Pemphigus antibody interaction with human epidermal cells in culture.

Abstract

A B S T R A C T The mechanism of pemphigus acantholysis has been studied with an in vitro system. Freshly prepared human skin epidermal cells were incubated in F-10 medium which contained the immunoglobulin G fraction from either pemphigus serum or normal human serum. During 18-h incubation periods, the pemphigus antibody became bound to the surface ofthe epidermal cells, caused the destruction of 75% of the viable cells as compared to only 14% in the normal immunoglobulin G controls (trypan blue exclusion), prevented the accumulation of newly synthesized proteins by nearly 60% as determined by radioactive tracer studies, and caused a dramatic shift in distribution of the newly synthesized proteins from an insoluble cell-associated fraction to an extracellular soluble fraction. These effects on the accumulation and partitioning of newly synthesized proteins were antibody concentration-dependent. Kinetic studies showed that at a fixed pemphigus antibody concentration the inhibition of protein accumulation preceded solubilization by about 1 h, at which time rapid solubilization of up to 70% of the insoluble cellular material occurred. Several lines of evidence suggested that this phenomenon was caused by enzymatic activity. Epidermal extracts solubilized a prepared substrate of radioactively labeled insoluble epidermal cell material. This activity was heat labile and pH dependent, with pH optima ranging from 4.5 to 6.5. Enzymes with pH optima between 6 and 6.5 were recovered in the culture medium after a 2-day incubation of pure, intact epidermis with the pemphigus antibody.We propose the following hypothesis to account for pemphigus acantholysis. The pemphigus antibody reacts with the epidermal cell surface and produces such a severe disturbance that the integrity of the cell

Identification of pemphigus vulgaris antigen extracted from normal human epidermis and comparison with pemphigus foliaceus antigen.

“…Exactly how autoantibodies from these patients interact with these molecular complexes to cause loss of cell adhesion, whether directly by interfering with their function or indirectly through protease release by keratinocytes (23,24), complement activation (25), or combinations of these processes, merits further study. In any case, the autoantibodies from these patients can now be used to absolutely distinguish PV and PF at a molecular level.…”

Distinction between epidermal antigens binding pemphigus vulgaris and pemphigus foliaceus autoantibodies.

“…In vitro models using organ culture of skin have demonstrated that PV or PF IgG, in the absence of complement or inflammatory cells, can cause acantholysis (5)(6)(7). It is thought that the pemphigus IgG bound to the surface of the epidermal cell causes the release of one or more proteolytic enzymes, which results in acantholysis (7,(10)(11)(12)(13)(14).…”

Pemphigus Antibodies Identify a Cell Surface Glycoprotein Synthesized by Human and Mouse Keratinocytes

“…Indirect immunofluorescence has been used to show that most patients with pemphigus also have circulating antibodies that bind to normal epidermis of most mammals and birds in the same intercellular pattern (2,3). Although light microscopic tissue immunofluorescence patterns appear to be intercellular, immunofluorescence performed on cell suspensions and immunoelectron microscopy have demonstrated that pemphigus antibodies bind to the keratinocyte cell surface (4)(5)(6)(7)(8) (9). The binding of pemphigus IgG to the keratinocyte cell surface probably results in the release of proteolytic enzymes that can cause acantholysis (6,(10)(11)(12).…”