Immunopathological factors in peripheral nerve allograft rejection: quantification of lymphocyte invasion and major histocompatibility complex expression.
The numbers of helper T and cytotoxic T lymphocytes and macrophages were quantified, and the expression of major histocompatibility complex (MHC) class I and class II molecules was examined in rat peripheral nerve allografts from 1 to 14 days after implantation, using the indirect immunoperoxidase method for light and electron microscopy. Two centimetre segments of peripheral nerve freshly obtained from inbred Dark Agouti strain rats were inserted in a gap created in n. fibularis or n. tibialis of young adult inbred Wistar strain rats, using fascicular nerve repair techniques under general anaesthesia. There was a gradual increase in the number of helper T and cytotoxic/suppressor T cells from day 2 with peak numbers of both types of T cells observed around day 7. The results suggest that the critical time for T cell proliferation is between day 6 and day 7 post-operatively. The number of macrophages increased over 10 days, with peak numbers being observed at day 10 post-operatively. This is in accord with the pattern of rejection observed in allografts of other tissue. Schwann cells were found to express MHC class I and class II molecules by day 2 post-operatively, which is well before there is any substantial T cell and macrophage infiltration. It may be that the donor Schwann cells act as antigen presenting cells, triggering the immune response and finally becoming a target of the rejection process.
Ansselin
A D
AD
Microsearch Foundation of Australia.
Pollard
J D
JD
D000818:Animals; D006084:Graft Rejection / Q000276:immunology*; D008213:Lymphocyte Activation; D008285:Major Histocompatibility Complex / Q000276:immunology*; D010525:Peripheral Nerves / Q000276:immunology / Q000637:transplantation* / Q000648:ultrastructure; D051381:Rats; D011919:Rats, Inbred Strains; D014184:Transplantation, Homologous