CHARACTERIZATION OF ANTIGEN-PRESENTING CELLS AND T-CELLS IN PROGRESSING SCABIETIC SKIN-LESIONS

Experimentally infested dogs expressed successful adaptive immunity an d self-cured of scabies after previously having scabies that required treatment to cure. A biphasic increase and decrease of CD1a(+) Langerh ans cells (LCs) in the epidermis of hosts infested the first time (sen sitized) and infested a second time (challenged) suggested that these cells were actively involved in the hosts' early immune response to sc abies, In contrast, in the dermis CD1a(+) cell densities during both i nfestations increased to a single peak that followed the first peak of these cells in the epidermis. In addition, there was an influx of T-l ymphocytes (CD3 epsilon(+) cells) and CD11c(+) cells into the dermis f ollowing the first peak of LCs in the epidermis. The influx of T-lymph ocytes in the dermis coincided with the peak density of CD1a(+) cells in the dermis and epidermis during the second infestation. In both the epidermis and dermis, MHC Class II+ cell density profiles were simila r to that of CD1a during the first infestation and then exhibited sing le peaks during the second infestation. The increases in CD1a(+), CD3 epsilon(+) (T-lymphocytes), CD11c(+), and MHC Class II+ cell responses in the dermis occurred earlier and were more intense in the challenge infestation compared with the first infestation. These data indicate that T-lymphocytes (CD3 epsilon(+)), CD11c(+), MHC Class II+, and CD1a (+) cells in the dermis played a major role in the successful immune r esponse to scabies mites.