ABSTRACT
Figure 1. Mechanisms o f sensitisation in delayed-type IV hypersensitivity. This schematic represents the current theory of the processes involved during the sensitisation phase o f ACD. A hapten (square) is first absorbed into the epidermis, where it can bind to skin protein thus forming an immunogen. These modified-proteins may then be recognised and internalised by a LC (a). The LC then migrates from the epidermis into the dermis (b) and finally to the draining lymph node (c), whilst maturing into a dendritic cell. The LC processes the immunogen into peptides (c) that ‘carry’ the hapten, which is bound covalently, and display them on their surface (d). The peptide-hapten complexes are then recognised by the TC R of a naive C D 4+ T cell residing in the paracortex of the lymph node (e). This recognition, then stimulates the generation and proliferation o f a population of memory T cells.
