Abstract
1. The antigenicity of cancellous bone has been investigated in ninety-seven rabbits.
2. The immune responses of lymph nodes draining fresh homografts of cancellous bone (Burwell and Gowland 1961b) has been used as a histological indicator of the antigenicity of components of fresh homologous cancellous bone and also of the antigenicity of homologous bone subjected to a variety of physical or chemical treatments.
3. The principal antigenic component of a fresh homograft of iliac cancellous bone is the nucleated cells of the red marrow.
4. Homologous marrow-free cancellous bone does not usually produce cytological evidence of an immune response in the lymph node draining the graft, unless new homograft bone formation occurs.
5. The treatment of marrow-containing cancellous bone by boiling, freezing at - 20 degrees Centigrade, freeze-drying, irradiation or by merthiolate solution impairs the transplantation antigenicity of the tissue as a homograft.
6. The immersion of cancellous bone in a glycerol-serum-Ringer solution which is then slowly cooled to - 79 degrees Centigrade, stored for one week and then rapidly thawed, allows considerable preservation of the antigenicity of the red marrow.
7. Knowledge concerning the antigenicity of fresh and treated homologous bone is discussed.
8. Evidence is presented to show that the large and medium lymphoid cell response of lymph nodes draining homografts is due principally to the T-antigens, rather than H-antigens, of the grafts.
9. The changes which occur in the first regional lymph nodes draining tissue homografts may provide another test system to assess the transplantation antigenicity of foreign tissues or extracts of foreign tissues other than bone.
