with or without Dental Caries

“…Additionally immune cells in dentin-pulp interfaces have been found to be inhibited by HLA-G molecules [ 20 , 21 ]. Recently, it has proven that the antigen-presenting cells (APCs) such as dendritic cells (DCs), have an essential role in the initiation of immune responses [ 42 , 48 ]. The sHLA-G is the main ligand for the ILT2 and ILT4 receptors which are expressed on DC surface.…”

Class II Antigen-presenting Dendritic Cells and Macrophages in Healthy and Carious Human Teeth

“…Similar lymphocyte infiltration was reported during enamel caries. [26][27][28] The relationship between these data on carious teeth is suggested by the results of in vitro experiments which show that dendritic cells in dental pulp have the capacity to co-stimulate T lymphocytes, a relationship of importance during the early stages of pulpal immuno response. 15 More advanced caries induced more expanded aggregations of HLA-DR-positive cells and macrophages along the odontoblast layer and subodontoblastic area of the pulp.…”