Monoclonal antibodies recognising stage and region specific epitopes in embryonic mouse palatal epithelial cells.

Four monoclonal antibodies raised against murine embryonic palatal epithelium were used to stain frontal cryosections of embryonic mouse heads (d 11-15). One antibody (6A11) recognised the nasal epithelium at the angle of the palate prior to shelf elevation (embryonic d 11-d 13) and the epithelia at the tips of the approximated shelves (embryonic d 14.5). Two further antibodies (2H6 and 3H2) recognised epitopes on the entire palatal epithelium until shelf elevation (embryonic d 14.5) when their expression ceased. The epitope recognised by antibody 6D3 was absent from the palatal epithelium until embryonic d 13 when it displayed region specific expression, being present on the nasal aspect in the midpalate and the tip of the palate posteriorly. On embryonic d 14.5 staining of the medial edge epithelia was present in all regions. Whilst the nasal palatal epithelium stained in the anterior and mid regions, only patchy staining of the oral epithelium was detected. By embryonic d 15 staining was present throughout the palatal epithelia. These antibodies are directed against intracellular epitopes, possibly keratins. Indeed, immunoblotting assays revealed that antibody 2H6 recognised keratin 18. The developmental regulation of the epitopes recognised by the antibodies corresponds with differentiative events occurring during murine palatogenesis.