Immunological evidence for a novel marker protein in basal cells of bovine nasal mucosa

Murine monoclonal antibodies were raised against a preparationof bovine odorant-binding protein, OBP. A monoclonal IgM, mAbC8.235, was purified. Although it did not show any reactivitywith bovine OBP, the priming antigen, mAb C8.235 showed an unexepectedreaction with high sensitivity and specificity towards an antigenlocated in bovine basal cells of nasal mucosa, eye conjunctivaand pharynx. Western blot analysis of dissociated and partiallypurified basal cells led us to identify the actual antigen.It is a protein of 18 KDa that sediments with a BC fractioncontaining membranes and nuclei, and is not recognized by rabbitaffinity-purified anti-OBP polyclonal antibodies. Up to now,the data can neither explain why mice have raised an antibodyagainst a different protein than OBP, nor demonstrate if thereis any relationship between the actual antigen and OBP. Moreover,the exact intracellular localization of this protein in BC isstill vague. Nevertheless, for its characteristics, this antigenmay be used as a marker protein of basal cell differentiationin the specific neurogenetic matrix that supports olfactoryneuron turnover.