Monoclonal antibody AHS-7 defines a specific basement membrane antigen localized to the hemidesmosome zone.

MoAb AHS-7 labels the basement membrane of the skin. In this report, we have determined the precise localization and molecular nature of the antigen(s). After epidermal-dermal separation by suction blistering, the antigen(s) were detected on the epidermal side. Immunoelectron microscopy revealed the reaction product observed as a discontinuous line along the plasma membrane of the basal keratinocytes, which corresponded to the distribution of the hemidesmosomes. We extracted the proteins from the normal human epidermis separated from the dermis by suction blistering. After being separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the proteins were electrophoretically transferred to nitrocellulose sheets, and the antigen(s) were identified by immunoperoxidase staining with MoAb AHS-7. We detected 4 protein bands of molecular weights of 82 kd, 104 kd, 120-135 kd, and 140-160 kd when unreduced, in contrast to only two bands of 41 kd and 52 kd when reduced. These data suggest that the antigen(s) recognized by MoAb AHS-7 defines a unique antigen, different from bullous pemphigoid antigen on the hemidesmosome zone.