CHARACTERIZATION OF LYMPHOCYTE SUBTYPES IN SCABIETIC SKIN-LESIONS OF NAIVE AND SENSITIZED DOGS

We delineated the density of cells expressing CD4, CD8, CD21 and CD45R A antigens in the cellular infiltrates in the epidermis, dermis and fo llicular epithelium in scabietic skin lesions of naive hosts and sensi tized hosts that expressed resistance to scabies infestation. No cells expressing CD21 (B-lymphocytes and follicular dendritic cells) were p resent in the epidermis and only a few were occasionally present in th e dermis during both the first and second infestations. Naive T-cells (CD45RA +) and CD8 + cells (cytotoxic and suppressor T-lymphocytes) we re present in varying densities in the infiltrates throughout the epid ermis, dermis and follicular epithelium with no apparent differences i n density and the rate of appearance between sensitizing and challenge infestations. CD4 + cells were abundant in fluctuating densities in t he dermis, epidermis, and follicular epidermis during the sensitizing infestation and these cells became the dominant cell type early during the challenge infestation. The density of CD4 + cells in the infiltra te was much greater during the challenge than during the sensitization infestation. This population of CD4 + cells consisted of both T-helpe r/inducer cells and neutrophils and the large increase in their number s during the challenge suggested they played a key role in the success ful immune/inflammatory response that resulted in resistance to scabie s infestation.