Monoclonal antibody immunohistochemistry of adult rabbit olfactory structures

Immunohistochemical staining patterns of two monoclonal antibodies produced against the rabbit olfactory bulb were studied in adult rabbit olfactory structures. One monoclonal antibody 112D5 (monoclonal antibody 2D5) stained all of the olfactory receptor cells, whereas the other 114G12 (monoclonal antibody 4G12) stained the upper two-thirds to three-fourths of the receptor cell layer. The negative region in the receptor cell layer was designated the deep compartment. Neither monoclonal antibody stained the supporting cells, basal cells, or Bowman's glands. Monoclonal antibody 2D5 stained the olfactory nerve layer and glomeruli in the olfactory bulb, whereas monoclonal antibody 4G12 stained the whole of the olfactory bulb, particularly the glomeruli and the mitral cells. The piriform cortex was unstained by monoclonal antibody 2D5 whereas the highest immunoreaction to monoclonal antibody 4G12 was in layer Ia. Immunoblot analysis revealed that the molecular weight values of monoclonal antibody 4G12 antigens in the olfactory epithelium were approx. 26,000. Thus, monoclonal antibody 4G12, specific to neurons, recognized an epitope different from the olfactory marker protein specific to the olfactory receptor neurons.