Complement fixation by pemphigus antibody. II. Complement enhanced detachment of epidermal cells.

Area of Science:

• Immunodermatology
• Cell Biology
• Complement System

Background:

• Pemphigus antibodies bind to epidermal cells and activate complement.
• The precise role of complement in pemphigus-induced cell detachment is unclear.

Purpose of the Study:

• To investigate the role of complement in pemphigus antibody-mediated epidermal cell detachment in vitro.
• To elucidate the mechanisms underlying pemphigus pathogenesis.

Main Methods:

• Cultured murine epidermal cells were treated with pemphigus IgG in the presence or absence of complement.
• Complement activity was manipulated via heat inactivation, C1q depletion, and F(ab')2 fragments.
• Plasminogen depletion was performed to assess its role.

Main Results:

• Pemphigus IgG induced significant cell detachment only when complement was present.
• Inhibition of complement activity (heat inactivation, C1q depletion) abolished detachment.
• Using pemphigus F(ab')2 fragments reduced detachment, indicating IgG Fc region involvement.
• Plasminogen depletion did not affect complement-mediated cell detachment.

Conclusions:

• Complement activation by pemphigus antibodies is a key mediator of epidermal cell detachment.
• The plasminogen-plasmin system is unlikely to be the sole cause of cell detachment in pemphigus.
• These findings highlight complement's critical role in pemphigus pathogenesis.