Monoclonal antibodies against gastric H+ + K+ ATPase.

Monoclonal antibodies were prepared against a purified membrane fraction from hog gastric mucosa containing the H+ + K+ ATPase. On sodium dodecyl sulfate gels the molecular weight of this fraction corresponds to a single band of about 95,000. In contrast, on isoelectric focusing gels three groups of peptides are resolved with isoelectric points of 5.7, 6.2, and 8.5. One of the monoclonal antibodies (HK111) was shown to react selectively with the acidic peptide, whereas another antibody (HK113) reacted with the alkaline peptide, showing that the three peptides were antigenically distinct. Both monoclonal antibodies selectively labeled the parietal cell, and antibody HK111 labeled the tubulovesicles of the resting parietal cell and the microvilli of the secretory canaliculus of the secreting cell. This finding suggests translocation of membrane from the tubulovesicles to the secretory surface on stimulation.