Every living being is endowed with its own individuality and is unique in its own right. It acquires the faculty of recognizing something foreign-non-self in its embryonic life or immediately after birth.
Each species of mammal thus far studied in recently has one major histocompatibility complex and several minor histocompatibility complex in their chromosome which determine the fate of an allogeneic organ transplantation. On the basis of these knowledge, many authors have investigated about the fact that heterotopically transplanted skin; that is, they are rejected when the donor and recipient are genetically dissimilar at either the major histocompatibility complex or at multiple minor histocompatibility complex in their chromosome_(13)16)).
Ivanyl’s experiments_(6)) indicate that, in the combination of Lewis and BN rats, only 2~3 histocompatibility loci affect the fate of the tooth bud grafts, whereas 14 loci are responsible for the rejection of skin in the same combination of strains.
Sharav_(13)) commented on his report that one of the loci responsible for rejection of tooth and bone allograft in rat is the Ag-B locus which is shared by skin. On the contrary, former researcher have regarded the problems of tooth transplantation as similar to those of cornea, blood vessel and cartilage transplantation, and have considered that teeth and tooth germs could be used successfully as allografts.
Within the last eighteen years, there have been controlled experiments to clearly indicate that allogeneic dental tissue are, in fact, immunogenic and do evoke a rejection mechanism. On the other hand, allogeneic bone have the diversity in their transplantation anUgcnicity by their disparity of cIluIar component or preservation technique_(3)9)14)15)).
On the antigenicity of bone, Langer_(9)) confirmed recently the biological phenomenon of enhancement in fresh allogeneic bone graft by leukocyte migration inhibition test. He claimed on his report that immunological blocking phenomenon induced by transplantation of fresh allogeneic bone is transplantation-antigen-specific and is an important phenomenon in the immune response to bone allografts. He also demonstrated that the marrow is resorbed very slowly by host tissue and the exposure of marrow(donor antigen) to host immunocompetent cells occur over an extended period. This may allow a balance to be established between release of antigen and formation of antibody.
The majority of this study involved the histological comparison of transplantation antigenicity between fresh allogeneic bone and tooth.
For the purpose of this study, two biological method were used, that is, one is to examine the skin graft rejection time and the other is the histological difference of the mononuclear cell infiltration intensity between those two.
Though the situation between two heterotopically transplanted sites were dissimilar, their histological difference by infiltration of mononuclear cell and destructive pattern could be well defined to compare the transplantation antigenicity between these two allogeneic materials.
The results were as fallows :
1) Both the intensity of mononuclear cell infiltration and the destruction pattern of skin allografted regions were significantly higher in rat previously immunized with allogeneic fresh bone than allogeneic fresh tooth. (Fig. 7, 8)
2) In 5wks allogeneic tooth specimens, the pulp had undergone slight degenerative change near the root apex and grafted tooth was wholely encapsulated by fibrous connective tissue with sporadical infiltration of mononuclear cells (Fig. 1. 2. 3).
In 5wks allogeneic fresh bone specimens, grafted bone was also encapsulated by the fibrous connective tissue with compact infiltration of mononuclear cells(Fig. 6.). The conspicuous findings of in this specimens were as followings : one side of the grafted bone was resorved by osteoclast-like cells and had empty lacunae in their bone trabeculae. On the contrarely, the other side was revealed gradual apposition of new bone with osteocyte invasion(Fig, 4.).
This results were presented the hypothesis that fresh allogeneic bone have bone inducing substances and transplantation antigens in it codominantly. Furthermore, these phenomenae may be suggested the appearance of blocking antibody by the transplantation antigen.
3) Though the condition in heterotopic allografted site were differently given, the comparative study between allogeneic fresh bone and tooth with histological findings, that is, the destructive pattern of grafted area and the intensity of mononuclear cell infiltration suggested the fact that allogeneic fresh bone have more strong transplantation antigenicity than allogeneic fresh tooth.
4) These above mentioned results were suggested about the fact that the investigation of mononuclear cell infiltration intensity on the skin grafted area after proceded by preimmunization of other allogeneic materials may be useful to compare the differential strength of transplantation antigenicity.
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