Antigenicity of bone tissue. I. Immunological and immunohistochemical study of non-collagenous proteins of the bovine cortical bone.

From powdered bovine bone cortex an extract has been prepared with 0.15 M NaCl and its collagen-free fraction obtained on DEAE-cellulose column was used for the immunization of rabbits. The non-collagenous protein fraction (NCP) produced against immune serum two precipitation arcs both on agarose double gel-diffusion and with immune electrophoresis. After decalcination in 10% EDTA PH 7.4, direct and indirect immune histochemical examinations were performed with fresh, freshly lyophilized, as well as with bones kept for three and six months at 20 degrees C, and the antigens were localized. Prolonged storage increased the antibody-binding capacity of the bones, whereas lyophilization decreased it. Fixation in cold acetone was suited best for immunohistochemical study of the cortical bones.