A 62-year-old woman presents with tense bullae on flexural surfaces and lower abdomen for 3 weeks. Histopathology shows subepidermal bulla with eosinophil-rich infiltrate. Direct immunofluorescence (DIF) reveals linear IgG and C3 deposits along the basement membrane zone. Indirect immunofluorescence (IIF) on patient's serum shows circulating IgG antibodies against 180 kDa antigen. Which of the following best explains the pathogenic mechanism in this patient?