Detection of pemphigus-like antigens on tumor cell lines

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.

Preliminary serological studies comparing immunofluorescence assay with radioimmunoassay

We assayed serum from 12 patients with untreated cicatricial pemphigoid affecting the conjunctiva for circulating autoantibodies directed against the epithelial basement membrane zone. We employed a conventional indirect immunofluorescence assay, with monkey esophagus and human conjunctiva as substrates, and compared the results with those obtained employing a radioimmunoassay measuring antibasement membrane zone antibody binding to COLO-16 and to SCaBER tumor cell lines. The indirect immunofluorescence assay on normal human conjunctival substrate detected circulating antibodies to conjunctival epithelium in 6 of 12 CP patient serum specimens. Monkey esophagus failed to detect antibodies to the epithelial basement membrane zone. In contrast, autoantibodies were detected in all 12 specimens by the radioimmunoassay. Specificity, as demonstrated by appropriate controls and assay of normal human serum, was 100%. These results demonstrate that radioimmunoassay employing COLO-16 or SCaBER cells is an exquisitely sensitive and specific assay for detection of circulating antibasement membrane antibodies in patients with cicatricial pemphigoid affecting the conjunctiva.

Binding of bullous pemphigoid and pemphigus vulgaris sera to SCaBER cell line in an ELISA

Specific antibodies present in the sera of patients with bullous pemphigoid or pemphigus vulgaris were detected in an enzyme-linked immunosorbent assay (ELISA) employing a squamous carcinoma cell line, SCaBER, as substrate. Bullous pemphigoid sera bound preferentially to permeabilized cells, suggesting that the antigens are largely intracellular. The assay may prove to be a useful addition to current methods of detecting circulating antibodies in these patients.

Antibody-mediated rosette formation of epidermal cells with leukocytes in pemphigus vulgaris

Human peripheral-blood leukocytes (PBLs) were found to form rosettes with cultured human epidermal cells or a mouse epidermal cell line (Pam cells), but not with fibroblasts, when preincubated with heat-inactivated sera from patients with pemphigus vulgaris. Increased rosette formation was observed, however, when untreated sera were used for passive sensitization. Complement was not required for this reaction, because purified IgG fractions from a protein-A/Sepharose column retained the ability to induce rosette formation. Blocking experiments with alpha-methyl-mannoside suggested that a carbohydrate moiety is involved in the binding of sensitized cells to epidermal cells. Thus, human PBLs can adhere to cultured mouse epidermal cells in the presence of PV IgG antibodies.

Identification of pemphigus-like antigens expressed by SCaBER cells

Indirect immunofluorescence revealed the presence of pemphigus-like antigenic activity on SCaBER cell monolayers after incubation with sera from patients with pemphigus vulgaris. In contrast, no fluorescence was observed after incubation of the cells with sera from patients with bullous pemphigoid, systemic lupus erythematosus or healthy individuals. In order to identify this pemphigus-like antigen, the SCaBER cell membrane proteins were solubilized in non-ionic detergent, separated according to their molecular weight by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and electrophoretically transferred to nitrocellulose sheets. After incubation with pemphigus serum followed by 125I-radiolabelled goat anti-human IgG, autoradiography revealed pemphigus antibody binding activity in the 105 Kd region in electrophoretograms of the unreduced SCaBER cell membrane extracts. This pemphigus-like antigen was isolated by affinity chromatography on the Sepharose-linked IgG fraction of sera from patients with pemphigus vulgaris.

Diagnosis of bullous disease and studies in the pathogenesis of blister formation using immunopathological techniques

Several skin diseases may present as vesicles or bullae. Immunofluorescent studies are very helpful in differentiating the various disease entities. Familiarity with the procedure and the various kinds of patterns that are specific and non-specific is essential for the practicing dermatologist. Immunofluorescent patterns are particularly helpful in differentiating pemphigus, bullous pemphigoid, cicatrical pemphigoid, herpes gestationis, dermatitis herpetiformis, linear IgA dermatosis and porphyria. Immunofluorescent studies of the skin and sera of these patients were vital to an understanding their pathogenesis. Immunoelectron microscopy has further helped in delineating the exact sites of immunoglobulin deposition, and, thus, identifying the location of the antigens. In pemphigus, studies at the molecular level reveal that the basic pathological process is mediated by an anti-cellular cement substance antibody. The binding of this antibody at the cell surface level results in a process that is seen at the light microscopy level in the form of acantholysis. In bullous pemphigoid cells may play an important role. It appears that the mast cell, eosinophil, and the lymphocyte in harmony with the polymorphonuclear leucocyte work together to bring about an enzymatic degradation of the basement membrane. The specific role of the anti-basement membrane zone antibody is also under current study. With advances in molecular immunology, especially monoclonal antibodies and gene technology, it is hoped that these cellular and molecular interactions will be better understood and further defined.

Concanavalin-A binding sites, pemphigus antigens, and beta 2 microglobulin in epidermal hyperproliferation, premalignant and malignant lesions

Three cell surface parameters of epidermal cells have been studied by immunofluorescence, pemphigus antigens, concanavalin-A binding sugars, and beta 2 microglobulin. Biopsy specimens were taken from a total of 59 patients with psoriasis, seborrheic and solar keratosis, squamous cell carcinoma, and basal cell epithelioma. We found a loss of demonstrability of all parameters in dedifferentiated tumors or tumor areas in squamous cell carcinoma, premonitory changes in solar keratosis, and no changes in seborrheic keratosis. In the psoriatic epidermis a granular redistribution of the cell surface parameters was occasionally observed in circumscribed areas of the epidermis. A selective loss of the demonstrability of beta 2 microglobulin was the prominent feature in basal cell epithelioma. Our findings demonstrate that the alterations of the cell surface differ in malignant and premalignant skin tumors, in basal cell epithelioma, and in benign psoriatic hyperplasia.