An assay for estimating the cytotoxicity of synovial fluid from patients with rheumatoid arthritis

Pemphigus antibodies and shedding snake serum enhance susceptibility of epidermal keratinocytes in natural cytotoxic reactions

In order to clarify the role of natural cytotoxicity (NC) in the damage of epidermal keratinocytes (EK) in pemphigus vulgaris (PV) we used the direct 51Cr-release assay in studying the cytotoxic activity of large grandular lymphocytes (LGL), obtained from 34 acute PV patients and 19 healthy donors against EK of PV patients, donors, intact newborn BALB/c mice and mice with experimental PV, shedding and non-shedding grass snakes. We also investigated the effect of pemphigus antibodies and shedding snake serum protein (SSSP) upon EK sensitivity to cytotoxic effects of NC effectors. In other experiments, studied were the amount of serine proteinase secreted by donor LGL in the presence of membrane antigen of antibody- or SSSP-transformed EK, and direct effect of pemphigus antibodies and SSSP upon the release of radioactive label and endoproteinases from EK. It was found that EK, which had interacted with pemphigus antibodies or SSSP, became a sensitive target for NC effectors. Membrane antigen of antibody- and SSSP-transformed human, murine and snake EK induces the secretion of endproteinases by NC effector cells. The conclusion was made that the effect of both pemphigus antibodies and SSSP on EK resulted in the emergences of a new antigen on EK cellular membrane which is recognized by NC effectors and plays the role of the ligand in receptor/ligand interaction between LGL and their targets.

Autoreactive cytotoxic T lymphocytes in pemphigus and pemphigoid

In order to know whether effector cells are capable of recognizing the epidermal targets in pemphigus vulgaris (PV) and bullous pemphigoid (BP), non-adherent cells (NAC) of peripheral blood from 27 primary PV, 19 BP patients and 12 healthy volunteers were used in cytotoxic tests. Autologous, allogenic and murine epidermal keratinocytes as well as autologous and allogenic fibroblasts were employed as targets. Total esterase activity of serine proteinases was measured in supernatants of samples and the results obtained were compared with the data received in 51Cr-release assay. These two techniques yielded similar results. The effector cells of PV and BP patients were found to lyse the epidermal target cells without presensitization in vitro. Epidermal cells from involved and uninvolved skin of PV patients, as well as from perilesional skin of BP patients, were highly sensitive to cytotoxic effect on the part of effector cells. The NAC activity in BP was higher than in PV. On the one hand, the obtained data suggest that PV and BP patients develop autoreactive cytotoxic T lymphocytes, sensitized to pemphigus and pemphigoid antigens, respectively, and on the other hand that epidermocytes in pemphigus and pemphigoid patients turned to be more fragile compared to normal human epidermal keratinocytes. It was supposed that cell-mediated cytotoxic reactions are probably related to enhanced proteolytic activity in the site of bullous eruption.