A study of the humoral immune response to osteoarticular allografts in the sheep.

Production of antibody against major transplantation antigens has been studied in sheep receiving osteoarticular allografts at the knee joint. These investigations have shown that this type of allograft leads to the rapid production of serum antibodies in the recipient animal. It was found that a high proportion of the sheep used in these studies possessed antibodies before operation. A large number of the animals which possessed antibody against major transplantation antigens prior to operation developed a wide spectrum of antibodies after operation more rapidly than did those recipients who had no pre-existing antibody. A smaller number showed an increase in antibody spectrum which was comparable with non-sensitized recipients. An analysis of the patterns of antibody production was carried out in order to assess the possible benefits of reducing the bony component of the graft in lowering its immunogenicity. It was found that the thickness of bone carried by the graft was largely irrelevant and the immune response was initiated with only small amounts of bone. There is some evidence in this data that the surface area of bone is important in determining the pattern of the immune response.